All Small Six A little porting advice

[nearGettysburg]

Before I put this engine back together, I want to clean up the ports--just a little. I plan nothing extreme. I have been playing around on an extra head I have.
I have a 1" ball steel cutter. With just a few minutes' work, I can get it past the bottom of the valve guide and clean up the flashing in the port so that the 1: cutter gets into the intake "manifold, or the exhaust port by gasket flange.
How much on the protruding valve guide can I safely remove? The Falcon HiPo book looks like I take cut it6 flat with the top of the port. Is that safe?

 

[wsa111]

Should be fine providing your valve guides are ok.
On the intake valve take them to a machine shop & have them do a 30 degree cut to the lap in area of the valve. Easy 5 HP gain.

 

[nearGettysburg]

Machine shop did the back cut when they did the valve job. I like "easy" HP gains.
It looks like the 1" ball cutter is the right tool. It easily fits past the valve seats --don't want to accidently hit them!
Valve guides are new--cutting the guides flush with the casting is OK? That would seem to smooth out the air flow.

 

[hodaka100]

I use a Dremel with tiny carbide bits. I like the oval bit. Takes less than an hour to clean up any sharp/mismatched spots including the combustion chamber. It is easy to be careful around the seats with the small tool.

 

[Frank]

Machine shop did the back cut when they did the valve job. I like "easy" HP gains.
It looks like the 1" ball cutter is the right tool. It easily fits past the valve seats --don't want to accidently hit them!
Valve guides are new--cutting the guides flush with the casting is OK? That would seem to smooth out the air flow.

Inserting a valve when grinding near the seats is good insurance.

 

[DON]

Mine head is ported and the bosses the rise into the intake are not cut flush, they just made them narrower. Cutting the guide only, to be flush with the “boss” that sticks up, wouldn’t make much difference. I think I would rather have the extended support for the valve.
Unless you are looking for those”10 th’s of a second “

 

[Frank]

Mine head is ported and the bosses the rise into the intake are not cut flush, they just made them narrower. Cutting the guide only, to be flush with the “boss” that sticks up, wouldn’t make much difference. I think I would rather have the extended support for the valve.
Unless you are looking for those”10 th’s of a second “

Agree. Rounding the bottom facing the port and smoothing the protruding guide is a worthy flow assist, by reducing turbulence caused by the abrupt edges of the stock casting.

 

[aussie7mains]

Having done a tonnes of cast iron port jobs, my advice is this:- If your a newbie to it, start with a selection of stones, carbide cutters are great when you get some experience, but can ruin a job if let get out of hand.
Do run the stones fast, 20,000rpm is good.
electric die grinders with and extended nose are what I used, Bosch made a good one.
Good stones are a must, the cheapie ones will only last a few minutes.
A selection of stones is needed, balls, cones and cylinder stones, nothing bigger than about 20mm.
You need good lighting to see what your doing.
A vacuum clearer if great to suck the dust out of the ports, use an old one, it will end up worn out.
Be carefull, it easy to wreck valve seats with a small slip.
Basicaly what you are doing is smoothie any sharp corners.
Never forget the the valve head is the greatest problem area, getting air to go round the valve head is the biggest problem area.
Go to it!

 

[nearGettysburg]

Thanks for the advice. I will narrow and smooth around the valve guide. This is a basically stock engine so I just want to make it a little better--nothing extreme.
Here is something I have wondered about---Since these long log manifolds are noted for poor breathing--especially for the end cylinders...would it make sense to spend a little more time and effort on cyls 1 and 6 to try and even out the flow?

 

[drag-200stang]

I would make them all the same. If they say the end cylinders run lean, would that be because the fuel is not getting there, and more air flow would make it worse? Air flows easier than fuel. When in doubt do less what looks right to the eye may flow less, that is where a flow bench is used to verify changes. One day you may fix the fuel distribution with carbs closer or on port fuel injection.

 

[aussie7mains]

Thanks for the advice. I will narrow and smooth around the valve guide. This is a basically stock engine so I just want to make it a little better--nothing extreme.
Here is something I have wondered about---Since these long log manifolds are noted for poor breathing--especially for the end cylinders...would it make sense to spend a little more time and effort on cyls 1 and 6 to try and even out the flow?

NO, the intake "manifold" has had some thought gone into it, even though its not ideal. The factory would have done quite a lot of work to get it as good as they could. Mixture distribution is most likely not as bad as you think, if it was the engine would idle roughly and have poor fuel consumption. So no, do not just work on the end cylinders. There isnt much to gain thining the guides, there is more to gain by blending the valve pocket immediately behind the valve seat. You cant get up the port very far, so not much to do there. Polishing the port makes it look shiney, nothing else.