So I bought a track car. Well, okay, two track cars.
11-08-2014, 12:15 PM
#406
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I spent probably 3 hours cleaning the grit and dust out of the head bolt bores before they were clean enough to create 20 holes' worth of thread shavings all over again, which were all then blown out and cleaned before the timeserts were inserted. The block then got cleaned all over again. Sometimes fantasy camp is more like boot camp.....
The nikasil is pretty tough, I was much more concerned about not scratching the deck surface, which I managed not to do.
The nikasil is pretty tough, I was much more concerned about not scratching the deck surface, which I managed not to do.
11-08-2014, 04:22 PM
#407
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Man.... that's a LOT of work! Good on you for keeping the motivation high. My GT has needs some similar motivation get back on track. I should make a post on that damn thread...
05-22-2015, 10:36 PM
#408
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Little more progress- I thought the 'old' Zombie cylinder heads would be plug n play but since they were last kissed Greg decided they needed some additional kissing. So that's all done.
And we sat down over spring break and I sat there and nodded at what I thought were the right times while Greg did all the math calculating desired compression ratios (making the committment to run this one on 25/75 race/street gas...), compression heights, and rod lengths. Greg ordered everything up, and it all arrived today.
Old v. New- coupla changes vs. the original 968 pistons:
New, longer rods (more bigger is more betterer, right?).
And we sat down over spring break and I sat there and nodded at what I thought were the right times while Greg did all the math calculating desired compression ratios (making the committment to run this one on 25/75 race/street gas...), compression heights, and rod lengths. Greg ordered everything up, and it all arrived today.
Old v. New- coupla changes vs. the original 968 pistons:
New, longer rods (more bigger is more betterer, right?).
05-23-2015, 01:24 AM
#410
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whats the coating on the piston and is it needed on the top portion or not? I would think that the tops are small diameter and not in contact with the cylinder walls, but I don't know for sure. who's pistons are they and why not use the stock 968 pistons?
05-23-2015, 01:56 AM
#411
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No coating on the pistons, they're raw aluminum. They're from CP/Carrillo.
I would use the old 968 pistons but they're full of gouges and scratches from the shrapnelfest when the last motor let go. And new 968 pistons are $640 a piece right now. So the CPs are a relative bargain. And about 50 grams a hole lighter.
I would use the old 968 pistons but they're full of gouges and scratches from the shrapnelfest when the last motor let go. And new 968 pistons are $640 a piece right now. So the CPs are a relative bargain. And about 50 grams a hole lighter.
05-23-2015, 03:23 AM
#412
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Rob, viewing your first picture I can see an air grinder and a lot of aluminum chips. Porting job on the go? Fifty grams lighter pistons means rebalancing of the crank. Since a number of years I have this type of mill mounted crank balancer in the shop, I find it very handy. http://www.crankbalancer.com/
Åke
Åke
10-01-2015, 02:44 PM
#413
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Great thread about the transition of ownership of a 928 legend.
So mark takes the S4 engine modified by Greg out for just a few laps and it grenades? Lets look at the differences of that car, motor and mine. running R888s on a glorified autocross track, (edit: i mean WSIR) so anyway, grip is much much less, AND the engine (stock, unknown condition out of an automatic S4) has been modified. (pan spacer, windage tray, etc) I think the later mods are the only thing different (besides not using Amsoil) and that could be a likely cause. as i had theorized, the windage tray can certainly restrict oil from going back to the sump as well as reducing the "splash" effects of the oil on the rotating parts.
we will proof this when Mark drives my car at willow springs in a few months.
Mk
So mark takes the S4 engine modified by Greg out for just a few laps and it grenades? Lets look at the differences of that car, motor and mine. running R888s on a glorified autocross track, (edit: i mean WSIR) so anyway, grip is much much less, AND the engine (stock, unknown condition out of an automatic S4) has been modified. (pan spacer, windage tray, etc) I think the later mods are the only thing different (besides not using Amsoil) and that could be a likely cause. as i had theorized, the windage tray can certainly restrict oil from going back to the sump as well as reducing the "splash" effects of the oil on the rotating parts.
we will proof this when Mark drives my car at willow springs in a few months.
