Problems with fresh 455 rebuild, machine shop

Hi all.. this is my first post here, and I was hoping you all can help me with this.

My apologies for the length of this post, but I am detail oriented and want to try to cover everything. In a nutshell, I have a fresh, professionally rebuilt 455 that is apparently trashed and needs to be rebuilt again. Now, the story..

Brief background: I am a professional mechanic with 15+ years experience, including extensive experience with the various classic GM big blocks, including the Buick OHV V8, as well as with TH400 transmissions.

I have been working on a customer's '69 Buick Wildcat, with a later model 455 transplanted it. This engine was apparently a Kenne Belle built engine many years ago, but it was knocking and needed to be rebuilt. I removed the engine from the car, the owner had a local machine shop handle the full rebuild and all machine work, and I reinstalled the engine in the car. It was bolted to the very same TH400 that was in the car before, was never removed from the car, and the torque converter never removed from the trans.

Just prior to initial startup and cam break-in, I filled it with the specified 10W-30 motor oil with a pint of the break-in lube provided by the machine shop. I primed the oil pump with a drill for 30-45 seconds, and saw about 70psi on the mechanical oil pressure gauge. Good to go. I the installed the distributor, double and triple checked everything to be sure it was ready to fire, and fired it up. After a few odd seconds to let it smooth out and come to life, I quickly checked the timing with the timing light I had already hooked up, and quickly brought it up to the specified break-in RPM of 1200-1600. Oil pressure was showing about 65psi, and all seemed well. We were on our way.

I proceeded to vary the RPM slowly within the specified range, and all seemed well, it was running nicely, sounded good, saw and heard no signs of trouble. The owner was sitting in the car watching the gauges while I was watching everything carefully underhood. After several minutes, the oil pressure had dropped to around 25-30 psi as I recall, which seemed a little low to me, but it was fully hot, so I assumed it would not drop any further.

Unfortunately, within about 15 minutes of startup, the oil pressure had dropped to zero psi. I immediately dropped the RPM and shut it off as soon as the owner pointed out the lack of pressure. Total run time from initial startup to shutdown was approximately 15 minutes. The

The engine was also leaking a considerable amount of oil from the rear main seal, as well as a smaller amount from around the timing cover/oil pump area. Both plenty to leave noticeable spots on the ground, especially the rear main.

After letting the engine cool down for a while, we restarted it again very briefly, only to still see zero oil pressure. Very disappointing.

So now, fast forward a few weeks, and the car was sent off to the shop that did the engine rebuild for them to check it out and see what went wrong. I finally got word today. Their claim is that the engine was installed wrong, and the torque converter somehow was forced into the crankshaft causing it to tear up the engine thrust bearing. Within just 15 minutes of run time, having never been taken out of park, with the engine RPM slowly varied from 1200-1600. They claim that the engine needs to be thoroughly rebuilt again, at the owner's expense.

When I installed the engine, I of course mated the transmission bellhousing to the engine first, verified that the torque converter was free to spin and was not binding against the flexplate or anything else and had a small amount of in-out play as it should, then I bolted the transmission to the engine. I then lined up the torque converter bolt holes and bolted it to the flexplate, the same way I've done it on countless GM V8s mated to TH400s. There was no sign of trouble or binding whatsoever.

So.. is it possible that I somehow missed something here, or is the machine shop telling tall tales to cover their ass? I know in my heart that I did everything right, as I've done it many, many times prior to this. I cannot possibly see how there could be any truth to their claims.

I have heard of torque converters ballooning under extreme loads, and wiping out thrust bearings over time and lots of hard abuse, but I cannot possibly see how that could be an issue running in park for 15 minutes for the camshaft break-in.

Any insight from the fine folks here? Thank you all in advance. I want to be absolutely confident in my assessment before I take the machine shop to task for this. Not only is my customer's money on the line, since they're asking him to pay for another full rebuild, but they're trying to blame this all on me, and as you can imagine, I am very upset about that. As a human being, I've made mistakes before, and I'm willing to admit when I do, but I sure don't think I made any here.

Thank you for your time.

 

If you mated the engine to the transmission,like you say,by bolting up the bellhousing,then pulling the converter slightly forward,to mount to the flexplate,you did it correctly.
If the thrust surfaces were wiped-out,as they claim,I would want to see them,or take the pan off and inspect for yourself. You might get “oh,they were trashed,so we threw them out already”,and then you won’t really know.

 

It is possible to have the converter gave too much pressure and wipe out the thrust. Should only see about 70 psi in the cooler circuit....... Not sure how to test that without a motor driving it unless a local shop has a trans dyno. This normally is not an issue unless the pump pressure is turned up, or a blockage in the cooler.

Sound almost like the shop is tring to cover themself.

It doesn't sound like they provided you with paperwork telling you what all the clearances were set at the time the build was completed, including thrust.....sounds like it's about to get into a he said she said match. But without those specs you don't know where it even started at

The only thing I would had different myself is more time priming........I'm firm believer you can't do too much.

