Broken pistons, only half the motor

#2, #4, #6, and #8 pistons (driver's side) are broken on a fairly freshly built Cadillac 500. Like 700 miles and 8 hours.

Other side of the motor looks like brand new. Like only 3% leakdown with cold cylinders.

It pretty much always had blowby (enough where the PCV valve couldn't keep up since day 1) but I was told it was because the rings hadn't seated but seemed strange to me. 10-15% leakdown depending on cylinder (#4 and #6 the worst). First motor I paid someone else to assemble and I regret it now. Anyway, I kept running it. Blowby never got better. It was also better when the engine was cold than warm.

Crazy part is that it still ran fine right up to when it started pushing all the oil out the front of the motor due to so much blowby. Limped it 200 miles home pissing out a quart of engine oil every 15 miles didn't help the bearings any but it still held 40psi at idle but basically only stopped when the lifters didn't keep the valves open. Leakdown when I got it home was 80%.

I did have spark knock for a brief period (Davis Unified Ignition/DUI sent me a garbage distributor with 40 degrees of advance that went to 16 degrees of advance at idle and 40 by 3100rpm). Never seen all the pistons on only *one* side of the motor go from detonation. There is no pitting in the crows or any cracks. Most of them aren't even broken between the two compression rings. It is always on the front of the piston below the oil control rings.

Dual plane intake so if it was running lean on one side (TBI motor) it should have taken out two pistons on each side of the motor.

Ideas?

http://wrath.com/images/Cadillac500_Driver_S.jpg

Ring gap

All of the non-broken rings I've checked have been spot on. Same for the bores.

If any of the pistons weren't all on the same side or all of the pistons on one side weren't broken I wouldn't have questioned it.

I don't have the tools to measure the deck height for precision or accuracy. The pushrods are the same length but that doesn't mean much. I did measure the heads and they're within half a CC across all chambers between each head (they're the common 76cc heads). I was wondering if that side had a higher compression ratio from milling but I calculated that in order for it to make a difference on a motor that size it'd have to be a lot of missing material.

So I got the block back from the machine shop/engine builder yesterday and was going down the road of buying new pistons and rings (already ordered rods/mains/cam and gaskets a couple weeks ago). I was like "well, I don't want to buy the same ones".

So I'm looking at my options knowing I want to stay south of 9.25:1 so I can run pump gas... Which is what I was aiming for the first time and either had the option of 10:1 or 8.5:1 according to the engine builder. I went with the 8.5:1.

Not a lot of options in .040" overbore that don't require a call to Diamond or Probe. Kind of realized a 4.340" piston is a big one...

Well...

I looked at the old pistons from the last two motors for a starting point. The ones from the first engine failure (owner dropped a bolt down the throttle body) were the peculiar +30cc peanut shaped dish pistons. The ones that came out of the engine this time were Federal Mogul/Sealed Power 609p according to the machine shop's build sheet. Which have a tiny dish. When I bore scoped it it didn't really occur to me because I figured they were just sitting down in the bore a little bit more than normal...

So I got a little curious and measured the pistons, CCd them with a crappy medicine dropper I usually use for my chickens. I got +8cc or so on the dish. So then I get out my caliper to measure the compression height. The holy shit moment started.

While looking at the second failed set of pistons (the ones shown above) I notice they have Keith Black wrist pins in them. So I look at the pistons more carefully. The top have 609P engraved in them but on the inside of the piston skirt is 1817 cast in. They're actually UEM/Keith Black/Silv-o-Lite 1817 pistons. +9.5cc advertised effective dish. So Federal Mogul just reboxed them.

Do some math.

Old motor was about 9.8:1. New motor is at least 11.5:1.

Look at the build sheet some more. Driver's head had .015" milled off with a fine cut.

The previous machine shop had milled off .015" also due to the previous engine failure (but did a rough cut) on the same head. Passenger head hasn't been milled as far as I can tell. I never CCd them but I guess I should now.


Anyway, mystery solved. Engine builder put the wrong pistons in it. It was probably on the ragged edge of detonation all the time. Explains a lot of things like why the first starter on the engine lasted 40 years but when swapped it quickly ate the bendix.

What do you guys think my chance of the engine builder making it right is? The whole reason I paid someone else to build the motor was so it would save me time and I'm 200+ hours into assuming I did something wrong. I know I'm not getting my time back but I think they should pay for their work and the parts to make it right. Or am I way off base?

Was there only one machine shop contracted to do the engine initially? The machining work should have been baselined to establish an overall tolerance for knowing what is needed for parts specifications in building the long block. The specifications ideally call out the type of parts needed & the sizes-tolerances in order to achieve the mutually agreed [on paper] end results.

Quote:

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Originally Posted by wrath

So I got the block back from the machine shop/engine builder yesterday and was going down the road of buying new pistons and rings (already ordered rods/mains/cam and gaskets a couple weeks ago). I was like "well, I don't want to buy the same ones".

So I'm looking at my options knowing I want to stay south of 9.25:1 so I can run pump gas... Which is what I was aiming for the first time and either had the option of 10:1 or 8.5:1 according to the engine builder. I went with the 8.5:1.

Not a lot of options in .040" overbore that don't require a call to Diamond or Probe. Kind of realized a 4.340" piston is a big one...

Well...

