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Hi all,
As part of an EFI upgrade I decided to check the valve lash on my 69 427/390. I bought the car about 4 years ago and the previous owner said he’d had the engine rebuilt by a local shop some time back but didn’t know anything about what they did to it other than “it’s stock”. Upon inspection I found a very slight bend in the #3 intake pushrod so I decided to replace them with a fresh set of one-piece pushrods of equal stock length (they actually used two different styles of pushrods in the valvetrain). Assuming hydraulic lifters, I set the lash with the engine off to 1/4 - 1/2 turn past zero lash. When I went to start the car there was no compression, just an occasional backfire. I then reset the lash on all valves to zero and was able to start the car easily. From there I went about adjusting the lash with the engine running, starting with the #1 cylinder. At an idle speed of 900 and working slowly I hardly made it to the #5 cylinder before the engine sputtered out. It was apparent that the additional preload was only opening the valves and not compressing the lifters. With the engine off, I observed the tip of the valves while loosening the rocker nuts; on every rocker only the valve & spring moved, not the lifter & pushrod.
I removed the two most easily accessible lifters using a magnet, one on either side of the engine. I assumed I’d see a classic solid lifter but what I found looks like most hydraulics. The only difference is that the snap ring is a different design that I don’t recall seeing before. Using various picks I was unable to remove the snap ring so I decided to leave them alone. After letting them sit overnight I was unable to compress the lifters at all with my own bodyweight. So, I decided to throw them back in and set the valve lash to .024/.028”. It runs better than ever. The only question is whether I have hydraulic or solid lifters. Maybe they’re hydraulics acting like solids due to failure, or my own incompetence in adjusting them. Maybe they’re just solids that look like hydraulics. Any thoughts?
I’ve attached a couple pictures of my lifters just in case anyone can positively ID them. Thanks!
Bent pushrod means some valve train interference. Too much lift or maybe too much RPM?
Next, the lifters all have snap rings even solid lifters do..
The adjustment method is in question....how are you doing it? LOTS of threads on this. If you have feeler gages, do you tighten the nut until it only slightly feel a drag or are you going all the way to a hard pull required to pull it out?
From your description it sounds like you are going too far.
To address the bent #3 intake pushrod, it’s only very slightly bent and could have been that way for years. I doubt I’ve ever had this motor over 3500 RPMs, and only 1 of 16 were bent. It could also have happened when starting it in the winter at -15F a few times.
The procedure I used to adjust the lash is the one detailed on this site: https://www.centuryperformance.com/v...procedure.html
It’s tedious but seems to rule out any other sources of error.
To be clear, the engine currently runs beautifully using stock 427/435 valve lash specs for solid lifters. I set the lash with a feeler gauge engine-off but nice and hot. I’m not sure if those are good lash settings since I don’t know exactly what sort of cam is in it, but I figured it would be a good starting point.
It seems like I might need to pull a lifter back out and try some other way to get that snap ring out. I don’t want to risk damaging it or breaking off the point of a pick. All 6 pick combinations I tried earlier failed.
Your car should have hydraulic lifters you likely dialed. In too much pre load.
Just tighten till it won't wiggle up and down add a quarter turn more. See how it works. It's possible of it bends again your springs re weak.
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i think the .024 is a cold setting, allowing for expansion so that you have .006 to .010 hot. OTOH, VW guys feel as long as you can hear the valves, you know you aren't burning them by holding them open. so too loose damages nothing until they are so loose the rockers jump off the pushrods...
69 Big Block Lifter Identification