Mk
Update-
I have been slowly collecting parts and pieces, Shawshank style, here and there, attracting little/no attention, over the past year to build a replacement engine for the Zombie. But I couldn't resist the appeal of sticking a used S4 motor in there and hitting the track. When I told Greg of this plan, he used up all his daily supply of diplomacy to not pimp-slap me right then and there, and managed to smile weakly and say, 'Well, that's a different direction than I thought you were going.....'
Lesson #1: If you're going to half-*** something, don't share that fact with Greg.
Thrashed on the Zombie up through last Tuesday, at which point I cried 'uncle' and had it flatbedded to Greg's. Whereupon three full days of idiotproofing commenced. And ended only when we absolutely positively had to put the car in the trailer on Friday night.
Couple of old lines (power steering, trans cooler) got swapped for new, new clutch MC guts, adjusted the clutch, transmission mounts, re-charged the shocks with nitrogen, etc., etc....
Lesson #2: Race car prep is not done until you're sticking it in the trailer.
When Greg learned that Mark was going to be my instructor, and the plan was to have Mark do a shakedown session first, he opined that the S4 motor was not going to last the weekend. We joked a lot about putting a valet mode into the PEMs. What I didn't realize was that Greg assumed that we'd be running the Streets course at Willow. Not the big track. (_average_ speed for the lap record is 132 mph....)
Lesson #3: When your mechanic is betting on the dead pool for the engine based on the smaller, slower track, you should start to worry.
At this point the Zombie has a 1991 S4 motor that came out of an automatic, stock except for a pan spacer and Greg's windage trays. I did pull the rod caps and checked all the bearings, they all looked good.
Mark and I drove up to Palmdale Friday night, watching YT videos on the line around WIllow Springs.
Morning comes early, get to the track, get the car out of the trailer, beautiful morning.
Mark takes the car out for the first 25 minute session. Comes back, says the car is running great. I jump in, we head out for my first session. I am utterly overwhelmed- Six-point harness, HANS device, limited field of view, can't hear ****, R888 tires, Pagid blacks, no working speedometer, first time on the track and they have us start with point-by passing drills. Car runs great, I'm utterly hooked. But man, I am terrible at this....
Can't wait for the next session, we head back out for more lapping. On the grid, warm idle oil pressure is 3.5 bars. About 3 laps in I get on it a little bit, up to maybe 5000 rpm in 4th gear down the front straight. Through the 90o left turn 1, power feels a bit down at track out. Thought I smell something as we turn into the first half of turn 2, at which point the dash lights up INSUFFICIENT OIL PRESSURE. Flipped off the key, coasted off the shoulder between 2 and 3. Watched the rest of the session from the best seats in the house. No holes in the block, no coolant in the oil or vice versa. Hopefully the bores are ok.
Towed back to the pits, back in trailer, back to civilization. I pulled the oil filter and cut it open.
Eww.
Lesson #4. Don't bet against Greg.
Lesson #5. You're not special. You can kill an S4 motor in just over an hour by running long sweepers one after another, and never hit 6000 rpm.
Lesson #6: Shoulda used Amsoil.
Still working on pulling the motor, will post the autopsy pics when I have the engine out. I suppose it's possible this motor was sick to begin with, though I had a good look at the bottom end. Or maybe I did something stupid that Greg didn't catch, or ????
Or maybe, simply, Zombie + WSIR+ R888's + stock S4 motor = rapid rod bearing suicide.
I have been slowly collecting parts and pieces, Shawshank style, here and there, attracting little/no attention, over the past year to build a replacement engine for the Zombie. But I couldn't resist the appeal of sticking a used S4 motor in there and hitting the track. When I told Greg of this plan, he used up all his daily supply of diplomacy to not pimp-slap me right then and there, and managed to smile weakly and say, 'Well, that's a different direction than I thought you were going.....'
Lesson #1: If you're going to half-*** something, don't share that fact with Greg.
Thrashed on the Zombie up through last Tuesday, at which point I cried 'uncle' and had it flatbedded to Greg's. Whereupon three full days of idiotproofing commenced. And ended only when we absolutely positively had to put the car in the trailer on Friday night.
Couple of old lines (power steering, trans cooler) got swapped for new, new clutch MC guts, adjusted the clutch, transmission mounts, re-charged the shocks with nitrogen, etc., etc....
Lesson #2: Race car prep is not done until you're sticking it in the trailer.
