Advice on tinkering with my 71 383.

[71 Bee Man]

Hi guys.

In the next month or so I was planning on taking out my Bee's original 383, and tidying it up a little....mainly presentation wise. However......the other day I decided to check my plugs, found a couple with a bit of oil on them and then did a compression test......one of the oily plugs (no. had woeful compression....like about 40p.s.i.
The others that I could get to were all around 115-120, which is pretty ordinary......but it was a cold engine. Mind you, that no.8 plug is still disgraceful.
I squirted some oil into it, and it made no difference.
The thing is, the engine runs beautiful, and has decent enough power, but there has always been a bit of noise a little like valve noise if that makes sense, that you can just hear when it's running.
In any case, I'm digressing a tad. When I pull the motor out I'm going to have a good look and see what's going on. My mechanic reckons it's probably just a sticking valve.
In saying that, I'm wondering what little things I could possibly do whilst it's out. I haven't ripped a motor down before, but I am mechanically inclined and don't mind jumping in and having a go. I've watched a few videos of stuff, and wondering if things like cams and new valves all round are the go.
I've read about the higher H.P of the earlier 383's and wondering if I shouldn't consider doing some simple stuff to get the most out of it. I hear the 71's were "detuned" to 300h.p but I'm not sure in what way, and if that's easy to reverse.
Anyway.....just started typing on the spur of the moment. I'm curious what people think....motor is the original and had new timing chain done a few years back. Seems all stock. It has a set of Dougs headers, and a Holley 750 on the standard inlet. Automatic. 123,000 miles.
I'm not really keen on ripping the whole thing down into a million pieces, because it runs so darn nice, but I am going to sort out that low compression issue. I keep thinking if it runs so good now, imagine how good she'll run when that's fixed.
Anyway......sorry for waffling.....just throwing it out there if anyone's interested.

Peter

[XH29N0G]

People on here will be able to help and to give specific advice.  I just did some looking at the specifications between the 1970 and 1971 and have conflicting information about compression and cams (someone will know).  My old chilton's has the same advertised compression for the HP version of both listed the same and the only difference I see is one number (exhaust lift) on the cam.  Another source lists a different CR for the HP 383. 

If it is CR, I assume there would have been a change in pistons and that wouldn't be an easy swap.  If I were you, I would want to figure out what the low compression test number and take it from there.  I would figure out what I wanted from it to get the most specific advice. I went through this about 10 years ago and swapped the heads, intake, and cam (to a lunati 702), and then also the rear differential gear ratios (which made the biggest difference).  I made mistakes along the way, and had to ask people to help get me out of them.  It was a fun process for a novice, and I have no regrets.  I then sent the motor to be rebuilt and that is what made the biggest difference. 

Good luck.  I'll be interested to read how this progresses.

[John_Kunkel]

My mechanic reckons it's probably just a sticking valve.

A leakdown test can pinpoint the source of cylinder compression leakage.

Valve stem seals are often the cause of oily plugs and they can be replaced without major disassembly of the engine.

[Sublime/Sixpack]

One cylinder at only 40 psi and the engine runs beautifully? Even the others at 115-120 seem pretty low. When performing the compression test how many times did you let the piston in the cylinder being tested reach TDC on the compression stroke?

[71 Bee Man]

Thanks for replying guys.

I know it sounds wrong, but it really does idle and drive great.......but that cylinder has stuff all compression in it. I gave it heaps of time to build up pressure too......it's 40 p.s.i.
That's why I'm looking forward to pulling it out and seeing what's happening.

I will be doing the valve seals. Preparing myself to do the rings, but if I find an obvious problem with that No. 8 cylinder, I might be happy just getting that sorted. She doesn't use much oil at all, but I reckon the valve stem seals are a definite.

