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Gen II Hemi Valve Seat Install

General engine tech -- Drag Racing to Circle Track

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Krooser
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Gen II Hemi Valve Seat Install

Post by Krooser » Mon Sep 09, 2019 6:41 pm

Anything special that you guys can advise on replacing the valve seats on the early Gen III Hemi's? Materials, supplier, how much interference fit?

I've heard the factory fit was only .003 to .005 and that was the reason so many dropped out after overheating.

I'll be running stainless valves.

Any advise is welcome.
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bentvalves
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Re: Gen II Hemi Valve Seat Install

Post by bentvalves » Mon Sep 09, 2019 7:46 pm

SBI for the goods.

they will also be able to advise you on what type of press will be adequate with their seats.

Krooser
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Re: Gen II Hemi Valve Seat Install

Post by Krooser » Mon Sep 09, 2019 9:11 pm

Thanks... I'll likely remove the seats myself but have a local shop reinstall the new ones.

This guy does lots of good work but not much performance stuff so I feel better guiding him to the correct seats and materials.

I wish I had learned more of this machine work stuff instead of chasing skirts when I was young.

Plus you guys get all the pretty girls....
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ProPower engines
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Re: Gen II Hemi Valve Seat Install

Post by ProPower engines » Tue Sep 10, 2019 3:53 am

Krooser wrote:
Mon Sep 09, 2019 6:41 pm
Anything special that you guys can advise on replacing the valve seats on the early Gen III Hemi's? Materials, supplier, how much interference fit?

I've heard the factory fit was only .003 to .005 and that was the reason so many dropped out after overheating.

I'll be running stainless valves.

Any advise is welcome.
What valve size are you going to use??
What engine 5.7 or 6.1 etc.???
I do lots of these with a larger valve so be sure to check the OAL of the valve before you order them.
There is 3 different lengths depending on what years the heads are which drastically affects the rocker are location on the valve tip.
Also use a minimum of .005 and go with a durabond 7000 series seat.
Unless you can get an SBI 2N series seat of the correct OD and depth they won't last long in a hi-perf type build!!!
The single number or a 1N is not good enough to stay put as the Durbond 7000 series seats as the other seats are too soft
Also a slightly deeper seat will help keep them in place as well as allow for doing a nice radius on the exhaust seat and a 5 angle on the intakes.
These mentioned seats are larger OD and smaller ID then the factory size seats.
There is a bee hive spring we use for a BBC engine that works nicely if using a stock 6Lt cam.
Also a work of advise DO NOT USE HI-LIFT JOHNSON LIFTERS IN YOUR BUILD!!!
Go with the other Johnson lifters as the above are no where near as good.
Yes they are more money but it will keep your sanity when your lifters are not noisy.
And get the preload right when you get to the pushrod length. Just get new correct length push rods to start with.


PM me if you want more details for part numbers for seats etc.
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