Exhaust valve inserts available for 1978 3.3l I6? Are they needed?

Robert92867

New member
Supporter 2019
HI all,
I am looking at the specs for the motor I had built and the builder listed Stellite J-loy exhaust valve inserts. I am unable to find a product listing in the S.B. International e-catalog for valve inserts for my 1978 200 I6 cylinder head. Although I did find them listed for older cylinder heads. Do they make valve inserts for my head? Are they even needed, since the 1978 heads were designed for unleaded gas and probably have hardened valve seats? I need to know whether I should push to have the builder install the exhaust seats as advertised in his spec sheet, or realistically, are they even available or needed?
 
If you are installing larger exhaust valves, install the hardened seats.
 
Howdy Robert:

As you suggested, with stock size exhaust valves seat inserts are probably not needed. THe stock seat were induction (heat) hardened when manufactured. Although the induction hardened layer is not very thick it is thick enough to accept one or two typical vlave jobs.

Good luck.

Adios, David
 
Thank you all for your valuable input. The valve size is stock, and I suspect at least 2 valve jobs have been performed since I found a stamp indicating the engine was rebuilt in '91. Therefore I will push to have the exhaust valve seats installed. As for having looked. I want to avoid pulling the head so the builder can't claim the integrity of his build was compromised. So far I know the head was not ported, bronze valve guides were not installed, so I'm assuming no exh seats installed either. I am so thrilled to have this source of expertise available!
 
It's debatable whether they are needed or not. I'd leave it to the machinist, they are available. Bronze guides should be installed for sure. You may as well have the guide bosses machined for viton seals as well. The 78- 'hardened' seats were induction hardened. My machinist told me it was a gm/chevy problem in the 70's, valves receding into the heads, and that ford used higher nickel content iron and it wouldn't be an issue. I took his word for it. He did install valve guides. It couldn't hurt to put the seats in though, other than cost or in the unlikely event one falls out. When I do the 2v mod on my spare head for efi I'm going to have hardened exhaust seats and stainless valves put in for peace of mind.

My only experience with hardened inserts in these heads was when I went to port a D7 or 8 head that had inserts and found half way through the head was cracked between the center 2 exhaust ports. That head had inserts but figuring if the inserts had anything to do with the fact that it cracked between 3 and 4 would be a reach at best.
 
Back
Top