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'95 Engine build

These are the nazty ones, proving what I suspected in living color. Two piece crank, three webs cracked. 141 block is now boat anchor status.
Been there, done that! If you wouldn't mind telling us: How many miles on the engine? What performance upgrades did it have? How much boost pressure did it see? 21:1 compression ratio? Stock lower end, no girdle or heavy duty splayed main bearing caps? Was it used for heavy towing, especially into the mountains?

It is just good information to help understand, or verify why this happens.

Thank you!
 
That can happen with just a 100% Factory Stock motor, under light duty, just putting around town, having its P.O.S. factory harmonic balancer's rubber layer fail and snap the crank and break the main webs - part of the reason why we preach on here to check the H.B. regularly and replace it every 80-100K miles with either ONLY a genuine GM part or bite the wallet and go with a Fluiddamper H.B. for permanent replacement. Same with the crankshaft main pulley and its replacement - GM only.
 
Been there, done that! If you wouldn't mind telling us: How many miles on the engine? What performance upgrades did it have? How much boost pressure did it see? 21:1 compression ratio? Stock lower end, no girdle or heavy duty splayed main bearing caps? Was it used for heavy towing, especially into the mountains?

It is just good information to help understand, or verify why this happens.

Thank you!
My signature line shows what additions were made. Stock engine with about 177k on the odometer. Sustained 14-15 psi boost for minutes on some hills in southern Ohio during some trips loaded A/C on. Loaded with stuff going from Ohio to Mobile, Alabama after Katrina once - normal towing. Only heavy a few times (probably half a dozen tims) on flat roads and short trips (under 15 miles one way) grossing just over 30,000 lbs.

Harmonic balancer looked good, but I never changed it. Rubber on crank sheave looked good.

I'm pretty sure it's already been nailed down - probably too much sustained boost intermittently over 20 years of use. See post 135 for pressures that likely didn't help the situation. I always thought the worst that could happen would be a blown head gasket. Had I known I was risking breaking the bottom end apart, I would have backed it way off.
 
Exactly- puddy knife. Just drive the puddy knife around with a hammer. Do not pry the cover at all, once you get it cut all the way around, it will lift off like it was never attached.

I use a 2” or 3” wire wheel in a cordless drill to clean the valve cover after its off.
Maybe on a head and engine that is coming apart. Don't let debris get all over your valve springs and down oil drains!
 
Maybe on a head and engine that is coming apart. Don't let debris get all over your valve springs and down oil drains!
The puddy knife cuts through gaskets and or silicone. Because it is done in one swipe instead of back and forth scraping action, almost no debris comes free. It will stick to the metal.
I have done literally thousands like this - never had a debris field in the head.
 
Thankfully I had a sacrificial valve cover to practice with. I didn't realize there was a rolled lip that turned down. I rolled up a nice spiral razor blade because of it. I marked the necessary depth with masking tape also before the second, which went better, but still got a little damage when I went too far and created a toothpick from the rolled edge. Third and fourth went just fine. Thankfully - those were the two I most wanted to keep intact.
 
That can happen with just a 100% Factory Stock motor, under light duty, just putting around town, having its P.O.S. factory harmonic balancer's rubber layer fail and snap the crank and break the main webs - part of the reason why we preach on here to check the H.B. regularly and replace it every 80-100K miles with either ONLY a genuine GM part or bite the wallet and go with a Fluiddamper H.B. for permanent replacement. Same with the crankshaft main pulley and its replacement - GM only.
Sadly there are no more GM harmonic balancers I did some research into locating one. our only hope now is the fluidamper unless going with aftermarket changeouts every 30k miles. although I did find that Dorman makes two styles. one that is similar to factory and a heavy duty version. not sure what all that is about. I can try finding the part numbers and docs on them if anyone is interested.
 
Sadly there are no more GM harmonic balancers I did some research into locating one. our only hope now is the fluidamper unless going with aftermarket changeouts every 30k miles. although I did find that Dorman makes two styles. one that is similar to factory and a heavy duty version. not sure what all that is about. I can try finding the part numbers and docs on them if anyone is interested.
Nopers. AC Delco is still making them for GEP, the division of AM General in charge of the power plants for hmmwvs which are under contract to be made until 2035. So anyone can order parts directly from AM General- but it is a pain. It is easier to buy from one of their authorized dealers- or someone that you know who is working with one of the authorized dealers. (Well, until AM General releases info on the new improved one we want).

Leroy Diesel is one of the Authorized Dealers, and so is Unique who Chris of Twisted Steel Performance is in cahootz together on stuff. So little ol us have no farther than asking one of two of our forum sponsors!

Now, I will say for anyone who has not balanced their lower rotating assembly that adding the fluid dampr makes an instantly noticeable improvement. Inhave never built an engine that was balanced assembled with a stock, then swapped for a fluid dampr to see how much you can feel the difference- but remember it smooths out the harmonics across multiple rpm ranges better than the fixed weight- so it will still help more than stock one.
I already have my lower end balanced sitting on The parts shelf, as well as the fluid dampr. So if you can at all afford the added cost- it is worth it. Overheating is the biggest killer in my experience. That weak bottom end is the second. So in my book anything done in those two areas should be on the list, As much as I never want to see someone use a doorman because they only last 30,000 miles- if a guy builds a new engine and can’t afford it at the time of build- but knows 100% he will be able to in a year- put money inside the engine in balancing while it is apart. Then “rent” the doorman for a year and buy the fluid dampr afterwards.
 
@Will L. I only see the fluidamper on leroys site. I looked on Unique Diesel and see one listed but it doesn't show anything about being AM general or Delco. I had no idea Unique was in Lubbock, TX. that's not far from me!!!
 
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