Help! Comp 262AH and PTV Issues!

[85 Coupe 5.0]

let the fun begin........

Was recently installing a set of Comp 262ah's on my '96 PI converted shortblock and ran into a problem. Upon installing and degreeing the cams, I am getting PTV interference. I degreed them back to -4 degrees from spec and can only free up .030 of clearance.

I need to get .060 or more, and after posting over at the depot, a few have suggested using Manley valves, as they are somewhat different than the stockers and will give me around .060 more clearance.

Any suggestions on that? Also, are there any other options? I had been told that the 262's would fit without PTV issues, but my heads have been milled, probably causing my issues, and am unsure of how much they have been milled.

I ended up putting the stock PI cam back in the right bank and checking the PTV on it, it only has .065 and i've been running that setup for over a year, so i believe I will be o.k. with that clearance.

can somone help me out here? my poor stang sits in pieces untill I find a solution.

I forgot to add, it's the intake valve that's hitting, the exhaust has miles of clearance from -15 deg. BTDC to 20 ATDC.

 

[85 Coupe 5.0]

bump.

 

[hotmustang331]

Same thing happened reciently to a guy on here while installing the VT stg 1 cams...but he didnt degree the cams. Looks to me like the NPI motors have issues when installing cams, because I believe he had PI heads as well. Something about them is causing this. That definatly shouldnt happen. As far as the valvaes, im not sure.

Other options are buying pistons with valve reliefs, running the cams with 5-6*s retarded (more high RPM powa!), or sticking with the PIs

 

[85 Coupe 5.0]

Same thing happened reciently to a guy on here while installing the VT stg 1 cams...but he didnt degree the cams. Looks to me like the NPI motors have issues when installing cams, because I believe he had PI heads as well. Something about them is causing this. That definatly shouldnt happen. As far as the valvaes, im not sure.

Other options are buying pistons with valve reliefs, running the cams with 5-6*s retarded (more high RPM powa!), or sticking with the PIs

I tried Retarding them more, i had them at 17 deg retarded and only had .060 clearance, but it would be a dog with that much retardation.

If I am reading the specs right, the manley valves are .270 or so smaller on the head size, I believe this would give me the clearance I need. I only need around .030 or so more to squeeze the cams in at -4 degrees.

 

[Stan Weiss]

What does Comp call for the intake centerline to be set at? Did you cut your heads to increase CR? You maybe able to retard the cam some and use a .015 - .020 thicker head gasket. But you best option is to get the pistons valve reliefs cut.

Is it possible that the valves are moved in the PI heads as compair to NPI heads and contact the pistons in a different location?

 

[hotmustang331]

Holy cow...yea dont run it - 17*s. You would have no torque.

Another thing you could do is run a thicker head gasket...im not sure but you should be able to run 2 as long as they dont have a metal seal ring...only down side is that your compression will go down. So with that said, there are options...but changing the valves would probably be the best thing to do. you should also get a few more CFM with them as they should flow better. Just do some more reasearch and if its CONFIRMED that they will give you .060 more than you should be good to go....but its still going to be CLOSE. I think you should also buy some high performance valve springs, so you have better valve control. If you have even a small amount of play, your valve may tap the piston...because at the same time your rods will stretch a tiny amount @ 6000RPM. You dont want to take any chances

 

[85 Coupe 5.0]

Holy cow...yea dont run it - 17*s. You would have no torque.

Another thing you could do is run a thicker head gasket...im not sure but you should be able to run 2 as long as they dont have a metal seal ring...only down side is that your compression will go down. So with that said, there are options...but changing the valves would probably be the best thing to do. you should also get a few more CFM with them as they should flow better. Just do some more reasearch and if its CONFIRMED that they will give you .060 more than you should be good to go....but its still going to be CLOSE. I think you should also buy some high performance valve springs, so you have better valve control. If you have even a small amount of play, your valve may tap the piston...because at the same time your rods will stretch a tiny amount @ 6000RPM. You dont want to take any chances

My bad, I also installed the recommended comp springs with the cams. A lot of people say not to change the head gasket as it messes up the swirl in the chamber moving the head away from the piston.

