5 replies to this topic

[Iain L]

Im just statring to fit my 12g295 head to my 998 and when i bought the head off ebay i asked if the hardened valve seats had been fitted and the guy said he didnt think so. But, this head has had a fair chunk of work done to it, including full port an polish, increased inlet an exhaust ports and larger valves fitted.

So what are the chances that the hard valve seats would have been fitted?

Thanks

[sonikk4]

Im just statring to fit my 12g295 head to my 998 and when i bought the head off ebay i asked if the hardened valve seats had been fitted and the guy said he didnt think so. But, this head has had a fair chunk of work done to it, including full port an polish, increased inlet an exhaust ports and larger valves fitted.

So what are the chances that the hard valve seats would have been fitted?

Thanks

Ask him where the work was carried out then contact them. If its had larger valves fitted then you would like to think the seats would have been replaced to suit the increase in valve size, so on that train of thought hardened seat may have been fitted???

[Turbo Phil]

It's impossible to say. Why not remove an ex valve & have a look ? They're usually fairly clear to see.
Just because the valve sizes have been increased it doesn't mean that inserts will have been fitted.

Edited by Turbo Phil, 27 December 2010 - 01:14 PM.

[Iain L]

It's impossible to say. Why not remove an ex valve & have a look ? They're usually fairly clear to see.
Just because the valve sizes have been increased it doesn't mean that inserts will have been fitted.

What exactly should you be able to see if the hard seats are there?

Thanks

[Turbo Phil]

Look into the port throat and look for a line/ring all the way around. There should be a visible line about 7-8mm or so down from the valve seat.

[tommy13]

A word of warning, slightly off topic. We recently fitted a 12G295 ( heavily skimmed) onto my lads 1100. I had not realised at the time that the valves had been replaced with 1275 items and the ports opened up accordingly ( no unleaded seats). This cost us 4 bent pushrods and 2 broken rocker arms as the exhaust valves hit the top of the block. Amazingly the valves did not bend, but it was neccessary to pocket the block to use this head.
I would suggest you check yours for the same fault before completing the build.

Edited by tommy13, 27 December 2010 - 05:11 PM.