Got my heads back today...may have a problem

[82 GT]

I finally got my heads back from the machine shop today. I was suposed to have 2.02/1.60 valves installed but he said they were too close together in the chamber and was afraid that after the guides wore down after while they would end up hitting each other.
He decided to go with the 1.94/1.60 valves just to play it safe.
Well that was ok with me but................tonight I took an old intake valve and set it into one of the valve reliefs on my pistons and noticed the relief isn't much bigger than the old valve(1.78)
Should I be worried about my piston/valve clearance now because the relief may not be big enough or is it really too hard to to tell just by looking?
I bought clay tonight to check clearance but I just got a little worried when I noticed this.
The difference in size between the old/new valves is only .16
Has anyone increased their valve size in a stock head and not have to fly cut the pistons?

[Nixon1]

Are your piston reliefs at LEAST the size of STOCK piston reliefs? I've got a set of 1.9/1.6 valved heads over stock pistons and they fit just fine. 1.94's will work with the stock pistons too...just 2.02's won't. I assume your reliefs are at least the same size as the ones from Ford, considering you've got performance ones....

By the way..while I've got your attention on this post..I'm just curious if you've driven your car yet with that stall converter? I'm trying to decide between a 2500 and a 3000 and I'm just curious how it drives with that stall speed...whether there's a lot of slippage during normal acceleration...

[82 GT]

Yeah, the reliefs are as big as the stock valves with just a tad bit more room to spare(not much).
Since my engine isn't together yet, I can't tell you how my converter works.
My best advise is to call whereever you buy your converter at and ask them to recommend a converter for you that will work best with your cam. That's what I did because I didn't want one that was too much for street use.

[Nixon1]

Alright thanks man..thats a good idea...what are the specs on your cam?

[82 GT]

My cam is from COMPETITION CAMS and the specs are:

274*/286* (advertised duration) 230*/235*@.050 lift
110* LSA
.519/.523 lift

The COMP salesman recommended between a 2500-2800 stall speed converter.
My converter is from TCI. Their website also has information regarding converters and tips on choosing one.
You want the stall speed a little higher than where the powerband of the cam begins. My powerband will begin at 2000rpms
I hope this helps.

[82 GT]

Here is a link that will help you out

http://www.tciauto.com/tech_info/tor..._explained.htm

[Nixon1]

Thanks for the site man. I was originally going for a 3000 stall but now I'm thinking that might be too high. The motor really starts to put you in the seat at that rpm but it's got decent low end too...dont wanna go past the powerband. My cam's torque peak is supposed to be down low..like 2000-2500, somewhere in there...not sure. I'm getting the car dyno-ed in August so I'll know....but I probably cant afford to wait for the tranny so unfortunately I cant use the dyno sheet to help judge what kind of stall I want. I'll just take a 2500 and go with it.

[Shaggy]

Hey 82' What pistons are you running... I will assume the "mini dome" speed pro/TRW if that is the case then your valve relief's will actually take the 2.02's as well.... remember unless you have some sort of instant open and close cam then not the whole valve go into the relief area just a portion of on side of it... imagine trying to stick a 50 cent piece in a quarter pool table the whole coin won't fit in the slide action thing but if you put it at an angle then the curved shape of it allows a portion to actually get into the slot.

[82 GT]

shaggy , I'm not positive what pistons I have. I bought the engine rebuild kit from Summit racing. There are are 4 half moon valve reliefs in them and the pockets are about 1/4 deep.(guess)
Tonight I checked the piston/valve clearance. Here is how I did it:
I clayed the top of #1 piston, installed the intake/exhaust rocker arm/pushrod assembly and turned the crank 2 complete turns.
I removed the head and found no valve marks in the clay at all.
The lifters were pre-loaded and the test was done without a head gasket. I guess that means I'll have plenty of clearance with the head gaskets installed.
I'm running the COMP CAMS 274 extreme energy cam(hydraulic)
with 230/236* duration @ .050 and .519/.523 lift.
The machine shop guy predicted that I probably would have any valve marks in the clay when I checked the clearance.
He said with the engines he has built(Ford), he doesn't usually run into piston/valve clearance until the lift is well over .500 or someone is running TRICK FLOW HEADS due to the different valve angles.

[Shaggy]

He is correct ot what i have seen as well... I forget you are a 351w that actually makes a big difference...... The biggest I have run in recent years off the top of my head witout custom notches is..

Ad dur @.50 lift
284° IN 220° IN .540" IN
296° EX 228° EX .540" EX

on 110° centers and installed -4°.

I still had room to go on that one too.

PS I usually do my checking with the cam retarded becasue if it is goign to be an issue then retarding will show it up first, and then you don't have to worry if ytou awant to change your cam timing later.