How to balance an Engine?

[Challenger_7]

Hi all
This should be either a challenging question or one impossible to deal with
Few weeks back I bought my third 71 Challenger with a 400 souped up engine and slap stick, see photo. I was thrilled by the purchase as the car has awesome power.
Quite a few things needed attention such as hard shifting, misfiring plugs, bad idling etc whcih I assumed will be easy to deal with. Some were, but when I got to the gearbox, we discovered it leaking oil. After stripping it, we found extensive damage in the gears, pump and torque converter, all of which were changed.
The core of the problem turned out to be a badly vibrating engine which led to wear on the neck of the torque converter thus leaking oil and some driving without oil leading to burning of clutch plates.
Now having changed everything, the mechanic is trying desparately to balance the engine because he said if left like this, it will wear out the torque converter's neck again and lead to the same destruction. The way he is doing it is by welding on some weights to the surface of the converter, as sometimes is the case fom the factory, and see if it helps.
So far he managed to reduce the vibration, but it is still bad, and he is still trying by "trial and error" method. I asked around if there are any shops that deal with this but found nothing.
What can you Gurus suggest ? Please help me save my car 

[firefighter3931]

Nice car....looks great in the pics. 

Ok, onto the balance issue : a 400 engine is externally balanced. That requires the proper harmonic balancer on the front and weighted torque converter for the balance to be properly maintained. The first thing you need to do is make sure you have the correct harmonic balancer on that engine. The cast crank dampner is approx 2in thick and that is what you should have on there. If the tq converter is neutral balance and has no weights you need to purchase a weighted tq converter or a flexplate that is designed for a cast crank engine and neutral balance torque converter. B&M makes that exact part for those types of applications. 

Basicly, you need to do a little research to see what's on that car; first thing is to check the harmonic balancer to make sure it's correct. Second thing is to check the torque converter to see if it's neutral balance or has weights welded on. From your description it sounds like a neutral balance converter. That being the case, a simple flexplate swap will solve the problem. 



Ron

[Challenger_7]

Wow !!! Thank you Ron
I will certainly sleep better tonight, and thanks for the compliment
Ok on the balancing issue, I will check for the harmonic balancer tomorrow. It is visible without opening up the engine, right? It fits just before the pulleys on the crank?
As for the converter, it came balanced with roughly 15-20 grams. The mechanic took this off and the vibration became worse, so he welded new ones on, and will be trying to add more on tomorrow.
You say B&M supply flexplate. What is this, and how do I use this? Also in view of the fact that the converter has weights, do I still need the flexplate?
Also please keep in mind that the 400 engine is not standard any more and has been souped up. So only God knows what the previous owners have done to it, and I have no contact with the owners that have souped up the engine. So the question of balanced 400 engine, to me is in question. Right?

[firefighter3931]

Yes, engine balance could be an issue. I would start off by making sure that the correct balancer is on there. 

Here's a pic of the 2 styles of balancer.....the thicker one is what a cast crank 400 engine should have on it. 

The tq converter weights need to be in the correct location for the balance to be spot-on. I would remove the weights and verify neutral balance on the converter....then order the B&M flexplate that is correct for the application.  Here is the B&M plate that is needed for a neutral balance converter with an external balance engine. There is a scallop cut out of the plate that compensates for the balance issue when parts are mismatched.

http://store.summitracing.com/partdetail.asp?part=BMM%2D10237&N=700+4294925134+4294839071+4294863762+4294908078+400004+4294840135+4294925079+4294871900+115&autoview=sku

* the image in the link shows 3 flexplates....the bottom one has the scallop cut-out and is correct for the neutral balance converter/cast crank combination.



Ron

[Challenger_7]

Ok Ron, I logged onto the B&M site and this is the photo of what they are offering. The kit includes all 3 discs or do I choose from them?
And whats with the toothed one? Is that a replacement for my flywheel teeth?

[firefighter3931]

That photo show's several different flexplates/flywheels. The toothed wheel is for a GM vehicle. Why they don't just show the correct part (alone) i don't know ?  The bottom flexplate is the correct one for a cast crank/neutral balance converter assembly.  When the part is ordered you will recieve only one flexplate. 


Ron

[kamkuda]

Did you determine if you have the correct balancer.  I may a spare if you need one.   BTW, nice car!

