Valve Seats for Bigger Exhaust

[mugsy]

I just got my 250 c.i. D7BE head back from the machine shop. They cleaned it and magnafluxed it; it looks great!! The machinist thinks that it has hardened seats for both the intake AND exhaust valves. There is zero to little wear, according to him, on all 12 seats 8)

So my question is: if I go with the "144 Intake for the 200 Exhaust" valve swap, will inserts have to be installed? is the hardening deep enough into the metal so that all that has to be done is cut a new, bigger seat?

Mugsy

P.S. the intakes valves are 1.75 dia.

 

[CZLN6]

Howdy Mugsy:

That is exctly what my brother and I did. I put the 144 intakes in the exhaust side of a D8 head with out hardened inserts.

We keep waiting for something to happen for an excuse to pull the head to check on wear, but, so far, so good. Dennis pulled his head last winter to do some block work and found no descernable wear. That was after 4,000 miles on his 200.

I'd reccommend you go with the stock seats on a D7 head on a mildly modified street engine.

Good luck.

Adios, David

 

[mugsy]

David,

Thanks for the info. If the bang for the buck isn't there I'll spend my money elsewhere in the engine .

I would be interested in hearing how the seats look with some more miles on her. So if/when that head is pulled let us know.

Thanks again.

Mugsy