5 replies to this topic

[Zami]

Doing some research on exhaust valve inserts and found that there seems to be inserts made from different materials. Excluding aluminum heads what is the recommended material inserts for the cast iron 940 head.

[Spider]

Fit these;-

 

http://www.minispare...|Back to search

 

I haven't looked into what they are made from. I think sometimes one can tie themselves in knots looking too deep.

[Zami]

Yea I made the mistake of googling insert material.  Way more info than I probably need.  I have an old big valve longman head that I have been putting off having inserts put in as I was concerned about cracking occurring between the inlet and exhaust.thks

[Ethel]

How much use does it get? 

 

Cost of the inserts & machining will buy quite a bit of fuel additive. 

[nicklouse]

Yea I made the mistake of googling insert material.  Way more info than I probably need.  I have an old big valve longman head that I have been putting off having inserts put in as I was concerned about cracking occurring between the inlet and exhaust.thks

Don’t do it.  
 

if you want inserts on a head like that you really need a very clever person who will actually cut out both seats and fit a double one.

 

one issue cost. 
 

just use it and add additive.

[T.Harper]

Bear in mind that your seats may not be in such good nick anyway - there's only so much that lapping and relapping can do.  So if your seats need recutting/guides need replacing/guide seals need replacing/you're having porting work then it's worth doing alongside.