Rob

[tecmopar]

As Ron said, check the dampener first before you go any further with the converter issue. Its been a while since I played with these "later" motors but I seem to remember the damp/balancer having an offset weight on it and stamped " for cast crank only", good luck.

[Challenger_7]

Ok comments noted with thanks.

I will be going over to the mechanic today and will check the car out to see if the damper is there. Will take some photos if I can.

Rob, thanks a bunch too for the offer. I live in Lebanon and sending that thing from there might cost a lot. In case I need one, I feel I can get it here, but if not, I will sure take you up.

Thanks.

[Challenger_7]

Ok here we are again. Went to the mech who had parked the car outside, almost froze to death, but here I am
I could barely reach from the top for a reasonable picture but I managed to catch part of the damper. So it looks like I am ok there?? Please see Pic.
As for the Torque Converter, this is a photo of the old one, which had no weights. Also pls see pic. Now if you look at the screw on the upper right hand, approx 2 o'clock, the mech said that the new one came with 2 weights welded, each one approx one inch from each side of this screw.
As for the plate that connects the engine to the converter, he said it is square in shape, and not round like the one from B&M.
So from what Ron said, do I replace the old plate with the one from B&M, AND take away the weights on the new converter, or keep the weights?
Another thing, is there a specific way to mount the flexplate, i.e. where should the cut-out part be?
Another thing from an engineering point of view, how can this plate, with a missing part in it (so to speak) "determine" how much off-balance the engine is, and eliminate that imbalance?? I dont get it
Thanks again for your input. I will be away from my computer till Tuesday, and wish all of you the best for the year to come, to you and all your loved ones, full of love, prosperity and peace.

Farouk

[firefighter3931]

Farouk, those pics help clear up some questions we had. 

(1) You have the correct harmonic balancer on that engine which is good news.
(2) The original TQ converter that is pictured is for a neutral balance engine.....this was causing your vibration issues.

The new converter is supposedly for an external balance engine but the weight could possibly be in the incorrect location.

If it were mine: I'd knock the weights off and use the B&M flexplate with the new converter. The converter will only bolt up to the flexplate one way....the bolt pattern is assymetrical. That means that the scallop (cut out) is in the correct location to create the external balance. Since the converter can only be bolted on one way....you can't go wrong.  This will be obvious to whoever is installing the flexplate....the converter will have to be moved around until all 4 bolts line up with the holes in the flexplate. 



Ron



Ps. I would have the mechanic verify that the Tq converter is in fact neutral balanced (after removing the weights) before re-installing it in the car with the B&M flexplate.

[Steve P.]

I like to paint on alignment marks on both the flex plate and the converter before final install. That makes it real easy to line the bolt hole up without having to spin the converter around. The tranny will be out for the job anyway, why not??

[Challenger_7]

Happy new year guys, and hope your year ended with a blast

Thanks Ron and Steve for the useful comments.

Ron, some more questions from me, and please bear with me as I am new to challengers (and muscle cars), and some questions are for my benefit and not so much the mechanic's.
I am an auto engineer, graduated from England (UK), but spent most of my years (and still) taking care of family business, so many times I am very much in a "back to the drawing board" situation, and have little opportunity to do stuff personally
Also being somewhat close to a "perfectionist", I always want to be sure to understand issues perfectly in order to make sure that my mechanic performs a correct job. I follow every bit of work very meticulously, and take tons of pics for records and follow up purposes.

Now to my questions:
1. To make sure I understand this well, the flex plate from B&M will replace the original plate?
2. Is the original plate also called a flex plate?
3. What is the meaning of "neutral balanced" and how would I check it out?

Thanks again, Farouk

[Challenger_7]

Ron, one more help needed.

I just logged on to the B&M site to order the flex plate, and when I clicked on it to be added to my cart, it showed the following description
"Flexplate, External Balance, 2-Piece Rear Main Seal, SFI 29.1, 6-Bolt, Chrysler, B/RB, 727, Each ".
I am confused by the word "2-Piece". Is this describing the rear main seal as 2-peice or is it referring to the flexplate?
In short, am I ordering the correct part?

Thanks buddy.

PS. Would appreciate some comments on the "engine colors" post which I made today, if you wish.

[firefighter3931]

Now to my questions:
1. To make sure I understand this well, the flex plate from B&M will replace the original plate?
2. Is the original plate also called a flex plate?
3. What is the meaning of "neutral balanced" and how would I check it out?

