350 CID engine damper is pissing me off

[haysonj]

Originally Posted by Billla

Sorry to go OT, but I don't understand this at all - if the crank is machined to the correct dimensions there should be no issues at all here. OCCASIONALLY you might need to swap in 1/2 shell of a .001 oversize...but that's been rare for me. If you're having to go through 3 sets of bearings, then you're buying junk bearings or your machine shop needs to learn how to hold a clearance.

I also don't understand what you mean by chamfering the back of the bearings - I wouldn't do ANY prep on main bearings for installation.

Sorry - maybe just a difference in experience.

I do agree that someone that doesn't know which bearing is the thrust bearing shouldn't be making this change; Killer - you really need to get someone else to tackle this IMHO, maybe pay the shop to do it. Sorry again - but that'd be my recommendation.

I just had over a thousand dollars worth of machine work on my 383 go down the tubes because of a ballooning torque converter and I have all the service bulletins from GM about the thrust bearing and its problems with rebuilt engines. I don't know everything but I have built a few engines including the 600 HP small block in my boat. I don't buy cheap anything. Also my machinist does the work for all the circle track guys here and they swear by him.

[Billla]

Again, just differing experiences - I've never run into that problem (never) and so offered my experience.

[killer_mike]

All i need right now is a long screw driver, maybe 2, to properly remove the cam and crank gears and the propper endplay clearance. Im a novice, but i dont want to go to mech school empty handed

[67_C-30]

Originally Posted by killer_mike

All i need right now is a long screw driver, maybe 2, to properly remove the cam and crank gears and the propper endplay clearance. Im a novice, but i dont want to go to mech school empty handed

The crank gears have nothing to do with it. You have to have the rear main cap loose engine for the rear thrust bearing to move.

[killer_mike]

I knew i was missing something thats why i checked again; so i dont need to take all that stuff off, even better; but i will do the check with the torque wrench tomorrow, im done today, getting that trannie assembled kicked my butt. Is heavy as hell. In case is bad, it shouldnt be that bad, i wasnt using a sledge hammer

Originally Posted by 67_C-30

The crank gears have nothing to do with it. You have to have the rear main cap loose engine for the rear thrust bearing to move.

[Nachos82]

Beating on the harmonic balancer is wrong? Wish someone would have told me that before doing it to every motor I have ever worked on.

[67_C-30]

Originally Posted by Billla

Sorry to go OT, but I don't understand this at all - if the crank is machined to the correct dimensions there should be no issues at all here. OCCASIONALLY you might need to swap in 1/2 shell of a .001 oversize...but that's been rare for me. If you're having to go through 3 sets of bearings, then you're buying junk bearings or your machine shop needs to learn how to hold a clearance.

I totally agree. If you're having to do all that then either your rods/mains are out of spec or the crankshaft is. You can get away with mixing and matching shells on a street engine, but they will never live on a high peformance or heavy towing engine (meaning like a 1 ton or medium duty hauling truly heavy loads, not a 1/2 ton pulling a trailer) . Mixed shells may make your tolerances right, but the ID bearings are not truly round. If it wasn't the crank (and it usually is) I'd have the block aligned honed or have the rods machined to correct the problem, but that's just me. On 99% of motor machine work, +/-.001" is plenty suffice, and compared to the kind of machine work I do everyday, a .001" tolerance is a mile. I mean that's a Stevie Wonder with a file tolerance there!!


Also, I don't know the problems on the GM crate engines, but I can also tell you that on a high RPM high performance engine, .003" is on the tight on end play. .002" - .006" is the production range, but with HP race engines, you have to shoot for the high side. I've always liked at least .006" and up .008" on circle track engines. The same thing applies to rod side clearance. If run production specs on a substained high RPM engine, they will rub. I've also ran a minimum of .015" clearance on those. I know this may not apply here, but these are common problems with severe duty engines.

[killer_mike]

According to Chevy High Performance 0.0020 - 0.0025 is the ideal clearance

[67_C-30]

According to GM, .002 - .006 is the tolerance. As I said, .002 will live on street engine, but it will not a performance engine. This is from someone has been building engines for 15 years and race engines for 12 of them. If I were you I would not touch the bottom end of that engine until you check the end play now and put a torque wrench on it as Billla said, and see how many ft lbs it takes to turn it over. If you can turn it by the flywheel, I bet its not even hurt. There have been 1000's (probably 100's of 1,000's) of Old timers and shade tree mechanics that have beat balancers on SBC's. It's actually more likely that is OK than not...

