View Poll Results: Pull the Holbert engine and transplant it with the 6.5 liter Rennlist engine?
Pull the engine and replace it now and start winning some races!
31
54.39%
Run the Holbert engine 'til it blows, or run mobil 1 in it and see what happens
3
5.26%
Replace it after this season
17
29.82%
Sell the Holbert car on the aution TV show and put the 6.5 liter in a stock S4 race car conversion
6
10.53%
Voters: 57. You may not vote on this poll
Should The Holbert 928 get an engine transplant mid season, or ever?
07-31-2008, 01:07 PM
#91
Rennlist Member
Thread Starter
the compression is supposed to be 10.7:1 so ill probably run a light mix of race gas and pump at the races, and pump gas on the street. Ill verify the compression ratio by CCing the heads and pistons again to be sure.
bore is 103.5mm
mk
bore is 103.5mm
mk
First things first: Are you going to run race gas or 91 octane? Now would be the time to make that decision.
What's the bore & stroke? Also what's the rod length? Is it a standard 5.85" or something else?
Also what's the piston dish volume? You might want to cc the pistons to see where you are right now.
With the above info along w/ the timing of the closing of the S3 intake cams, you could figure out the dynamic compression ratio. With the DCR, you could find out what kind of gas you'd need to run with the parts you have as they sit. Or if you need to make modifications to run the gas you want.
What's the bore & stroke? Also what's the rod length? Is it a standard 5.85" or something else?
Also what's the piston dish volume? You might want to cc the pistons to see where you are right now.
With the above info along w/ the timing of the closing of the S3 intake cams, you could figure out the dynamic compression ratio. With the DCR, you could find out what kind of gas you'd need to run with the parts you have as they sit. Or if you need to make modifications to run the gas you want.
07-31-2008, 02:06 PM
#92
Supercharged
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Mark-
I understand the emotional drive behind your decision. A lot of people have "invested" a lot into this endeavor along with you. Please do not be cavalear in your approach. This is not just a simple swap. I'm not saying it has to be perfect, but it needs to be pretty close or I'm afraid this motor will become a very fancy coffee table before the end of this season.
Have you addressed your oil cooling needs?
Are you sure your coolant loss wasn't from somewhere other than the Holbert engine?
Are you re-using the Holbert heads? If so, what are your plans for refurbishing them?
What is your tuning plan?
Are you prepared to miss the rest of the season if things aren't quite right?
I understand the emotional drive behind your decision. A lot of people have "invested" a lot into this endeavor along with you. Please do not be cavalear in your approach. This is not just a simple swap. I'm not saying it has to be perfect, but it needs to be pretty close or I'm afraid this motor will become a very fancy coffee table before the end of this season.
Have you addressed your oil cooling needs?
Are you sure your coolant loss wasn't from somewhere other than the Holbert engine?
Are you re-using the Holbert heads? If so, what are your plans for refurbishing them?
What is your tuning plan?
Are you prepared to miss the rest of the season if things aren't quite right?
07-31-2008, 02:58 PM
#93
Burning Brakes
Well since Mark is "in it now" and going ahead W/ the swap I think between he and Bill it should go fine. Another way to look at this now is that Mark will race W/ the stroker for the rest of the season and if he needs to re-do anything on the motor i.e. head work he will have all winter to tear down and take his time. Also if he does he will have a better way to compare the work and use the rest of this season to "test" the motor and know what needs to be done to fine tune it for next season.
07-31-2008, 03:06 PM
#94
Rennlist Member
Thread Starter
Im not cavalear, Im just swaping out the air pump and leaving everything else the same. 
.
anderson ran a stock radiator for a long time while at 420rwhp. also, my oil temps are 240 to the hotest being 260 on the hotest of days. (last weekend we saw 130 degrees F on track temps) Ill certainly be able to moniter to make sure that they stay in check. Anderson and fan didnt do any tuning other than using the fuel reg to make sure mixtures were in the safe range. Ill probably do the same.
Heads are in good shape, but will check things out. springs dont have many miles on them after all, they dont know that they have been raced, just compressed real fast for a few years. if they are weak and break, they could do that anytime anyway, independent of the bottom end. Id be worried more about dropping a valve, but ours have pretty good strength in those areas and the rpms i use are pretty low. (even lower with the stroker, even though it is built for 7000rpm. Ill be using more like 6krpm )
Ive come to terms that if this doesnt work out, i loose the rest of the season. I have enough 2-3rd place championships. I dont need another. so, why not take a chance at winning if it all works as we think it should? So yes, im prepared to walk away if things arent right.
as far as coolant loss in the holbert engine, i see no leaks and its using near 2 pints after every race. i suspect a slight headgasket issue, its not pushing it out like scots was as the level is high after a race. after it cools, there is missing water.
we will find out in a few days based on what we see on the holbert heads and gaskets.
mk
.anderson ran a stock radiator for a long time while at 420rwhp. also, my oil temps are 240 to the hotest being 260 on the hotest of days. (last weekend we saw 130 degrees F on track temps) Ill certainly be able to moniter to make sure that they stay in check. Anderson and fan didnt do any tuning other than using the fuel reg to make sure mixtures were in the safe range. Ill probably do the same.
