Generation IV External Engine - PTV clearance issues LS2, MS3 cam




View Full Version : PTV clearance issues LS2, MS3 cam


mactizen
04-04-2012, 12:31 PM
I'll try and not be long winded to avoid clouding things up. I was sold the ms3 cam by the vendor along with ported heads from the same vendor, at the time I was told ptv clearance wouldn't be an issue but would be "about as tight as you'd want to go". I was looking for bolt on power to a stock LS2 shortblock, figured I was good to go. Now a year later I'm having an actuall engne builder go thru all my stuff and make sure everything is good and generally just checked out for the year. He calls me and says the ptv clearance should be a minimum of .080 and .100 respectively, yet I have .060 and .065. Assuming the vendor isn't going to do anything for me a year or more out, what are my options to get things more inline? Can I just take the compression hit and stick a thicker head gasket in there? Is there something I can change enough in the stock valve train to get a little room? Or is fly cutting the piston the only option? Sadly I ordered a cam under the instruction of as big as possible without cutting the piston, and although I didn't "need" I'm now a bit worried about just sticking it all back together and saying "f it".

Any help/ideas appreciated!


LSHUNT
04-10-2012, 01:47 AM
Imo you have a few options:
Slightly thicker cometic gasket
Flycut
Swap the cam
Leave as is

I'm assuming he has your heads off or easily removable for checking ptv and if you don't mind losing a little cr the gasket change is probably your best option. I know some people have run even less clearance then that, though it's one unlucky valve float from a kiss of death.

gectek
04-10-2012, 01:53 AM
Flycut if you want to run that cam then. Or get a diff cam. Going that much larger on the cometic gasket over (what I am assuming is the stock Gm .053) would net you a horrible quench.


DietCoke
04-10-2012, 02:13 PM
Plenty of clearance. Run a good spring.

mactizen
04-11-2012, 10:38 AM
I decided to go with a PatG cam, I figured I'm 99% drag race anyway so there's probly power left on the table by using an off the shelf cam. I'm too much of a worrier to just run it and hope for the best, everytime I made a nitrous hit i'd be nervous and distracted over something relatively cheap to fix. Thank you all for the input!

Nebulus
04-12-2012, 10:35 PM
Plenty of clearance. Run a good spring.

This. If it was tighter than what it is, then i would recommend flycutting, but it's unnecessary at the moment IMO.

apena99ss
12-01-2012, 06:02 PM
this is on an ls2 what about the ptv on an ls1?

Sales1@Texas-speed
12-01-2012, 06:34 PM
We have run setups tighter with no issues. You were fine with .060 clearance.

bww3588
12-02-2012, 01:52 AM
I'll try and not be long winded to avoid clouding things up. I was sold the ms3 cam by the vendor along with ported heads from the same vendor, at the time I was told ptv clearance wouldn't be an issue but would be "about as tight as you'd want to go". I was looking for bolt on power to a stock LS2 shortblock, figured I was good to go. Now a year later I'm having an actuall engne builder go thru all my stuff and make sure everything is good and generally just checked out for the year. He calls me and says the ptv clearance should be a minimum of .080 and .100 respectively, yet I have .060 and .065. Assuming the vendor isn't going to do anything for me a year or more out, what are my options to get things more inline? Can I just take the compression hit and stick a thicker head gasket in there? Is there something I can change enough in the stock valve train to get a little room? Or is fly cutting the piston the only option? Sadly I ordered a cam under the instruction of as big as possible without cutting the piston, and although I didn't "need" I'm now a bit worried about just sticking it all back together and saying "f it".

Any help/ideas appreciated!
I'd swap the cam. There are plenty of people that will buy that cam off you and you can get a better cam and not be out too much.

apena99ss
12-02-2012, 05:12 AM
We have run setups tighter with no issues. You were fine with .060 clearance.

so no fly cut?

Sales1@Texas-speed
12-02-2012, 10:05 AM
Yes sir no fly cutting. Now obviously more clearance is always better, but like I said we have run tighter setups with no issues.

1bad lad
12-04-2012, 03:43 PM
run it...clearance is fine as long as you have good springs!!

apena99ss
12-06-2012, 01:34 AM
Thanks for the help

Zfan
12-07-2012, 07:47 AM
run it...clearance is fine as long as you have good springs!!

X2, don't get stingy (pocket book) on the springs!