Engine rebuild questions...
#152
11-15-2013, 11:50 AM
Just in general, if it can be done, I always think it's a win win situation to do that on a performance motor..
Know one ever answered if we have any type of oil scraper or windage tray. I would think dry sump oil systems aren't in need of them as bad.
Know one ever answered if we have any type of oil scraper or windage tray. I would think dry sump oil systems aren't in need of them as bad.
#153
11-15-2013, 03:01 PM
Sure, if you have money to burn. I'm being just a little harsh. It is far from being a good bang for the buck. Yes, you will gave a few ponies, but there are better places to put your bucks.
Another thing, it isn't as simple as feather edging. It needs to balanced and nitrated. Doing a proper job isn't as cheap as some people think.
Another thing, it isn't as simple as feather edging. It needs to balanced and nitrated. Doing a proper job isn't as cheap as some people think.
#155
11-15-2013, 03:18 PM
Some engines have crankshaft wipers/scrapers to wipe Excess oil off.. There is a slight gap between it and the counter weights.
#157
11-15-2013, 06:08 PM
A week ago I had a Cochlear Implant. At times the pain pills have left me with some brain fog. 993GT is correct, the 996tt crank is forged. 
The 996TT and GT3 (same with the GT3 Cup/ GT3R) all use a similar crankshaft (material). Differences I am aware of are, looking at journals, the GT3 rod journal is smaller vs. thinner (narrower), The rod is 53 mm at the crank and 22mm wrist pin. I believe the width of the journal is 25 mm. The 996tt has a 55mm journal at the crank and a 23mm wrist pin. So the rod journal diameter is larger than the GT3 crank. The GT3 crank has wider journals but narrower diameter journal. Probably to reduce reciprocating mass on the high revving GT3. Another difference in the cranks is internal oil circuits. The 996tt lubricates every 360 degrees while the GT3 lubricates every 180 degrees. I believe the 996tt crank was used in the racing GT1. I believe these cars base produced 600 hp. .
The 996TT and GT3 (same with the GT3 Cup/ GT3R) all use a similar crankshaft (material). Differences I am aware of are, looking at journals, the GT3 rod journal is smaller vs. thinner (narrower), The rod is 53 mm at the crank and 22mm wrist pin. I believe the width of the journal is 25 mm. The 996tt has a 55mm journal at the crank and a 23mm wrist pin. So the rod journal diameter is larger than the GT3 crank. The GT3 crank has wider journals but narrower diameter journal. Probably to reduce reciprocating mass on the high revving GT3. Another difference in the cranks is internal oil circuits. The 996tt lubricates every 360 degrees while the GT3 lubricates every 180 degrees. I believe the 996tt crank was used in the racing GT1. I believe these cars base produced 600 hp. .
#158
11-15-2013, 07:05 PM
What are you going to knife edge?
That is the turbo crank. DO NOT TOUCH IT. I make 1300 to the wheels. no issues as yet.
That is the turbo crank. DO NOT TOUCH IT. I make 1300 to the wheels. no issues as yet.
Last edited by cjv; 11-15-2013 at 09:32 PM.
#160
11-15-2013, 07:31 PM
Chad,
My desire for a 7500 rpm redline is not for more power but rather for the flexibility the higher redline affords you in a road course situation when in many cases the extra 500 rpm allows you to stay in gear during certain parts of the track where a gear change would upset the balance of the car. If you can delay a shift and keep accelarating throught those parts of the track than you have shaved some time. An extra 500 rpm may not sound like much but if you can avoid or delay a shift 2 or 3 times during a 2 min lap than you are potentially saving over a second or so. That may not seem like much but it's huge. Having the extra 500 rpms to play with in a road course setting is much more benefitial than having an extra 100hp. As it stands, I really can't utilize full throttle anywhere except the long straight aways at most tracks. Having an engine that is operating at a higher RPM also makes the throttle easier to modulate as the turbos are spooled up. The more technical the track with more turns and less straights, the more a higher redline would be beneficial. Being able to operate at a higher RPM also allows you to use the engine more effectively as a breaking source than if you were in a higher gear / lower RPM situation. If you add all of this up you can see how a higher redline holds tangible benefits.
