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head porting hard?


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Posted

just got done reading a whole walkthrough on head porting and i cant say it looked easy but it didnt look that hard to do a basic port and polish job. the walkthrough was on some 305sbc heads, would the LQ1 heads be totally different or roughly the same idea? and is it possible to really screw up these heads or as long as you dont go crazy is it fairly safe? any info appreciated. thanks.

 

Posted

Its not hard to screw something up, and the DOHC heads are a lot more involved than the pushrod heads. If you decide to port them yourself, get a spare head at the very least to practice on. Remove the least amount that you can following the guide. SBC heads really aren't the same thing but the theory is the same.

Posted

ok, i may give it a try, im still undecided but thanks for the info.

Posted

I think someone said porting the LQ1 heads isn't usually worth the trouble. Of course, I have no idea who said that. It might have been Prospeeder for all I know.

Posted

It might have been Prospeeder for all I know.

 

:lol: i know ben was porting them and will be proting them once he gets some flowbenched but im sure a good port and polish job would help, not sure if what i can do will but i guess well see.

Posted

Not that I have any idea what I'm doing, but I started porting my TGP heads now that the exhaust manifolds are off. I don't intend on touching the combustion chamber at all, just opening up the ports to gasket match them (manifolds are next).

 

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I've barely begun to start it (the one port I started didin't come out clear so I didn't put it online).

 

You can see the rings around the ports on the heads though, and how far out the gasket goes. All that material is going. I need better stones though, I think. Taking a looong time and barely getting anywhere (doesn't help that my compressor is so small).

Posted

yea thats basically what i was planning on doing, i was also going to smooth over where the valve stem comes through the port and the short side radius. those are supposed to be big areas of restriction. and as for the combustion chamber all the walkthrough said to do was polish it, not to remove any metal.

Posted

Don't touch the short side radius and don't open up the exhaust to the gasket or the black ring. I can't share what to do exactly but I can tell you not to do those. The combustion chamber is the big area of focus honestly but you gotta know what to do on it or you can screw your flow. (talking pushrod on this one). Don't use stones on aluminum, its a big waste of stones and time. The metal is too soft for them. Carbide cutters and sand paper rolls are your best bet.

Posted

Don't touch the short side radius and don't open up the exhaust to the gasket or the black ring. I can't share what to do exactly but I can tell you not to do those.

 

Not that I doubt you, but can I ask how it will hurt?

Posted

You want a ridge around the exhaust port to help keep the gases from flowing back through the head. That and the larger exhaust port itself allows the gases to expand,which cools them down and you loose velocity. You can open the exhaust ports up some but you really want to go more for shape than size.

Posted

What if I were to make them more D-shaped, a la 3x00 heads?

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