Head porting question

[4.whoa]

I just started porting my 1st head, and was wondering what kind of oil should I be using, and how much? I used a little wd40,but I'm not sure that's correct.

[SilverXJ]

Oil for what? The polishing part with the cross buffs?

[4.whoa]

I heard you're supposed to use oil to keep the bits cool. Was that wrong? I've never done porting before.

[Bodo]

only for cutting, not for grinding. Wear a particulate mask and eye protection and have at it!

[4.whoa]

Thanks. I hate getting misinformed.
Another question- I've been reading and was wondering if the exh is so much better with a raised floor(like the 0331) since you really can't build up the 7120's floor- what if you lower it towards the manifold? If you give it 2-3". From the valve then drop it a bit won't it do the same venturi effect? Probably not as strong, but better then not?

[unlimitedrubicon]

Unless you have the experience and the proper tools (flow bench, variety of calipers, etc) to verify what you are doing (on a spare head first), it is best not to modify the port shapes. By doing a basic bowl blend, cleaning up the rough spots, and polishing the exhaust you should obtain very good results.

[unlimitedrubicon]

A good guide to get started with:
http://www.pirate4x4.com/tech/billavist ... asives.pdf

[Cheromaniac]

A good guide to get started with:
http://www.pirate4x4.com/tech/billavist ... asives.pdf

Yeah, that's a good one for cutting your teeth with.

[4.whoa]

Thanks,guys i've done a little already, but that will help

[IH 392]

Another question- I've been reading and was wondering if the exh is so much better with a raised floor(like the 0331) since you really can't build up the 7120's floor- what if you lower it towards the manifold? If you give it 2-3". From the valve then drop it a bit won't it do the same venturi effect? Probably not as strong, but better then not?

It's not a venturi effect, the raised port floor is to aid in the flow from vertical to horizontal, turn it to fast and you get turbulence, the raised floor makes the transition more gradual and reduces turbulence, as the article suggests, "smooth" the radius, you should never lower the port floor to make the port bigger, the port will flow more than the valve/seat will so there is really no need to increase the port size, especially on a low revving engine like the AMC/Jeep six.