Knock under load ??

[DougP]

Just wondering if you can check the flywheel bolts (actually get a wrench on them ) while everything is bolted up. I was able to check the flywheel to converter bolts but cant get to the flywheel bolts. I have a 9/11 converter and cant remember what it looked like down there. Could this converter ballooned and thats what causing knock.

 

[Chuck Leeper]

Not w/ the verter bolted up...
Could be, the knok is elsewhere. IE: down pipe, bad motor mounts, bad gas, excessive boost, the list goes on and on.
What does your scan tool say??

 

[DougP]

No engine light on, scanmaster shows everything is good. I've had a few bad yeas with the car. First started with oil seal on turbo the MAF screen took out the turbo put new turbo on bigger of course. Then the following year went to the track and the fuel line that goes from the pick up to the pump split half way down the track. Boom there goes the head gasket blew into the intake no antifreez into the oil. Fixed that, had heads checked out everything is good. The following year the tranny is slipping out it comes refreshing everything add big external cooler with the fan on it. At this point I'm done with the car, I put it a way for a year. I pulled the car out the other day and now it sounds like a rod knocking. There does not appear to be any exhaust leaks I will have to check the motor mounts and pipes. The oil pressure is lower than normal but that oil has been in there for a good year and a half. It had 10 psi hot at idle and now is down to about 5psi. The engine is a complete roller setup with girdle and forged pistons, Steel GN1 heads. I've had this car since 93 and just cant let it go. Other nice cars have come and gone but I just love my Buick.

 

[Phoneguy]

Unbolt the converter, check flywheel bolts, fire it up before bolting converter back in if the flywheel bolts were tight. If the converter is the problem the noise will stop. Good luck

Bryan

 

[DougP]

I will try that. I also read the sticky post on the noisy comp cam roller lifters. Well I have these in my motor as well. A while back I remember one of my T&D roller rockers coming loose. I wonder if these things have finally took a dump. If they were bad would that cause lower oil pressure ? I remember one day at the track feeling like the valves were floating on the top end and it was only an 1/8 mile track??

 

[DougP]

I re-adjusted the valves because I have a feeling its in there. Well they were fine and noise is still there. One thing I did notice was that the oil pressure drops about 10psi when Im on it and then goes back up when I let off it. What would cause that???

 

[BlackBandit]

Did it sit without starting for an entire year and if so did you at least prime the engine before you started it? Also, was the noise there as soon as it started?

 

[DougP]

The car was started several times over the course of a year. I was thinking that maybe when the turbo was wiped out some of the metal wen't down the return and was pumped through the motor. I also notice the oil pressure gauge flutters under acceleration. I was going to pull the motor on Monday and take a ride to Webber Racing with it. Is there anyone else a little closer in the Buffalo NY area Webber is a 2 1/2 hr ride?

 

[chevellejoe]

Maybe I missed it but did you change the oil yet? That is one of the easiest things to do before I would try anything else. Drain the oil and cut open your filter. That should give you a good idea how the motor is. The drop in oil pressure when on the gas sounds almost like you are low on oil, oil pickup issue or there is cavitation. Also how old is the gas? If it is over a year, it’s possible that its varnished it not sealed. I looked at a GN that sat for a few years, the gas was never changed but he started it once in awhile. Anyway the gas went bad and the car began to ping and knock all the time while I was looking at it. Hope this helps, good luck.

 

[DougP]

Gas is fresh and so is the oil. I did not cut the filter open tho. I do have cavitation and the oil is just above the full line.

 

[chevellejoe]

Did you inspect the oil pump? I have run into an issue with the oil pressure regulator piston not sliding freely in the pump cover causing my pressure to be low all the time. It was stuck a little open, bleeding off oil pressure.