Thread: Freshly Built 383, Oil question

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Hey guys, Ive just finished and installed a freshly built 383 engine into my 78 camaro. When I started it up it was incredibly tappety and still is, Im curious how much adjustment of the roller rockers I can do. Now engine has been built for gas. First quick description engine
Pro topline heads 64cc 200cc runners
Holley Contender single plane manifold "for gas"
Msd HEI dizzy swung for lpg
Scat crank
400 harmonic and flexplate
I beam scat rods 5.7"
Dished 8cc Hyper pistons with valve reliefs short skirts
Machined 4 bolt block decked to pop pistons out 27"
Comp cams Hydraulic camshaft 212-12-2 480 lift intake/exhaust 280 deg rotation
Performance lifters
Mellings High volume oil pump with welded on pickup tube
Yella terra roller rockers pedestal mounted

Now when it was really tappety I popped the valve covers off and the oil flow out the top of each roller rocker was really piss week, it was a weep more than a squirt, the front rockers didnt even have oil for quite some time and high revs finally made them weep. The rears spalttered a bit when revs were up around 2500 but dont know if thats because of rocker movement or pressure. I actually expected a higher oil flow. The second part after the oil was on all rockers it was still very tappety. I adjusted the roller rockers as per instructions, take cylinder to point were non lobe section of camshaft adjust finger tight until nil movement of pushrod wind barrell nut down pedestal shaft further half turn lock up with internal brub screw. Now there pretty noisy, do I simply redajust again, or can you wind them down further until no noise, bit concerned how far to wind them down as pistons pop out of block by 27" and gasket compressed is 39"
Any help would be appreciated
Thanks Steve

I don't know if I'm reading this correctly, but are you saying you have .012" head to piston clearance? If so, tighten the rockers all you want, the tapping won't go away. Need a min. of .035" between the head and piston with gasket compressed.

Did you use the Comp lifters? If so, what part no.? A lot of lifters are the anti-pump up style and unless you got the ,#812-16's, you probably got the anti-pump up style and they are always noisy.

Yep thats right 12" clearance between head and piston, this machine work and combo was recommended by the local hotrod engine rebuilders, I said if thats what you recommend go for it. I simply did the assembling. I measured all the pistons as they came out the bores and they ranged from 8" out to 27" out on a dial indicator, as the machine shop pointed out to me when I questioned this they said thats just small inaccuracies between all the components, even though there new and supposedly the same between crank rods and pistons they can vary. So worst piston is 27" out next is 22,20,18 and so forth. So is what your saying that its not the rockers that are making the noise but the pistons. Surely there not hitting if they did it would be really bad, it sounds like its the rockers. The lifters Im not to sure there silver with like a copper coloured bottom section, there hydraulic, as supplied
Steve

The pistons are going to rock in the bore and slap the heads. No doubt. Could be whats happening now.

If it's the lifters, you most likely got the anti-pump up style.

I'd be very worried about the head to piston clearance....

Yeh after your post I rang another engine specialist and he said what the f@@@@, you need at least 35" clearance, I told him about the small inaccuracies and he said thats fine but the tops should have been machined to suit, so there all the same height. Gonna have to buy thicker gaskets and strip it down again and put them in, not happy, hope I havent already cracked or stuffed something
Steve

i was kind of scratching my head with the oil question . You should be making a mess with oil. What kind of oil pressure are you running? Were oil Restrictors used in the back of the block? I use them for solid cam's, but never for a hydraulic. Even with Restrictors in on a solid roller cam i still make a bit of an oil mess.

ha clearences who needs them? how hot was the oil was motor up to temp?what weight oil are u using? how long after u adjusted was it running u have to give the lifters time to bleed down. just jokeing bout the clearence .035 is prolly min. i always heard .060 but never built a racing motor either

Gonna get a direct reading oil pressure gauge today the car only has an idiot light. Oil is 15w/40 brand new, oil pump is mellings high volume. Never heard of block restrictors for oil what and were would these be. The only thing I know that causes bad oil pressure is excessive clearances, but being new find that hard to believe, gauge should tell all, just a bit surprised that it was weeping out of the top of the roller rockers not spraying, could also be a function of the roller rocker to not to sure about that but. Im gonna have to pull the heads of again and run thicker gaskets but like to know about the oil problem if there is one before I start stripping it back down
Thanks Steve

I was just thinking about the noise. These guys are most likely on the correct path with the piston clearance. I just wanted to add something different. The oil restrictors would be in the back of the block and screw in beside the cam plug. We use them all of the time to keep the majority of the oil in the bottom end where we need it the most. If they were used on a hydraulic lifter they might starve the lifter to the point that they dont pump up and make noise. This might also explain the trickle of oil at the Rockers. I am curious to hear what kind of oil pressure you have. Keep in mind if the restrictors were used that it would not show up on an oil pressure check. I have some ideas if your oil pressure is low. but i will wait to spout off until you know what it is.

Yeh the short motor was built by local drag racing specialists, but I said I wanted it for street use. I still ended up with piston pop ups all over the place of varying sizes. I assume your talking about the three allen screws around the rear cam plug, do you restrict oil flow by using larger screws

no. there are actual restrictors that screw in with a small orfice. some look alot like a standard plug on the outside, but when you remove them they are around 1 1/4 long with an O ring.

Okay cant get really thick head gaskets here locally but can get decompression shims there .8mm which is about 32" throw on m,y standard felpro gaskets 39" and now I have 71" gasket,worst pop up piston is 27" means I have a clearance of 44" not exactly what I was after but hey shit happens gone from a 11.3:1 comp engine down to 10:1. I checked oil pressure with screw in direct gauge next to dizzy and cold it was reading 70psi at a 1000rpm, didnt want to wait for it to warm up just in case I do some more damage
Steve

COLD???? Oh that right its WINTER there We finely got summer here in MI. and glad of it.

Cold here is only 18 degrees C mornings its about 3degrees C

Simso, maybe you should pull that engine and go over everything. .027" out the hole and .008" out the hole is way to much tolerance stacking. I got a cheap built 385 on the stand and just to see, I checked mine. This is a standard deck height, .040" over bore with cheap hyper pistons, cast crank, and 5.7 I-Beam rods. No decking, no line bore, cheap, cheap, cheap. My pistons are .024"-.025" in the hole. I checked them all and the .001" could have been me trying to hurry. I checked the block with a straight edge also and it is pretty straight.

I know if I had .019" difference, I would suspect something isn't right. You should be throwing oil all over with the valve covers off. Cam bearings could be shot. I would check all clearances and if you paid these guys to build the short block, I'd go bring it back to them to fix my piston out the hole issue. If they had to deck the block more than .025", they should have started with another block. I could handle a little bit out the hole, but .027" is excessive in my book. I like Zero decked and .039" head gasket but will settle for .025" in the hole and embossed .015" shim gasket.

BTW, that 3 degrees from freezing gave me shivers and goose bumps. Got to go to bed and snuggle up to the wife.