Crank Scraper/Windage Tray at Road America
05-13-2006, 11:13 PM
#1
Developer
Thread Starter
Crank Scraper/Windage Tray at Road America
Wet and Cold. Connie's shoes got soaked and her feet froze. It was totally strange to see guys jacking up their Boxsters to put on their track tires... wearing winter parkas with fur-lined hoods. Weird.
Anyway - in the first lap I had an oil event - filled the catch tank and burped it over. I do not understand how I overfilled it... but I did... and after that event I ran a 30 minute session without incident. And the dip stick still said the engine was full of oil.
The new engine was strong and eager. I ate a couple BMW M3's without difficulty, a Mustang Cobra SHO, and played with a 951 for a lap before I put him in my rear-view also. They gridded 2 Corvettes behind me at the start, and I never saw them. Track conditions what they were, big cars were having trouble getting the power to the ground while little cars faired better.
An Acura NSX and a 944 hit the wall in 8.
As to the Ishara-Johnson crank scraper and windage tray... because of the wet track, I could not pull buckets of lateral G's... but what I did see I liked. In the Carousel at Road America the engine held consistent oil pressure throughout the entire turn - unlike last time where, without a windage tray, the oil pressure would drop as the turn went on and on until finally the Accusump had more pressure than the engine and the Accusump activated.
That never happened today, I never saw the oil pressure in the corners drop. I credit the windage tray from Ishara-Johnson with that, and probably having a tight new motor. My oil temp is about 10 degrees cooler this year than last year... that can be the crank scraper too, and/or the effect of the new 3000 CFM pusher fan I have mounted on the front of the radiator/oil cooler.
So far, so good. Maybe this next Saturday I will have dry pavement and can throw the car around a little harder.
Anyway - in the first lap I had an oil event - filled the catch tank and burped it over. I do not understand how I overfilled it... but I did... and after that event I ran a 30 minute session without incident. And the dip stick still said the engine was full of oil.
The new engine was strong and eager. I ate a couple BMW M3's without difficulty, a Mustang Cobra SHO, and played with a 951 for a lap before I put him in my rear-view also. They gridded 2 Corvettes behind me at the start, and I never saw them. Track conditions what they were, big cars were having trouble getting the power to the ground while little cars faired better.
An Acura NSX and a 944 hit the wall in 8.
As to the Ishara-Johnson crank scraper and windage tray... because of the wet track, I could not pull buckets of lateral G's... but what I did see I liked. In the Carousel at Road America the engine held consistent oil pressure throughout the entire turn - unlike last time where, without a windage tray, the oil pressure would drop as the turn went on and on until finally the Accusump had more pressure than the engine and the Accusump activated.
That never happened today, I never saw the oil pressure in the corners drop. I credit the windage tray from Ishara-Johnson with that, and probably having a tight new motor. My oil temp is about 10 degrees cooler this year than last year... that can be the crank scraper too, and/or the effect of the new 3000 CFM pusher fan I have mounted on the front of the radiator/oil cooler.
So far, so good. Maybe this next Saturday I will have dry pavement and can throw the car around a little harder.
Last edited by Carl Fausett; 05-14-2006 at 12:03 AM.
05-14-2006, 12:32 AM
#2
Team Owner
Hi, Goodluck Carl , I hope you dont have any problems with your new engine, Stan
05-14-2006, 03:35 AM
#4
Drifting
cool stuff, definitely keep us posted with more data as you acumulate track time. how do you know when the oil pressure drops, do you have the gauge mounted higher up in the dash? how much more hp is the engine making on previous, how was traction in the wet?
05-14-2006, 04:59 PM
#5
Developer
Thread Starter
No new vids.... I set up a new digital camera with stereo audio and everything, was all excited about it... tested it thouroughly... amazing audio and video. Went to the camera after the sessions to see what I had captured - I had taken the CDVD-R out of it yesterday and never put one back in it. Empty camera. Doah!
