930 valves in a 951 8v head ?
10-08-2008, 02:21 AM
#31
Race Car
personally I am thinking about going with these
http://www.manleyperformance.com/dl/2008/valves.pdf
part numbers 11553-8
11563-8
I may look into the .100 long and use a smaller base circle cam (regrind)
If I am correct they should be able to retain the stock guides (with machining)
they will need new seats obviously and the portwork to match.
If I were tracking the car full time I would probably go with a more exotic exhaust valve but I have seen these valves hold up to over 1600 deg and for the type of driving I do that should be fine.
It should be pretty inexpensive for a large valve head.
http://www.manleyperformance.com/dl/2008/valves.pdf
part numbers 11553-8
11563-8
I may look into the .100 long and use a smaller base circle cam (regrind)
If I am correct they should be able to retain the stock guides (with machining)
they will need new seats obviously and the portwork to match.
If I were tracking the car full time I would probably go with a more exotic exhaust valve but I have seen these valves hold up to over 1600 deg and for the type of driving I do that should be fine.
It should be pretty inexpensive for a large valve head.
10-08-2008, 02:46 AM
#32
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Ya know, this seems to me, to be one of the most valuable and important topics, for our specific cars, that has really not been discussed.
I have a sensibility that those who do this kind of work, effectively, have a vested interest in not giving away their specific techniques; so we should have this discussion without vendor input, wherever possible.
It also seems, to me, that our brothers, in Europe, are putting the cash and *** behind making these large experiments, and are also most willing to share their techniques.
What mods can we push, with the 8 valve head? How far can we push it, with quantifiable results?
Ya know, I'm a Marine, and a fighter at heart. I live to mix it up. I've been trying to keep that way from this baord, over the last 6 or 8 months, but I'm still guilty.
We're going to need each other, the vendors that do so much to support us, regardless of allegiances, and we're going to need to bring in those who read silently, to really get where we all want to go.
CPR just busted his *** to make us some flexible splitters.
We have other guys willing to go and try to make positive changes, with good faith, but fail.
We have vendors, who frankly, give great service, but sort of created, by their own inter-industry fighting, on boards, a climate of rivalry and discord.
Honestly, we, as end users, go to bat for the vendor who has last treated us well, and often continues to do so.
Some don't remember the way it was in 2000, 01, 02. I was around then, from a whole different account. So some of our discord actually still occurrs, based on the old ways of the board, and a good bit of that came from the vendors, themselves.
It's time to change that; first by us, and then by them. No more vendor wars! It hurts us all. (Let them bitch slap each other over the phone!)
Let's start with 8 valve heads. If we can flow more, more efficiently, we can run bigger turbos, with more boost, and walk those fat assed 928 hosedogs, at every light! (simulated ofcourse!)
Anyway, let's make this thread count.
Our Euro brothers are doing some cool **** with their cars!
I have a sensibility that those who do this kind of work, effectively, have a vested interest in not giving away their specific techniques; so we should have this discussion without vendor input, wherever possible.
It also seems, to me, that our brothers, in Europe, are putting the cash and *** behind making these large experiments, and are also most willing to share their techniques.
What mods can we push, with the 8 valve head? How far can we push it, with quantifiable results?
Ya know, I'm a Marine, and a fighter at heart. I live to mix it up. I've been trying to keep that way from this baord, over the last 6 or 8 months, but I'm still guilty.
We're going to need each other, the vendors that do so much to support us, regardless of allegiances, and we're going to need to bring in those who read silently, to really get where we all want to go.
CPR just busted his *** to make us some flexible splitters.
We have other guys willing to go and try to make positive changes, with good faith, but fail.
We have vendors, who frankly, give great service, but sort of created, by their own inter-industry fighting, on boards, a climate of rivalry and discord.
Honestly, we, as end users, go to bat for the vendor who has last treated us well, and often continues to do so.
Some don't remember the way it was in 2000, 01, 02. I was around then, from a whole different account. So some of our discord actually still occurrs, based on the old ways of the board, and a good bit of that came from the vendors, themselves.
It's time to change that; first by us, and then by them. No more vendor wars! It hurts us all. (Let them bitch slap each other over the phone!)