For how I use the car - even though getting more performance sounds great - I'm happy just getting it running nice and as it should be. I take it out once or twice a week. I've had Aussie Mopars all my life, and another 71 Bee years ago - I just like my Mopars. I love the shape of the 3rd Gens. It's a pretty neat car this one.....pretty original, looks good etc. people think I'm mad for pulling the motor out soon just so I can tidy it up a bit, but that's what I do. I just haven't ripped the motor apart before (myself), and am looking forward to it, but don't want to end up not knowing what to do.

Thanks again guys. Surprising that I couldn't find a darn webpage that said "This is how you get 335 hp from your 300 hp"...... Or is it all simply bolt on performance, like an article I found in an old Mopar Muscle issue ?

Peter

[Sublime/Sixpack]

Most everyone has their own approach to issues such as this, and you certainly have options but only you know how far into the engine you want to go. If it has 123,000 miles on it without ever being rebuilt personally I would go for a full rebuild. At the very least a refreshing of the engine (hone cylinders, re-ring pistons, new cam bearings if needed, new rod and main bearings, valve seals, cam and lifters, etc). Also decarbonize pistons, valves and combustion chambers before replacing any parts.

But to be honest with you I would want to determine why the one cylinder is so low on compression before tearing into it. Maybe it is a sticky valve, or even a small piece of carbon stuck on one of the valve seats not letting that valve close completely. I'd bring the piston of the weak cylinder up to TDC on the compression stroke then run compressed air into the cylinder through the spark plug hole then listen to the carb and then the tailpipe to determine whether it's an intake or exhaust valve leaking. Or maybe the air will be getting past the piston and going into the crankcase, if this is the case you'll hear it by removing the oil fill cap and listening there.

Before any of this you may even try pouring a can of "Sea Foam" into the crankcase and putting some miles on the car to see if this resolves the issue. I've seen this work on sticky valves and lifters.

Hope this helps provide you with at least some direction.

[71 Bee Man]

Many thanks Sublime.

Yeah......if I'm pulling it out, it seems a bit of a waste not to do the things you mentioned. Just a bit daunting I guess, but as I mentioned earlier, I honestly don't mind having a go. I enjoy learning stuff like this. I think I'll do the compressed air trick tomorrow.
Haven't got a clue what Sea Foam is......I've heard of it on the forum, but we certainly don't have it down here.

I was thinking earlier......I used to have an Aussie Charger with a 340 in it. It too ran really nice, but used heaps of fuel which wasn't the fault of the carb. From memory I went to a speed shop, they ran some tests and said it had a worn lobe on the cam shaft. They were right.....it was crap. That was ages ago. I'll do the stuff you guys have suggested and see how I go.

Peter

[XH29N0G]

Sea foam is an engine treatment and your best bet is probably to search on the web if that is the route you take.  I don't know the plusses and minuses.  I think we used it in the 1980's in a boatyard/shop I worked in, but have not used it on my engine.  It produces a lot of smoke,

Whenever it comes up, I think of seafoam candy  (which is what my wife calls it) and what I believe you have as honey comb candy on your side of the world. 

[Sublime/Sixpack]

FWIW I use SeaFoam periodically in the fuel of several vehicles and none of them smoke. Have also put a little in the crankcase of a couple small engines to free up a sticky valve, and they didn't smoke either. 

[71 SE3834V]

The smoking comes in when you use it to decarbonize the engine.
Pour some in the carb while keeping the engine running then pour more in and stall the engine. I believe you're supposed to leave it sit for about 15 min. and restart engine. Carbon will be loosened and blow out causing a lot of smoke.
I've used it on small engines and have seen a piston totally covered with carbon taken down to where you can see the metal at the center of the piston.

[Laowho]

Have used Sea Foam on some small engines to great effect, the smoking way. Guess it comes from marine applications as part of a winterizing regimen. Whatever the case, it worked great both times to get non-running engines started on our brother's farm.

