Adding Material To The Inlet Ports????

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Duk
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Adding Material To The Inlet Ports????

Post by Duk » Fri Sep 28, 2012 9:22 pm

I've been looking to tidy up the ports in my 12 valve heads, but what I've noticed is that there isn't really a short side radius in the inlet port, where the port floor turns and meats the valve seat. It's more like a mitered corner. You can actually feel the back edge of the valve seat in 1 of the ports.
Another area of concern is the bowl area. It appears (measures with inside dividers) to be too big in some places.

So I'm considering adding some material to help me get good clean curves and keep cross sectional areas as consistent as possible.
Obviously TIG welding some aluminium into the ports would do this, but it's not practical for me to pay someone (IE: No coin for that) to do that.
I'm also not too keen on using epoxy (tho I have done something similar in my other car).
So I thought about using some of the aluminium brazing rods that are readily available.

Has anybody had any experience with aluminium brazing rods?
I figured I'd preheat the head(s) in the oven, but what would be an safe temperature to go to?

Thoughts and opinions, please.
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Mats
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Re: Adding Material To The Inlet Ports????

Post by Mats » Sat Sep 29, 2012 1:58 am

I would NEVER heat the area around the valve seat, that is a sensitive area.
Epoxy filler has been used for 20-30 years (?), surely there must be knowledge about it?
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scott.venables
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Re: Adding Material To The Inlet Ports????

Post by scott.venables » Sat Sep 29, 2012 3:34 am

The company I work for make 120hp/litre aircooled motorcycle engines. They've used epoxy, Devcon I think, in the inlet ports without problem

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Re: Adding Material To The Inlet Ports????

Post by Duk » Sun Sep 30, 2012 2:32 pm

Mats, I was thinking the same thing about welding or brazing near the valve seats.
If I was getting really into Alfa head development, I'd add lots of metal to the port floor (to get a better short side radius happening)and have new valve seats put in.

After getting stuck into it a bit, it's probably not as bad as I first thought. No real spare material around the SSR but I'll tidy it up as best I can. Still would have liked more metal there and in bowl area.
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Re: Adding Material To The Inlet Ports????

Post by Mats » Mon Oct 01, 2012 3:14 am

Check out guy croft's site, he has some nice tech stuff on there about adding material.
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Re: Adding Material To The Inlet Ports????

Post by gran turismo » Wed Oct 03, 2012 3:09 pm

I did it to the inlet ports on my 12v 3L. I used devcon titanium putty (recommended by Devcon). I haven't run the motor yet though, been busy on other stuff. I'll let you know how it works out though (Richard Jemison told me it is a bad idea and I should "remove that plastic"!).

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Re: Adding Material To The Inlet Ports????

Post by squadragrunn » Mon Oct 29, 2012 4:08 am

filling with epoxy is common practise in the bikeworld, check this http://mototuneusa.com/homework.htm
this is on bikes with>150hp/l!!!
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