I think my new roller lifters are bleeding down, maybe not ever pumping up completely. This is one noisey top end, rattles all the time. On cold start it's like a wore out, low oil pressure motor. Just overhauled, I have run the valves several times, no improvement. There was one of several times when I pulled the valve cover, I was able to depress the lifter end of several rockers (+/- .250), very easily. I cannot ever remember being able to do that. Rough idle on startup until everthing is pumped up. I think this is my hard start and somewhat rough idle problem. This is an 88 Vette 5.7 TPI. Stock roller lifters, Stamped steel rockers, mild cam, Z-28 springs. I dont want to go in there again. Any ideas? - Tell me where I am wrong... Thanks for the input...

 

Are you able to try adjusting the valves with the car running?

 

Had the problem on a 90. Ended up changing the lifters. Customers car, had to cure the problem. Guys at GM said they had seen it before also. Before I did that, I made sure I had good oil pressure with a mechanical gage. Good luck.. :chevy

 

I am not saying this is your problem, but the first thing you have to do is rule out an oil pressure problem. Install a known, good, mechanical oil pressure guage at the rear of the intake mainfold, where the stock sender goes. Once you have established the pressure is good, we can go from there. Good luck, and...

RACE ON!!!

 

"Scorp" - Yes I have done that, but they ended up right back where I set them static. But, I will tell you when you back them off running, and gain clearance past zero lash, it is not near as clear a distinction, differentiation, clatter, as I am used to from many past years of doing this.

 

You guys are right about the oil pressure. I have not tried a mech. gauge. I run about 60 pbs. hot down the road, and about 40 pbs. hot @ idle by the display, new pump, but you are still right, I have to find the problem. That does not explain the easy depression of the lifter though...

 

Is the stock distributor in the car? Isn't there a grove on the dist. that pushes the oil up to the lifters/pushrods.

 

"Scorp" - I believe it is the stock distibutor, because I have replaced the pickup and module, but I do not know the oil galley path off-hand. But the oil pump bolts to to the rear main cap, and is driven by the dist. How would it go thru the distributor, or shaft, etc...?

 

:iagree: To much gap between the dist and the block will not give you the volume to pump up the lifters. Just a thought. :chevy

 

Too much gap between the Dist. and the Block will allow internal oil leakage and not enough volume to the lifters??? I did not know that... I'm going to check that out. What about being able to depress the lifter???

 

You guys are awsome. That will give me plenty to check out tommorrow. I will let you know what I find... :thumbs:

 

I still think you will end up changing the lifters but if the volume is not there you could have aireation and those bubbles are getting trapped in the lifters. The air bubbles will allow you to push the rocker arm down. Just a thought. Good luck. :chevy

 

Hey guys, 99.9% sure I found the problem. I read on this forum, several weeks ago, that you should only have one of two pushrod guide systems. So, back then I had pulled drivers valve cover to see. Well I did have both, guide plates and self locating rockers. I felt of several and didn't really see a problem with it. I was talking with my machinist today and he said, "no,no,no, one or the other, but not both". So, bought a new set of lifters this morning from him, came home and started scattering stuff. Damn, I forgot how far in there that passenger valve cover is. Pulled all the plugs, rolled to TDC #1, and zinged all the lifters off. On one of the guide plates, the pushrod had wore into it 0.030 on the side. About half off all of them had some wear to some extent. You could look at the rocker and see where the valve stem had come in contact with tapered locater on one side of all the rockers, and then looks like , it jumped over to the surface it should be riding on. And the lifters that I had isolated being the most noisey had the most wear at the pushrod guie plate. Next time, I will listen a little closer to the posts, we never stop learning. I won't get my new guide plates till tommorrow. Pushrods and valve stem ends look ok. Thanks for all the help, will let you know tommorrow, I hope... :thumbs:

 

So you had guideplates AND self alignign rockers?

 

That is correct "MrNuke"....