How much more HP? Dunno yet. Will go to the dyno soon.
How much more HP? Dunno yet. Will go to the dyno soon.
05-15-2006, 02:34 AM
#6
Rennlist Member
I had 5 bar around the carrocel with nothing, not even an accusump. I wonder what kind of oil you were running last time you ran there and saw the lowered oil pressure. mobil 1?? Scot and i have both see this with hot oil on the older 79 and his 82 before Amzoil. now with Amzoil, 5 bar everywhere, even turn2 at Thill and the carrocel at Sears Point.
maybe the windage tray is doing something with the oil venting up?? just a guess.
Mk
maybe the windage tray is doing something with the oil venting up?? just a guess.
Mk
Originally Posted by Carl Fausett
Wet and Cold. Connie's shoes got soaked and her feet froze. It was totally strange to see guys jacking up their Boxsters to put on their track tires... wearing winter parkas with fur-lined hoods. Weird.
Anyway - in the first lap I had an oil event - filled the catch tank and burped it over. I do not understand how I overfilled it... but I did... and after that event I ran a 30 minute session without incident. And the dip stick still said the engine was full of oil.
The new engine was strong and eager. I ate a couple BMW M3's without difficulty, a Mustang Cobra SHO, and played with a 951 for a lap before I put him in my rear-view also. They gridded 2 Corvettes behind me at the start, and I never saw them. Track conditions what they were, big cars were having trouble getting the power to the ground while little cars faired better.
An Acura NSX and a 944 hit the wall in 8.
As to the Ishara-Johnson crank scraper and windage tray... because of the wet track, I could not pull buckets of lateral G's... but what I did see I liked. In the Carousel at Road America the engine held consistent oil pressure throughout the entire turn - unlike last time where, without a windage tray, the oil pressure would drop as the turn went on and on until finally the Accusump had more pressure than the engine and the Accusump activated.
That never happened today, I never saw the oil pressure in the corners drop. I credit the windage tray from Ishara-Johnson with that, and probably having a tight new motor. My oil temp is about 10 degrees cooler this year than last year... that can be the crank scraper too, and/or the effect of the new 3000 CFM pusher fan I have mounted on the front of the radiator/oil cooler.
So far, so good. Maybe this next Saturday I will have dry pavement and can throw the car around a little harder.
Anyway - in the first lap I had an oil event - filled the catch tank and burped it over. I do not understand how I overfilled it... but I did... and after that event I ran a 30 minute session without incident. And the dip stick still said the engine was full of oil.
The new engine was strong and eager. I ate a couple BMW M3's without difficulty, a Mustang Cobra SHO, and played with a 951 for a lap before I put him in my rear-view also. They gridded 2 Corvettes behind me at the start, and I never saw them. Track conditions what they were, big cars were having trouble getting the power to the ground while little cars faired better.
An Acura NSX and a 944 hit the wall in 8.
As to the Ishara-Johnson crank scraper and windage tray... because of the wet track, I could not pull buckets of lateral G's... but what I did see I liked. In the Carousel at Road America the engine held consistent oil pressure throughout the entire turn - unlike last time where, without a windage tray, the oil pressure would drop as the turn went on and on until finally the Accusump had more pressure than the engine and the Accusump activated.
That never happened today, I never saw the oil pressure in the corners drop. I credit the windage tray from Ishara-Johnson with that, and probably having a tight new motor. My oil temp is about 10 degrees cooler this year than last year... that can be the crank scraper too, and/or the effect of the new 3000 CFM pusher fan I have mounted on the front of the radiator/oil cooler.
So far, so good. Maybe this next Saturday I will have dry pavement and can throw the car around a little harder.
05-15-2006, 07:55 AM
#7
Race Car
Originally Posted by mark kibort
I had 5 bar around the carrocel with nothing, not even an accusump.
Do you know what your speed was at the apex (..inside rumble-strip) and turn-out?
