ninetres

iTrader: (35)

My mechanic and I were talking about lightly buffing the nearly invisible machine marks off the bottom of my heads with something like 600 grit sandpaper. We figured it might help reduce pushing water or lifting heads. Thoughts?

kp

iTrader: (34)

It will most likely INCREASE the chance of pushing water. If the finish isnt smooth enough for MLS gaskets get them surfaced by a machine shop that knows what they are doing..

ninetres

iTrader: (35)

Interesting. It isn't "rough" per-say.....Just the very faint, barely visible machine lines that are on heads.

Did you use copper spray or anything on your set-up? I know you have pushing issues on high boost....but for some reason I figured I could get away with GM MLS gaskets...and ARP studs. Now I am not so sure that by it-self will hold 18-20 psi.

I am soooooooo far over budget (like 1,000s over the 1,000s I anticipated being over) that I really can't afford to have them o-ringed.

Derek @ EDO

iTrader: (73)

pics of these "scratches"?

ninetres

iTrader: (35)

I don't have any and I dropped the heads off at my boys house tonight....who is taking them to his shop tomorrow. I'm not even sure if a camera could pick them up.

They are just patriot stg 3 heads that have never been re-surfaced. The marks are just the very uniform lines from the surfacing of the deck. You can't even feel them.

My buddy (mechanic) said he recently installed 2 different sets of heads on different mustangs and he said the shops/companies that ported the heads did this "sandpaper finish" on the heads.

He was guessing that although EXTREMELY MINUTE.......the small lines form the machining can create passages for air/coolant at 20psi.

Are we totally over=reacting here?

kp

iTrader: (34)

I dont use any spray on mine at all, cant see what that would help unless it was leaking water somewhere. All you can do is try it. Absolute number on thing is the heada are flat and if you start hitting them with sandpaper they may not be flat when you are done. 600 will cut aluminum fairly quick..

All you can do is try it and see what happens if you are out of cash..

ninetres

iTrader: (35)

That is what I was thinking about taking them out of "flat". But my mechanic is VERY meticulous and he seemed to think a LIGHT polish might be a good thing. I think I am just gonna leave them and cross my fingers.

How much does it usually cost to have block/heads o-ringed? What gaskets would I then run?

kp

iTrader: (34)

Just take them somewhere and get them surfaced for MLS gaskets. 3.8 fords use a very fine finish with their gaskets and most any machine shop can do it quickly and cheap. That way you know they are flat when you put them on.

kp

iTrader: (34)

200-300 depending who does it. But then you have to use copper gaskets with o-ring/receiver and then you best break out the gasket sealer and you have to retorque. If you just o-ring the heads its 100-200.00 amd thats what the ohio boys did with MLS gaskets and they say it helped them.

ninetres

iTrader: (35)

Ohio boys method sounds interesting. I am quite connected with some machine shops around here too, so $100 doesn't sound too bad....for a little added insurance.

MIGHTYMOUSE

iTrader: (59)

just put them down with what you have, copper spray is fine.

i think the head seal will out last the 76mm capability, at least it did on my car with the same combination of parts.

Assassin

iTrader: (3)

on a side note, if your tying to get a smooth, high polish surface, 600grit is WAAAAAY too low.... do 1500grit, then 2000g, then polish.....

pwrtrip75

iTrader: (8)

The smoother it it the easier it will be for pressure to slip out of it. I run a large file over the head to knock any burrs off, lightly coat regular old felpro gaskets with engine enamel, let them tack up and bolt it together. Paint is some tough stuff baked on, Ive been doing it for years, nitrous cars, .....currently 15psi and holding strong. And its a hard to get the heads off cause they are stuck on, the head gasket usually seperates leaving half on the head and half on the block.

383LQ4SS

iTrader: (33)

believe it or not...i usually take some grade S metal polish and a rag and circle the general path of the seal ring where the head gasket would mate. Then clean with MEK. I have had good luck with gasket sealing. Of course there is almost no way to test things like that unless you have already found the limits and then try another method and then immediately repeat to the same limit to see if it made any changes.

My thought on the polish was to knock down any high ridges to get the surface as smooth as possible only in the area of the seal without really changing the overall flatness since its so mild. And if it did change the flatness...it would only be in the area of the sealing ring...which is the high point.

Juiced

iTrader: (2)

don't forget that if you o-ring the block that you have to tq plate & re-hone as the bore can be distorted with the addition of the fire-wire.