And. If your studs are pulling out, that means something metal is hitting something else that is metal. If the studs didn't pull out, something else more expensive would have bent or broke. While you have the heads off, take the time to verify your TDC marks and properly degree your cam. I would reinstall one head with soft springs in the #1 cylinder. Use the old head gasket and install your pushrods for those rockers. Slowly turn the engine to TDC on overlap for #1. Push those valves up and down as you go so that you know how much clearance you have between the valves and piston. Find what caused the studs to pull out. Soft springs are a good way to observe the rocker geometry on the valve tip to see if indeed your pushrods are proper length.
With SHORT incorrect pushrods the adjustment would RUNOUT or you would run out OF adjustment BECAUSE the rocker nuts bottom out , leaving /throwing the geometry OFF ,AND making the springs tight, and tight (short) springs CAUSE more pressure CAUSING the studs TO PULLOUT. 7.2" or 7.3"push rod is MOST likely the culprit.... normal (old sb's) are the 7.8" All of us are trying to help you, these guys in here, ARE the BEST... we come from different places so READ each of the OTHER posts and sifer out the INFORMATION. good luck -n- don't forget to let us know the FINAL outcome.
Use a solid lifter cam- adjust them and run it - use the poly locks that stay put with your screw in studs and your set DND
I ***embled a Pontiac engine that had a DeLong roller cam with a Comp Cams valve train that John DeLong had sold the owner. The owner, for some reason subs***uted BBC exhaust pushrods for the ones that came with the cam. It bent and broke pushrods all the time. Threw out lifters and bent the connector bars. it was a mess. When I did the soft spring deal i could see the rocker roller was almost off the valve stem tip at rest. As the valve opened the roller was pushing across the stem tip almost as much as down. I made a quick adjustable pushrod and found that his were .100 short. I called him and told him he needed new pushrods .100 longer. He said he already had the pushrods that came with the cam and they were + .100. Put them in, no more trouble. If you ask him now he will tell you that he never ran Chevy pushrods in his motor.
Regular old 350 Chevy push rods are 7.794" long, what is the length of stock Vortec pushrods? I would invest in a checking push rod before you break something real expensive. Have the heads machined for screw-in studs first.
I don't mean to be a smart *** or a dumb **** or debate the ideas of people with much higher skills than me. But when putting together a bunch of mis mated parts, or even stock one's, don't you 1 use a piston stop to verify TDC 2 put a degree wheel on the cam 3 put solid lifters in #1 4 clay the piston tops, put the head on, and check the clearance Am I that far out of date?
I'll do all that. My current SBC build, I had a shop do the lower end and install the cam, degree it in. Engine building 101. Mine was a little simpler, I just used aftermarket aluminum heads and had a pretty good idea of what the push rod length was before I started.
I can't raise a rt hand to it, but how compatible is LS stuff with the SBC we know and love? Is the LS the same firing order? Also, timing gear alignment, In many cases I've found that it has little or NOTHING to do with TDC. Some yes, some no, me, I don't give a **** until I get to that point with the distributor or if advance/retard of the cam comes into play. That's when we go TDC, stops, clay, rope, degree wheels, dial indicators, coffee and Elvis comes over to help. (and y'all thought I don't pay attention )
Am I to understand that you are saying that you don't degree your cam until after your distributor is installed?
No, not at all. What I'm saying is that some engines will not be #1 at TDC with the cam/crank gears aligned at the dots. I know for a fact Mopar "LA" engines (318, 340, etc) are not #1 TDC when the gears are right. Helped a friend with that struggle many moons ago. Vintage engines could be anywhere, but yes indeed some are at #1 TDC for gear alignment. Once I have a short block ***embled then I go into checks for valve interference, lobe/valve lift checks, degrees of advance/retard, etc. Why muller up the build worried about stuff before you get to it? And as to cams, I kinda know what I want/need before I buy it, or make sure I have new or near perfect stock stuff for restoration work. Quick edit for disclosure: I don't do a whole lot of engine building, but what I have done I feel I've done quite well with it. I focus more on tuning, and with restoration being my primary gig that should be of little surprise. I have a source for full vinatge engine rebuilds.
If the cam is 180 out just turn the engine over one time and the marks will line up. If the studs are pulled you should have a lot of valve lash. Pull the left valve cover turn the engine and watch the rockers on #1 when the exhaust closes and the intake starts to open look at the timing mark it should be close to TDC. If not the cams out of time. Did you use one of those multi keyed crank gears they can be confuseing?
sounds like he (in post #1) has run OUT of threads on the STUD... it sounds like he was re- tightening as they WERE pulling OUT... Just MIGHT be the springs he's using are experiencing coil bind,
Coil bind can easily do it. Never asked or I missed it, are the rocker arms stock? Have to watch for them making contact with the top of the valve retainers if they don't have enough valve spring clearance. It was mentioned that the Vortec push rods are shorter than the ones in use. How much shorter? It may be wise to install one cylinder's worth and bring it around by hand.
A thought on this: OP mentioned that he "upgraded" the springs. They could be too highly rated, creating more spring pressure than the press-in studs can handle. It doesn't have to be coil bind, though it likely is. Mike
If you read from the start you will see that coil bind was asked about on post #6 and answered in the negative on post #7
Just to check, on the timing gear set. For SBC, the dots line up when #6 is at TDC. Are you sure that you have this right? As #1 is also at TDC (firing order 18436572) so both #1 and #6 are at the top of the cylinder at same time, but the valve positions relative to pistons between #1 and #6 is significantly different.
As long as the dots line up, the cam timing should be good. Distributor timing may be 180 out. But that isn't going to effect anything the OP is asking about that I can think of. In fact, if you rotate the crank 360 degrees the situation will clear it self up.
I can't explain what's happening but what Rich said earlier about using the light springs is what I do with every engine. No matter how much I plan, I still place the head on with a used head gasket, light springs, and adjustable push rods. On over lap and at any degree near it I can push down on the valve to see how much piston/valve clearance I have and get the proper pr length and correct geometry. Sometimes I'll try it with no head gasket. To me unless you have roller cam springs the should be no way the rocker stud should be moving unless the fit is way off. In sixtys we drilled and taped set screws to hold the stock studs when using a roller. Anyway good luck.
If he used a multi keyway timing set the are 3 or more alignment marks it would not be the first time the wrong mark was used.
Jim and I have the advantage here because the springs between the rockers on a GMC are Perfect to use as soft springs. And if you use the clay method and have interference, All you will know is you have interference.
I don't do a lot of engine work, but the last couple of sets of lifters I've installed, it seems like they were bottomed out from the start. When I went to zero lash plus a half turn, the valves were cracked open. I think I went to zero lash or a little less and got it running, and reset them while running. Gary
They would be bottoming out. New lifters have not had pressurized oil in them so you can bottom out the plunger when tightening the adjuster down. I always do the initial valve adjustment with the intake off. I will use a paper clip that has been straightened out and a 90° bend put on the end. Tighten the adjuster until the paper clip can just be slid between the pushrod cup and the wire retainer. All you need is a little bit of preload on the cup. You can't go by feel on lifters that have not been pumped up. Takes some time and one lifter at a time so you can watch and make sure that lifter is on the heel of the lobe. I have never had to re-adjust hydraulics after initial fireup using this method. Sent from my LG-H343 using The H.A.M.B. mobile app
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