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View Full Version : PTV clearance and piston notching

Mr.Slave
05-19-2008, 06:53 PM
Moving forward with my barrage of questions, I have 2 more.

1: I have a hydraulic lifter with a flipped plunger to test PTV clearance with. Someone on another forum told me that it will be .030 on the high side as compared to a solid lifter. I just want to double check this, is that true?

2: I'm fairly certain even before I check PTV that I'm probably going to need to notch my pistons. When I do this, do I have to take the pistons back out afterward to clean everything? I'm just worried about shavings getting inbetween the pistons and the walls, is this a possibility? I've even thought about turning the engine upsidedown on the stand while notching to prevent this but maybe I'm worrying for nothing.
qkjuicedpony
05-19-2008, 07:01 PM
You will need to notch your pistons with the cam you mentioned and twisted wedge heads
SkurdalenFox
05-19-2008, 07:03 PM
You could have just searched.

http://www.streetstangs.net/showthread.php?t=8303&page=4
Mr.Slave
05-19-2008, 09:33 PM
You could have just searched.

http://www.streetstangs.net/showthread.php?t=8303&page=4

Did you run the engine to get the lifter pumped? Thats not an option for me because its on the stand right now. Forgive me for being confused by that thread, this is my first build and I'm not even doing most of it, I'm still not sure what you ended up doing to get your measurements.

Although the putty was a great idea when notching! I'll definitely be doing that.
coupe
05-19-2008, 10:07 PM
Spread some grease around the edge where piston and cylinder meet to keep aluminum shavings from falling down into the ring-lands. Then wipe/scrape up the grease and clean out the edges. As you do the job, go ahead and take pictures to give us a "play-by-play" of the progress.
SkurdalenFox
05-20-2008, 11:06 AM
Flip the plunger in the lifter. That'll simulate a fully pumped up lifter accurately enough. Even if the flipped plunger shows a bit less P-V clearence than what is actually occurring in a running engine, I don't really see how a little more P-V clearance is a bad thing.

Assemble the valve train with a checking spring on the cylinder you are checking, I'd check every cylinder. Determine proper pushrod length and P-V clearance. Don't forget a head gasket.

I prefer a dial indicator over clay. I could never measure the clay very accurately. But, I did check with clay just to see where the valve was closest to the piston.

Trim piston as necessary. I attempted to remove the same amount of material from each piston as to not screw up the balance.