Thanks again, Farouk

Happy new year to you as well Farouk !

To answer your questions:

(1) Yes, the B&M flexplate will replace your original.
(2) the original plate is also referred to as a flexplate. All BB mopars running an automatic trans will use this plate to attach the converter to the crankshaft.
(3) Neutral balance can be verified with a balance machine....a transmission shop should be able to do this.



Ron

[Challenger_7]

Hi Ron, and glad you are there and thanks for the information;)

I was afraid you would answer my 3rd question with what you said. Out here there is no one with such a facility
What should my course of action be??

As previously mentioned, just to refresh your mind, the current (new) converter came balanced with 2 weights on. The engine is vibrating.
The Mech then took both weights off and the vibration increased a lot, so he returned them back on, and tomorrow he intends to try with some heavier weights.

How should I proceed now?

[firefighter3931]

I would wait for the B&M flexplate and remove (all) the weights from the converter. I would not be experimanting with a heavier weight on the converter.

As for balance verification : do you have an old style "bubble" wheel balancer available ? Possibly, the converter could be placed on the wheel balancer to check for balance. Just an idea....

The description of the B&M plate is referring to the rear main seal which is indeed a 2 piece unit.

What brand of converter is this ?



Ron

[Challenger_7]

Again excuse my ignorance, but what is a "bubble" wheel balancer? Can you provide me with a photo?
In view of the difference in language, no one here will understand what is a "bubble" balancer, and I would need to show them a photo or a specific description, and hope that someone still has this old type.

As for the converter, it is "Trans Star" make.

[firefighter3931]

Again excuse my ignorance, but what is a "bubble" wheel balancer? Can you provide me with a photo?
In view of the difference in language, no one here will understand what is a "bubble" balancer, and I would need to show them a photo or a specific description, and hope that someone still has this old type.

As for the converter, it is "Trans Star" make.

Farouk, years ago wheels used to be balanced on a machine that was very simple....the hub of the wheel was placed on the machine and there was a sight glass with a bubble that told you if the wheel was in balance....similar to using a level in carpentry work. Nowadays, wheel balancers are electronic and computerized.

Here is what a newer style bubble balancer looks like :


http://www.sjdiscounttools.com/atd-8615.html


Member John Kunkel is our resident Tranny Guru....send him a message. Maybe he has an easier way to check for balance.



Ron

[Challenger_7]

Thanks again Ron. From the photo you provided, I now know how it works, and will look for one.
I will also check with John Kunkel, as you suggest.

One question though, you repeatedly said to remove the weights off the converter. These weights are not there to balance it, and removing the weights will not make it imbalanced?

By the way, what is your comment on "Trans Star"? Is it a good make? My mech says it is very good?

Thanks, Farouk

[Challenger_7]

Hello John

As advised by Ron, who has been extremely helpful in guiding me, I am addressing this question to you (pm copy to you).
If you have the time to read through the thread (How to balance an engine) for any possible additions that will be great, otherwise your input on how to balance the converter will be helpful.
We have no machines in Lebanon that can do such a job, and Ron suggested an old bubble wheel balancer, which I will try to locate.
Do you have any other suggestions, or should I not find a bubble balancer, what should I do?
I have ordered the flexplate from B&M in the hope of getting rid of the engine vibration, and awaiting its arrival.

Thanks, Farouk

[firefighter3931]

One question though, you repeatedly said to remove the weights off the converter. These weights are not there to balance it, and removing the weights will not make it imbalanced?

By the way, what is your comment on "Trans Star"? Is it a good make? My mech says it is very good?

Thanks, Farouk

Farouk, the converter should be neutral balance without the weights. The weights are added for engines that are externally balanced with a cast crank....like your 400 and later 440 engines (74-78) Removing the weights will bring it back to neutral balance and the flexplate will take care of the "external" balancing issues. 

Trans star is a descent brand from what i've heard....


Ron

[John_Kunkel]

A couple of observations, the cast crank 400 doesn't always have the humongous harmonic balancer as pictured in firefighters post, most just have an elliptical offset on the inner hub just like the 440 6-pack only thicker; the outer ring is the normal size.

The cast crank 400 needs 100 grams of weight on the face of the converter, this is accomplished by welding two 50 gram weights, one on each side of the drainplug. As mentioned earlier, the B&M #10237 flexplate is a much easier way to go.