[c00nhunterjoe]

Noisey valvetrain, 40 psi compression, oily plug, 120k miles. I dont see seafoam fixing this. 110 psi isnt good on a stock mill in my opinion unless you are in the rockies. It sounds like its time for a major overhaul, not just valve stem seals. And odds are, the guides are wore out causing the oil consumption moreso then the seals. Its still worth airing the cylinders to see where the compression is going in the bad cylinder prior to teardown.
    Im going to go on record here and speculate you will find a wore out cam, excessive cylinder wear (large ridge), wore out valve guides and seats when you tear it down.

[alfaitalia]

I'm going for valve or seat damage. You would get more than 40 psi on the test if the pistons had no rings fitted at all!

[71 Bee Man]

Noisey valvetrain, 40 psi compression, oily plug, 120k miles. I dont see seafoam fixing this. 110 psi isnt good on a stock mill in my opinion unless you are in the rockies. It sounds like its time for a major overhaul, not just valve stem seals. And odds are, the guides are wore out causing the oil consumption moreso then the seals. Its still worth airing the cylinders to see where the compression is going in the bad cylinder prior to teardown.
    Im going to go on record here and speculate you will find a wore out cam, excessive cylinder wear (large ridge), wore out valve guides and seats when you tear it down.

Yep......I'm with you. Been thinking about it over the last couple of days. I have a big Mopar show early March, so I'm going to leave stuff till after that, but then I think I'll pull it out and get stuck into it.
I've always wanted to play around with the engine internals, but just never tried. The more I read and see I reckon I can handle it.
I keep coming back to how good it runs at the moment. Idles good, drives good, could have a bit more "go" in it, but it's certainly not stuffed. I'd be mad though not to do a full overhaul.
Here's a possibly dumb question......to air the cylinder, it needs to be at the top of the compression stroke, right?
How the heck do I know when No. 8 is at the top of the compression stroke ? I mean it's right at the back of the dam motor, and it's pretty hard to see into the cylinder.

[Sublime/Sixpack]

Yep......I'm with you. Been thinking about it over the last couple of days. I have a big Mopar show early March, so I'm going to leave stuff till after that, but then I think I'll pull it out and get stuck into it.
I've always wanted to play around with the engine internals, but just never tried. The more I read and see I reckon I can handle it.
I keep coming back to how good it runs at the moment. Idles good, drives good, could have a bit more "go" in it, but it's certainly not stuffed. I'd be mad though not to do a full overhaul.
Here's a possibly dumb question......to air the cylinder, it needs to be at the top of the compression stroke, right?
How the heck do I know when No. 8 is at the top of the compression stroke ? I mean it's right at the back of the dam motor, and it's pretty hard to see into the cylinder.
[/quote]

Now you're talking! I figured you'd toss it around in your mind a bit then make the right decision. As I mentioned earlier, if your engine has 123,000 miles on it (without ever being rebuilt) I personally would go with a full rebuild.
Based on some of your statements it sounds as though you want to do some of the work yourself. This is great. I encourage you to do so if you feel you have the knowledge and confidence. It can really help if the shop you choose is willing to work with you and guide you along the way. Most shops won't do this, they're more concerned with doing the job and getting paid.

To answer your question about finding TDC on #8, one easy way is to connect a hand held starter button so you can turn the engine over, remove #8 plug, place a finger over the plug hole then hit the starter button until you feel pressure on your finger. Let off, then go easy with short hits to get to TDC. If you go too far, just around again.

[c00nhunterjoe]

With 100 psi numbers, you can spin it over with a 3/8 ratchet. Have a helper Rotate it by hand til number 8 is at the top of compression then verify fully top with a pocket screwdriver.

[71 SE3834V]

I think you'll find most of your valve seals are going to be cracked and/or in the oil pan like mine were. Pulled a handful out of the oil pickup. Guess that explained alot of the low oil pressure!