When Greg learned that Mark was going to be my instructor, and the plan was to have Mark do a shakedown session first, he opined that the S4 motor was not going to last the weekend. We joked a lot about putting a valet mode into the PEMs. What I didn't realize was that Greg assumed that we'd be running the Streets course at Willow. Not the big track. (_average_ speed for the lap record is 132 mph....)
Lesson #3: When your mechanic is betting on the dead pool for the engine based on the smaller, slower track, you should start to worry.
At this point the Zombie has a 1991 S4 motor that came out of an automatic, stock except for a pan spacer and Greg's windage trays. I did pull the rod caps and checked all the bearings, they all looked good.
Mark and I drove up to Palmdale Friday night, watching YT videos on the line around WIllow Springs.
Morning comes early, get to the track, get the car out of the trailer, beautiful morning.
Mark takes the car out for the first 25 minute session. Comes back, says the car is running great. I jump in, we head out for my first session. I am utterly overwhelmed- Six-point harness, HANS device, limited field of view, can't hear ****, R888 tires, Pagid blacks, no working speedometer, first time on the track and they have us start with point-by passing drills. Car runs great, I'm utterly hooked. But man, I am terrible at this....
Can't wait for the next session, we head back out for more lapping. On the grid, warm idle oil pressure is 3.5 bars. About 3 laps in I get on it a little bit, up to maybe 5000 rpm in 4th gear down the front straight. Through the 90o left turn 1, power feels a bit down at track out. Thought I smell something as we turn into the first half of turn 2, at which point the dash lights up INSUFFICIENT OIL PRESSURE. Flipped off the key, coasted off the shoulder between 2 and 3. Watched the rest of the session from the best seats in the house. No holes in the block, no coolant in the oil or vice versa. Hopefully the bores are ok.
Towed back to the pits, back in trailer, back to civilization. I pulled the oil filter and cut it open.
Eww.
Lesson #4. Don't bet against Greg.
Lesson #5. You're not special. You can kill an S4 motor in just over an hour by running long sweepers one after another, and never hit 6000 rpm.
Lesson #6: Shoulda used Amsoil.
Still working on pulling the motor, will post the autopsy pics when I have the engine out. I suppose it's possible this motor was sick to begin with, though I had a good look at the bottom end. Or maybe I did something stupid that Greg didn't catch, or ????
Or maybe, simply, Zombie + WSIR+ R888's + stock S4 motor = rapid rod bearing suicide.
Last edited by mark kibort; 10-01-2015 at 03:22 PM.
10-01-2015, 02:50 PM
#414
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Uh, Greg didn't touch that junkyard motor, he told me I was an idiot for taking a stock motor to Big Willow and that it would die that first day, and he was right.
10-01-2015, 03:14 PM
#415
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yes, putting a suspect engine and tracking it, is a big risk......... we did it once, and it failed too. (it was ugly and we knew it was a chance... one day and it locked up).. however, whenever you just re-ring the engine and make sure the head gaskets are new and put on some new bearings, its pretty much a guarantee it will survive track days. all of the motors Ive done that with, had never had issues at the track. 3 of scots, 4 of mine, petty's, etc. and these were the most raced 928 engines besides Brian and his track cars.
you put a good running engine on the track, that is not suspect and it will survive , no problem.... however, dont put any of those other bolt on devices, that interjects unneeded risk. if you are going to put an engine in, may as well take it apart and put new gaskets, rings and bearings on it. so easy, and can be done in a few days.
the engines that have blown have been running MUCH less g's than the group who's engines have not blown and are run for 100s of more track hours combined. again, i know its a touchy subject and there are all sorts of wise mechanics that say the 928 cannot be on the track, yet there are those that track it very successfully with no issues at all. but, again, you ran the big track, im sure the laps were not very fast and not a lot of Gs were pulled due to the R888 tires.
when i come down, we can mount the G-meters, video, telemetry ,etc and trust me, it will be going a lot faster than mark drove yours and survive.... and, its already 60 race days into its life!