Forget the bubble balancer idea, the stator inside the converter is free to float from side to side until actually installed in the transmission, this prevents either spin or bubble balancing without the proper apparatus.

[firefighter3931]

Forget the bubble balancer idea, the stator inside the converter is free to float from side to side until actually installed in the transmission, this prevents either spin or bubble balancing without the proper apparatus.

Thanks for the input John.  The bubble balancer was just some hair brained idea that i thought might work given the limited test equipment available to Farouk. I hadn't even considered the stator being an issue, but now that you mention it...it makes perfect sense. Well i learned some thing new....

Seems we're in agreement on the B&M flexplate and weight removal from the converter to return it to neutral balance. 



Ron

[Challenger_7]

Thank you both for your input, highly appreciated.
As I said, I have orded the B&M Flexplate, and will post my work in progress.

Just for info's sake, in the meantime my mech has continued to add some weights until he felt that the vibration had gone 90%. I asked him why he did not add even more to get rid of it totally, and he said he did, but that took up the vibration to 3000RPM, so he left it where it is.

So, when the flexplate comes, we will have the weights removed off the converter and try it out.

Till then, happy motoring

[Challenger_7]

Hello again and please enlighten me some more.
The flexplate arrived 2 days ago and the mech will be taking my car in tomorrow.
I opened the package and found an installation note from B&M which warns about ensuring perfect alignment between the engine and transmission and ensuring that this should not exceed .008". Everything is understood in that paper, photo attached, except the part where they explain how to check the alignment, (the higlighted part). They say "Rigidly attach indicator to crankshaft and indicate on the oil pump bore in the case". What is "indicator", a special tool or is it part of the engine?
A photo will also help, if possible.

Thanks again.

[John_Kunkel]

While dial checking the case/crank alignment is a good idea, it's seldom done because it requires emptying the case.

The the "flex" in flexplate is intended to allow for some misalignment. The B&M flexplate is less flexible than the original factory style but few people experience problems because of it so just bolt it in and go.

It's a good idea to trial bolt the flexplate to the converter to be sure all of the holes line up before installing it on the crank.

[firefighter3931]

While dial checking the case/crank alignment is a good idea, it's seldom done because it requires emptying the case.

The the "flex" in flexplate is intended to allow for some misalignment. The B&M flexplate is less flexible than the original factory style but few people experience problems because of it so just bolt it in and go.

It's a good idea to trial bolt the flexplate to the converter to be sure all of the holes line up before installing it on the crank.

Just bolt it in and go ! 


Ron

[Challenger_7]

The the "flex" in flexplate is intended to allow for some misalignment. The B&M flexplate is less flexible than the original factory style but few people experience problems because of it so just bolt it in and go.

Ok thank you both, I will do just that, bolt on and go!
But for the sake of argument, if the B&M is less flexible than the original one, how then is it going to do a better job and rid me of the vibrations Just trying to follow the logic of things.

[firefighter3931]

[But for the sake of argument, if the B&M is less flexible than the original one, how then is it going to do a better job and rid me of the vibrations Just trying to follow the logic of things.

The scallop (cut out) in the B&M flexplate is what fixes the balance issue.

The stronger SFI rating means it won't break when you drive hard. 



Ron

[Challenger_7]

Thank you Ron. Where would we be without the wonders of technology

My luck that the mechanic has caught a serious flu, so I will have to wait a bit longer before feeding you back.

Have a lovely week end All.

Farouk

[Challenger_7]

As I had mentioned in my other topic, seeing so many irregularities in the transmission/converter, I decided to open the engine up and check things inside, before installing the "B&M" flexplate. The engine is confirmed to be a 1970 400 engine (with a cast date on the block 11.10.70), originally blue in color, and has signs of corrosion inside one of the cylinders. somehow water must have gotten inside and stayed there for a very long time, thus causing pit marks in that particular cylinder.
The heads have been "shaved" once, and there is leakage between some cylinders at the cylinder head gaskets. The cylinders have already been bored 20 thou over, and will probably need another 20 to clear the pit marks of the corrosion.
The crank shaft has the main bearings standard, and the piston bearings at ten thou over. All will need to be machined another ten thou so will be left with main bearings at ten over, and piston bearings at 20. I suppose it is acceptable to have a difference here?
Pistons are the flat type and will be replace with oversize ones. Of course the valves will be grinded or lapped, as the need arises, and everything else checked.
The cam shaft seems to be a non standard one, probably a higher rpm one, but no idea what. I will take some measurements of the cams to have some idea.