Heads are in good shape, but will check things out. springs dont have many miles on them after all, they dont know that they have been raced, just compressed real fast for a few years
. if they are weak and break, they could do that anytime anyway, independent of the bottom end. Id be worried more about dropping a valve, but ours have pretty good strength in those areas and the rpms i use are pretty low. (even lower with the stroker, even though it is built for 7000rpm. Ill be using more like 6krpm )Ive come to terms that if this doesnt work out, i loose the rest of the season. I have enough 2-3rd place championships. I dont need another. so, why not take a chance at winning if it all works as we think it should? So yes, im prepared to walk away if things arent right.
as far as coolant loss in the holbert engine, i see no leaks and its using near 2 pints after every race. i suspect a slight headgasket issue, its not pushing it out like scots was as the level is high after a race. after it cools, there is missing water.
we will find out in a few days based on what we see on the holbert heads and gaskets.
mk
Mark-
I understand the emotional drive behind your decision. A lot of people have "invested" a lot into this endeavor along with you. Please do not be cavalear in your approach. This is not just a simple swap. I'm not saying it has to be perfect, but it needs to be pretty close or I'm afraid this motor will become a very fancy coffee table before the end of this season.
Have you addressed your oil cooling needs?
Are you sure your coolant loss wasn't from somewhere other than the Holbert engine?
Are you re-using the Holbert heads? If so, what are your plans for refurbishing them?
What is your tuning plan?
Are you prepared to miss the rest of the season if things aren't quite right?
I understand the emotional drive behind your decision. A lot of people have "invested" a lot into this endeavor along with you. Please do not be cavalear in your approach. This is not just a simple swap. I'm not saying it has to be perfect, but it needs to be pretty close or I'm afraid this motor will become a very fancy coffee table before the end of this season.
Have you addressed your oil cooling needs?
Are you sure your coolant loss wasn't from somewhere other than the Holbert engine?
Are you re-using the Holbert heads? If so, what are your plans for refurbishing them?
What is your tuning plan?
Are you prepared to miss the rest of the season if things aren't quite right?
07-31-2008, 03:28 PM
#95
For the cometic gaskets, you will need a very very smooth surface on the heads. VERY smooth. And use some hylomar.
07-31-2008, 03:35 PM
#96
Rennlist Member
Thread Starter
what is hylomar? Ill take the heads to the machine shop and see if they can get the surface real smooth.
does anyone have any racing experience using cometic on a 928? I think joe and mark still use the stock stuff (968?)
mk
does anyone have any racing experience using cometic on a 928? I think joe and mark still use the stock stuff (968?)
mk
07-31-2008, 03:46 PM
#97
Maybe you should just use the stock stuff mark.
Any old shop will not get the surface proper for cometic. I know the engine deck is good, since Todd did it, but the heads you are in control of.
Cometic is a great gasket, but you need to have someone who is willing to use certain procedures to do it right.
Any old shop will not get the surface proper for cometic. I know the engine deck is good, since Todd did it, but the heads you are in control of.
Cometic is a great gasket, but you need to have someone who is willing to use certain procedures to do it right.
07-31-2008, 03:49 PM
#98
Rennlist Member
Thread Starter
this is the shop that did some of the Devek block work in the early days, and did scots Alusil work (bore, process) and lots of 944 engines. they are one of the best small shops around, but I dont know how much more they need to know to do it right. I can ask. the shop locally here is called Elsworth
Mk
Mk
Maybe you should just use the stock stuff mark.
Any old shop will not get the surface proper for cometic. I know the engine deck is good, since Todd did it, but the heads you are in control of.
Cometic is a great gasket, but you need to have someone who is willing to use certain procedures to do it right.
Any old shop will not get the surface proper for cometic. I know the engine deck is good, since Todd did it, but the heads you are in control of.
Cometic is a great gasket, but you need to have someone who is willing to use certain procedures to do it right.