[killer_mike]

Ok, wilco, now my question is Billa said 40f/p or so, but whats the actual range that a new engine, never used the crank should turn?

Originally Posted by 67_C-30

According to GM, .002 - .006 is the tolerance. As I said, .002 will live on street engine, but it will not a performance engine. This is from someone has been building engines for 15 years and race engines for 12 of them. If I were you I would not touch the bottom end of that engine until you check the end play now and put a torque wrench on it as Billla said, and see how many ft lbs it takes to turn it over. If you can turn it by the flywheel, I bet its not even hurt. There have been 1000's (probably 100's of 1,000's) of Old timers and shade tree mechanics that have beat balancers on SBC's. It's actually more likely that is OK than not...

[Billla]

Coming down to brass tacks, I agree completely that folks have been pounding these things on for a long time - I still have little piece of oak 2x4 that I used to use for this along with my small sledge "Mini Marge" (daughter of Large Marge) just in case anyone thinks I'm coming off as "holier than thou"

Today, there's no reason to, and good reasons not to - mostly about the experience of the person doing the beating. First, if you miss and hit the ring it's very easy to break the bond between the hub and ring - and that's going to have catastrophic results. Second, the problems I've seen with bearing damage have come from two things - hitting the balancer off-center, and beating the living daylights out of it. And I have pulled down engines that have gone bad due to these.

Using the right tool eliminates these risks - especially for someone that doesn't do a lot of engines. Given the price of these things, why risk it? Smooth, easy and predictable.

Killer, I have to tell you (again) you're setting yourself up for trouble - your posts cause concern for anyone experienced in engine building because they show a lack of experience and knowledge. I'm not trying to be a d*ck, but at the same time it's hard for me to see someone heading for a cliff and not say something. It gets me in a fair bit of trouble here - but so be it. Take the thing to a shop or get an experienced engine builder to see if the balancer is on all the way - and then just leave the thing alone.

[hotrod 80]

Today, there's no reason to, and good reasons not to - mostly about the experience of the person doing the beating.

There have been 1000's (probably 100's of 1,000's) of Old timers and shade tree mechanics that have beat balancers on SBC's. It's actually more likely that is OK than not...

X2 on both of these .

[killer_mike]

Ok, ft/lbs 40-45; end play: clockwise rotation 0.206" & counter clockwise rotation 0.209"; i used a jimmy bar to pull it back a little on clockwise rotation and it gave me 0.209 from 0.206, on counter clockwise rotation game me 0.209 1/2 from 0.209.

The measurement was from the block to the crankshaft, and the difference is a nifty 0.003.
So spparently the engine is good

Billa, i dont have my head up my ass, i do listen to ppl that know about this more than me, so dont think ur advise is going to deaf ears. But like i said, money constraints, but i will look if theres an engine builder nice enough to come to my house and check it out, if i get lucky.

[Billla]

Originally Posted by killer_mike

end play: clockwise rotation 0.206" & counter clockwise rotation 0.209"; i used a jimmy bar to pull it back a little on clockwise rotation and it gave me 0.209 from 0.206, on counter clockwise rotation game me 0.209 1/2 from 0.209.

The measurement was from the block to the crankshaft, and the difference is a nifty 0.003.
So spparently the engine is good

I have no idea what you're talking about with clockwise and counterclockwise end play rotation or the process you used.

Originally Posted by killer_mike

i dont have my head up my ass

Never said you did, and I understand the budget issue (trust me) - you're the one that said you wanted to inspect. But if you're going about this the way you are them I'm not adding anything useful and I'll sign off.

Good luck!

[killer_mike]

I didnt mean to be a dick, when i said i dont have my head up my ass, i meant to say that i listen to advice.
I will take a pic how i meassured.

Originally Posted by Billla

I have no idea what you're talking about with clockwise and counterclockwise end play rotation or the process you used.



Never said you did, and I understand the budget issue (trust me) - you're the one that said you wanted to inspect. But if you're going about this the way you are them I'm not adding anything useful and I'll sign off.

Good luck!

[Billla]

FWIW, I talked with my Level 4 machine shop guy today about something else and asked him about this. He stated that bearing manufacturing tolerance is typically .0003. If you assume that both bearing shells were out by max allowable, this makes for a .0006 clearance...which is why we might very, VERY rarely end up swapping in 1/2 a .001 bearing shell to take up .0005 clearance. We're typically shooting for .002 - .0035 main clearance for warm street engines...so you can do the math on how far off a bearing set (or journal diameter) would need to be.