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Insight on valve seat/machining

MJTru

By MJTru,
in Engines & Forced Induction

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MJTru Mentor

MJTru

Posted
Posted

Hello everyone.

Its been awhile since i was here. Last time was when i was changing out rb26 guides to a bc units that needed to be cut to the right length. Simple truth the supertech stuff are the exact same as oem nissan rb26 guides no cutting just install. After i bought a tool that pulls the guid in the head. KEEPING in mind the head was very hot and guides frozen in nitrogen. I got the in with no problems, no galling nothing. It was all an experiment really. So i started to lap the valves, and yes now i have to have the seats cut to the new center line of the new brass guides. Wow. What a damn workout after all those tools i bought.

So i spent the last month and a half refecting on what i want to do. I could send the heads out, as i have 2 heads that are new and will need the works basically done to them. From guids to seats valves, relief cut for cams. Small bit of porting and so on.

This got me thinking. So i started looking into way i can cut the seats myself. And correct me is im wrong here but at minimum ill need a accuracy of 001 of an inch for racing, and the old school guys that used stones and blades to cut the seats were around 003 of an inch, as well as takes lots of skill at minimum a machine that can be bought today for about 15k usd.

I started to look at methods used to cut seats. I came across lots, one machine floats heads and machining bit on a cushion to find true center line. Next was one of my favorites Newen fixed tuning contour BB.

In short guys im looking to have my shop move into this field of machining, i enjoy the stuff. I want to redirect my funds to provide a service rather than waste it racing.

I know this topic might me in the wrong section, but there is reliance to it. First we know you need to cut seats when we change guides, next the method to changing rb26 guides i can show anyone if there willi g to pm me. Next we know the heads needs to be heated and guides frozen, so its not all a waste, last bc guides needs to be cut to size. I dont like that so go with supertech one i would say.

If anyone here can help point me into the right direction, like a head machining forum, or a place i can gather lots of info on methods to service heads cutting tools anything. I can see an initial investment of over 500k. A contour bb is about 80k new. But this is the path to my future. This is what i want. Ill be the first in my region if i can accomplish this goal. Thanks for taking the time to read over my thread, and i thank you in advance.

Marcus.

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KiwiRS4T Grand Master

KiwiRS4T

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If you are going to invest that amount of money maybe you could spend a few bucks visiting some top machine shops (in the guise of scoping out someone to do your heads) and see what modern day best practice looks like...and what machines they are using.

MJTru Mentor

MJTru

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Thats in the books. As im taking a trip next month. Im also looking to visit some trade shows regarding the subject. But its all new so im searching where ever i can. I was hoping for a good machining form.

GTSBoy Grand Master

GTSBoy

Posted
Posted

PM TK (Tony Knight) on Performance Forums. Adelaide guy, does engines and heads and is a guru and is usually fairly willing to help people out.  He is usually flat out busy, so don't be too taxing in what you ask him.  I would suggest asking what he would recommend for someone who wanted to set up to do the sort of machining you're talking about with low cost but good results.  Special emphasis on being in a fairly remote place (from Australia) and being not quite 1st world, if you know what I mean.

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