Can I just put an N/A head onto the turbo block, it seems I can get those cheaper and they are remarkably simular except for the camshaft....I dont have any experience or knowledge in the internals of the 951 motor. Thanks for any help.

 

The turbo heads have ceramic in the exhaust ports, but that is not necessary.

 

They also have sodium filled exhaust valves.

-Darwin

 

O, I just assumed you were swapping everything over while you were keeping your cam. Springs are stiffer as well I think? Not sure on that one.

 

I actually like the idea of a ported na head better. This way you wont have to worry about the ceramic chipping off and taking out the turbo

 

I was under the impression that as long as the car doesn't venture much past stock, the N/a internals are ok. I think the N/a head has a different cooling block though, so it might not work.

 

N/A head can be used with turbo block and in turbo applications. It bolts on. Differences to turbo head are ceramic liners in exhaust ports, sodium filled exhaust valves and valve springs. With those differences the really usable part is only the head, and only when you're planning significantly bigger valves.

In other words N/A head is excellent baseline for custom built high-flo turbo head. You can pick all parts for that from ( for example ) Manley's catalogue and get easily like 48mm in and 44mm ex valves, in stainless and even with sodium filled exhaust valves. Custom job then requires new valve seats and guides. Porsche original valves have very thick stems, actually thicker than ( almost ) any aftermarket manufactures has. Sturdy but heavy ( and not good for high rpms ). Custom job also includes some modifications to retainers etc. but any good shop can do that.

Actually I'm wondering that why this hasn't been done more, it's not rocket science or blasphemy...and at least there over the Atlantic are lots of shops, parts and racing engine building experience. Just think out of the box.

Cost? Over here, with parts, around €1000,- .

 

[QUOTE=pete95zhn]Actually I'm wondering that why this hasn't been done more, it's not rocket science or blasphemy...and at least there over the Atlantic are lots of shops, parts and racing engine building experience. Just think out of the box.QUOTE]

Its been done a lot. The only real problem is that it requires a lot more porting just to get it to flow what a stock turbo head can do and then more work to get it to flow its max. In stock form the n/a head is a small downgrade over a turbo head.

 

So the ceramic liners in the exhaust ports really arent necessary? I was under the impression the head would take in too much heat or something without them.

 

If not having ceramic liners is a big concern, you can have them coated by someone like Swaintech. The applied coating probably won't be as good as the OEM cast in liners, but it'll be better than nothing.

 

That would make sense. As long as you arent going too exotic you could simply replace the valve springs (which you would want to do on a rebuild anyways,) and plan on some lapping and a good set of turbo valves? Im looking to put a cheap broke motor back into service...

 

I have a full set of EXCELLENT (uncut) condition 951 valves for sale, if anyone is interested.

 

The exhaust ports are shaped differently.

The ceramic coating is mainly for emissions, I hear it has no noticeable effect on power.

 

Mark,
Where is the difference? i have a NA and turbo head, i didn't notice a difference.

 

Is your sledgehammer head based on a 951 or and N/A head?