07-31-2008, 04:08 PM
#99
this is the shop that did some of the Devek block work in the early days, and did scots Alusil work (bore, process) and lots of 944 engines. they are one of the best small shops around, but I dont know how much more they need to know to do it right. I can ask. the shop locally here is called Elsworth
Mk
Mk
Hylomar is a tacky thin sealant spray. You put it on both sides of the gasket (or even in between the layers)
Also, you must remove two rivets so the heads can seat properly.
07-31-2008, 04:33 PM
#100
Rennlist Member
Thread Starter
Ill ask and see if this shop is comfortable with this. does the cometic have the rivets that need to be removed? Tim and Todd didnt mention it.
mk
mk
You need a 50RA surface or better and TOTALLY flat, not angled like most head surfaces get - to make the cometic seal. AND hylomar for extra safety.
Hylomar is a tacky thin sealant spray. You put it on both sides of the gasket (or even in between the layers)
Also, you must remove two rivets so the heads can seat properly.
Hylomar is a tacky thin sealant spray. You put it on both sides of the gasket (or even in between the layers)
Also, you must remove two rivets so the heads can seat properly.
07-31-2008, 07:20 PM
#101
Drifting
Join Date: Jul 2002
Location: Los Angeles, CA
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Well, if you are going for it, then good luck!
You will have lots of great help and advice from everyone on Rennlist...
I suppose you can look at it as a work in progress.
My guess is that your stock components will not be enough to take full advantage of the block's potential.
So you can work on new heads perhaps during the off season, and swap them later. Same with cams, valves, and sharktuning.
You can add those things later, to get more power out of that motor...
You will have lots of great help and advice from everyone on Rennlist...
I suppose you can look at it as a work in progress.
My guess is that your stock components will not be enough to take full advantage of the block's potential.
So you can work on new heads perhaps during the off season, and swap them later. Same with cams, valves, and sharktuning.
You can add those things later, to get more power out of that motor...
07-31-2008, 07:29 PM
#102
Banned
Well, if you are going for it, then good luck!
You will have lots of great help and advice from everyone on Rennlist...
I suppose you can look at it as a work in progress.
My guess is that your stock components will not be enough to take full advantage of the block's potential.
So you can work on new heads perhaps during the off season, and swap them later. Same with cams, valves, and sharktuning.
You can add those things later, to get more power out of that motor...
You will have lots of great help and advice from everyone on Rennlist...
I suppose you can look at it as a work in progress.
My guess is that your stock components will not be enough to take full advantage of the block's potential.
So you can work on new heads perhaps during the off season, and swap them later. Same with cams, valves, and sharktuning.
You can add those things later, to get more power out of that motor...
07-31-2008, 07:32 PM
#103
Rennlist Member
07-31-2008, 07:35 PM
#104
Rennlist Member
Thread Starter
The shop is very comfortable in doing the 50RA surface. I think they want something like $150 for both heads to do it.
What about torquing the heads? Todd and Tim passed on the techique i should use, but in the manual, it states, that there are only (2) 90 degree tightening movements on the Bolt versions, while the stud versions (earlier) have (3) 90 degree tightening movements. What is the reason for this difference??? seems odd that the S4 might effectively get less tightening, or is part of the movement of the nuts, go up in deformation?(that doesnt occur in the studs?)
MK
What about torquing the heads? Todd and Tim passed on the techique i should use, but in the manual, it states, that there are only (2) 90 degree tightening movements on the Bolt versions, while the stud versions (earlier) have (3) 90 degree tightening movements. What is the reason for this difference??? seems odd that the S4 might effectively get less tightening, or is part of the movement of the nuts, go up in deformation?(that doesnt occur in the studs?)
MK
You need a 50RA surface or better and TOTALLY flat, not angled like most head surfaces get - to make the cometic seal. AND hylomar for extra safety.
Hylomar is a tacky thin sealant spray. You put it on both sides of the gasket (or even in between the layers)
Also, you must remove two rivets so the heads can seat properly.
Hylomar is a tacky thin sealant spray. You put it on both sides of the gasket (or even in between the layers)
Also, you must remove two rivets so the heads can seat properly.
07-31-2008, 07:39 PM
#105
Rennlist Member
Thread Starter
I dont know, we all know what the capabilities of a 400rwhp 928. Its not going to get "blown away" down the straigths that I visit anymore. All i need to be is close and I have a chance! Right now, im getting pretty wasted on the straights. an extra 80hp will come in quite handy and be fine for the occasional WC GT car that decideds to show up. I figure, if im killing the car and running 1:38.7 at Laguna, i should be able to get in the high 1:35s. I would be plenty happy with the high 1:36s too!
mk
mk