 

Its machining and assembly imho. They(shop) are just blaming someone else for their inept work as is evident by various leaks. Go inspect engine, that oil filter or oil screen had to be really plugged to drop oil press. to 0. I trashed a thrust bearing as a result of machine work but never lost PSI. If you get to see engine, my guess is you will find more than a wiped bearing......

 

I may be asking obvious or even stupid questions here but I've probably seen every crazy thing.
What oil filter are you using, have you cut it open and drained the oil to check things out, Is there a knock primarily from the rear?
I've not seen 0 oil pressure even from a wiped thrust. See if you can move the balancer back and forth with a large screw driver, I've seen wiping a thrust with a plugged or partially plugged trans cooler line. Pull the distributor, see if the pump gear shaft is intact, also the bottom of the distributor gear.Are the cam bearings backgrooved from TA.? The pick up tube may have come loose if it wasn't properly tightened or plugged up due to junk in the pan.
You're going to be pulling the motor to fix those oil leaks anyway, I know that sucks but it will only get worse if you don't fix it now. You can check these things then.Get the clearance specs, from the shop.better yet check them yourself. Seen too many machine shops Know better what the clearances should be and set them up like a chebby.Sure eventual failure.
It sounds like you did everything right, more of a build issue.
gary

 

What's scary in this day and age is any place letting an assembled engine go out the door without being test run at complete risk to whoever might fire it up for the first time, and whatever other problems the vehicle might have.
Was there ever a conversation over the cost of that service and the costs involved?
It definitely sucks to be in the middle of the blame game.
Also sucks that there's a catch 22 to dismantling it for your own inspection because it probably cancels their warranty.
Sounds like an assembly problem.
Agree with seeing the parts and inspecting the engine.

 

I will tell you on my 464 we damaged late fall.......it had 2 main bearing about to spin, lots of brass in everything that we cleaned, and we only lost 10psi at warm idle, still 15, still had 50 at 3000 and over 70 on the pass before it showed the pressure drop at idle.........

There is more going on than they are telling you.

Had gs 400 in the shop with a low oil pressure complaint, when warm almost 0, when I changed the oil it came out thinner than water.....new oil and good pressure, owner said after the fact it had been 15 yrs since it was changed. As Gary said 0 psi is probably hard to actually do

 

One more unlikely issue. if there are no tell tale knocks,did you try a different oil pressure gauge?

PS every engine I build goes on a test stand where cam is broken in,timing is set,carb is tuned,checked for oil pressure, overheating and leaks, total run time is over 45 minutes.

 

One of the main reasons I like to dyno the engine. I want to make sure all is good before I put it in the car. Finding out the power is just a bonus. A run-stand is also great,if you don’t have a dyno. You can still run it,check all the vital signs,and get everything broke-in.

 

Something like a little ding on a crank's locating surface of about a thou might have everything mic up just fine and even be difficult to find an issue with an indicator, for example.
Curious of the proposed cost to fix the failures.
Also curious of their run-in chrge.
I wouldn't expect it to be much and I'm surprised they won't budge on taking part in that.
I guess if they are tough to resolve problems with, I wouldn't use them.

 

Wow, lots of replies, thank you!

Ok, so, to answer some questions and clarify a couple things..

This engine had a total of 18 minutes run time, having never come out of Park. I have video of the whole initial startup, break-in and then shutdown, including priming the pump prior to startup. I installed a new Wix oil filter, and used 10W-30 Castrol GTX.

As far as length of time priming, I've heard two schools of thought on that, and the consensus amongst most experienced folks that I've spoken with is to prime enough to get oil up to the rockers and that should be plenty if you plan to start it right away afterward. I've heard more than a few folks say that excessive priming washes away critical assembly lube, which offsets some of the benefit of priming.

We decided it would best for the shop who did the engine rebuild to inspect it while still in the car, running, exactly as it was when I fired it. That way they can test the oil pressure for themselves, see how it runs, take whatever measurements or notes or anything else they needed. As such, I did not have the opportunity to inspect the oil filter, inside the pan, bearings or anything else on the engine. I hoped that they would be honest about whatever the issue was, but it sure seems that trust was misplaced.

The shop apparently told the owner of the car that the engine was full of metal shavings, and they then pulled the engine from the car and tore it down. They apparently "determined" after the fact that somehow the converter was bolted up wrong, trashing the thrust bearing in the process. They made no mention of excessive line pressure or converter ballooning, they simply said the engine was assembled to the transmission wrong.

Again, the converter spun freely and had the correct amount of play between itself and the flexplate after snugging up all the bellhousing bolts. It tightened up as normal with no sign of binding or any other trouble whatsoever.

I too have seen engines with trashed thrust bearings, for various reasons, but these engines also never ran out of oil pressure. There is no way, from my understanding, that even completely losing any one bearing would drop oil pressure to zero.

In the 18 minutes that the engine ran, neither of us heard any abnormal noises from the engine. No knocking, tapping, clicking or ticking, no rattling or squeaks or screeches or anything like that. It sounded great, sounded healthy and gave no sign of trouble aside from the lack of oil pressure and two big oil leaks.

