Paid for timing chain replacement- lower oil pressures after repairs- need opinions

[Evans Ward]

Just had the TR down for a needed timing chain replacement. I secured the parts ahead of time from reputable Buick TR vendors and took the parts and car to a local shop. Went with the Cloyes timing set, HD needle bearing design cam button/ spring, new S oil bypass hose, new tensioner/bolt, etc. Car had 119,000 miles on original nylon set so I knew it was time. Oil pressures prior to repairs were 38-40 PSI hot around 65 mph, 15-20 PSI hot idling. Pressures were much higher of course when starting up. The shop apparently took off the front timing cover to vat and clean it. They had set up my GS455 before so I knew they knew about the tight tolerances of end play at oil pump for the Buicks(.002-.003) as well as knowing to prime it before start up. Well, got the car back yesterday and the oil pressures are running 10-12 PSI LOWER than when I took it in! Reading about 10 PSI hot idling and 28-30 hot around 65 in OD. Having read that Buick engines need about 11 PSI per 1000 RPM, it looks like it is meeting that figure barely, but I have concerns why the oil pressures are lower after this repair. I went to the shop this morning to discuss and the young guy that did the work became quite defensive saying that nothing was changed from before. I asked him if he primed the oil pump and set the end play at cover/ pump to specs and he said "yes". The shop owner wasn't there so I couldn't discuss with him. I told them that I really wanted to know if there was any problems driving the car and risking any internal damage to the engine. Of course, he said "no problems". Am I out of line to have some concerns here? I wonder if the oil pump clearances are not within spec? If I had known that they were going to dissasemble the cover/ pump, I would have given them my TA oil pump gasket shim set so that it could have been correct. I have no idea what gasket or thickness they used here??? Just wanted to run this by the board to see how some of you would react and to see what I should do next. If I don't need to be alarmed, please let me know and I'll try and get a grip. BTW, I haven't paid yet even though I have the repair bill for $422.00 AND.... before some of you start to flame away on me, I didn't feel like fooling with this repair job on my own and had decided to farm it out so not to be bothered. Thanks for any and all opinions!

 

[gn-t-type]

what type of oil and weight of oil did they use

rob

 

[Nick Micale]

Originally posted by Evans Ward
......................... Oil pressures prior to repairs were 38-40 PSI hot around 65 mph, 15-20 PSI hot idling. Pressures were much higher of course when starting up. The shop apparently took off the front timing cover to vat and clean it. They had set up my GS455 before so I knew they knew about the tight tolerances of end play at oil pump for the Buicks(.002-.003) as well as knowing to prime it before start up. Well, got the car back yesterday and the oil pressures are running 10-12 PSI LOWER than when I took it in! Reading about 10 PSI hot idling and 28-30 hot around 65 in OD.............................................

Maybe a different guy did the V-6 and did not know how to set clearances?

They should not be paid until they finish the job by making it right. Nothing else they would have done during this job would affect the oil pressure.

You "assumed" they knew how to set the pump. I will not dis-assemble a stock, never opened factory pump when doing a timing chain.

It is hard to improve upon the factory assembly unless they do the upgrades to the cover and pump for more volume/flow at your original pressures.

 

[WarpSpeed]

I'd have to say that a stock , unopened motor, making 15-20psi hot oil pressure is pretty high. Sounds like you're running 20w50 oil.. "They" may have refilled with 10w30, which would explain the situation... 900-1400 hot idle, untouched pump, is about right...

 

[Evans Ward]

Oil used was what I supplied to them. 10W-30 Valvoline Durablend which I have used for years so that's also a constant there too. I will discuss with the owner when he returns from medical leave. Thanks- it validates that I need them to get this right before payment.

 

[MistaScott]

So did they open the pump? If they did, they had no need to. If they didn't, there is no way the pressure would have changed as a result of their work. As long as they primed it, it should be fine.

Timing chain is a PITA, but if it isn't your driver, I would do it yourself and take your sweet time -- it will give you an education on how the car works.

 

[Evans Ward]

Yes they opened the pump to vat and clean everything inside cover. I still think gasket thickness may be wrong and could be the culprit here. They did prime it.

Question: can the clearance on the oil pump be checked without removing entire front timing cover? I tried to look and see but the IC bracket is blocking the view of the bottom of pump. Just wondering if this can be an easy fix without taking everything off again. On the 455 Buicks, this can be done and I think the oil pumps are identical with the BBB 455 and V6 Buick 231.

Guys.... keep some insight and thoughts coming. I'm going to print out the posts to take to the shop mgr Monday morning. Thanks!

 

[fast eddie]

yes you can get to the pump without takeing the front cover off,I think they used a thicker pump gasket
Ed

 

[Nick Micale]

Originally posted by Evans Ward
.......Question: can the clearance on the oil pump be checked without removing entire front timing cover? I tried to look and see but the IC bracket is blocking the view of the bottom of pump. Just wondering if this can be an easy fix without taking everything off again. ...................Thanks!

To set the pump gears to the proper clearance, a dial indicator should be used. This is the way it should have been done initially.

We always set it when the timing cover is on the bench. On the car, it is just a guess, as end play needs to be checked with an indicator when assembled.

 

[GN Greg]

Taking the pump apart and putting it back together should not lower your oil pressure IF it was reassembled with the GM gasket.
A thicker gasket will increase clearance and reduce oil pressure.

Check around the pump at the gasket and see if any sealant has been squeezed out. Sealant will also increase clearance.