A lot of my questions and considerations are centered around this. The reason I was considering the GT3 crank is the fact that it is lighter. I figured that may be beneficial in allowing the engine to rev more. However, the more I read the more it seems that the stock 996TT crank is just fine. Maybe knife edge it?? I've also read about guys using a GT3 exhaust cam which I believe is a direct bolt of if I'm not mistaken. Would that be of any benefit?? I don't know. Same with the 3.8 pistons/liners. Benefit of those in my mind would be the ability to run slightly lower boost to attain the same power but at $5K are probably not very cost effective. The GT3 pump as you suggested is definitelly on my list along with the rods. Carillos or Pauter? Which would be better for my goals? I'm assuming ligher rods would be more desirable to allow higher revs. I am also very interested in finding out about the Clevite extreme load bearings you mentioned. I am assuming Clevite is an OEM supplier of bearings on these motors?
Ultimately I'm thinking durability here on a motor that I would like to be able to run hard for at least 100 track hrs between rebuids. My definition of running hard is 30 min sessions where the engine is operated in a racing environment with most shift around the 6800/7000 mark and the occasiasional 7500 shift while running in the black group with GT3s, Cups, and other race prepped vehicles. This is how I operate my car now (obviously minus the ability to shift at 7500) but with over 55 hours of track time on the clock I feel that a rebuild/refresh is somewhere in my future maybe at the end of next season. My limit is a max of 650 crank HP (maybe 550 whp) with a goal of a reliable 7500 redline. I guess I'm trying to ascertain if this is a realistic goal/expectation without resorting to some exotic mega dollar rebuild. I'd like to keep the parts cost around $10K or so. So far my engine is running strong without any issues but I would like to have a plan and parts on hand when the time comes for a rebuild. I hope this clarifies my goals and explains why I'd like a higher redline and such. Again thank you for your continued support and input as I'm open to suggestions. I'd like to chat with you sometime via phone if you'd be up for it. Thx...
My desire for a 7500 rpm redline is not for more power but rather for the flexibility the higher redline affords you in a road course situation when in many cases the extra 500 rpm allows you to stay in gear during certain parts of the track where a gear change would upset the balance of the car. If you can delay a shift and keep accelarating throught those parts of the track than you have shaved some time. An extra 500 rpm may not sound like much but if you can avoid or delay a shift 2 or 3 times during a 2 min lap than you are potentially saving over a second or so. That may not seem like much but it's huge. Having the extra 500 rpms to play with in a road course setting is much more benefitial than having an extra 100hp. As it stands, I really can't utilize full throttle anywhere except the long straight aways at most tracks. Having an engine that is operating at a higher RPM also makes the throttle easier to modulate as the turbos are spooled up. The more technical the track with more turns and less straights, the more a higher redline would be beneficial. Being able to operate at a higher RPM also allows you to use the engine more effectively as a breaking source than if you were in a higher gear / lower RPM situation. If you add all of this up you can see how a higher redline holds tangible benefits.
A lot of my questions and considerations are centered around this. The reason I was considering the GT3 crank is the fact that it is lighter. I figured that may be beneficial in allowing the engine to rev more. However, the more I read the more it seems that the stock 996TT crank is just fine. Maybe knife edge it?? I've also read about guys using a GT3 exhaust cam which I believe is a direct bolt of if I'm not mistaken. Would that be of any benefit?? I don't know. Same with the 3.8 pistons/liners. Benefit of those in my mind would be the ability to run slightly lower boost to attain the same power but at $5K are probably not very cost effective. The GT3 pump as you suggested is definitelly on my list along with the rods. Carillos or Pauter? Which would be better for my goals? I'm assuming ligher rods would be more desirable to allow higher revs. I am also very interested in finding out about the Clevite extreme load bearings you mentioned. I am assuming Clevite is an OEM supplier of bearings on these motors?
Ultimately I'm thinking durability here on a motor that I would like to be able to run hard for at least 100 track hrs between rebuids. My definition of running hard is 30 min sessions where the engine is operated in a racing environment with most shift around the 6800/7000 mark and the occasiasional 7500 shift while running in the black group with GT3s, Cups, and other race prepped vehicles. This is how I operate my car now (obviously minus the ability to shift at 7500) but with over 55 hours of track time on the clock I feel that a rebuild/refresh is somewhere in my future maybe at the end of next season. My limit is a max of 650 crank HP (maybe 550 whp) with a goal of a reliable 7500 redline. I guess I'm trying to ascertain if this is a realistic goal/expectation without resorting to some exotic mega dollar rebuild. I'd like to keep the parts cost around $10K or so. So far my engine is running strong without any issues but I would like to have a plan and parts on hand when the time comes for a rebuild. I hope this clarifies my goals and explains why I'd like a higher redline and such. Again thank you for your continued support and input as I'm open to suggestions. I'd like to chat with you sometime via phone if you'd be up for it. Thx...
