Race Engine Built Question
11-09-2007, 09:04 PM
#16
Rennlist Member
Thread Starter
John V aka The Dude
- I will be using GT cams, JDS re-map of EZK and LH, Ford injectors and 928 Intl headers to take advantage of the bigger valves. Anything else I should be considering?
11-10-2007, 12:44 AM
#17
Three Wheelin'
Join Date: Jan 2007
Location: not where you think I am
Posts: 1,466
Likes: 0
Received 0 Likes
on
0 Posts
First---
DO NOT TAKE A DREMEL TO THE PISTON NOTCHES as Mark had said. You cannot cut them precisely, and you cannot get the angles correct.
(sometimes I can't believe what experienced racers will say....no offense Mark)
have your machinist flycut the valve notches deeper, especially if you are changing cams (either adding lift or adding duration or both). while he's doing it, do both the intake and exhaust valve notches.....maybe .100 inch, but you won't know for sure unless you test fit the cams thru their entire rotation. use clay on the piston tops, and do not use a regular valve spring while testing. check the clay thickness or lack of, after rotating the engine thru the entire camshaft rotation. I have no idea what valve/piston clearances the Porsche race teams are running these days, but when I built my race engines, I never went any closer than .100 inch for the entire engine rotation.... SEE Crane Cams website for checking valve/piston clearances.
Second---
if you are wanting to do performance head work, be careful how big you open the ports. Too big, your engine will not run for s*** at low rpm. Same thing with cams---too big, especially if you run a slushbox, the car will not "leave" worth a damn. be sure to do port matching on both ends, intake and exhaust.
I just got my heads (Euro 16V) back from Nickens Bros Racing, and they did a wonderful job---- $1650 for porting, polishing, 5 angle valve job, unshroud the valves, clean up the pockets, lightly mill the heads (still within spec's).
Third---
do not mill the heads any more than is necessary to clean up the mating surface. while you may gain some compression ratio values, you will cause the cam timing to be off (unless you install one of Porken's adjustable cam timing kits). The FMW's have a standard for head/deck measurement, and it is not to be violated, or they recommend using another head.....Again, your performance will suffer if you don't follow these suggestions.
Fourth---
if you are changing valves, go with a valve that is:
1. lighter---preferably titanium ($$$$$$)
2. bigger in diameter (at the seat--requires changing the valve seat to match the bigger valves)
3. has smaller diameter stems (requires smaller diameter valve guides)
Fifth---
have you considered the valve spring installation (making sure they are of correct pressures and installed heights)???? =this is something that is overlooked all the time. there are other alternatives in valve springs as well....lighter, stronger, etc.---$$$$$$.
Hope this helps----
---Russ
DO NOT TAKE A DREMEL TO THE PISTON NOTCHES as Mark had said. You cannot cut them precisely, and you cannot get the angles correct.
(sometimes I can't believe what experienced racers will say....no offense Mark)
have your machinist flycut the valve notches deeper, especially if you are changing cams (either adding lift or adding duration or both). while he's doing it, do both the intake and exhaust valve notches.....maybe .100 inch, but you won't know for sure unless you test fit the cams thru their entire rotation. use clay on the piston tops, and do not use a regular valve spring while testing. check the clay thickness or lack of, after rotating the engine thru the entire camshaft rotation. I have no idea what valve/piston clearances the Porsche race teams are running these days, but when I built my race engines, I never went any closer than .100 inch for the entire engine rotation.... SEE Crane Cams website for checking valve/piston clearances.
Second---
if you are wanting to do performance head work, be careful how big you open the ports. Too big, your engine will not run for s*** at low rpm. Same thing with cams---too big, especially if you run a slushbox, the car will not "leave" worth a damn. be sure to do port matching on both ends, intake and exhaust.
I just got my heads (Euro 16V) back from Nickens Bros Racing, and they did a wonderful job---- $1650 for porting, polishing, 5 angle valve job, unshroud the valves, clean up the pockets, lightly mill the heads (still within spec's).
Third---
do not mill the heads any more than is necessary to clean up the mating surface. while you may gain some compression ratio values, you will cause the cam timing to be off (unless you install one of Porken's adjustable cam timing kits). The FMW's have a standard for head/deck measurement, and it is not to be violated, or they recommend using another head.....Again, your performance will suffer if you don't follow these suggestions.
Fourth---
if you are changing valves, go with a valve that is:
1. lighter---preferably titanium ($$$$$$)
2. bigger in diameter (at the seat--requires changing the valve seat to match the bigger valves)
3. has smaller diameter stems (requires smaller diameter valve guides)
Fifth---
have you considered the valve spring installation (making sure they are of correct pressures and installed heights)???? =this is something that is overlooked all the time. there are other alternatives in valve springs as well....lighter, stronger, etc.---$$$$$$.