Comp wants the cams installed at 113 deg, I took them all the way up to 127 or so and can only get .060 clearance. I also degreed my stock PI cams and I have been running at .065 clearance with no apparrent problems.

I'm still looking for that confirmed case, I have contacted someone over at the depot and am sill working with him on the case.

Anyone else been here, got some ideas??

 

[rugster]

I had PTV with my VT stage 1's and finally talked to a ford tech the other day and he told me that the windsor heads are very different than the romeo heads so Im going to call VT to see if that may be the case...try calling Comp and see what they say

 

[85 Coupe 5.0]

I had PTV with my VT stage 1's and finally talked to a ford tech the other day and he told me that the windsor heads are very different than the romeo heads so Im going to call VT to see if that may be the case...try calling Comp and see what they say

I called comp before all this started. The wanted me to go with the smallest non-pi cam they offered. they said the cam I have now would have ptv issues. The only reason I bought them anyway was because i had read about a few people here that have done it and had no issues as long as they were degreed in, but i don't think any of them had shaved heads.

 

[RandyStinchcomb]

I had PTV with my VT stage 1's and finally talked to a ford tech the other day and he told me that the windsor heads are very different than the romeo heads so Im going to call VT to see if that may be the case.

What?!?!?!

 

[85 Coupe 5.0]

What?!?!?!

yea, comp wanted me to install the smallest cam they offer in their pre '99 linup. it would have basically been a stock pi cam with a little more duration.

so i basically called b/s and went on my own.

 

[RandyStinchcomb]

LOL, no I was referring to what the "Ford Tech" said, total

 

[85 Coupe 5.0]

LOL, no I was referring to what the "Ford Tech" said, total

gotcha.

 

[rugster]

Randy, any idea why the Stage 1 cams wont fit? I have tried installing them 5 times and the timing is perfect but still gets PTV. My stock cams fit right in at the same position and the car runs great...

 

[85 Coupe 5.0]

Randy, any idea why the Stage 1 cams wont fit? I have tried installing them 5 times and the timing is perfect but still gets PTV. My stock cams fit right in at the same position and the car runs great...

It's been my experience with the comp's I have, that the opening ramp rate is soo aggressive that the valve chases the piston till it catches and hits, around 0-15 deg. ATDC for me. I Beleive I have found a solution to my problem, but won't know till tomorrow when I receive the valves.

 

[rugster]

so you are buying shorter valves? Let me know the outcome!

 

[85 Coupe 5.0]

so you are buying shorter valves? Let me know the outcome!

I'm using valves with a smaller head diameter, not shorter. Apparrently the stock valves have extra material on the head that makes them fatter. We'll find out tomorrow, the valves arrive. Got the motor pulled tonight. i'll keep you all posted, and take pics.

till then,

 

[RandyStinchcomb]

I'm using valves with a smaller head diameter, not shorter. Apparrently the stock valves have extra material on the head that makes them fatter. We'll find out tomorrow, the valves arrive. Got the motor pulled tonight. i'll keep you all posted, and take pics.

till then,

a smaller head on the valve will kinda' defeat the purpose of a bigger cam and getting max air-flow out of the heads + the fact that a smaller faced valve will require alot of seat work to make it work.
I think your going about this the wrong-way

 

[85 Coupe 5.0]

a smaller head on the valve will kinda' defeat the purpose of a bigger cam and getting max air-flow out of the heads + the fact that a smaller faced valve will require alot of seat work to make it work.
I think your going about this the wrong-way

Sorry for not clarifying. I'm not really decreasing the valve head dia at the seat, I believe there is just less material on the valve head itself to work with as opposed to a stock valve. I'm only needing about .040 more clearance to get the cams installed at the recommended degree point. I'm not quite sure on the vavle thing either, Mike at Modularperformance is giving me some pointers on this one, their claiming around .070 more clearance with this valve.

 

[85 Coupe 5.0]

here's the thread over at the depot with the specs and such:

http://forums.************.com/4-6l-2v-tech/102793-ptv-contact-need-help.html

it's at Modular Depot the link probably won't work.