10-08-2015, 03:30 PM
#416
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So Rob, you said you didnt modify the engine at all, but there was the windage tray. (and a pan spacer) . is there any conclusive theory that shows that it couldnt have a chance of being a potential cause?
to me it seems most obvious, but thats just me... i think the oil being whipped around without a tray is a good thing, and i dont think the pool of oil below gets near the crank, specially in turns or braking and certainly not during acceleration which are the mildest of g forces.
did devek fit the early strokers with any kind of oil baffle , or windage tray?
the 6 liter stroker owner is wondering if he has one on his car. i think i remember the GTS baffle being talked about.. is here such a thing? the GTS has some kind of different oil pan set up than the S4?
and maybe i missed this, but was it Mobil 1? not that would be the absolute cause, especially after only one session. that kind of failure is usually done to an engine with something wrong with it. plenty of guys have run their cars at the track, a heck of a lot faster with no issues. I remember Rons car (stock GT prepared like my S4) he had no issues with the car at willow springs.
as far as the pan spacer, im not convinced that is any answer to the problem at all, in fact, it gives the oil more distance and volume to climb the walls under high g turns. the worst part is that the lower pan height off the ground is not a friend at laguna seca. at my curent ride height, im already barely nicking the pan, and have hit it during spirited street drvign on the bumps of a mountain hyway.
so what is your game plan now with the great white shark? whats up with the stroker plans?
any interest in selling the CF intake system?
to me it seems most obvious, but thats just me... i think the oil being whipped around without a tray is a good thing, and i dont think the pool of oil below gets near the crank, specially in turns or braking and certainly not during acceleration which are the mildest of g forces.
did devek fit the early strokers with any kind of oil baffle , or windage tray?
the 6 liter stroker owner is wondering if he has one on his car. i think i remember the GTS baffle being talked about.. is here such a thing? the GTS has some kind of different oil pan set up than the S4?
and maybe i missed this, but was it Mobil 1? not that would be the absolute cause, especially after only one session. that kind of failure is usually done to an engine with something wrong with it. plenty of guys have run their cars at the track, a heck of a lot faster with no issues. I remember Rons car (stock GT prepared like my S4) he had no issues with the car at willow springs.
as far as the pan spacer, im not convinced that is any answer to the problem at all, in fact, it gives the oil more distance and volume to climb the walls under high g turns. the worst part is that the lower pan height off the ground is not a friend at laguna seca. at my curent ride height, im already barely nicking the pan, and have hit it during spirited street drvign on the bumps of a mountain hyway.
so what is your game plan now with the great white shark? whats up with the stroker plans?
any interest in selling the CF intake system?
10-08-2015, 05:15 PM
#417
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I remember sitting along the side of the track just beyond turn 2, joking with Mark that I'm really bummed that I didn't fill the engine with Amsoil. I was using Torco TR-1 20W50.
That '91S4 motor was high miles, the thrust bearing was at the limit of spec, I ended up putting new main bearings into it to be 'safe' but maybe I didn't assemble something correctly (?). I wouldn't spend too much time speculating about why that particular motor blew up. I don' think the spacer and trays made any difference whatsoever. Like we said at the outset- junkyard motor. I just wanted to get out on the track.
Zombie motor's coming together, I have all the parts in hand now, ID'ed a good set of cams from Mark's stash. Block, heads, crank (wait'll you see this f'ing crank....), pistons, rods, new dry sump pan are all done, just need to be assembled. Carbon intake's not for sale. it's a little piece of history.
That '91S4 motor was high miles, the thrust bearing was at the limit of spec, I ended up putting new main bearings into it to be 'safe' but maybe I didn't assemble something correctly (?). I wouldn't spend too much time speculating about why that particular motor blew up. I don' think the spacer and trays made any difference whatsoever. Like we said at the outset- junkyard motor. I just wanted to get out on the track.
Zombie motor's coming together, I have all the parts in hand now, ID'ed a good set of cams from Mark's stash. Block, heads, crank (wait'll you see this f'ing crank....), pistons, rods, new dry sump pan are all done, just need to be assembled. Carbon intake's not for sale. it's a little piece of history.
10-08-2015, 06:39 PM
#418
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Why that style pistons, why not the much lighter x-forging or whatever they call them, box-in-box strut? I'm talking about the types of pistons that Simard used in his 7.0L motor. Is there a particular reason for going with the full skirt extending below the piston pins on the sides? I am sure the pistons in the picture will be a step forward from what the engine used to have, so I am not criticizing anything here.
