Lifter preload measurement
07-04-2005, 08:14 PM
#1
Lifter preload measurement Just checking with you guys to make sure this is correct. I installed my Tea 5.3 heads finally today that were milled .010 and I used .045 Cometic gaskets. I installed the lifters with 2 rockers and 2 pushrods. Rotated the engine to make sure those 2 lifters were on the base of the cam. Adjusted the rocker to the point of no lash and zeroed my dial indicator. Torqued the rocker bolt to 22 ft. lbs. and it measured .086" on the dial. So I am assuming if I get 7.35" pushrods it should put my preload back to where it needs to be between .030"to .060"? I checked both intake and exhaust and they were within .005" apart from each other. Does all this sound right?
07-05-2005, 12:18 AM
#2
TECH Senior Member
When you measured .086, then you need to untorq the rocker back to 0 lash and a little more so it starts moving, let the lifter bleed and take another measurement. deduct the 2 readings and:
THAT is your preload measurement.
THAT is your preload measurement.
07-05-2005, 12:32 AM
#3
This was done on an engine that hasn't been started in over 2 weeks with brand new stock lifters and Harland Sharp rockers. I measured several times and on 2 different valves. Predator, I also tried the way you described by laying a straight edge across the valve cover gasket area, but that can't be done because the pushrods don't come up high enough to get a measurement that way. Is that accomplished only on certain types of heads?
07-05-2005, 12:57 AM
#4
TECH Senior Member
lifters need to pump up.
The other way is an "old school method" and can be done by fashioning a straight Z small tool to access below head lip on the #1 cylinder. The area where you make the mark is irrelevant. I made mine at where the p-rod whole is on the head, by sticking some flat Z tool I made from an old feeler gauge that I bent and U'd one end to wrap around the p-rod. (just a little creativity).
The other way is an "old school method" and can be done by fashioning a straight Z small tool to access below head lip on the #1 cylinder. The area where you make the mark is irrelevant. I made mine at where the p-rod whole is on the head, by sticking some flat Z tool I made from an old feeler gauge that I bent and U'd one end to wrap around the p-rod. (just a little creativity).
07-05-2005, 08:01 PM
#5
I'm confused on the whole lifter pump up bleed down procedure. I have read a ton of post about lifter preload and most all talk about letting the lifters pump up first then let them bleed down before measuring preload. Wouldn't that be the same as measuring them dry because they would already be in the same bleed down position? I know we have several preload post going on this first page and I realize you are posting in all of them Predator. I really do appreciate your time and input.
07-06-2005, 12:06 AM
#6
TECH Senior Member
If you measure dry there is no resistance in the internals and readings will be more than actual, hense a false reading. That is why accurate readings should be done hot also, to have the lifter at operating pump up level.
07-06-2005, 09:35 AM
#7
TECH Senior Member
Originally Posted by Unaffiliated Racing
You are getting way too technical for a stock style lifter. Just do them dry and don't worry wether they are hot or cold. If you have like .086" in it now...just let it go. Stock lifters are so forgiving, there is plenty of room in there. Just don't bottom lifter out.
Too little and you better get ear plugs (will also lead to cup failure)
.050 range in tolerance is very forgiving.
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07-17-2005, 12:10 PM
#10
Well, I ended up marking the valve stem ends on 2 different cylinders with a Sharpie and put it all back together. Cranked the engine over to get oil pressure without the fuel pump fuse installed and the coil packs disconnected. Pulled the valve covers and pulled the rockers off the cylinders that I marked. The swipe was off center towards the intake. Added a stainless .036" washer under each rocker arm pedestal for those 2 cylinders and marked them again and rotated the engine again. The swipe was dead centered on the valve stems. I measured the preload again and it was between .050" and .053" on those 2 cylinders with 7.40" pushrods. Will there be a problem running that big of a shim under the Harlan Sharp pedestals? If not, I'll leave the shims and won't need to buy shorter pushrods.
07-17-2005, 06:34 PM
#12
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When I followed Cranes install procedure...I measured a preload value of 0.090"...So you are right where you should be...
By the way...Preload must be measured in the totally bled down state, otherwise you will not be measuring a true preload...Also, if you have a lifter pumped up and you put 0.090" of preload on the pumped up lifter...You will run the chance of smacking a valve with a piston if you try cranking the engine over at all...
Peace...Gman
By the way...Preload must be measured in the totally bled down state, otherwise you will not be measuring a true preload...Also, if you have a lifter pumped up and you put 0.090" of preload on the pumped up lifter...You will run the chance of smacking a valve with a piston if you try cranking the engine over at all...
Peace...Gman
07-18-2005, 10:33 AM
#13
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Originally Posted by HavATampa
Well, I ended up marking the valve stem ends on 2 different cylinders with a Sharpie and put it all back together. Cranked the engine over to get oil pressure without the fuel pump fuse installed and the coil packs disconnected. Pulled the valve covers and pulled the rockers off the cylinders that I marked. The swipe was off center towards the intake. Added a stainless .036" washer under each rocker arm pedestal for those 2 cylinders and marked them again and rotated the engine again. The swipe was dead centered on the valve stems. I measured the preload again and it was between .050" and .053" on those 2 cylinders with 7.40" pushrods. Will there be a problem running that big of a shim under the Harlan Sharp pedestals? If not, I'll leave the shims and won't need to buy shorter pushrods.
Preload is fine for aluminum engine parts when cold...
I'd bolt it up and run it...
BTW... Good to see someone who actually checks things and doesn't just slap thing together and pray it works!!! Good job.
Ed
07-18-2005, 12:51 PM
#14
Thanks Ed. Yeah, I put the shims under the rest of the rockers and it cranked right up. Runs pretty good so far. Will get it to the dyno in a few weeks to see how much the Tea 5.3's bumped up the power. Then I'll be looking for a bigger cam. There isn't an end to this madness is there!
