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E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
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Quote:
Originally Posted by Ollies930 View Post
DonE, what I meant with an "oversized cylinder stud" is a bigger diameter than stock. Even the Supertec or SRP studs are essentially only a stronger version of the stock studs(similar dimensions). I am looking for a stud that has a much larger base thread(thereby eliminating the need for case inserts), and a bigger diameter throughout to better cope with the much higher cylinder pressures I am planning to subject my engine to. From what I am told, all commercially available studs will fail at the 25-30lbs boost range.

Oliver
I dont think that may be the most accurate information..... ARP studs are used in my friends diesel engine, which has over 60 PSI of boost. Another one uses them in his twin turbo big block that has over 2,000 HP, and no failures.

I think the problem with our engines, is that regardless of which stud we use, there maybe a point at which the threads fail that are cut into the case... after all they are only Aluminum. I have never heard of larger diameter studs for our engines. If they are out there, you would have to machine the heads as well as the cylinders for the studs to pass through, which would not be that big of a job. ( Unless you are just searching for a stud that has a larger diameter thread on the bottom). I would think that a finer thread would be better option then a larger diameter, as with a finer thread, you would have more threads, which would equal more contact area...... more holding power... but you are still dealing with AL.....

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Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 08-26-2009, 07:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
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Join Date: Jan 2002
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and I also have had JB Racing cross drill my crankshaft and complete the center oil mod. I also had my crank "offset ground" at CCR in CA. Armundo stroked the crank to a 78.8mm stroke....

Both companies did AWESOME work!!!!
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Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 08-26-2009, 07:22 PM
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Quote:
Originally Posted by onboost View Post
Tim, what kinda Benjamins are we talking for this mod including the bearing?


DonE, does the JB Racing mod include wotrk to the bearing as well? Cost?

Thanks
I don't know - call Mike or Jim and ask. I think Brad (turbobrat930) had his done there.
Old 08-26-2009, 08:02 PM
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We send the cranks to Armondo to be cross drilled. I'm not sure if its proper that I post the cost to us, a shop... We have many cranks every year prepped by CCR and get a different rate than a one time customer.

If I were you I'd give Marine Crankshaft a call
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Old 08-26-2009, 09:07 PM
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Turbobrat930, I completely agree with you that ARP has some very high quality studs, but if you compare the diameter on the big block studs to the Porsche studs, you will find a big difference in diameter. I am not objecting to the quality of the studs, but their near stock dimensions. The reason I want a bigger thread on the bottom is to offset the studs propensity to pull out of the cases. And I know how much more work is in store for me(oversized stud holes in heads and cylinders). As for the studs availability, I am trying to match them up with something that already exists(car or motorcycle), so I will not have to have something made up custom.
Also, another perk of using bigger diameter studs is the fact, that they have more resistance to stretching under load and therefore resisting against the heads lifting off the sealing surface. As an example, Mr. Turbo built a Kawasaki ZX-11 for the Daytona HP shoot out in 1996, where he made nearly 500rwhp. To keep the cylinder head on the 1109cc 4-cylinder he supposedly needed 1/2" studs. As a comparison to the above mentioned big block Chevy, the studs (to the best of my recollection) are only7/16".

Oliver
Old 08-27-2009, 09:45 PM
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Quote:
Originally Posted by TimT View Post
We send the cranks to Armondo to be cross drilled. I'm not sure if its proper that I post the cost to us, a shop... We have many cranks every year prepped by CCR and get a different rate than a one time customer.

If I were you I'd give Marine Crankshaft a call
I've spoken to Armando/CCR years back while working for one of the local shops. Was curious as to who you used... but you guys do the bearing mod in your shop am I correct?

Why would you reccomend Marine?
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Old 08-28-2009, 04:39 PM
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Quote:
Originally Posted by onboost View Post

Why would you reccomend Marine?
I would recommend Marine because they are the sole crank vendor used by a certain well known and occasionaly cantankerous, but very, very highly respected builder on this site. Not to mention they also manufacture scratch built, to spec cranks for any make or marque.

They did my crank and did a wonderful job at a price that came without the Porsche tax, to boot.
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Old 08-28-2009, 05:00 PM
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what? me worry?
 
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Quote:
Why would you reccomend Marine?
We have a long time relationship with CCR.. Armondo...but...

From what I have learned about Marine, and the price for there services...It might warrant giving them a call....

I wont post prices for services we get from machinists or shops since we get a different price schedule than an individual..

The bearing mod is easy peasy machining.. we made a fixture



A few minutes in a lathe and you have the modified center bearing..
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Rent a GT3RS from us!! Call or e-mail.
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Old 08-28-2009, 06:08 PM
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I talked with David at Marine. They sound very reasonably priced and good turn around (quoted typically a week).

David indicated that when they cross drill a crank shaft, they also machine the main journal (oil groove). While I have seen this done, it seems to me this would weaken the crank shaft. I think I would much rather modify the bearing to carry the oil, as TimT does.

Anybody have thoughts or better yet experience with what Marine proposes?

Thanks for any insight!
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Old 08-29-2009, 05:08 AM
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Thanks for the input guys..

I will probably give them a call...

Tim, I'll be talking with you guys in the near future about the bearing mod

Thx
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Old 08-29-2009, 07:51 AM
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Join Date: Jun 2008
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Quote:
Originally Posted by bahnzai View Post
I talked with David at Marine. They sound very reasonably priced and good turn around (quoted typically a week).

David indicated that when they cross drill a crank shaft, they also machine the main journal (oil groove). While I have seen this done, it seems to me this would weaken the crank shaft. I think I would much rather modify the bearing to carry the oil, as TimT does.

Anybody have thoughts or better yet experience with what Marine proposes?

Thanks for any insight!
It's equivalent to making the whole main bearing journal diameter smaller. There might be some marine diesels and big block gasoline engines with enough margin in the crank design to pull that off, but I wouldn't assume we have it.

After reading through this thread I have alot of questions about what problem is trying to be solved. Are you actually breaking cranks, or failing rod bearings?

Almost every mod mentioned here has significant drawbacks, in my view:

Grooved main bearing - this takes away about 10% of the bearing area of the crank, while at the same time you are increasing the load on it by running at high rpm. The oil in bearing is going to get squeezed even harder, making it hotter and less able to support load.

Cross-drilling - N/A motor guys swear by it in some cases, others avoid it like the plague. Drilling a hole through the crank definitely makes it less stiff (easier to bend). Will it live at 8000 rpm? What if your clutch and flywheel are a bit heavy?

Here is the hard fact that everybody from Armando The Crossdriller on down better keep in mind: The load on the crank increases with the square of engine speed. If you double the rpm, you have FOUR TIMES the load. You can't make that go away with more oil.

There is one mod that will solve this problem without messing with the crank. It costs about 9K worth of "Benjamins". Any guesses on what it is?

Old 08-29-2009, 08:00 AM
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