I say stay 3.6 and this is why. 3.6 cup 40 hrs (most go 60) 3.8 30 hours. 4.0 20 hrs but the teams I know never made it to 20.. 3.6 is the proven winner.
#161
11-15-2013, 08:50 PM
Carrillo rods w/carr bolts. gt3 oil pump. raceware studs. stock head gaskets. stock pistons, stay 3.6L! ID1000 injectors with a walbro 450 in tank. Then get alpha 28s with the money you would have spent on the 3.8 kit. Run at low boost 1bar your hp goals will be met safely and tons of torque to pull you out of the corners. Add a trans cooler the help your box live or source a gt2/3 box and gear it for the track you run mostly.
I say stay 3.6 and this is why. 3.6 cup 40 hrs (most go 60) 3.8 30 hours. 4.0 20 hrs but the teams I know never made it to 20.. 3.6 is the proven winner.
I say stay 3.6 and this is why. 3.6 cup 40 hrs (most go 60) 3.8 30 hours. 4.0 20 hrs but the teams I know never made it to 20.. 3.6 is the proven winner.
My transmission is sorted. The gearbox has steel synchros and a very efficient oil cooler already so I have no issues there. Even in 120F track temps I rarely ever see gearbox fluid temps over 220F at the end of a 30 min session which is very good considering the added heat an LSD normally adds. I run a Guard LSD. I am measuring oil temps near the LSD, so at the hottest point in the gearbox near the oil pick up before it goes to the cooler. Gearing wise I'm pretty much where I want to be as I run a 25.5" tall front and a 26.4" tall rear tires (997GT3 sizes) which makes the gearing slightly taller by the virtue of the rear tire being 1.5" taller than stock. I may add the taller 1/2/3 997 shaft when the gearbox is opened sometime down the road but at this time I'm happy with the gearing.
Thanks again...
Last edited by pwdrhound; 11-15-2013 at 09:02 PM.
#162
11-15-2013, 09:31 PM
Tim,
I though your recent pic (bottom) would make a somewhat similar comparison. Very nice work. Looking at the previous post .... is the case shuffle pinned?
Knife edging, with 1300 hp what's another 8?
It's pretty much known that as you squeeze the last bit of power out it gets extremely expensive. It ranks up there with the costs of pulling a 12-15 HG case vacuum or boat tailing to extract 15-20 ponies. The builds appear to be similar and different in many ways. From listening and I could have listened wrong, your build is for quarter mile and mile fun. Our build is for the track. Very quick response over a wide rpm range. It was not designed and will never be used for off the line.
Thanks for sharing.
URL=http://s1241.photobucket.com/user/tim941nyc/media/IMG_1050.jpg.html]
I though your recent pic (bottom) would make a somewhat similar comparison. Very nice work. Looking at the previous post .... is the case shuffle pinned?
Knife edging, with 1300 hp what's another 8?
It's pretty much known that as you squeeze the last bit of power out it gets extremely expensive. It ranks up there with the costs of pulling a 12-15 HG case vacuum or boat tailing to extract 15-20 ponies. The builds appear to be similar and different in many ways. From listening and I could have listened wrong, your build is for quarter mile and mile fun. Our build is for the track. Very quick response over a wide rpm range. It was not designed and will never be used for off the line.Thanks for sharing.
URL=http://s1241.photobucket.com/user/tim941nyc/media/IMG_1050.jpg.html]
Last edited by cjv; 05-06-2022 at 03:26 PM.
#163
11-16-2013, 12:40 AM
pulling a 12-15 HG case vacuum or boat tailing to extract 15-20 ponies
- how does a vacuum in the crank case create more power?
- what excatly does boat tailing to gain more power? In that place I would never had though that there is anything to gain.
Thanks
Andreas
#164
11-16-2013, 02:55 AM
to become very small windage losses..(ventilation losses reduced inside the engine)
#165
11-16-2013, 06:48 AM
I hate to see those helical cut gears with all your guys HP because straight cut ones would be more efficient and take that side loading effect away but I know the straight cuts are noiseyer.