Heys guys, getting my lq4 short block back from the machine shop in a week. I am going to be putting my ported and milled .030 243 heads onto the 6.0 after its back. I'm in the process of picking a cam out, but I am concerned for ptv issues. I ended up reusing the stock lq4 dished pistons on the rebuild. Looking to go with a cam around 228/232 .600 .600 ish and 112 lsa. Wondering how big I can go without ptv issues? Hoping maybe one of you can help out or a Texas Speed rep. I am purchasing a stall, so that is not a limiting factor.

 

PTV clearance isn't so much lift as it is duration.

Duration = hold valves open longer during stroke

This is what causes PTV clearance issues. You're doing what everyone else has or will do. The cam is a sensible cam and *shouldn't* cause issues. Of course, it's better to measure to be safe.

 

I was thinking about putting a head on without a gasket with the bolts just snugged up, and then slowly rotating the crank to see if it hits. Whats the best way to check for clearance? I've heard that some people use a clay on top of the piston to see if it indents it I guess.

 

Use old gaskets and use clay. Cut it out where the valve mashes into it, using a razor blade to keep from deforming it. Measure the thickness of the clay.

 

I use clay.... you can cut it off or for a slightly rougher measurement but still as accurate I push the end of my digital caliper in through the clay at the thinnest spots to see what I have. I honestly just use orange playdough haha.

 

Who'd you use for the engine work? Building a lq4 myself with shaved 243's. Should be plenty fine with .030 shaved with a 228/232. check over on ls1 tech. found some good info there on same setups