I did not try another oil pressure gauge, as again, we decided to send it off to the shop who did the rebuild for them to inspect it for themselves. In hindsight, I probably should have dug deeper into it myself, but I was concerned that the shop would deny any potential claims I made and say it was not their problem now that I had torn it down.

As far as transmission line pressure pushing the torque converter forward.. yes, I've heard of that happening, but can it happen even in Park? With less than 18 minutes of run time?

My feeling from the start has been that they were inept in their assembly, and I was not happy to see what they had reused the old crusty timing cover. I wouldn't be at all surprised to see the timing cover oil pump housing torn up bad, causing the lack of oil pressure.

Ugh. Very frustrating indeed. I'm going down there today to see what they have to say, and hopefully they will still have all of the parts to show me. I won't be surprised if they tell me they already tossed the bearings, or that the crank is already back at the grinder. The owner already signed of on paying to have it all done again, taking them at their word without talking to me first. He told me what they said after the fact.

Wish me luck, guys.. I'll be back with an update on this soon.

 

This might be one of those times where you let the owner install his own engine,and cut bait. You currently have a circle of fingers pointing at each each other. I could go on all day about some of the horror stories from one of the local shops here. Good work usually is hard to find.

 

Well, the owner told me last night that the machine shop will be reinstalling the engine after they "rebuild" it again. I think it's complete BS that the shop is trying to put the blame on someone else, thus not only effectively stealing more money from the customer, while harming my reputation and ruining what was a good relationship with my customer up until this point. The owner of the car didn't say so in as many words, but he's clearly very upset with me and believes the machine shop when they say this was my fault somehow, and I am NOT ok with that. I'm not going to stand by while a machine shop screws up a rebuild and harms my reputation as a result. I take a lot of pride in the work that I do, and I care very much about my customers getting good, honest work, so to have someone else try to make me look bad is something I take very personally.

 

I would ask for a list of all the specs they built the engine to. Then ask why the oil was pouring out from both ends. Did the converter problem cause the oil pump to leak???? I would never throw an engine together with an OLD CRUSTY oil pump from the 70's, and an engine builder should have said something. Ask him what the gears to housing clearance was and end play in the pump, get those specs in writing also. Also check trans and lines before motor goes back in car. (maybe complete disassembly is in order) Does your engine builder have a dyno or run stand. It is always worth the money!

 

Also, to address the matter of running it in on a stand.. I did not oversee or have any involvement in the engine rebuild process unfortunately. The owner of the vehicle already had the plan in place to have the engine rebuilt by this shop, and my task was simply to remove the long block from the car(I never saw it run prior to this, as some of the removal work had already been done). He picked the engine up from the machine shop three months later and I handled the complete install, turned every nut and bolt. I personally saw for myself that there was no binding whatsoever with the torque converter, everything lined up right, there was no sign of trouble.

I don't know if the owner of the car discussed with the machine shop whether or not they could or should handle the initial break-in, and I don't know if said shop even offers that as a service. Some do, some don't in my experience. I'm going to discuss all of this with the shop when I head down there in a little bit.

The owner of the car initially wanted me to just handle the harder part - getting the long block in the car and bolted up, but he was going to handle the rest of the accessories and such. However, he decided part way through that he wanted me to finish it, and of course I was happy to, having done so many times before. I know how critical the first few minutes are in the life of an engine, so I like to oversee that and make sure everything is right whenever I can.

 

I would ask for all of the specs from when it was built the first time,and the bearings,etc. Naturally,they don’t want to eat the bill,and neither do you. It is good that you document and photograph your work as you go. You can never have enough proof. Now you know you need to document even more. Pretty soon,we will all be wearing go-pros when we do our work.

 

couple observations from the peanut gallery.

regarding the oil pump - if you had 70 psi of pressure on initial start up the pump and cover are in adequate shape still.

thrust bearings only fail for a couple reasons. obviously force from the back from the trans and also being too tight.

did it turn hard when you were rolling it over to install the converter?

the bad thrust doesn't explain the total oil pressure loss. if the oil gauge went to zero while you were breaking in the cam at high rpm there would have to be a bearing spit out but you were clear there was no bad noises.

I'm wondering if the sump came off or if it it became plugged from too much RTV during assembly -which is common.

again with zero oil pressure the lifters would bleed down immediately and you would hear knocking almost immediately as well with no oil cushion between the crank and bearings. this doesn't add up.

Im wondering if the gauge failed and the builder found metal during the tear down due to a poor final clean? a coincident maybe?

 

First, welcome KenneBelle455! Sorry its under these conditions. Hope you and your customer continue your relationship. Maybe after the machine shop proves they can't build an engine he will come back to you. BTW, where are you located? Obviously you care a lot about your work. Its great to hear from folks like you!

 

It's a tough position to be in, to have the car's owner and the machine shop negotiate everything around you, leaving you completely exposed and ready to be the scapegoat.
Even if they claim responsibility and also take on the install to ensure nothing happens as a matter of principle, there's no reason to go around you completely with them both making decisions...and you not having a chance to inspect or contribute to the diagnosis or solutions.
I'd love to say "don't put yourself in that position", but it's almost required as a part of your business.
I don't know what else to say my friend...