Another thing about the pistons... the compression height looks about the same. Now, if the compression height is the same and if the deck clearance is the same and the rod length is longer... drum rolls... the stroke has to be shorter!!! ;-) Did I eyeball the piston compression height correctly?
Which cams did you decide to use? I am curious about the profile. Since you can now map those profiles, how about punching all the data into pipemax and see what it says? I think it would be fun, and then would also generate the "required" CFM curves.
Another thing about the pistons... the compression height looks about the same. Now, if the compression height is the same and if the deck clearance is the same and the rod length is longer... drum rolls... the stroke has to be shorter!!! ;-) Did I eyeball the piston compression height correctly?
Which cams did you decide to use? I am curious about the profile. Since you can now map those profiles, how about punching all the data into pipemax and see what it says? I think it would be fun, and then would also generate the "required" CFM curves.
10-08-2015, 06:48 PM
#419
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I remember sitting along the side of the track just beyond turn 2, joking with Mark that I'm really bummed that I didn't fill the engine with Amsoil. I was using Torco TR-1 20W50.
That '91S4 motor was high miles, the thrust bearing was at the limit of spec, I ended up putting new main bearings into it to be 'safe' but maybe I didn't assemble something correctly (?). I wouldn't spend too much time speculating about why that particular motor blew up. I don' think the spacer and trays made any difference whatsoever. Like we said at the outset- junkyard motor. I just wanted to get out on the track.
Zombie motor's coming together, I have all the parts in hand now, ID'ed a good set of cams from Mark's stash. Block, heads, crank (wait'll you see this f'ing crank....), pistons, rods, new dry sump pan are all done, just need to be assembled. Carbon intake's not for sale. it's a little piece of history.
That '91S4 motor was high miles, the thrust bearing was at the limit of spec, I ended up putting new main bearings into it to be 'safe' but maybe I didn't assemble something correctly (?). I wouldn't spend too much time speculating about why that particular motor blew up. I don' think the spacer and trays made any difference whatsoever. Like we said at the outset- junkyard motor. I just wanted to get out on the track.
Zombie motor's coming together, I have all the parts in hand now, ID'ed a good set of cams from Mark's stash. Block, heads, crank (wait'll you see this f'ing crank....), pistons, rods, new dry sump pan are all done, just need to be assembled. Carbon intake's not for sale. it's a little piece of history.
I must be missing something. i truely think if all was in spec, the pan spacer doesnt seem to have a benefit, and the "trays" say to me, oil flow to sump restriction.. we all know this, the question is how much. its my theory, and i know everyone has one on the subject. when I run willows with anderson driving as well, and we lap around at full tilt, you will see.
this new block, with pistons and a special crank... is it a stroker or something stock ish? going 6.4 liter?
Now, the intake... history??? well, yes it is the most NA power anyone has seen with a 928... so, well, how about I lease it from you? (and of course copy all the components).
im excited for you .... get the pics on the list here!!
10-08-2015, 06:53 PM
#420
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Why that style pistons, why not the much lighter x-forging or whatever they call them, box-in-box strut? I'm talking about the types of pistons that Simard used in his 7.0L motor. Is there a particular reason for going with the full skirt extending below the piston pins on the sides? I am sure the pistons in the picture will be a step forward from what the engine used to have, so I am not criticizing anything here.
Another thing about the pistons... the compression height looks about the same. Now, if the compression height is the same and if the deck clearance is the same and the rod length is longer... drum rolls... the stroke has to be shorter!!! ;-) Did I eyeball the piston compression height correctly?
Which cams did you decide to use? I am curious about the profile. Since you can now map those profiles, how about punching all the data into pipemax and see what it says? I think it would be fun, and then would also generate the "required" CFM curves.
Another thing about the pistons... the compression height looks about the same. Now, if the compression height is the same and if the deck clearance is the same and the rod length is longer... drum rolls... the stroke has to be shorter!!! ;-) Did I eyeball the piston compression height correctly?
Which cams did you decide to use? I am curious about the profile. Since you can now map those profiles, how about punching all the data into pipemax and see what it says? I think it would be fun, and then would also generate the "required" CFM curves.
what about the cams you didnt pic... whats left over that i might be able to install. i think my 375rwhp could use a little non stock racing stuff!