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blackhat · Posted: Thu May 29, 2008 9:38 am Post subject: Manley Custom Valves

Hey all!

I was talking to a wrench turning buddy of mine at work today about my head and we got to talking about doing the large valve swap. I don't really have the money to send my head off to EuroMod and figured my machinest here would be able to put larger valves in if I could supply them and it would come out cheaper in the end.

We were trying to figure out where to start looking for valves that would fit and decided to check out some manufacturers' websites.

We decided to go to Manley's site and looked around. It was the first site we went to and BAM in the top right corner it said "Order Custom Valves". I didn't have the measurments and they didn't list the prices so I decided to give a call. I figured it wouldn't hurt to ask someone what they run.

A very nice lady answered the phone and said that the average for their Custom Gen II Race valves was $25 per valve. I was shocked! To me, that seems cheap. Am I off base here? This seems like a decent price to me and would put the big valve swap with in my grasps. I was so shocked at the price I forgot to ask about a bulk purchases so, I'm not sure if we got a group together if they'd knock the price down.

Thoughts anyone?

The link to the order form is here.
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My First Porsche
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1978 Porsche 924 N/A

flosho · Posted: Thu May 29, 2008 10:24 am Post subject:

$25/ valve is a very good price for 931 valves, I'm not sure what the cost of OEM replacement valves are for the 924 n/a but I don't think they cost as much as the turbo's.

For $200 plus the cost of your local machine shop, seems like a good investment. I'm sure the guys with n/a experience will chime in.
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[This Space For Rent]

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11723 Location: PacNW

The 931 exhaust valves may be sodium filled. . .someone may pipe in if I am incorrect!
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

bass gt · Posted: Thu May 29, 2008 11:45 am Post subject:

blackhat · Posted: Thu May 29, 2008 11:48 am Post subject:

bass gt · Posted: Thu May 29, 2008 11:59 am Post subject:

The advantage of sodium filled valves is their ability to deal with the heat generated within a turbo motor. In terms of valve sizes, it's the inlet you want to make bigger. the exhaust isn't so important. performance comes from the ability to get more air fuel mixture into the cylinder. So my advice is stick with the stock exhaust valves and go as big as possible on the inlets. Works for me

Steve
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Front Wheel Drive is the Devil's work.

blackhat · Posted: Thu May 29, 2008 12:17 pm Post subject:

bass gt · Posted: Thu May 29, 2008 12:45 pm Post subject:

My car is a little too modified to be used as a comparison

My latest engine will be making north of 350 at the crank, maybe 400. however, have a read of this article to get an idea of the principles. http://www.pumaracing.co.uk/Exvalve.htm
Depending on what kind of power you are looking for, i doubt very much you need to mess about with the exhaust side. The limiting factor is the heads design. I really is shite in terms of flow. The turbo head is a little better, but thats like saying smallpox is better than bubonic plague.
if you are talking about the normally aspirated engine, i would be suprised ifyou saw the quoted 125bhp stock value. Even the most extreme mods will only get this engine up to about 150bhp. If you want to turbo the engine, then you have more options, but don't think huge numbers are easy to find. 250bhp seems the average power once the engine has been intercooled and worked on fuel wise.
Oh, and if this is for an N/A car, you won't need Sodium valves. Just go with what you have found. You would be better off fitting decent fuel injection, a good ECU and exhaust system. If you then fit a cam, raise the CR and dial the cam in with a vernier wheel, that will see you there. But be sure your motor is in good order, such as rings ect, as this will cut you off at the knees if you try to tune her up with a shot bottom end.

regards,

Steve
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Front Wheel Drive is the Devil's work.

blackhat · Posted: Thu May 29, 2008 1:08 pm Post subject:

bass gt · Posted: Thu May 29, 2008 1:25 pm Post subject:

46=48 mm is fine. If you look at the set up, going too large actually causes the valve to be shrouded by the cylinder wall. Not an ideal situation. So 46 & 33mm, good cam, and sort out the fuel/spark. lots of guys here have switched to megasqirt/vems, and there are various Ford parts that can be used as well. Check out Todd (endwrench) for really good fuel rails and injector bungs. But be prepared for little return for a lot of work. In all honesty, you would be better off making sure she is running well, and concentrate on the handling. The whole point of these cars is their balance. This would probably make the car faster in the real world, as oposed to 20-25bhp.

Steve
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Front Wheel Drive is the Devil's work.

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

I'm with Steve, there are limits to what you can get out of the NA engine. Do what you feel you can afford, at a minimum rebuild what is required in the engine to get it at least performing at stock levels. Then save some money for the suspension, these cars can be made to handle frighteningly well for a 30 year old platform.
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1987 951 - M193 Version for Japan

blackhat · Posted: Thu May 29, 2008 2:27 pm Post subject:

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11723 Location: PacNW

Blackhat, a 931 might make you happier, but I sense you need a 951.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA