I have a 232/234 .595 .598 cam and im in the middle of doing a head swap and decided to take some carb cleaner and razor blade to clean my pistons, and they cleaned up GREAT....but i noticed 1/4 of a circle shape from the valves. The heads that came off recently had no damage to them at all, but my old heads with the stock cam had bent pushrods.


Is it possible to have PTV problems from stock cam, by missing a shift?

Stock heads had around 132K on them(bent pushrods)

Marks did not look fresh, didnt discover them till i removed all the hard carbon build up, and NOT ALL PISTONS HAD A NOTCH IN THEM

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Also getting ported 5.3L heads in the mail, ya'll think it will be ok to run stock MLS gaskets and not have PTV problems. I have a 7.4 pushrod.

 

Yep, I think it would be fine unless they have bigger than OE LS1 valves and are milled a fair amount.

What's the LSA on your cam? Do you know how much your heads are milled?

Ben T.

 

they are the new PRC Stage 2.5 5.3L heads with 2.02 valves


LSA is 112+2

 

So you eyelashed your pistons with the Torquer or the stock cam? Were you getting any kind of valve float? retainers were TI right?

 

stock retainers, comp 918 springs. But the heads I took off had NO sign of contact

 

Sometimes the valves will not show it. Stock valves I take it? If so, you might want to consider a thicker gasket if you plan on going oversized with those 5.3's.

 

I've been thinking about some 5.3L heads for my F14 (same specs, different lobes) I wasn't to sure if they would fit and I dont know if I want to get myself into flycutting.

 

The 5.3 and the 243 heads have the same clearance guys. It is the oversized valves that should be worrying.

 

yall think my 132K springs and valve guides didnt hold up to my high revs and limiter bouncing and possibly some valve float occured. I DID have oil all the the time on my spark plug threads so I took it my valves seals/guides were shot.

 

Are you saying the 918's had 132k on them with that cam? If so then that would be my guess is YES your rev limiting and those miles on those springs with that cam would have been the reason.

 

132k on some springs!!! What? Tell me that we are reading this wrong Travis!

 

the aftermarket cam will clear fine. When you overrevved and bent the pushrods thats probably when you smacked the piston with the valve.

 

I would think it should clear, depends on how milled the heads are. Im wiling to bet they milled being the 2.5's. but, you should ALWAYS check ptv clearance even if you dont want to flycut the pistons. its a pretty expensive thing to overlook only to save a couple hours of easy mockup work. search on here its been posted about tons of times the diff. ways to check this.

 

Your PTV clearance with the stock heads and with the new PRC 5.3 heads will be fine. I'm guessing the valve hit the piston when it was overrevved. The stock springs don't hold much more than the stock cam itself. So, when the it tagged the limiter, I'm sure it floated the valve and hit the piston. The same thing it what caused the pushrod to bend. I wouldn't be concerned with your new setup. The PRC Platinum Dual Springs are coming on your new heads. Valve float or PTV will not be any issue.

 

sweet..so I guess this problem has been "nipped in the bud"

thanks!

 

no sign of valve float on the dyno, hince i didnt see a sudden drop off of power.
this is with the stock cam i suspect, stock retainers.

 

hey jon are my heads milled ANY?

Cause i dont want them milled, and also do ya'll recommend a 7.4 pushrod aswell, cause i already have ya'lls 7.4 comp cam style pushrods.