Hope this helps----
---Russ
Last edited by largecar379; 12-14-2008 at 02:28 AM.
11-10-2007, 07:10 AM
#18
Addict
Rennlist Member
Rennlist Member
http://www.federal-mogul.com/en/Afte...ain/AE-Valves/
11-10-2007, 08:12 AM
#19
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Anything else I should be considering?
I think Louie Ott has a set of individual throttle bodies on the shelf
Last edited by John Veninger; 11-10-2007 at 10:02 AM.
11-10-2007, 09:57 AM
#20
Rennlist Member
11-14-2007, 01:13 PM
#24
Rennlist Member
Thread Starter
I have the side spacer plates cut out to 8mm thickness as I will leave the injector foam off, which should allow me to fit them at a tight squeeze
With regards to Louie Ott's product - I have been thinking about it recently... The problem is that Dr Nick of Orange Car fame got me into yachts too, so now I "need" to buy a 44' carbon fibre racer and every penny / cent is beginning to count...
I will pm Louie anyway...
11-14-2007, 04:35 PM
#26
Drifting
Join Date: Nov 2001
Location: zürich, switzerland
Posts: 2,233
Likes: 0
Received 0 Likes
on
0 Posts
about
2 out of 3 is enough; cars & boats do not take your house with them when you scrap them...
Marton
HTML Code:
you guys with jobs in the city... cars, boats, women...!
Marton
11-14-2007, 04:42 PM
#27
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 60 Likes
on
34 Posts
Thanks to Greg for the port sizing question. Yes, the TRW valves are made by kolbenschmidt - TRW bought Kolbenschmidt a while ago. The world of automotive components is a weird and wonderful place - Febi owns Bilstein, Goetze and Mahle are part of the same family, TMD Friction of Germany owns Pagid, Textar and Mintex. My BMW's interior trim is made by Faurecia, which usually supplies Peugeot with seats and so on and so forth.
John V aka The Dude - I will be using GT cams, JDS re-map of EZK and LH, Ford injectors and 928 Intl headers to take advantage of the bigger valves. Anything else I should be considering?
John V aka The Dude
- I will be using GT cams, JDS re-map of EZK and LH, Ford injectors and 928 Intl headers to take advantage of the bigger valves. Anything else I should be considering?
11-14-2007, 07:38 PM
#29
Rennlist Member
Russ, no offence taken. Im the first to admit i often take the short route, but always try and do the homework to make sure im not taking any unesessary risks.
You are making an assumption with the 1mm broading of the valve pocket diameter, not depth. (remember the euro 84 cams have more lift, yet the valve pockets are 1/2 as deep.) one assumption is that the engine will be interference. If you read my build up thread on the 5 liter 2 valve engines, you see that you cant (or at least , not easily) rotate the engine over with clay on the pistons. (hydrolic lifters have to be replaced for that test to mean anything)
Since we know the engine is "interference" it is VERY easy to clay the pistons and dremel out the diameter to match the valves. by using a lever arm, you compress the valve directly and see wear they end up on the pistons. often, you will see contact with the depth of the valve pocket at .3",while lift can be .5". the valve pocket depth on the 5 liter piston will be near .175" thats all that is really safe to remove from those pistons. claying shows that there is clearance, (some clearance) and this is to protect the valves on the intake/exhaust stroke when they chase the piston down. if the belt breaks, the reliefs help, but not for full rotation of the engine.
I also dont think that valve weight and matched springs are much of an issue, as our engines typically only run to 6500rpm (928s) those factors become much more important to real race engines with redlines in the 9000 rpm range.
below show before dremel and after dremel effect on valves that touched the valve reliefs during clay test.
Mk
You are making an assumption with the 1mm broading of the valve pocket diameter, not depth. (remember the euro 84 cams have more lift, yet the valve pockets are 1/2 as deep.) one assumption is that the engine will be interference. If you read my build up thread on the 5 liter 2 valve engines, you see that you cant (or at least , not easily) rotate the engine over with clay on the pistons. (hydrolic lifters have to be replaced for that test to mean anything)
Since we know the engine is "interference" it is VERY easy to clay the pistons and dremel out the diameter to match the valves. by using a lever arm, you compress the valve directly and see wear they end up on the pistons. often, you will see contact with the depth of the valve pocket at .3",while lift can be .5". the valve pocket depth on the 5 liter piston will be near .175" thats all that is really safe to remove from those pistons. claying shows that there is clearance, (some clearance) and this is to protect the valves on the intake/exhaust stroke when they chase the piston down. if the belt breaks, the reliefs help, but not for full rotation of the engine.
I also dont think that valve weight and matched springs are much of an issue, as our engines typically only run to 6500rpm (928s) those factors become much more important to real race engines with redlines in the 9000 rpm range.
below show before dremel and after dremel effect on valves that touched the valve reliefs during clay test.