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05-22-2006, 03:46 AM
#8
Three Wheelin'
Originally Posted by Kevin Johnson
<snip>
Lacking any other venting the system would reach an equilibrium when the depressed surface of the oil reached the level at which the hole in the sump casting begins to be uncovered or at about the six quart level. This may well be – OR PERHAPS SHOULD BE -- the normal operating level of oil in the 928 engine since it is easy to imagine that two quarts are in active circulation at any given time.(4)
-----------------------------------
(4) Two to three liters in circulation from a 4.5 to 5.0 liter sump fill was the figure given for a Ford V6 during a windage tray foaming study published by the SAE – see “High-speed Video Observation of Engine Oil Aeration” by Manz, Cowart, Cheng, SAE 2004-01-2913
-----------------------------------
I should mention that the figure I read kicked around as the factory fill is 7.9 liters or ~8.34 quarts. Actually, the oil aeration failures in the 928 engine are very consistent with the failures one often hears about when an oil pan is overfilled.
Summary: At high rpm usage the crank scraper system both partial and full system caused increased oil ejection through the 928 crankcase breathing systems. Importantly, this was not associated with damage to the engine but rather the reverse – stable oil pressures were reported, even during 12 hours of racing.
In my opinion the crank scrapers and windage control system is doing exactly what it is supposed to do but the 928 engine is highly complex AND CONSTRAINED and requires further significant modifications to the crankcase breathing system as many people have said for many years. The empirical data here allows that breathing problem to be separated away from the much more serious oil aeration problem.
Certainly a well designed dry sump system would address these issues by moving them external to the engine but the point is that it does not appear to be necessary.
Kind regards,
Kevin Johnson
Ishihara-Johnson Crank Scrapers
Post script: I think it is important to mention that once I heard feedback from Glen (the first person to give me feedback in about eight months) I reported the information to Rob, who I knew was preparing the car for Spa. He had just installed the engine when I reached him and after some hard thinking decided to proceed with his plans. I then read that Carl was planning on racing at Road America and tried to contact him by phone prior to this but was unsuccessful. The information here is for other 928 owners who may or may not have had similar results with our equipment.
Lacking any other venting the system would reach an equilibrium when the depressed surface of the oil reached the level at which the hole in the sump casting begins to be uncovered or at about the six quart level. This may well be – OR PERHAPS SHOULD BE -- the normal operating level of oil in the 928 engine since it is easy to imagine that two quarts are in active circulation at any given time.(4)
-----------------------------------
(4) Two to three liters in circulation from a 4.5 to 5.0 liter sump fill was the figure given for a Ford V6 during a windage tray foaming study published by the SAE – see “High-speed Video Observation of Engine Oil Aeration” by Manz, Cowart, Cheng, SAE 2004-01-2913
-----------------------------------
I should mention that the figure I read kicked around as the factory fill is 7.9 liters or ~8.34 quarts. Actually, the oil aeration failures in the 928 engine are very consistent with the failures one often hears about when an oil pan is overfilled.
Summary: At high rpm usage the crank scraper system both partial and full system caused increased oil ejection through the 928 crankcase breathing systems. Importantly, this was not associated with damage to the engine but rather the reverse – stable oil pressures were reported, even during 12 hours of racing.
In my opinion the crank scrapers and windage control system is doing exactly what it is supposed to do but the 928 engine is highly complex AND CONSTRAINED and requires further significant modifications to the crankcase breathing system as many people have said for many years. The empirical data here allows that breathing problem to be separated away from the much more serious oil aeration problem.
Certainly a well designed dry sump system would address these issues by moving them external to the engine but the point is that it does not appear to be necessary.
