So I have a 75 eldorado motor that I have built and dropped in my 70 Deville. For the upper end, it has a Cad Co 275 cam, relatively mild, with new johnson lifters, their stage 3 rocker shaft setup, 2.19 intake valves with 1.85 on the ex, and the springs that came with the cam. I had a head shop cut the valves and set the seat pressure, and everything looked good before assembly.

I got the engine running and have had a valve tick ever since, but it is getting worse. I have 25 psi at idle and 50 at 2,000, so oil pressure is not the issue. I run 10W30 with a Zinc additive, so it is not the oil either. I have run everywhere from 0.040 to 0.120 inches of preload on the lifters, and 40 thousand was the worst out of them all, so I am running 80 right now. I pulled all the lifters, cleaned them, and verified they were good. I also have a relatively uniform tick, and I don't have 16 bad lifters right out of the box. All the push rods are straight. The rockers have no slop in them either. I am at a loss.

I called Cad Co, and they said it could be sticking valves due to the head shop I went to put on locking valve stem retainers. I have read that the clearances on these 500s are tight, like 5 thousand tighter on the valve guides than Chevys of the time. Would the lack of oil on the valve stem cause a little stick and my tick? The noise is faint while the engine is cold and gets loud as it warms up. Should I throw some umbrella seals back on and hope it solves my issue?

I would greatly appreciate any help.

 

I'd hoped someone else would have answered, as this has me stumped.
Did the "head shop" do any guide work, or grind the seats?

Is the "stage 3 rocker shaft setup" properly oiled via the hollow pushrods? There isn't a secondary lube passage needed...right? The lifters pass oil to the pushrods, the pushrods are not plugged--so the rockers have lube at all 16 places?


Well...you'll find out eventually. Not much comfort, though.


I don't think that's a safe bet. "Zinc additive" doesn't mean much. Given the crappy cam cores and Communist China's proclivity to produce low-quality, and outright counterfeit parts, more "zinc" is not going to help defectively-soft iron.


Well, the good news is that you've inspected the lifter bottoms, and--likely--the cam lobes although you didn't mention that. There's a good chance that this isn't an actual lifter/lobe wear issue. The lifters are clean, so not stuck with varnish, anti-rust "shipping" preservative, or random metal chips from the manufacturing process.

Since it's not possible for us mere mortals to measure lifter-plunger to lifter-body clearance other than by testing for leakdown rate, I guess we still have the potential for "leaky lifters". If you pull them out again, verify the leakdown rate.


I don't know what "locking valve stem retainers" are. All valve stems have "locks" generally called "keepers". There's different styles, they have to match both the valve stem design and the retainer design (the tapered hole in the retainer can be machined for "7 degree" keepers, or high-performance "10 degree" keepers.)


"5 thousand tighter" doesn't make sense, neither does "5 thousandths" (0.005). 5 TEN-thousandths would be in the ball park (0.0005) of valve stem clearance variaton. But I don't know that valve stem clearance is something that varies by engine manufacturer. It might vary by valve material, or by valve stem diameter; but domestic V-8 automobile engine manufacturers use "about" the same size valve stems, low-budget valves, and usually cast-iron guides which may or may not be repaired with bronze liners.

What I'm saying is that the valves could stick in the guides because the workmanship of repairing guides and/or fitting the valves to the guides was faulty, but it's not likely that Caddy has some special exotic specs for valve clearance.


Lack of oil because of lack of clearance...maybe. The real problem would be the clearance, not the oil. Lack of oil would be a symptom, not a cause.

What valve stem seals are on there now? Are you thinking that umbrella seals will allow MORE oil to go down the guides than the seals you have already?