Shakes at cruising speed ,,, bad parts combo???

[ottawamerc]

Hi guys

My Charger is giving me some worries now and I'm trying to see if what I'm thinking may be the cause. History on the build, It is a 440 6 pack built from parts from all over North America, a 72 440 block bored .060 over, forged crank, LY rods shot peened and balanced, 10:1 pistons, a vibration damper that came with the crank and the torque converter was rebuilt/ altered but was the one on my car when it had the 400 in it. Here's where my worries kick in is the vibration possibly coming from a miss matched component? It's shaking pretty bad at around 100KMH kinda like a bad tire but a tight and constant shake Would I feel an engine shake if I reved the engine to the same RPM as cruise speed? or just under load...

Looking to you guys on if this could be the issue or help make this worry go away and maybe its a tire, hopefully although tires , rims etc are all new.

Thanks
Scott

[Cooter]

You say "When I had the 400 in it" Was the converter balanced for an external 400, with cast crank? (Were there little weights on the converter where you bolt it up to flex plate?)

Did you have machine shop Rebalance all those "mix and match" parts?

If it's the engine/converter itself, you should be able to feel the same vibration sitting still in park, and revving it till you feel it. Somewhere usually round say 1500-2300 RPM. I assume you didn't have this vibration until you built this engine correct? So, if you rev the engine till around the same speed as cruise, you should feel it if it's the engine.. but if not, and only does it at speed, under load, then you need look other places.

[ottawamerc]

Ok thanks Cooter, I think the weights were on the converter but I'm going to recheck tonight. I can rev the engine in neutral with no noticeable vibration, so I should be ok with the engine and tranny, maybe a drive shaft or tire issue?

[ottawamerc]

Ok I put he car on the hoist and checked the converter and there are no weights there, is that right? or should it be weighted?

[firefighter3931]

Scott, as Cooter mentioned ; the cast crank engines require an externally balanced torque converter. The balance is achieved by welding weights onto the Tq Converter so if you have an internally balanced engine (with an externally balance tq converter) those weights need to be knocked off to bring it back to neutral balance. 

If those weights are still in place then you need to remove them. 


Ron

[MSRacing89]

I would be looking at a bad U-joint first.  Bad drive shaft angles and U-joints will be show there stuff around 60MPH.

[ottawamerc]

I would be looking at a bad U-joint first.  Bad drive shaft angles and U-joints will be show there stuff around 60MPH.

Wow that would be MUCH!!! better and possible cause the driveshaft is one of the "new/ used" parts that were installed. I did nothing to the shaft and u joints other than clean and paint. I had the car on the hoist and ran it at idle in gear and did a visual of the drive shaft and it looked true.. but who knows. I'll pull the drive shaft off and check the joints again.

Scott

[Dino]

My car had a minimal vibration when I reached 50 ish last year.  Before I had the chance to turn back the vibration got real bad and noisy, turned out the u joint failed.  How's your engine mounts looking?

[ottawamerc]

My car had a minimal vibration when I reached 50 ish last year.  Before I had the chance to turn back the vibration got real bad and noisy, turned out the u joint failed.  How's your engine mounts looking?

They are new.

[Dino]

My car had a minimal vibration when I reached 50 ish last year.  Before I had the chance to turn back the vibration got real bad and noisy, turned out the u joint failed.  How's your engine mounts looking?

They are new.

Did you do the driver's side mod?  If not do it now before you forget. 

http://www.dodgecharger.com/forum/index.php/topic,13216.0.html

[ottawamerc]

Ya I read the article after I did the swap, wished I knew before but its a pig to take in and out so fingers crossed

[MSRacing89]

If you had a vibration related to the wrong damper or flexplate, etc....you would most likely feel it sitting in the driveway under minimal load.  We just had a customer car with '72 block in it, had a vibration at 2500rpm with no load.  Turned out it had the wrong damper on there.  Once you get to the 70's era 440 block, you have to be real careful on the damper's.  Talk to 440 source and make sure your numbers are correct for the year.

[ottawamerc]

Not the best pics of the damper but this is whats there.

[MSRacing89]

http://store.440source.com/Dampers-Balancers/products/14/

You can read up on what the different types are here.

[RIDELIKEHELL]

My next job is to figure out why I have a bad vibrationg at 65-70 mph...shakes the steering wheel quite a bit but doesn't do it all the time  I've been told wheels,driveshaft etc....will report back my findings but for now will only go 60 mph 

[ottawamerc]

Ok update on my shakey shakey. I replaced the U joints and it is better but the vibration is still there. I'm going to send it back to the shop and have the new tires rechecked.


Scott

[Tilar]

You have the original balancer for that crank but you changed the Torque converter, I'm betting that is your demon. 

[ottawamerc]

You have the original balancer for that crank but you changed the Torque converter, I'm betting that is your demon. 

No the dampener was picked up along the line as I was gathering parts too but it is the right one for a forged crank (I think) I checked the converter and didnt see any weights and I think thats right?

[Tilar]

That would be right. The dampener looks right from the pic, the one for a later model engine is wider than the older internally balanced ones.

[firefighter3931]

Ok update on my shakey shakey. I replaced the U joints and it is better but the vibration is still there. I'm going to send it back to the shop and have the new tires rechecked.


Scott

The driveshaft could be out of balance or have excessive runout. Another area to look at is the front yoke and tailshaft bushing. Excessive play will cause vibration at speed.

Ron

[ottawamerc]

The front yoke has some play on the tail shaft but is that not normal?

[firefighter3931]

The front yoke has some play on the tail shaft but is that not normal?

It should have a very small amount of play.....you should just be able to feel it move ever so slightly. 

Pinion angle is another possible source for vibration. 


Ron

[ottawamerc]

The front yoke has some play on the tail shaft but is that not normal?

It should have a very small amount of play.....you should just be able to feel it move ever so slightly. 

Pinion angle is another possible source for vibration. 


Ron

So that brings me back to another question I had earlier about bushings / shims on my transmission rear support. When I reassembled I couldnt remember if they went on top or below like in the pic?

[ws23rt]

The front yoke has some play on the tail shaft but is that not normal?

It should have a very small amount of play.....you should just be able to feel it move ever so slightly. 

Pinion angle is another possible source for vibration. 


Ron

So that brings me back to another question I had earlier about bushings / shims on my transmission rear support. When I reassembled I couldnt remember if they went on top or below like in the pic?

Whether they go on top or bottom of mount bracket would make only slight difference. This could be answered by knowing your pinion angle.
Also it looks like the studs in the trans are short. You need full thread in the nut for the stud to be all it can be. If you need the shim you need longer studs.

[ottawamerc]

good point ws23rt

Oh and another thing I remembered I used the flex plate off of my old 400 too, are they interchangeable?