Kind regards,
Kevin Johnson
Ishihara-Johnson Crank Scrapers
Post script: I think it is important to mention that once I heard feedback from Glen (the first person to give me feedback in about eight months) I reported the information to Rob, who I knew was preparing the car for Spa. He had just installed the engine when I reached him and after some hard thinking decided to proceed with his plans. I then read that Carl was planning on racing at Road America and tried to contact him by phone prior to this but was unsuccessful. The information here is for other 928 owners who may or may not have had similar results with our equipment.
Thanks for this detailed report. The CD with more than 6 minutes of active oil aeration as seen through the cam cover window at the track is on it's way to you. I mailed it last week. It's a lot more dramatic to see the aeration happening in video than in a still picture. Just for the record, I believe I had initially damaged my 2/6 bearings one or two track sessions before the one where I took the video. I saw a short quick drop in oil pressure to near zero at Thunderhill (left sweeper) and blew (burst) one of the crankcase vent lines at that event too. After that, the car showed steadily declining performance, seen on dyno runs, elevated oil temp, and not as lively feeling as it was. The next track session after I had taken the video, it was evident something was seriously wrong and I stopped driving it and found the spun bearing. The oil pressure was always normal and no unusual noises. I attributed the Redline 20W 50 oil I was using to extending the engine life until I figured out what the problem was. Of course no proof of that.
Question.. Do you recommend that 6 qts be used as the full sump volume? What about the 2 or more qts. circulating? I can see that with efficient scrapers, less oil will be in suspension and more returned to the normally overfilled sump which could increase aeration in a turn and that seems to be where it happens. I also did the same full sump test as you and found the same thing. Oil levels more than 6 qts. gets the level definitely out of the sump and dangerously close to the crank. That's one reason I made the 3/8" thick spacer between the block and sump to get the sump further away.
05-22-2006, 11:21 AM
#9
Addict
Rennlist Member
Rennlist Member
I've been thinking about possibility to extend head oil drains lower down to cut back returning oils exposure to rotating parts. Wouldn't it be possible to include all the way down extensions to these channels as part of scraper system? Obviously crank case breathing would also need radical changes then.
05-22-2006, 11:29 AM
#10
Developer
Thread Starter
I offer this post in the hopes that with Glen's information, Kevin's help, Louie's input, etc - we might be able to get all these pieces together for a solution.
I was at the Milwaukee Mile this Saturday, dry sunny day, 65 degrees, and we wore the big Hoosiers. (315/35/SR17 Fronts and 335/35/sr17 Rears).
The track is a NASCAR-type oval - 1 lap = 1 Mile, plus a Daytona-style road race course fitted to the infield. You do about 3/4 lap on the oval, then dive into a near-hairpin into he infield section, lots of twisty stuff in here, another hairpin,
and out back onto the oval. The oval does not have much of a camber to it, the other fellas there told me it was only 3 degrees of banking - but it looked a little more than that to me. Still - it's no Talladega. Its flat enough that you have to significantly brake for it.
Working off of Kevin's comments above - (and thank you for sticking with us 928'rs as this crank scraper Windage tray product gets dialed in, Kevin!) - I can add a little more to the comments above from this weekend.
To cut to the chase - I pumped oil out of my breather system so bad that I was only allowed one timed run then the officials pulled my tech inspection sticker. No problem, I was retiring anyway - I pumped oil so badly, I was fairly certain I'd blown a head gasket.
A little background: this is a new engine that has only about 550 miles on it. Forged low-expansion pistons that have 1/2 of the piston to cylinder wall clearance as stock ones do, the Johnson Scrapers and Windage tray system (First edition, I guess), the 928 Motorsports improvements to the oil separator,
then a Mann-Hummel Oil Separator (same one DR is using), then to a welded in Moroso nipple into the header collector to pull a vacuum in the crankcase. This motor is fitted with a Supercharger and pushing about 8 psi at the intake joint at 6000 RPM.