With this, and having taken a few pictures of the various parts pof the engine, I left the mechanic to send the engine to the machinist on monday and carry on with the work.
Any comments or words of caustion willbe appreciated.

Thanks, Farouk

[firefighter3931]

The engine is confirmed to be a 1970 400 engine (with a cast date on the block 11.10.70), originally blue in color, and has signs of corrosion inside one of the cylinders. somehow water must have gotten inside and stayed there for a very long time, thus causing pit marks in that particular cylinder.

Thanks, Farouk

Farouk, are you sure on those casting dates ? A 1970 "B" engine would be a 383...not a 400.  Maybe you should have the machinist measure the bores to see what you've got there. The 400ci didn't go into production until the 1972 model year.


Ron

[Challenger_7]

Yet again our Guru proves to be on the alert all the time Ok blame me for my limited knowledge , and as usual, help me clarify some points.

1. I saw on the side of the body of the engine, below the actual engine number, what appeared to be the number I quoted. I went back to the pictures and looked again, funnily the one with paint on looked clearer than having brushed the paint off, and what seems to be the number now is 11.16.73. Does this make sense. Attached is the pic of the casting date after brushing.
2. The engine number photo is also attached. There is a number that appears to be 3698630.400.(something looking like I or 1 after the 400).
3. Then on the front of the engine, there is a stamp with some numbers on it. Pls see attached photo. What are these?
4. I have also attached the photo of the piston that is on the engine now, and in any case, I asked the machinist to measure the cylinder for me.
5. Now the first of the reports coming back on the cylinder heads is that there is a bit of play on the valve guides, and the mechanic says there are no new guides for this engine. What they normally do is find the same size valve with a thicker stem and bore the guides accordingly. Is this correct or I can find new guides??
6. There is also the letters XL cast on the upper front of the engine. Any important significance?

Cheers, Farouk

[Challenger_7]

Two other things; out of the main bearings (five in all), only the middle one has a bearing with a lip (or whatever you call it). Photo attached. Is this normal, and as you can see, the lip does not go all the way down, is this correct?

I also included a photo of the "fleplate" that was on the engine, also very weird looking. Is this also normal? I would have expected to see a round one. You can also see the new converter under it with the weights grinded off, as suggested.

Thanks again, Farouk

[Steve P.]

All normal. The bearing in your hand is the THRUST BEARING. It keeps the crank from moving too far forward and back. The flex plate is mopar stock. Nothing strange there.

I totally believe all motors should be internally balanced. Many are not and I don't know why, but this leaves nothing to go wrong.

And for what it's worth, I met a guy a few weeks ago that has used many 440 Source kits and loves them. Never any problems. He does have his machine shop check EVERYTHING though, just in case...

[firefighter3931]

  Steve's observations are right on the money. 

I don't see anything to be concerned about in there. Just have the block hot tanked and magnafluxed to check for cracks. Also have the cylinders measured for taper to see if it needs an overbore. 



Ron

[Challenger_7]

Thank you both for the replies. I feel much better now, and thanks Steve for your assurance on the 440 source kits. It is appreciated
Ron, the cylinders will have to be rebored due to some wear and rust on one particular cylinder that has developed into pits. If we can find 40 oversize pistons available here, this is where we will have to go, otherwise we will insert a new sleeve (quicker and cheaper than importing new set of pistons).

Will keep you posted. By the way, do the XL letters cast on the front of the engine have any significant meaning?

Thanks

[Challenger_7]

Hello friends.
I have completed reboring the engine to 20 over, crank regrinded 10/20 over and installed everything new and now getting ready to paint the engine.

At this point and out of curiosity, I asked the mechanic to show me the harmonic balancer and here are the pictures. One thing attracted my attention, the part number on it, which has "318" at the end. Does this mean that it is for a 318 engine? If not, how can I get a confirmation if this is correct for my 400 block or not

I woud appreciate a quick response in case I need to change it.

Thanks and hope you all have a lovely week end.

Farouk

[Challenger_7]

The long journey is almost over, and we will see if all worked out well.

