JAKE

I'm asking some of these basic questions for the simple reason that in the many years I've been on this Forum I've read countless posts from guys who were having a problem only to find that they'd over-looked something very simple. Some of the threads ran for several pages.

A few had eventually given up and had their cars towed to the dealer for repair after supposedly having checked and re-checked the very thing causing the problem and never noticing the cause was right there in front of them. Only after getting the car back and learning the cause did they post of the cause and that it was something that someone had posted early on.

How about this: Check to see that the rocker arm is correctly installed on the stud. The trunion can go on two ways, but only one way is correct.

If you suspect you've wiped a cam lobe (which doesn't happen often with a roller cam), you can put a dial indicator on the retainer and manually turn the engine to cycle that cylinder through one complete opening/closing while making note of the dial indicator reading. If the lift on that valve isn't the same as another one, you can bet it's a lobe problem. Be sure to compare apples to apples on this : (exhaust to exhaust and intake to intake) if the intakes and exhausts have different valve lifts.

Jake

Tuff96LT1

OK, I will have to go on my gut instinct on this one.

After taking things apart and not seeing any visible damage or problems, I am going to replace the 2 lifters in #8 as one is the only one pumping oil like crazy all the time versus the remaining lifters. Can't buy the back lifters get more oil story because Cylinder #5 had one doing it when I first started the project though not nearly like Cyl # 8, but when this latest problem started and I removed the valve covers to check things out ALL the lifters on the drivers side had the normal oil dribble at idle and no noise. So seems whatever the excess oil problem is solved itself on the drivers side.

Lifters will be here today, gaskets tomorrow.

Should have back together by Thursday or Friday and will let all know then how it turns out.

MK 82

There is no debate. The question is lash not base circles. That is the same regardless of the type of lifter. You threw the flag not me.

JAKE

If you opt to go that route you must be absolutely sure that your pushrod length is correct since you'd be giving up all adjustability.

As far as which way the lifter should be installed in the lifter bore, I actually don't know if it makes any difference. I've often wondered about that, too.

I've never seen anything in writing one way or the other, so I've always believed that it doesn't matter. There are two basic types of oil metering systems; edge orifice, one is where the oil is metered based on the clearance between the lifter OD and the lifter bore. The correct name of the other type escapes me but it's the type where oil is metered through a hole in the lifter.

Is it possible the rocker arm trunion was installed upside down? The flat side must face UP.

Jake

lt4obsesses

I'm not sure about the GMPP kit, but I think the rockers are different. The studs for the stock LT4, which torque to 18ft lbs have the 7/16 base, but the top are 10 or 11 mm, I'm not sure which off the top of my head. So I think the rockers would be different.

I think you should be okay with the push rods as I changed those with the lifters and the part # was the same for LT1/LT4.

I don't know what the situation with the oil is. I haven't run mine with the covers off. Just thinking out loud here, but I would be more concerned about looking for valves that might not be getting enough. If there is a blockage somewhere it could cause that oil to go somewhere else? Maybe when you get it all back together it'll be fine. I'll be praying for you. Did the Hotcam make a big difference?

johnnymo63

Look at the spring locks to make sure there are 2 on each valve. Make sure they are still seated properly.

Check in the lifter bores with a light. Do the cam lobes look ok?

Besides lifters, I can't think of anything else. Good luck.

Tuff96LT1

OK folks here is the outcome.

1st, thanks to everyone for your input. It was most valuable.

Yep, It was the lifter.

I installed 2 new GMPP roller lifters in cylinder #8.
I certainly love not draining the coolant to replace these on the LT1.

Put it all back together. And TADA,

No more pumping oil from here to eternity on any of the rockers.
Just a nice steady flow at idle.
And most important the loud clattering at 2k plus is now gone.

Of course now I am now gun shy with all the noise that the roller rockers do make
thinking that any noise must be unacceptable, but I am sure I will get used to it.
At least the one loud clattering is gone, (FOR NOW, fingers crossed X)

Lesson learned, If I have to do this again (gut feel) I will NEVER use GMPP lifters again.
Probably not GMPP Roller Rockers either. Hotcam is great.

As for performance, I have now installed the GMPP Hotcam kit, bypassed Throttle coolant,
moved IAC sensor, have an SLP tri K&N air breather and SLP exhaust as well as a
PCM4LESS PCM tune. Car sounds great and runs very strong. Easy to get used to and hard to
remember stock power until I compared side by side with a friends stock C4 and the differance
is UNBELIEVABLE !

By the way, those who say a OBD2 car can run stock tune with Hotcam install are nuts, yea it will run
but like crap and throw all kinds of codes. PCM4LESS tune is a must and solves 100% of the running
problems caused by PCM.

Next up, 3.54 or 3.73 rear gears.

Nathan Plemons

Rumor has it that the GM rockers are made for them by crane, or at least that used to be the rumor 8 years ago.

As far as lifters I went with the comp cam pro mag R series lifters. I know several people who used these lifters and have never had a problem, but a LOT of people online say they're junk. To each their own I suppose.

FWIW if your rockers are still making noise, you might have them a little loose. If you adjust them right there shouldn't be any "ticking" sound, more a smooth whir. Think sewing machine.

cv67

Think they still make them for GM today if Im not mistaken.