Last year, I had installed a boost gauge on the crankcase to see what was doing when under boost. My tired old motor had cylinder wall scratches, and was an OEM 4.5L that would compression check only 65 psi each cylinder cold. (8.5:1 CR). We noted that, under 4 or 5 psi of boost, the crankcase would register only 1 psi of pressure - so we always thought the exhaust-venturi vacuum system was doing a good job of evacuating the system. BUT - under hard deceleration that included some engine braking, you could see the crankcase pressure go as high as 6 psi. That's when we decided to pull the motor and rebuild it.
Back to present-day: Between Road America and Yesterday, I found and installed a electric continuous-duty oil scavenging pump. See photos below.
I plumbed it to the bottom of the Mann-Hummel oil separator, ran it into a billet sintered-bronze oil filter canister to deaerate the oil, and then back into the passenger cam tower to return oil to the motor.
At the Milwaukee Mile - I observed the following interesting points:
1) I blew oil smoke out the tailpipe (remember that is where my crankcase PCV system ultimately terminates) in precisely 3 places on the track - each of them hard braking for tight corners. I'd be at full throttle, hard brake, downshift before the Apex, and as I accelerated out of that tight corner I was killing mosquitoes for 100 yards.
Then the exhaust would clean up gradually while I went into the back straight, then as I dove into the next corner (hard braking, downshift, etc) I'd repeat it again. 3 times per lap.
Sort of lends itself to this theory from Kevin:
The second thing I observed was:
2) I was playing with my new 2.2 FDR rear end and trying to find out the right gear for the back straight. On most of my practice laps, I ran 4th gear along the back straight (about 103 MPH at this point and accelerating) and observed no significant blow-by out the tailpipe.
But, I decided to shift into 5th gear once on that back straight for giggles... and immediately there was TONS of oil smoke from the tailpipe - even tho I was still under WOT. I promptly went back to 4th and the smoking reduced.
All I can think of here is that, at the lower engine RPM's of 5th gear, the suction from the exhaust nipple was reduced and that permitted the crankcase pressures to build up? It was if I'd thrown a fog switch both when I went to 5th and shut it off when I went back to 4th.
Back home - I compression checked the motor expecting to see a blown head gasket. No. Cold compression check was 150 psi all 8 cylinders. I will try to find time to run a leak-down test on it tonight.
Your thoughts?
I was at the Milwaukee Mile this Saturday, dry sunny day, 65 degrees, and we wore the big Hoosiers. (315/35/SR17 Fronts and 335/35/sr17 Rears).
The track is a NASCAR-type oval - 1 lap = 1 Mile, plus a Daytona-style road race course fitted to the infield. You do about 3/4 lap on the oval, then dive into a near-hairpin into he infield section, lots of twisty stuff in here, another hairpin,
and out back onto the oval. The oval does not have much of a camber to it, the other fellas there told me it was only 3 degrees of banking - but it looked a little more than that to me. Still - it's no Talladega. Its flat enough that you have to significantly brake for it.
Working off of Kevin's comments above - (and thank you for sticking with us 928'rs as this crank scraper Windage tray product gets dialed in, Kevin!) - I can add a little more to the comments above from this weekend.
To cut to the chase - I pumped oil out of my breather system so bad that I was only allowed one timed run then the officials pulled my tech inspection sticker. No problem, I was retiring anyway - I pumped oil so badly, I was fairly certain I'd blown a head gasket.
A little background: this is a new engine that has only about 550 miles on it. Forged low-expansion pistons that have 1/2 of the piston to cylinder wall clearance as stock ones do, the Johnson Scrapers and Windage tray system (First edition, I guess), the 928 Motorsports improvements to the oil separator,
then a Mann-Hummel Oil Separator (same one DR is using), then to a welded in Moroso nipple into the header collector to pull a vacuum in the crankcase. This motor is fitted with a Supercharger and pushing about 8 psi at the intake joint at 6000 RPM.