You might consider what I did. I knew I could do all the work but didn't want the job to drag on for too long so I was able to find a shop to rebuild the short block for not much more than the cost of the things I wouldn't be able to do (boring, pressing off/on pistons, installing cam bearings, etc.) so given the fact that it had to be done before the winter I tore it down to the short block and took it in w/the heads. In the mean time I stripped and painted the engine bay and everything in it. Got the shortblock and heads back rebuilt. I installed heads, valve train, etc and got it on the road Nov. 1. Put 50 miles on it before the snow started to fly.    Sad I had to wait until the next spring to really drive it but when the time came I had a lot of fun! 
Good peace of mind knowing someone who did it for a living put together the vital parts. Something to think about.

[c00nhunterjoe]

Just be prepared to hear that it needs to be bored and then you will be faced with the typical piston dilemma and yhe heads will require more cash to rebuild them then a new set of aluminums.

[71 Bee Man]

To everyone.....thanks a lot for taking time to comment. I really appreciate it, and I'm taking everything on board.
Sublime.....ill do that with the remote starter. I wondered if it was that easy.

Hunter Joe......I was only just sitting here looking at Pistons on the net and thinking "so what the hell do I look for if I need Pistons, and what of the bore needs honing, making them bigger". Yep.....that's already in my mind. If they only needs Togo a bit bigger just to clean the bores, would I have to really do anything to the heads, other than probably do the valves anyway ? I'm not after a huge mod job......to be honest I'd be happy just getting the most I can out of the standard 71 HP block.

71 SE.......I think I'll be doing what you did....I started thinking about this with the engine bay reaping in mind. Preparing myself that this will take a while, but I'm really looking forward to it.

Worst bit regarding parts is I'll probably be ordering everything from the States. Some places out here stock Mopar stuff, but I'm just not sure they specialise in it......that's why I thought I'd ask you guys. Postage will be a killer, but......that's what you have to do. Been looking at kits and things online.......will do some more research hear and see what's around and if anyone can give good advice down here.

Thanks again everyone......your comments don't go unheeded.

[Sublime/Sixpack]

Are there auto machine shops were you live? If so, I suggest that you ask around (friends, car club members, etc.) to get an idea of who does top notch work, and then stop in and talk with the people at these shops. Try to build rapport with those that you feel impressed with. Explain what you have in mind for your engine and ask for their input. If you find the right machinist/engine builder he'll be happy to spend some time with you and work out a good plan.

Based on what you've shared with us I agree with 71 SE3834V it's probably best to have the shop build you the short block, and do your heads, then if you feel confident enough to install the heads and everything else, go for it. I think you'll enjoy it. Just make sure you do your homework! If you're unsure about something just post up here. I think most guys are on here are looking to provide encouragement and help out however they can.

[71 Bee Man]

Ok....I made a quick video of the motor starting, idling and revving a bit.....just so you know I'm not lying about it running well. My son was at the key and giving it the revs.
I also did a proper compression check with a warm engine, and the numbers are as follows :

No. 1 - 120 psi
No. 2 - 110
No. 3 - 115
No. 4 - 115
No. 5 - 120
No. 6 - 110
No. 7 - 120
No. 8 - 37 psi

Couldn't upload it to the post, so it's on YouTube....goes for about 1 min 40 sec.

https://youtu.be/kIUu60uoXxE

And another one, 45 sec.

https://youtu.be/Qd2CE_D39fA



   

[c00nhunterjoe]

You can buy good pistons but you cannot shop by their advertised compression ratio. Those are wrong. You must look at the compression height of them.
    The heads will probably need a valve job, new seats, new guides, machining for pos lock valve seals, machining for valve spring clearance if you plan to put a cam in it. Just those items have put you at a set of new aluminum heads and your old ones will still have small valves and stock ports.

[sccachallenger]

Take off the pass side valve(rocker) cover, look at the valve springs for cylinder number 8.
You may find a broken valve spring or bent push-rod, fixable without removing engine!
and remove rocker shaft and see if all valve stems are approximately the same height.
Definitely let us know what you find.