Let's start with 8 valve heads. If we can flow more, more efficiently, we can run bigger turbos, with more boost, and walk those fat assed 928 hosedogs, at every light! (simulated ofcourse!
)Anyway, let's make this thread count.
Our Euro brothers are doing some cool **** with their cars!
10-08-2008, 10:18 AM
#34
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It was a bit long.. All I read was words, words, words.. j/k
Ehall, the only other problem here is that for every good idea, you get 3 people to bash them, 3 people who can make it cheaper in their garage(but really can't) and maybe 1 person who listens..
The simple fact that this thread came up now after headwork and cams have been around for YEARS, is amazing. JME has been the only real vender who did this. Others try but aren't anywhere near JME. Most of the cams made now are JME rip off's, including some other big name cam makers.
I'm not trying to stir things up, if you noticed, I added what I felt I could to this thread.
Let me continue to help,
Blown 944 is on the right track. If your going to do a big valve head, change the cam at the same time. Then get the valve lengths cut to suit the cam. If you don't, you will need lash caps.. Its not a big deal but if you continue to use 9mm valves, finding lash caps is not easy.
Ehall, the only other problem here is that for every good idea, you get 3 people to bash them, 3 people who can make it cheaper in their garage(but really can't) and maybe 1 person who listens..
The simple fact that this thread came up now after headwork and cams have been around for YEARS, is amazing. JME has been the only real vender who did this. Others try but aren't anywhere near JME. Most of the cams made now are JME rip off's, including some other big name cam makers.
I'm not trying to stir things up, if you noticed, I added what I felt I could to this thread.
Let me continue to help,
Blown 944 is on the right track. If your going to do a big valve head, change the cam at the same time. Then get the valve lengths cut to suit the cam. If you don't, you will need lash caps.. Its not a big deal but if you continue to use 9mm valves, finding lash caps is not easy.
10-08-2008, 02:02 PM
#35
Rennlist Member
How much room is there for larger valves in the head? I'm sitting here doing the math and I realized that the factory intake and exhaust valves are sized correctly to each other for the turbo, and the 2.7 valves are sized correctly for the n/a engine, but the 2.7 valves are not sized correctly for the turbo. (Going on the idea that for a turbo engine you want your exhaust valve to be 90-95% the size of the intake valve (70-80% the size for n/a engine) - the stock turbo valves have the exhaust valve at 89% of the intake valve size, while the stock 2.7 valves have the exhaust at 83% of the intake valve side)
Back to the question, any idea how large of an exhaust valve can fit into these heads without having to do major work to the combustion chamber on the head (assuming either the 45mm or 48mm intake valve)? I'm currently thinking I may try to go for something around a 47mm intake valve and then a 42mm or 43mm exhaust valve. Anyone have any experience with mixing up the sizes that much, or do people usually just stay rather close to the stock 2.7 valve size ratio?
Back to the question, any idea how large of an exhaust valve can fit into these heads without having to do major work to the combustion chamber on the head (assuming either the 45mm or 48mm intake valve)? I'm currently thinking I may try to go for something around a 47mm intake valve and then a 42mm or 43mm exhaust valve. Anyone have any experience with mixing up the sizes that much, or do people usually just stay rather close to the stock 2.7 valve size ratio?
Last edited by billthe3; 10-08-2008 at 02:57 PM.
10-12-2008, 01:03 PM
#36
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in reply to Dave's post I can make everything cheaper and faster from scrap metal in my dungeon don't dare ask how long it has been since any of my cars were driven .
yeh there are several gains to be had from going for a different valve reduced weight more choice in guides and seals and cheap cams(regrind) more valve size
seems i will probably have my 16 titanium valves retainers and a reground pair of cams for less than 800 bucks .and with the weight reduction i can reuse the old springs
yeh there are several gains to be had from going for a different valve reduced weight more choice in guides and seals and cheap cams(regrind) more valve size
seems i will probably have my 16 titanium valves retainers and a reground pair of cams for less than 800 bucks .and with the weight reduction i can reuse the old springs
10-12-2008, 08:32 PM
#38
Rennlist Member
Thanks for the info. Was it a ton of work to get the 44mm exhaust valve in there? Did you have to do any alterations to the combustion chamber in the head to fix any shrouding issues? How well is the SS valve holding up for the exhaust? I suppose you'd have to have pulled the head off again after the work was done to know about that last one. Thanks for any info.
