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Manley Custom Valves
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blackhat  



Joined: 23 Apr 2008
Posts: 66
Location: Junction City, Kansas

PostPosted: Thu May 29, 2008 9:38 am    Post subject: Manley Custom Valves Reply with quote

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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flosho  



Joined: 01 Jul 2004
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Location: Eau Claire, Wisconsin

PostPosted: Thu May 29, 2008 10:24 am    Post subject: Reply with quote

$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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Rasta Monsta  



Joined: 12 Jul 2006
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PostPosted: Thu May 29, 2008 11:45 am    Post subject: Reply with quote

The 931 exhaust valves may be sodium filled. . .someone may pipe in if I am incorrect!
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bass gt  



Joined: 02 Dec 2004
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PostPosted: Thu May 29, 2008 11:45 am    Post subject: Reply with quote

Rasta Monsta wrote:
The 931 exhaust valves may be sodium filled. . .someone may pipe in if I am incorrect!


yep, hence their cost!!
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blackhat  



Joined: 23 Apr 2008
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Location: Junction City, Kansas

PostPosted: Thu May 29, 2008 11:48 am    Post subject: Reply with quote

bass gt wrote:
Rasta Monsta wrote:
The 931 exhaust valves may be sodium filled. . .someone may pipe in if I am incorrect!


yep, hence their cost!!


So that leads me to belive the pre-80 924 N/A's were not? Is there any concern with putting the larger valves in a '78 that aren't sodium filled?
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bass gt  



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PostPosted: Thu May 29, 2008 11:59 am    Post subject: Reply with quote

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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blackhat  



Joined: 23 Apr 2008
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PostPosted: Thu May 29, 2008 12:17 pm    Post subject: Reply with quote

bass gt wrote:
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


What's your valve measurements? I've only seen the 44mm and 38mm setups so far. Did you do any dyno's before and after? I'm curious what the curves look like before and after. I don't think I've seen any dyno charts for the 924 stock or post-mods yet.

As for the exhaust valve size, when I used to work on Mustangs, it was common practice to get the whole head to flow better on both intake and exhaust. It seemed that the ability to flow the exhaust gases out quickly and easily was just as important as flowing air in. Exhaust flow was even more crucial in forced induction applications but had definate improvements on naturally aspirated setups. I was planning on opening the exhaust side up with the valves and then getting a set of headers to help the flow out.

I completely understand the concept of more air the better and colder the better and why but it kind of was always thought that the exhaust was a forgotten important piece. Am I wrong on this?
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bass gt  



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PostPosted: Thu May 29, 2008 12:45 pm    Post subject: Reply with quote

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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blackhat  



Joined: 23 Apr 2008
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PostPosted: Thu May 29, 2008 1:08 pm    Post subject: Reply with quote

bass gt wrote:
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


Nice article! Thanks for the link! I'll have to keep that one in my back pocket for the future. It seems that 33mm may just be large enough. That should shave $100 of the total cost. Looks like I'll just ensure that the exhaust ports are gasket-match ported and polished.

Since the exhausts will be left at 33m, any idea on how large I could take the intakes with out interfering with the exhaust valves? I noticed on the pics I've seen with the 44mm/38mm there wasn't very much room left over. Does 46mm seem a bit to far? Can I go bigger do you think?

I'm trying to keep an N/A setup though. The only forced induction I could see is something of cold ram air set up, but that produces no where near the amount of boost a forced induction setup would. Is there going to be a point where the larger valves actually hinders the performance of the engine w/o forced induction?

As for the lower end, I'm definately planning on swapping out the rings while I have the head off.
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bass gt  



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PostPosted: Thu May 29, 2008 1:25 pm    Post subject: Reply with quote

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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Chrenan  



Joined: 15 Jan 2003
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PostPosted: Thu May 29, 2008 1:50 pm    Post subject: Reply with quote

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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blackhat  



Joined: 23 Apr 2008
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PostPosted: Thu May 29, 2008 2:27 pm    Post subject: Reply with quote

Chrenan wrote:
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.


I'm with ya. I guess I still have alot of muscle car thinking left in me. I'm used to playing with bore & stroke, compression, and CFMs in the head. Thus leaving suspension a far second. I was always careful to try and balance handling and power the best I could. I wanted my 'Stang to handle a track if it had to.

I hated seeing cars go fast in a straight line and nothing else. I was raised with Porsches and knowing that real skill comes into play when you have to go fast and take corners. (I was into draging though so I'm not knocking it.)

Before I started to strip the 924 down, I did enjoy taking some corners at 40/45+ where other cars could barely hold on at 30 (mph that is). And that was even with a bent steering column and bad bearing.

I'm just trying to get a little more pull coming out of the corners. I know the 4 speed is probably holding me back a little bit with the gearing being so far apart but I was hoping to get a little "put you in your seat" coming out of the corner.
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Rasta Monsta  



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PostPosted: Fri May 30, 2008 1:35 am    Post subject: Reply with quote

Blackhat, a 931 might make you happier, but I sense you need a 951.
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Chrenan  



Joined: 15 Jan 2003
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PostPosted: Fri May 30, 2008 1:47 am    Post subject: Reply with quote

Rasta Monsta wrote:
Blackhat, a 931 might make you happier, but I sense you need a 951.


I didn't want to say that. When you come to the realization that the 924 is an amazing platform that could handle more power, you'll also come to the realization that Porsche made a drug to satisfy your needs....951...924 on steroids.
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John Brown  



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PostPosted: Fri May 30, 2008 6:50 am    Post subject: Reply with quote

Rasta Monsta wrote:
The 931 exhaust valves may be sodium filled. . .someone may pipe in if I am incorrect!


Having heard this more than once, including from my local guru. But could find no documentation of same. So, in the words of my currently favorite educational site: "Hot for Valves decided to investigate".

Cut one apart. No sodium. Stainless and probably other expensive alloys mixed in. But no sodium.

http://www.hotforwords.com/
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