Last year, I had installed a boost gauge on the crankcase to see what was doing when under boost. My tired old motor had cylinder wall scratches, and was an OEM 4.5L that would compression check only 65 psi each cylinder cold. (8.5:1 CR). We noted that, under 4 or 5 psi of boost, the crankcase would register only 1 psi of pressure - so we always thought the exhaust-venturi vacuum system was doing a good job of evacuating the system. BUT - under hard deceleration that included some engine braking, you could see the crankcase pressure go as high as 6 psi. That's when we decided to pull the motor and rebuild it.
Back to present-day: Between Road America and Yesterday, I found and installed a electric continuous-duty oil scavenging pump. See photos below.
I plumbed it to the bottom of the Mann-Hummel oil separator, ran it into a billet sintered-bronze oil filter canister to deaerate the oil, and then back into the passenger cam tower to return oil to the motor.
At the Milwaukee Mile - I observed the following interesting points:
1) I blew oil smoke out the tailpipe (remember that is where my crankcase PCV system ultimately terminates) in precisely 3 places on the track - each of them hard braking for tight corners. I'd be at full throttle, hard brake, downshift before the Apex, and as I accelerated out of that tight corner I was killing mosquitoes for 100 yards.
Then the exhaust would clean up gradually while I went into the back straight, then as I dove into the next corner (hard braking, downshift, etc) I'd repeat it again. 3 times per lap.
Sort of lends itself to this theory from Kevin:
The increased blow-by at high rpms was probably blocked from returning to the heads by the increased oil retention in the drainage paths (during forward and angular acceleration, force vectors would tend to “push” the oil back towards the rear of the engine and not allow it to drain as easily, creating more of a blockage for the blow-by gases). The blow-by would then pressurize the crankcase and the surface of the sump oil would be pushed down – the easiest hydraulic relief path would be straight up the fill tube where it could overwhelm the AOS system and exit to the catch-can.
2) I was playing with my new 2.2 FDR rear end and trying to find out the right gear for the back straight. On most of my practice laps, I ran 4th gear along the back straight (about 103 MPH at this point and accelerating) and observed no significant blow-by out the tailpipe.
But, I decided to shift into 5th gear once on that back straight for giggles... and immediately there was TONS of oil smoke from the tailpipe - even tho I was still under WOT. I promptly went back to 4th and the smoking reduced.
All I can think of here is that, at the lower engine RPM's of 5th gear, the suction from the exhaust nipple was reduced and that permitted the crankcase pressures to build up? It was if I'd thrown a fog switch both when I went to 5th and shut it off when I went back to 4th.
Back home - I compression checked the motor expecting to see a blown head gasket. No. Cold compression check was 150 psi all 8 cylinders. I will try to find time to run a leak-down test on it tonight.
Your thoughts?
05-22-2006, 11:32 AM
#11
Race Car
I did not see a price on your site for both the teflon crank scraper and windage tray for the 928.
Are these items attached to the bottom of the crank-girdle studs/bolts?
Are these items attached to the bottom of the crank-girdle studs/bolts?
05-22-2006, 11:45 AM
#12
Developer
Thread Starter
Swaybar - I do not have them listed because I do not think they are ready for sale yet. I will not list them until I can say they are tested on my own car and work correctly.
They are complicated to evaluate at this time - because there are so many other variables as well. But, the few of us that are wearing them and the manufacturer are at work to sort them out.
They are complicated to evaluate at this time - because there are so many other variables as well. But, the few of us that are wearing them and the manufacturer are at work to sort them out.
05-22-2006, 12:05 PM
#13
Three Wheelin'
I did lower the oil pickup tube by the same amount that the pan was lowered to keep the same oil pickup to pan floor distance. I made an "O" ring sealed spacer under the pickup tube mount. If I recall correctly, the distance was within the 0.25" to 0.375" finding. One problem with lowering the oil pan is that the stock starter won't fit and the high torque small starter needs modified to fit properly without hanging down too far or being positioned too close to the headers. Motor mount height can be a concern too. It never ends...
