5 angle valve job

[tta1401]

Is this overkill? I have stock ported heads with Manley SD valves, hd valve springs.. I dropped my disassembled motor off to the machine shop and he was telling me all the things he does and said he does a 5 angle valve job. I didn't ask what the cost was at the time but I'm thinking all the work he has to do the heads (pull them apart, deck them, etc) I can pick up a set of Champions, no? He hasn't gave me estimate on the whole project because he wants to hot tank and magnaflux everything which I understand.

 

[eric_1984ttype]

Who did you take it to? If it was a N/A motor it would be worth it. I think its overkill on something your forcing air into. Depends on how much extra he's charging to do it though. As long as he's not porting them it should be significantly cheaper than the champions. If your paying somebody to port them your better off with the champions by the time you pay for their time/experience.

 

[Nick Micale]

A 5 angle valve job on a Buick iron head will not hold up long especially on a street car, the 3 angle works best.

 

[tta1401]

Who did you take it to? If it was a N/A motor it would be worth it. I think its overkill on something your forcing air into. Depends on how much extra he's charging to do it though. As long as he's not porting them it should be significantly cheaper than the champions. If your paying somebody to port them your better off with the champions by the time you pay for their time/experience.

I took it to Jim Moran, MBJ Machine.

 

[tta1401]

The heads have been home ported; intake/exhaust runners, bowl work. They are 8445 casting, not NA heads.

Nick, can you explain a little more on why 3 angle works best on a street car?

 

[Nick Micale]

Since your engine is not experienced with turbo Buick builds, he will find the seats are small, and the 5 angles make small contact patches that quickly go away.

Too bad the search engine is not fully working as this has been discussed before. Even our race engine, as well as other builders I know, use 3 angle cuts.

No dis-repect to your builder, but the known Buick engine builders that have done them for 20 years or so have found certain quirks that have been incorporated in our builds for reliability as well as performance.

 

[turbofabricator]

I agree with Nick. (as usuall)

 

[charlief1]

So doing a back cut on the valves won't hold up and doesn't effect the flow numbers any?

 

[tta1401]

Since your engine is not experienced with turbo Buick builds, he will find the seats are small, and the 5 angles make small contact patches that quickly go away.

Too bad the search engine is not fully working as this has been discussed before. Even our race engine, as well as other builders I know, use 3 angle cuts.

No dis-repect to your builder, but the known Buick engine builders that have done them for 20 years or so have found certain quirks that have been incorporated in our builds for reliability as well as performance.

Cool, thanks for the heads up. Google searched it but way too much info. I usually use the search on here. That's why I only have 550ish post since 2001.

No disrespect taken. He dealt with Buicks way back in the day, having conversations with some well known Buick racers about this and that. A very well respected guy in the Pontiac world. He has done them before and I he is one of the best around. Now for our little motors, he can do them and I would like a someone in my area to build these motors. Seems like only a handful around and it would be nice to have another. Just have to get him back building these again. That's why I posed the question.

Thanks!

 

[ek02]

Back cutting the valve face may help flow some, but it will not affect reliability as long as the face of the valve is the same width as the seat and it is wide enough. When doing a 5 angle valve job, the width of the seat has to be thinner, and that affects reliabilty. The heat transfer is reduced due to the narrow contact area and there is more load on the narrow seat area from heavy valve springs. Not too good for a street driven engine.

 

[tta1401]

Back cutting the valve face may help flow some, but it will not affect reliability as long as the face of the valve is the same width as the seat and it is wide enough. When doing a 5 angle valve job, the width of the seat has to be thinner, and that affects reliabilty. The heat transfer is reduced due to the narrow contact area and there is more load on the narrow seat area from heavy valve springs. Not too good for a street driven engine.

That's more of the explanation that I was looking for. Thanks ek02.