My hot rod had this crazy backfiring thing going on, at deceleration but it ran great otherwise. I did a compression check and it was real bad (100 when it was supposed to be 170). The cam was ground pretty aggressively, by the previous owner, and adjustable push rods had been installed. Today I opened the engine up, and it turns out that the valves didnt close properly, because 14 out of 16 hydraulic lifters where seized (in the uncompressed position) not collapsed, weird. So here is my question: I have a set of new, working hydraulic lifters. How do I adjust the pushrods, for this particular engine, so this wont happen again????? Thanks, Chris. PS: How did the lifters seize in the first place??? Dirt, lack of oil, heat??? 1956 322 Nailhead
Do you know what the grind is? Are you even sure it's a hydraulic cam? It almost sounds like the previous owner adjusted them to the top of their travel so that they would behave like solid lifters. Also, if you run the pushrods the opposite way of how they are in the picture, you won't have to remove the intake manifold and valley pan to adjust the valves.
Check the oil galley ports. If they are sludged up your lifters may seize. Have you tried to pull any of them yet? I am in the middle of a 322 rebuild for my Buick. I had a bad seal mixing oil and coolant. The cam lobes were wiped out, but the lifters operated fine. Keep us posted with what you find, and good luck.
I just set mine like SBC lossened till they clatered then tighten till they just stop and 1/4 turn more. 53,55 cams and lifters interchange with 56 parts but the 56 322 has different metal and 56 Buick shop manual says not to mix them. Aluminum 401/425 rockers are direct bolt on and give 1.6 rocker ratio instead of 1.5 on 322 rockers.
Have you adjusted hydraulic lifters, like SBC, etc. before? If so, you are doing the exact same thing, except you are physically turning the pushrod "halves" to increase or decrease the lifter preload. Once you have the preload where you want it, you then tighten the lock nut on the pushrod. Since you have the intake and pan off, it's pretty easy to adjust them by sight, rather than by ear. There are three schools of thought on how to adjust them- but, since you don't know what springs the P.O. used, etc., I'd stay safe and adjust them so that the lifter plunger is about .060 below the retaining clip (with no spring pressure on the lifter, o'course.) Oh, and flip the pushrods so you can get to them in the future for fine-tuning of the preload. Adjustable pushrods are really more of a solid lifter deal, and are a crutch anyway, but, they can be made to work. BTW, the pictures may be deceiving, but that cam appears to have virtually no base circle left on some lobes...
Thanks guys. I'm going to put the whole thing together again, tomorrow. BTW, having the adjustable pushrods upside down, seems to be the way to go, since there is no way, to get wrenches under those rockers. SBC's might be different. Thanks Chris.
My nailhead had bad lifters. I put in a set of chevy solids. Try it, Give them about .012 to .016 on the intakes, and about .016 to .020 on the exhausts and see how it works.
Is it because the adjusting nuts are buried inside the cylinder head when they are flipped? Take a pic, if you get a chance...I'm no Nailhead expert by any means...but I haven't run across that before, I'm wondering if it's because the cam lobes have been ground so far down & the geometry is completely whacked....i.e. the pushrods are too short....or I might be reading too much into all this, it wouldn't be the first time.
So, I installed all the new hydraulic lifters, adjusted the pushrods, but now it sound like a sewing machine. I drove the car and I can feel increased power but that clacking noise is there. Loose pushrods, or will that noise eventually go away after a certain break in period? Sorry for all these silly questions but I am not really an engine guy. Thanks.
It sounds like you do not have adequate oil to the lifters, hence the clattering...or the pushrods are loose. Adjustable pushrods are invaulable for engines that do not have readily accessable adjustable rocker arms so don't worry about them being a 'crutch'.... Every adjustable pushrod that I have seen (and no doubt there are odd-ball out there) has a 32 TPI screw ***embly so the adjustment should go like this: •With the lifter on the back side of the lobe (no lift action), open/extend the pushrod so that there is a slight drag when you spin the pushrod between you fingers. The 'puck' should still be against the snap ring. •At 32 TPI (threads per inch), each full turn will change the overall length by 0.032". Most cam companies will recommend a pre-load in the range of 030" - 050" and 0.060" as a maximum. So, open the length about 1½ turns; this will give about 0.050" pre-load on the lifter. You will find several lifters on the 'back side' at the same time so keep track of which ones you adjust. .
Sounds like the preload is wrong on some/all valves...or, alternatively, there is no oil getting to the lifters. With new lifters that aren't full of oil, it can be tough to adjust them the first time out. Also, was each individual lifter on the base circle when you adjusted it? Dumb question...are you sure the old lifters were hydraulic? If I'm repeating stuff that's obvious to you, give a shout...it's hard to figure out someone's skill level over the Net and you can never tell whether the other guy is thinking "Yes, it's a frickin' hydraulic lifter!", or, "What's this shiny thing do?" Also, out of curiosity, where did you get the new lifters and what brand are they? Do they look identical to the ones you took out? Sometimes a company will take one lifter body design and stretch it to cover other applications that it really doesn't fit.
Thanks, must have been an oil flow problem, after about 20 minutes of letting the engine run, the noise went away. I hope this is it.
Do you have an oil pressure gauge on it? It does take a bit of time for them to settle down, not usually that long, though. Depends on the plunger & valve design, oil pressure, etc.
To help some folks understand, to produce a " aggressive " ground cam, several options can happen. First you can start with a new billet and grind your profile on that. You can start with a new casting and grind you profile on that. You could also weld each and every lobe and regrind your new profile that way. The most popular method from the old days, was to offset grind your current cam. To increase the effective lift of the cam, you need to offset or shift the lobe further away from the center of the cam. This is why it seems like there is no longer any " base circle " to the cam. It has simply been moved more toward the center of the shaft, allowing the cam grinder to now make the lobe higher and change the shape and or profile of the lobe. By changing the profile, you can change all of the opening and closing events, lobe seperation, centerlines, overlap, and duration. What happens then though, is you loose your valve train geometry. The lifter now comes down further in the lifter bore, the rocker arm tilts back further on its fulcrum, and the position in which the rocker arm tip contacts the valve stem all has changed. With modern engines and manufacturing, we can easily produce any length pushrod necessary to correct geometry and still be cost effective. Another alternative would be the adjustable pushrod like you see here. I hope that sheds some light on the topic. TR
Yep...seen a lot of regrinds. That one looks pretty far down...but then again, as I said...pics can be deceiving.
Hope it works for you but if it dont, I've ran an engle solid cam and adjusable pushrods on a 322 before, id leave the adjusters toward the lifter side. Up against the rocker its a ***** to get two wrenches on. And to hell with chevy lifters. Call TA performance, Buick ran the same size lifters in 50s strait eights into their late 455s.
The Jalopy Journal