The engine has been completely overhauled, assembled back and today was being re-installed into the car. Hopefully we will start it tomorrow or the day after.
Keeping fingers crossed that the B&M flexplate will do the trick and will have no more vibrations

Attached is a pic of the back of the engine, now painted orange.

[firefighter3931]

Looks very nice Farouk....hopefully the flexplate fixes the vibration issue. 


Ron

[Steve P.]

I think you'll be good to go.. Let us know.............   

[Challenger_7]

Hey guys, guess what.
Thanks to your good advice and guidance, the engine is purring like a tame cat All I need now is a new carb, as the current one is too small, but good enough to run the car in.
By the way, what would be the recommended running in proceedure. 500 KM, change of oil/filter then 1500KM before a new change? Pls advise.

Summary of events: Bought the car with a badly vibrating engine and leaking g/box. Ended changing all components of the gearbox, new converter (neutral balance), a B&M flexplate, reconditioned the engine completely (new cylinder sleeves) and new valves, new starter and new fan blade (but with clutch as I could not find the same type).
Hopefully tomorrow the car will be released to me to start the running in of the engine, after which time I will make one final post on this thread.

Lesson learned: Vibrating engine: install B&M flexplate, use neutral converter, all rest being normal you should be ok!

Thanks to all who contributed here, and a special thanks to Ron for being there all the time.

Attached photo is after having started the engine.

Cheers, Farouk

[firefighter3931]

That is excellent news Farouk ! 

I would change the oil/filter immediately after breakin and again at 500 miles then again at 1500 miles. After that normal intervals...say every 3000 miles or so. 

Enjoy the car and don't beat on it to hard for the first few weeks....3500-4000rpm short bursts to seat the new rings. After that....let er RIP ! 


Ron

[Steve P.]

  All the way..   Good luck buddy..   

[Challenger_7]

Ron and all. I took the car out on Saturday and Sunday and did 300 miles of gentle breaking in including the recommended short bursts. Only very occasionally going to 3500.
I was rather sad to note that there are still vibrations in the engine at different RPMs. It is nothing compared to what was there before, but they are still there
They are more significant at some levels than others. What do I do, and how bad is this for the engine?
Apart from that, the car handles like a dream and I discovered that the car, whilst originally was a 6 cyl car, was actaually exported to Lebanon, purchased here from the dealer and has been very well preserved. Everything in it is still original except for the engine/gearbox. Also it used to be Orange/white top Vynil, white interior but now changed to red/black/black. It stayed with one owner till 3 years ago whereby the new owner changed the engine to the 400, sold it to another person from whom I bought the car. Both owners never really drove the car.

Please tell me there is still something I can do to get rid of the vibrations

Just sharing with you, attached photo taken on Saturday just outside the city of Beirut

Cheers

[firefighter3931]

Farouk, are you sure it's coming from the engine ? Try reving up the motor in park and see if you have any vibration. It mght be a u-joint or driveshaft out of balance.


Ron

[Challenger_7]

Yes Ron I did check it out whilst not in motion.

According to the RPM counter attached to it (i.e. not 100% sure of its accuracy), at 900 the whole car rattles loudly, 1200 rattles less, 1700 rattles a bit louder, 2400 or there about rattles enough to vibrate even the console plate.
In between the rattling sort of fades away, or sways off and comes back but softly.

Please advise me what to do, even if I have to pukk the engine down again.

Regards

[firefighter3931]

Damn, that is disappointing. Ok, it's obvious something is causing the engine to go way out of balance. I would start by checking the pullies and belts.....remove the belts and fire up the engine to see if it still vibrates. Next, check the tq converter bolts to make sure that they haven't loosened off.

It's gonna be an internal or external balance issue. Start with the external (easy) things first. I'm starting to question your torque converter....i wish there was an easy way to verify neutral balance with it.


Ron

[Challenger_7]

Thanks Ron, I will do as you say in due course and let you know.

Can you explain to me what is the meaning of "Verifying neutral balance with it"? Are you saying to verify if the converter is indeed balanced without the weights on it?
If you recall, when I bought this converter, it had weights on it that we grinded off. I can always look for a new one that comes with no weights, and pray that it is indeed neutral balanced and try it on the engine.

