440 ordeal continued

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66dartman

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Still has no compression. I will try to be brief. Hyd. cam 440. After trying different pushrod lengths, I changed to a Crane adjustable rocker setup.
Set the rocker arms with cam on base circle to 0 lash. Engine started for maybe 1 second. Lifters pumped up and would not bleed down. Today I pulled the comp cam & lifters out and put a Crane 272 cam & lifters in. Set the new lifters to 0 lash + 1 turn. lifters had at least 1/4 inch travel left. I watched them as I had the intake off. They were on base circle. Engine started for 1 second. Again, no compression. Timing right at 0 for starting, cranking oil pressure 45. Been working on it for 3 weeks. It almst seems like the lifter galleys are overpressured or something. Please Help!
 
get a plug adapter for a vacum gauge. air up the cylinders with a compressor 1x1 with the piston on compression stroke. listen for where airs going thru xhaust or thru intake. loosen offending rocker to see if leak stops. do this on all 8 and then check for compression as this should allow valves to seat . turn motor over first with torque wrench first at damper with 15 ft pounds and plugs out to check for interference. install plugs if no piston to valve contact and fire it up. should run as long as valves are seating you may want to give an xtra turn out on each adjuster to allow for heat expansion.
 
Your lifters will only pump up as far as they are supposed to go and no farther. Have you backed the rockers off and measured your preload with the lifters pumped up?

Did you have the block decked or the heads shaved?

Any chance you have a solid lifter so you can check your pushrod length?
 
I thought that the lifters would only "fill the gap" also. That is what is strange. They are pumping up and holding the valve open. I have used a checking pushrod to get the right length pushrod. I have 3-4 threads showing under the rocker at 0 lash. Turning it over by hand, it has compression. With the pushrods out, it has major compression, enough to make the ratchet back up. Could it still be valves that are not seating?
 
You say that there is no compression after running for 1 second, did you determine this by doing a compression check or is it just real easy to turn it over by hand. Try this, adjust your valves to 0 lash then back the rocker adjusters off 1/2 turn, make sure that the lifter pistons are up against the cir clip that keep them retained inside the lifter assembly before this. One good reason that it may be running for only 1 second is that the ballast resistor is crapped out, this condition is very common.

Terry
 
Thanks for the replies. The engine has good spark, MSD system. I will back them off to the circlip, but could the oil pressure possibly blow the circlip out?
 
No compression is a result of either terrible ring seal, or the valves are not closing for some reason.

Causes of valves not closing: bent valves, valve bind in guide, rocker arms adjusted too tight and holding the valves open, etc.


-- "zero lash, and 1 turn"
This seems a bit much. In theory the lifters should be able to accomodate, but a full turn is a lot. I am referencing the small block chevy world, where it is quiet plus 1/4 to 1/2 turn. For reference, your adjustment is 1 full turn after tight, and that might be enough to unseat the valves, losing pressure??? Maybe?
 
I'll ask again. Was the block decked or the heads shaved? Do you have a solid lifter you can use to measure for pushrod length?
 
I hope that you have the push rods for hydraulic lifters and adjustable rockers. They are different than solid lifter pushrods. If you have adjusted solid lifter pushrods like you described, no valve seating.
 
Block nor heads machined. Adjustable rockers with ball/cup ends custom made to 8.750 by Smith Brothers. They were told it was a hyd. cam. What is different between hyd and solid pushrods? They are 5/16 by the way.
 
is that compression on 1 cylinder or all 8? back them off till it rattles and if it dont run you need to do a compression test, no one can fix this without solid numbers to work with. im sorry ,feels like, and i think it does is not concrete enough to diagnose by. Ive decked several sets of heads and shimmed the pedestals the difference the heads were cut and never had to buy pushrods and adjustable rockers unless i ran a solid cam. if lifters are pumped up tighten them till they dont rattle and its gotta work. if you have no compression with them loose something else is wrong. are the rocker shafts oriented right. oil feeds on the pedestals right with the shafts.if not the rockers can gall and keep valves open.
 
Finally had enough bull and pulled the left head off. All the pistons had nice valve marks in them where the exhaust valves kissed them. Must have happened the first time I tried to start it with the comp stuff in it and non adjustable rockers. Thanks everyone for the help. Lessons learned for me here and I won't use comp again for anything. Thier "stock replacement" cam is anything but.
 
what i suspected, why i wanted to see if there was compression with rockers backed off. get your push rod measurement after lifters are primed
 
well that answers that. Guess those pushrods were the wrong ones. Really sucks you have bent valves.
 
No stock sized cam will come close if the valve train is right. In fact, I've run .528 exh lift cams (solid and hydraulic) with stock pistons (no reliefs) and heads milled .100". The parts did not fit because they were teh wrong parts. Not Comps fault at all.
 
All I say is comp should not tell you to just drop it in and go. I wound up with pushrods 1/2" shorter than what was in there with a Crane cam. I had comp's tech line buzzing before I had the engine in the car and was told that they install this cam all the time and don't change a thing with no issues. I am the fool, yes. But I won't get fooled again by something like this.
 
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