I would try cutting back one quart initially -- baby steps. That is IF you are running some manner of scraper or windage control system. I know you have scrapers in your engine. Without scrapers or other active windage control it is difficult to know how much oil gets drawn into the cloud surrounding the crank -- that could easily be another 1-2 quarts.
I would recommend that everyone move the sump down as you have done but there is a big price tag there that comes along for the ride.
One relatively inexpensive thing to try is this (I don't have a short block any longer or I would check this myself): Determine the oil pickup to pan floor clearance with some modeling clay. Ford engineers have determined that the optimal distance from the pickup opening to pan floor (subsuming an opening parallel to the floor) is .25" to .375". Closer than this invites cavitation, further than this risks drawing in air. If the stock thick Porsche gasket is at the upper limit (Highly probable -- else why only 4mm? Heck, the 944 has an 8mm thick gasket and was developed off the 928 -- lots of little engineering bread crumbs to follow. ) you would need to make a spacer to extend the oil pickup a bit closer to the pan floor. What I was thinking was to stack and glue together Carl's gasket and the stock Porsche gasket. You could make some aluminum spacers like those used on the 944 to control crush.
Originally Posted by Kevin Johnson
I would try cutting back one quart initially -- baby steps. That is IF you are running some manner of scraper or windage control system. I know you have scrapers in your engine. Without scrapers or other active windage control it is difficult to know how much oil gets drawn into the cloud surrounding the crank -- that could easily be another 1-2 quarts.
I would recommend that everyone move the sump down as you have done but there is a big price tag there that comes along for the ride.
One relatively inexpensive thing to try is this (I don't have a short block any longer or I would check this myself): Determine the oil pickup to pan floor clearance with some modeling clay. Ford engineers have determined that the optimal distance from the pickup opening to pan floor (subsuming an opening parallel to the floor) is .25" to .375". Closer than this invites cavitation, further than this risks drawing in air. If the stock thick Porsche gasket is at the upper limit (Highly probable -- else why only 4mm? Heck, the 944 has an 8mm thick gasket and was developed off the 928 -- lots of little engineering bread crumbs to follow.
) you would need to make a spacer to extend the oil pickup a bit closer to the pan floor. What I was thinking was to stack and glue together Carl's gasket and the stock Porsche gasket. You could make some aluminum spacers like those used on the 944 to control crush.
05-22-2006, 12:07 PM
#14
Race Car
Originally Posted by Carl Fausett
Swaybar - I do not have them listed because I do not think they are ready for sale yet. I will not list them until I can say they are tested on my own car and work correctly.
They are complicated to evaluate at this time - because there are so many other variables as well. But, the few of us that are wearing them and the manufacturer are at work to sort them out.
They are complicated to evaluate at this time - because there are so many other variables as well. But, the few of us that are wearing them and the manufacturer are at work to sort them out.
http://www.crank-scrapers.com/
I think you have introduced too many variables at once in order to make a timely evaluation. You have a new engine, a non-stock crankcase breather system which vents into the exhaust, and an oil pump/sump which returns oil through one head which then drains back down into the crankcase. And somewhere in that mix is the Ishihara-Johnson crank-scraper and windage tray. There are too many things going on at once in order to determince which piece is causing what.
On the other hand, judging by the performance of the 928 which ran a race of 12 consecutive hours, it appears that the product is working correctly except for the oil sump level apparently being initially too high with the single addition of the new crankcase hardware.
Last edited by SwayBar; 05-22-2006 at 12:26 PM.
05-22-2006, 12:20 PM
#15
Kevin -
There are those three holes in the V of the motor - that lie directly above the mains of the crank- these, I have always though - could be used for crankcase evac port, or even vac ports.
If the sump was up to an inch from the motor, would this help even more?
There are those three holes in the V of the motor - that lie directly above the mains of the crank- these, I have always though - could be used for crankcase evac port, or even vac ports.
If the sump was up to an inch from the motor, would this help even more?