Fresh valve job am needing the seats cut if changing valves

[Matthewest91]

I recently got some 2.7 heads fully rebuilt with new oem stock size valves.

I am thinking to rev the motor a bit more so was thinking to install super tech valves and springs.

Wanted to get any experienced opinions on the matter about needing seats cut agin if I swap out to super tech.

I emailed super tech already and one of the reps told me I should not need to cut the seats agin if I am keeping the same diameter valves.


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[Silverex]

At the very least you’d want to lap them to make sure you have a nice contact patch but getting a new valve job would be the preferred way.

[travis_w]

I would at least have them lapped. The angles might still be correct, but the valves need to be seated the heads.

I had my heads checked and decked. I did new torque factory valves, springs, and lapped the valves. Tested and everything held vacuum. There is a process if you plan on doing it yourself. It takes time and a bunch of patience.

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[Matthewest91]

The super tech rep did say to lap and check them.
I’ve done my fair share of lapping.

I don’t like the idea of it tbh


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[Matthewest91]

I would at least have them lapped. The angles might still be correct, but the valves need to be seated the heads.

I had my heads checked and decked. I did new torque factory valves, springs, and lapped the valves. Tested and everything held vacuum. There is a process if you plan on doing it yourself. It takes time and a bunch of patience.

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How many inches of mercury did you pull on the heads when checking them ?
Your saying you did not have a valve job done and just swapped in the valves ?


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[Matthewest91]

It’s been about a year since I’ve lapped a head in.
If my memory serves me correctly. Isn’t there a port you need to plug up on the exhaust side to be able to vac test ?

I believe I stuck a silicone plug in it but remember it being a pain.
Am I recalling correctly. How did you plug it ?


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[Matthewest91]

This is exactly what the rep said.

“If you were to exchange valves, and if you are not change head diameters,
you should not need to do anything to the seats, other than lap them to make
sure the seats match the valves seats correctly.”


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[travis_w]

I did not have a valve job done. I checked them at 20inhg from both sides.

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[travis_w]

If you have a secondary air pump then yes. Obviously the spark plug needs to be in.

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[Silverex]

The super tech rep did say to lap and check them.
I’ve done my fair share of lapping.

I don’t like the idea of it tbh


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What don’t you like about lapping them?

[Matthewest91]

At the machine shop , they usually cut one seat and then lap only one to confirm.

If it were like that I wouldn’t have a problem. But doing all 30 I’d almost rather start over and use these heads for a k04 car or something.


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[travis_w]

It's really not that bad to do them yourself. You should get a good workout for sure, but a good weekend, and you can have them done.

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[ShelbyM3]

At the machine shop , they usually cut one seat and then lap only one to confirm.

If it were like that I wouldn’t have a problem. But doing all 30 I’d almost rather start over and use these heads for a k04 car or something.


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I’m with you. Having lapped all 30 of my valves, it’s a pain. And then you’ve gotta clean up really well making sure there’s no compound left over. Not to mention, the exhaust valves are always a pain because the carbon buildup on the valve face makes the lapping tool pop off all the time.


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[Matthewest91]

I’ll vacuum test the heads as they sit currently; fully rebuilt and together with a fresh valve job to see how well they seal.

Maybe that will change my mind.
I’m not hesitant about the work required. Just the quality of the seal after the lap job


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[Matthewest91]

The thought was to add 2.8 cams and to the 2.7 heads paired with spring kit, bw rs6 turbos and built bottom end.

Should I do both intake and exhaust super tech valves or will the Intakes hold up okay.
Blake said we could rev to 7500-7600 with this setup.
Another thing that crossed my mind. Is that going this route is decent amount extra for just a few hundred more rpm’s?


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[Matthewest91]

Thoughts on the 2.8 cams and super tech parts being worth it ?
I’ll be running 91 oct and water methanol


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[Silverex]

What turbos?

[Matthewest91]

Bw rs6


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[Silverex]

No I wouldn’t bother.

[Matthewest91]

No I wouldn’t bother.

Interesting.
Blake said can definitely benefit from the cams.
What are we talking here ~25whp or so ?


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[Silverex]

Interesting.
Blake said can definitely benefit from the cams.
What are we talking here ~25whp or so ?


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You will not gain 25whp on pump gas with RS6s

I did 2.8 cams on my F21s and didn’t gain much if anything and seemed to loose about 100-250rpm of spool.