I looked at the old pistons from the last two motors for a starting point. The ones from the first engine failure (owner dropped a bolt down the throttle body) were the peculiar +30cc peanut shaped dish pistons. The ones that came out of the engine this time were Federal Mogul/Sealed Power 609p according to the machine shop's build sheet. Which have a tiny dish. When I bore scoped it it didn't really occur to me because I figured they were just sitting down in the bore a little bit more than normal...

So I got a little curious and measured the pistons, CCd them with a crappy medicine dropper I usually use for my chickens. I got +8cc or so on the dish. So then I get out my caliper to measure the compression height. The holy shit moment started.

While looking at the second failed set of pistons (the ones shown above) I notice they have Keith Black wrist pins in them. So I look at the pistons more carefully. The top have 609P engraved in them but on the inside of the piston skirt is 1817 cast in. They're actually UEM/Keith Black/Silv-o-Lite 1817 pistons. +9.5cc advertised effective dish. So Federal Mogul just reboxed them.

Do some math.

Old motor was about 9.8:1. New motor is at least 11.5:1.

Look at the build sheet some more. Driver's head had .015" milled off with a fine cut.

The previous machine shop had milled off .015" also due to the previous engine failure (but did a rough cut) on the same head. Passenger head hasn't been milled as far as I can tell. I never CCd them but I guess I should now.


Anyway, mystery solved. Engine builder put the wrong pistons in it. It was probably on the ragged edge of detonation all the time. Explains a lot of things like why the first starter on the engine lasted 40 years but when swapped it quickly ate the bendix.

What do you guys think my chance of the engine builder making it right is? The whole reason I paid someone else to build the motor was so it would save me time and I'm 200+ hours into assuming I did something wrong. I know I'm not getting my time back but I think they should pay for their work and the parts to make it right. Or am I way off base?

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Holy shit... Yeah he needs to help making it right...

Heads were originally done by another builder. They didn't do a great job but they ran on the old engine just fine. The heads are fairly rare ones (76cc, no smog provisions) and have a lot of money into them. Howard full roller valvetrain with a custom grind cam.

New machine shop went through the heads including milling one head .015" and grinding three valves.

New machine shop was shipped a complete engine from a salvage operation. They disassembled it. They ordered all the parts that I didn't provide (oil pan, distributor, camshaft, heads, intake, valve covers came from the original motor). There were no cheapness on this, I even paid them to buy and install ARP head studs and ARP main studs. Engine was handed over to me with everything on it except the throttle body, dipstick, and waterpump (engine won't fit in motorhome with the dipstick and waterpump on).

I'm ignoring some problems like having to beg to get most of the old parts back (like the unused heads) and never getting some back (like all the accessories or brackets or or or). Or a couple other things.


I talked to them today. They said they'd look into it. I told them what I think happened (blindly ordered pistons based on compression ratio and never looked at the heads they worked on).

I'm expecting them to cover the cost of the destroyed parts (cam/rod/main bearings, gaskets, pistons, rings) and this last bout of machining. Basically so I can get the motor I paid for.

I'm kind of pissed because this is one of the few times that I paid someone else to do something for me and like pretty much all the times I've paid someone else to do something for me it's screwed me over.

So anyway, I ended up getting $380 back from them. Which is what the second set of machining cost me. So basically they paid nothing but labor for the machining the second time (which was inflated 10-20% over what I had done a year ago). Reichert Engines in Owosso, Michigan did the work. I won't ever take anything there ever again. Andy Reichert does nice work but I think he has a bunch of idiots working for him. Since he chose not to stand behind his work I have no use for them and will not recommend them for anything. He has cost me hundreds of hours of wasted time because I assumed they did a good job.

I ended up buying a new set of dished pistons. New rings, bearings, new gaskets, etc. Just about $1100 into it now in hard parts if I work for free. I ground out the divider between the valves to get all the combustion chambers to 71-22cc. I had CCd the heads back in November and found out that the side that blew up was at least 3cc smaller, which by math is .015", than the side that didn't. So one side was around 72cc and one side was closer to 69cc (smallest being 67.5cc). Keep in mind when I sent the heads to Reicherts for assembly they'd already been gone through by another shop and both the other shop and I had CCd the heads already and found them at 71-72cc. I still have no idea why Andy Reichert chose to mill just one head and take .015" off. Since he argued with me about it I'm guessing he has no idea why he only milled one head also.

So not only has Reichert Engines cost me hundreds of hours of wasted time now I'm hundreds of dollars of wasted money in.

I'm going to ignore the lost parts. Or the dented to shit intake pan (there is a piece of stamped tin that goes on the bottom of the intake that was dented to shit and full of oil inside because the dent caused a tear--this means the engine had a damaged tin put in it because it's not like it's going to fill with oil after I pull it out...). Or maybe I shouldn't ignore all the problems. I'm not sure. I sure as shit would never pay Reichert Engines to assemble a motor.

Ready to go back in the motorhome. Added more ARP to it while I was at it. I think at this point the only thing that isn't ARP are the flexplate bolts and the accessories. So much nicer to use new fasteners.

Kind of wish I'd done a MPFI setup instead of the FITech TBI but it is dirt simple. I've set it up so it has a spare part of everything that is simple to change on the road.

http://wrath.org/temp/Cadillac500.jpg