Farouk

[firefighter3931]

Can you explain to me what is the meaning of "Verifying neutral balance with it"? Are you saying to verify if the converter is indeed balanced without the weights on it?
Farouk

Yes, that is what i'm talking about. Either the converter balance is way off or the engine balance is way off. The harmonic balancer & converter/flexplate should offset each end of the crank if everything is well. That being the case....the internal balance being off could be the only other reason for this vibration you are experiencing. By Internal balance....i'm referring to the individual rod/piston assemblies and their weight relative to each other (static balance).


Ron

[is_it_EVER_done?]

I didn't see this post before, but any engine that is externally balanced is never going to be "great". Why didn't you have it internally balanced when you had it apart? I guarantee that ANY competent machine shop could have balanced it, even in your area, as all engines are the same from that standpoint. You are right back where you started!

Those offset flexplates are junk! they can only approximate what the engine requires. You don't even know if you have the correct harmonic balancer.

Sorry to be critical, but you should have had it neutral balanced. Never have an engine externally balanced for anything other than transportation. In fact, there is NO SUCH THING as a balanced assembly with counterweighted components. In all reality, even a neutral balanced engine is only in balance at specific RPM's, but an external one is guaranteed to be "out" most of the time.

At this stage all you can do is have your mechanic add and subtract weight to see if he can get it close. Or disassemble the engine, and throw the flexplate and damper in the trash, and have the internally assembly balanced with neutral components.

Sorry I didn't see this post sooner.

[firefighter3931]

Those offset flexplates are junk!

More nonsense....i guess the thousands of cars running these flexplates are vibrating all to hell too. 

Fwiw, the dampner is the cioorect unit for his engine.

For a "cruiser" application there is nothing wrong with a cast crank/external balance setup. 



Ron

[Challenger_7]

Ron, I could kick myself in the but, but my legs cant reach that far Only today, upon checking with the last mech that I know, he confirmed that he knows someone who has a balancing machine. If only I knew that earlier
Anyway, I will test out all the possibilities as suggested earlier, and if all fails, I will strip the engine apart and have the crank balanced.
I was told to send the crank, pistons and con rods. Is that correct?
Now two questions I have here, if the balancing is done, do I still use the B&M flex plate or go back to the orig one?
Secondly what about the torque conv, still use a neutral one or otherwise? Thanks
is_it_EVER_done? Hey, you are being a bit harsh here buddy and obviously you did not read the full thread thoroughly
My mistake from day one, I did not know of any one having a balancing machine in our area, so Ron was trying to see me through, and 80% of the problem has been resolved. But then again, by now you know me, I want the best and am getting info from the best on this forum So I do want to go that extra mile although as things are now, the caris perfectly driveable. We did check the damper photos and all - down to the part number and it is correct for my engine.

Cheers

[Challenger_7]

Hi all and Happy Easter (in arears).
Here I am back to report on my saga and my final results.

Between traveling and going back to bug my mechanic, As mentioned in my last report, we had the engine removed again to check on the vibration. I am glad we opened the engine as there was serious and irrecgular wear on the crank shaft bearings, and the last journal's bearing had gone down to the brass metal.
We took the crank, damper, felxplate and converter to the machinist for balancing, and discovered that he had a set of wheels where you center the crank between them and check if it stays put! Obviously the most primitive equipment. (see photo)
The machinist discovered that the one who turned the crank shaft to 20 thou under, had left a gap larger than recommended (4.5 instead of 2, I think) and said that this could also be responsible for vibration. I did not buy that but the gap waranted looking into. He suggested now going to 30 thou under, but we decided to check other makes of bearings. We were lucky to find "Clevite" that covered the difference in the gap.
Anyway, crank and damper showed ok, flexplate went slightly out but the converter, due to its internal parts and oil etc, would not check out.
Cleaned the crank, which was still ok, installed new bearings, and piston rings, and had the engine assembled again. Prayed like mad and started again. Same vibrations!!
I decided to change the converter and got a used one, zero balanced and guaranteed to have been ok. Installed it and my fears all disappeared. All is ok with only a minor vibration at 1200 rpm (I will yet confirm if the rpm reading is correct). So we can say that finally, Hallelua, problem is solved.

One question here, whilst reassembling the engine, the mechanic doubted the cam followers and said they might be wrong and changed them. Here is a photo of the two types. The ones I had are the ones without a hole in the center (on the right). The ones he installed are the ones with a hole (on the left), and are actually lower inside. Which ones are correct, and am I standing any risk in keeping them on if they are the wrong type?

Thanks again for all the help received.

Regards, Farouk