When I went to adjust my valve lifters last weekend I discovered that they were adjusted as if they were hydraulic (no gap). Now I'm confused, all the information I have on my engine says it should be a '70 Z-28 LT-1 engine with solid lifters. Here are the numbers off of my engine and their meaning (as best as I’ve been able to determine):

Engine Assembly Date/Suffix Code: V0528CTB - 28 May 1970 Camaro Z28-LT1 350/360HP 4 bolt main

Block Casing Number: 3970010 - 350 cubic inches

Block Casing Date: E270 - 27 May 1970

Intake Manifold: 3972116 - Service Replacement for 3972110 (70 Camaro Z28)

Head Casing Number: 3927186 - 2.02 intake, 1.60 exhaust, 63.305 cc, screw in studs & guide plates

Head Casing Dates: 29 Jan 1970 Passenger side
6 Mar 1970 Driver side

So did Buba adjust my lifters or does this engine have hydraulic lifters instead of the solids lifters I thought.

 

Can you be absolutely sure the engine has not been gone into before? Maybe someone changed out the solid cam for a lower maintenance hydraulic piece.

 

That's what I'm afraid of, I guess the only way to tell is to tear the engine apart? I did re-adjust the lifters as if they were solid lifters and everything seems alright (not noisy). The engine does look like it was re-built not too long ago, the heads were as clean as a whistle. I would hope someone wouldn't change out the solid lifters on a LT-1 engine, but who knows maybe they hated adjusting valves.

So now I don't know what my redline should be .

 

Even with the correct valve lash (adjusted) my solid lifters still make the distinctive clackety-clack noise unique to solid lifters.

You can hear the noise here......http://home.comcast.net/~eddiengerry/BB_startup.mpg

 

One thing you can check is to lean down hard on a few of the rocker arms that are over closed valves. You should be able to feel a little "give" from a hydraulic lifter where a solid will not "give" at all.

All lifters will make noise when adjusted as a solid, even the hydraulic ones.

After that you could go find a dial indicator and verify the cam lobe lift. This is pretty easy and can put your mind at ease as long as it turns out to be an LT-1 spec cam in there. If it is not, then you will need to dig deeper for more evidence of what was put in there.

-Mark.

 

That helps! I definitely have the clackety-clack noise but it is not as easy to hear as yours, but if I stick my head into the engine compartment it is there. From inside the car and off to the side I hear alot of noise from the fan (air flow, seems like huricane force winds), do you have an electric fan? I'll try again when the engine is hot (after some yard work, I'm setting the timing per forum instructions).

 

Things are looking better, I just re-adjusted the lash (all were very close since I did it last weekend) and did the lean test, no give. I tried it a number of rockers while trying to slide in the next size up feeler guage (.001 larger), none gave .

 

turn 1 valve 1 turn past 0
it will run like crap w/solids
will smooth out if H

 

Hi

The hydraulic has a snap ring on top in the outer edge of the cup

The solids do as well. Very difficult to see a difference. Also the solids have this snap ring and have like washers installed , probably because of it's oil passage through them and up to through the pushrods.
My 68 , when I bought it, had a solid lifter cam with hydraulic lifters installed. The previous owner renewed the engine and thought to buy new lifters because they where noisy.
I found out when checking engine numbers , that it had L71 heads, then checked the old original lifters which he gave along in a oily plastic bag to find solid lifters. They look alike the hydaulic lifters.

I am not sure if you can feel solid lifters by pushing on the rocker by a no give. Good hydraulic lifters don't give. If your a specialist, you might feel the initial difference, but they don't give.

I would think that hysraulic lifters , when adjusted like solids with a gap, are much less noisy as solid lifters due to this slight give that could dampen the initial touch clonk, but who knows how to hear this wihtout comparison.

I guess you will only be sure once you checked the cams numbers and took a lifter out and dimantel it.

By the way. You can install hydraulic lifters onto a solid cam , but wiseversa doesn't work. Solid cams are softer to eliminate lifter knock. Hydraulic cams don't need this because of the slight give of hydraulic lifters that dampens the knock.

Günther

 

Just installed a 70-LT1 cam and lifters, the lifters do have snap rings and look just like hydraulic lifters. Think the above test is the easiest way to determine what you have. Good luck.

 

if there is a chance that the engine has been gone through, i'd assume that the pistons and cam were changed to a lower CR and hyd cam. at one time, when a lot of engines were needing to be freshened up, and ethyl was going the way of the dodo bird, it was common to drop the CR and use an aftermarket (as opposed to GM) cam. many went with hyd, i think because at the time hyd grinds had improved and would perform as well under normal driving with better mpg, also having the advantage of not having to fiddle with solid lifter adjustments. the adjustment effort was more perception, and a lot of owners wanted to drive then, and not work on them at the time, i think.

Bottom Line: If it were mine, i would readjust the way they were (like they were hyd)(damage could eventually result from running hyd with zero or more lash).
then, try to confirm from previous owner what is in there if possible. at some point, you may have to dissassemble to see cam number. however, you may be able to map the lift vs crank/cam degree using travel indicator, etc., to get a profile close enough for a cam mfg to tell you if it is solid or hyd. maybe give your favorite mfg a call to see how they recommend you can most easily accomplish this; any tips, etc.

for whatever it's worth . . . hope this helps

 

Thanks for all the suggestions. I'm going to set the lifters as if they are hydraulic and see how that goes. When I adjusted the lifters the first time I backed off the rockers by 3/4 to 7/8 of a turn to get the solid lifter's lash (E=.026 and I=.21 cold and 90 degrees off of TDC). This time I do one full turn after zero lash and see what happens.

Next winter I'll try to muster up the nerve to pull the cam and see what it is.