10-13-2008, 04:23 AM
#39
Former Vendor
^^^The gentleman who did that head wrote me two sheets full of text what he had done... That was not his first 944 big valve head. Takes some time, but it's not rocket science. All parts related to valve mechanism are custom made, except stiffer springs. They can be obtained from eg. LR.
10-13-2008, 09:53 AM
#40
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You need to install the larger seats and then open up the port to match. On the combustion chamber, yes, you need to open it up around both larger valves. This should be done and tested on a bench. SS valves are fine for what we use them for. DE's and club race, I would coat the valve face and the port.
10-13-2008, 11:33 AM
#41
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your a believer in the coatings Dave ? seen any good back to back data ?
the concept of them makes sense but I've also wondered how effective realy .
these coating's can't seem to catch on in oem stuff and if they were realy effective wouldn't they help carry the heat to the catilitacic converter ?
and a stainless or titanium valve is not very conductive thermally wouldn't the coating's be more more effecive in the port and pipes ?
the concept of them makes sense but I've also wondered how effective realy .
these coating's can't seem to catch on in oem stuff and if they were realy effective wouldn't they help carry the heat to the catilitacic converter ?
and a stainless or titanium valve is not very conductive thermally wouldn't the coating's be more more effecive in the port and pipes ?
10-13-2008, 03:47 PM
#42
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While your right, some people do make a living off this, it is not the reason why I'm not sharing. There are a few reasons...
1. Its not an easy "bolt on" thing. So, its not an easy thing to write about and answer questions. I don't have time to walk everyone through this on a forum that I check every few days.
C. Every head is different and the guides I use are custom made to the head.
5. For the 3-4 people that would actually understand and carry through with it, there will be 15 people that will tell me I do it wrong. That has grown very old, as old as the amount of drama on this "tech" forum. Especially from the "protected"
Let me give you a "head" start. A 2.7ltr intake valve is 48mm SOooo, you are looking for a BB Chevy valve that is close to 1.890", which will be 1.88 0r 1.90" The most common use a valve 11/32 stem(which is a hair smaller then 9mm). They can be ordered and bought through Ferrea. If your looking for exhaust valves, the can be ordered with a sodium filled stem, see link. Use other pages on the link for intake valves..
http://www.ferrea.com/general-result...tegory_id=6036
You will need all the supporting hardware, guides, seats, locks, retainers, etc...
These are not what I would use but they are good for any street/De car.
Is that enough?
1. Its not an easy "bolt on" thing. So, its not an easy thing to write about and answer questions. I don't have time to walk everyone through this on a forum that I check every few days.
C. Every head is different and the guides I use are custom made to the head.
5. For the 3-4 people that would actually understand and carry through with it, there will be 15 people that will tell me I do it wrong. That has grown very old, as old as the amount of drama on this "tech" forum. Especially from the "protected"
Let me give you a "head" start. A 2.7ltr intake valve is 48mm SOooo, you are looking for a BB Chevy valve that is close to 1.890", which will be 1.88 0r 1.90" The most common use a valve 11/32 stem(which is a hair smaller then 9mm). They can be ordered and bought through Ferrea. If your looking for exhaust valves, the can be ordered with a sodium filled stem, see link. Use other pages on the link for intake valves..
http://www.ferrea.com/general-result...tegory_id=6036
You will need all the supporting hardware, guides, seats, locks, retainers, etc...
These are not what I would use but they are good for any street/De car.
Is that enough?
, lol
10-06-2010, 04:39 PM
#44
Bump...
Anyone knows the weights of :
- stock 2.7 intake valves
- stock turbo exhaust valves?
I totally forgot to weigh mine before assembling the head...
Do you remember the weights?
Anyone knows the weights of :
- stock 2.7 intake valves
- stock turbo exhaust valves?
I totally forgot to weigh mine before assembling the head...
Do you remember the weights?