Mk
First---
DO NOT TAKE A DREMEL TO THE PISTON NOTCHES as Mark had said. You cannot cut them precisely, and you cannot get the angles correct.
(sometimes I can't believe what experienced racers will say....no offense Mark)
have your machinist flycut the valve notches deeper, especially if you are changing cams (either adding lift or adding duration or both). while he's doing it, do both the intake and exhaust valve notches.....maybe .100 inch, but you won't know for sure unless you test fit the cams thru their entire rotation. use clay on the piston tops, and do not use a regular valve spring while testing. check the clay thickness or lack of, after rotating the engine thru the entire camshaft rotation. I have no idea what valve/piston clearances the Porsche race teams are running these days, but when I built my race engines, I never went any closer than .100 inch for the entire engine rotation.... SEE Crane Cams website for checking valve/piston clearances.
Second---
if you are wanting to do performance head work, be careful how big you open the ports. Too big, your engine will not run for s*** at low rpm. Same thing with cams---too big, especially if you run a slushbox, the car will not "leave" worth a damn. be sure to do port matching on both ends, intake and exhaust.
I just got my heads (Euro 16V) back from Nickens Bros Racing, and they did a wonderful job---- $1650 for porting, polishing, 5 angle valve job, unshroud the valves, clean up the pockets, lightly mill the heads (still within spec's).
Third---
do not mill the heads any more than is necessary to clean up the mating surface. while you may gain some compression ratio values, you will cause the cam timing to be off (unless you install one of Porken's adjustable cam timing kits). The FMW's have a standard for head/deck measurement, and it is not to be violated, or they recommend using another head.....Again, your performance will suffer if you don't follow these suggestions.
Fourth---
if you are changing valves, go with a valve that is:
1. lighter---preferably titanium ($$$$$$)
2. bigger in diameter (at the seat--requires changing the valve seat to match the bigger valves)
3. has smaller diameter stems (requires smaller diameter valve guides)
Fifth---
have you considered the valve spring installation (making sure they are of correct pressures and installed heights)???? =this is something that is overlooked all the time. there are other alternatives in valve springs as well....lighter, stronger, etc.---$$$$$$.
Hope this helps----
---Russ
DO NOT TAKE A DREMEL TO THE PISTON NOTCHES as Mark had said. You cannot cut them precisely, and you cannot get the angles correct.
(sometimes I can't believe what experienced racers will say....no offense Mark)
have your machinist flycut the valve notches deeper, especially if you are changing cams (either adding lift or adding duration or both). while he's doing it, do both the intake and exhaust valve notches.....maybe .100 inch, but you won't know for sure unless you test fit the cams thru their entire rotation. use clay on the piston tops, and do not use a regular valve spring while testing. check the clay thickness or lack of, after rotating the engine thru the entire camshaft rotation. I have no idea what valve/piston clearances the Porsche race teams are running these days, but when I built my race engines, I never went any closer than .100 inch for the entire engine rotation.... SEE Crane Cams website for checking valve/piston clearances.
Second---
if you are wanting to do performance head work, be careful how big you open the ports. Too big, your engine will not run for s*** at low rpm. Same thing with cams---too big, especially if you run a slushbox, the car will not "leave" worth a damn. be sure to do port matching on both ends, intake and exhaust.
I just got my heads (Euro 16V) back from Nickens Bros Racing, and they did a wonderful job---- $1650 for porting, polishing, 5 angle valve job, unshroud the valves, clean up the pockets, lightly mill the heads (still within spec's).
Third---
do not mill the heads any more than is necessary to clean up the mating surface. while you may gain some compression ratio values, you will cause the cam timing to be off (unless you install one of Porken's adjustable cam timing kits). The FMW's have a standard for head/deck measurement, and it is not to be violated, or they recommend using another head.....Again, your performance will suffer if you don't follow these suggestions.
Fourth---
if you are changing valves, go with a valve that is:
1. lighter---preferably titanium ($$$$$$)
2. bigger in diameter (at the seat--requires changing the valve seat to match the bigger valves)
3. has smaller diameter stems (requires smaller diameter valve guides)
Fifth---
have you considered the valve spring installation (making sure they are of correct pressures and installed heights)???? =this is something that is overlooked all the time. there are other alternatives in valve springs as well....lighter, stronger, etc.---$$$$$$.
Hope this helps----
---Russ
11-15-2007, 12:06 AM
#30
Instructor
Join Date: Dec 2003
Location: BC Canada
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
I swear that my 85/86 pistons that are in the blue car are complete flat-top - no dish at all.
I could be wrong of course (just ask my wife) and I could be confusing them with the 4.7 euro S pistons too... Anyone can confirm?
I could be wrong of course (just ask my wife) and I could be confusing them with the 4.7 euro S pistons too... Anyone can confirm?