Knock / Rattle after valve spring replacement uggh

[Pronto]

I almost wonder if you have low oil pressure at idle and the weak stock springs didn't have enough ass to collapse the lifter. With greater spring pressure there's a chance you have just a smidge more play and it's audible.


Does the oil idiot light work at KOEO?

Put an oil pressure guage on it. Earl's right, your hot idle pressure is probably real low and the heavier springs might be collapsing the lifters. It is too much of a coinsidence that you change the valve springs and suddenly you hear a noise at hot idle. If the flex plate was cracked it would have made noise before the spring change.

 

[Gbody5]

Further diagnosis has led us to the Cam Thrust Button. Suspecting it was already worn to some degree and the new valve springs have added load to the Cam and causing it to walk and thus bang against the front cover/block.
There is a GM Service Bulletin ( 87-6-21) addressing this with a GM Part # 25532588. It states that it's a needle bearing assembly with spring. Of course it is discontinued. I have found a few replacements from Melling and Pioneer but they indicate a solid design. Can anyone tell me if there is another aftermarket design out there with the needle bearing or which of the current offerings is best?

BTW we unbolted the TC so we know it's not the Trans/TC.

Thanks!!

 

[Ttype6]

Can anyone tell me if there is another aftermarket design out there with the needle bearing?

https://www.summitracing.com/parts/cca-269

 

[Gbody5]

https://www.summitracing.com/parts/cca-269

Is that for roller cam only or stock cam too?

 

[ek02]

That shim type cam button is mostly used on rollers and has to have the end play adjusted. This one replaces the original: https://www.summitracing.com/parts/slp-mr-1874/overview/make/buick

 

[Ttype6]

Is that for roller cam only or stock cam too?

Both.

 

[earlbrown]

Go the the pars house and get a cam button for a '95 Park Ave with the 3800.

 

[Gbody5]

Replaced, or should I say installed the GM needle bearing cam button, there was none, yikes! Crazy, this front cover had never been off, original cam sprocket with teflon teeth and original water pump, S hose etc. Of course new Timing set and water pump went in. Talk about relieved!

 

[earlbrown]

It's probably laying in the oil pan then.

 

[TURBOELKY]

Damn. That's scary. Was that the sound of lifters hitting lobes then??

 

[Gbody5]

Oil pan? Really? Nothing like a kick in the gut when you think all is well in Turbo land.

 

[Gbody5]

Damn. That's scary. Was that the sound of lifters hitting lobes then??

She's very quiet now, I'm sure the water pump was making a little noise to boot.

 

[Gbody5]

It was very clean inside, cam gear not missing any teeth, tensioner had slight wear but no deep grooves and not all all torn up. Car only has ~54K miles and has always been very well maintained and not drag raced.

 

[Ttype6]

Oil pan? Really? Nothing like a kick in the gut when you think all is well in Turbo land.

All is well. That cam button won't hurt anything being in the oil pan.

 

[TURBOELKY]

Glad you got it fixed up! Enjoy.