Port matching

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Dec 16, 2012 | 01:39 AM

brandon k

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Joined: Nov 2012

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Port matching

I just got some new heads from my machine shop, with new valves, springs, guides, seats, and all put together. So my question is can i port match them still? Or am i risking damaging my new machine work and valves? Can i port match and then clean out the debris as well as possible and be fine? Thank you!

Dec 16, 2012 | 09:19 AM

HIO Silver

Fleet Owner

Joined: Dec 2009

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From: NorCal

Yes still doable but this shouldda been done before getting the heads rebuilt.

Install a valve cover and tape the mating surfaces to seal it. Stuff each runner with a rag. Some guys use shaving cream. You have carbide attachments and a die grinder, right? Other tools: scribe, machinist dye, shop vac. Port match only the first inch of each runner. Leave the runners slightly rough to preserve some surface turbulence and to avoid laminar flow.

Dec 16, 2012 | 11:12 AM

turbohunter

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From: Northern and Southern Cal

Think about investment vs reward. What will you achieve?
I would think manifold to head.

Dec 16, 2012 | 04:07 PM

stromburg

Senior User

Joined: Oct 2012

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From: Arlington

I am doing the same thing, so i bought a spring commpressor to take my heads back apart [cheap insurance]

Dec 16, 2012 | 04:33 PM

turbohunter

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From: Northern and Southern Cal

Maybe this will help illustrate my point. The heads flow fine for the street already IMHO and IMHO just need cleaning up. But the manifold to the head intersection is where the shape could use a little help. Take a look at the manifold in the pic. Thats how much extra material is there that has to be taken out to match the head port.
I'm just saying if you're going to run it on the street, you don't need to go over board with porting on the head.
Just my opinion.

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Dec 17, 2012 | 01:49 AM

Rory428

Mountain Pass

Joined: May 2006

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What is the intended application for this engine? For most applications short of a race engine, unless there is a huge port mismatch, I doubt that spending a bunch of time grinding on the heads, or intake for that matter will give you any more than a bunch of metal dust in your hair, and that awful taste in your mouth. I can`t imagine you would see any performance gain that could be felt either on the street, or at the track, at least for most street applications.

Dec 17, 2012 | 02:14 AM

7636074460

More Turbo

Joined: Oct 2011

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From: down a red dirt road

I don't usually mess with the intake side, for one reason it can ruin the turbulence needed for a good mixture and stay street able and two, usually way to much work/too much material will have to come out.
My lil 306 I built I fully matched the exhaust ports to the gasket and fully matched the manifolds and polished as far in as I could. I believe it gave very noticeable throttle response although the bottom end was fully balanced also and probably what made the biggest difference!
my new FE build I did the same but I've yet to run it... I'm like five wires away!