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concentric's Avatar
 
Join Date: Nov 2003
Location: Kingsport, TN
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Anyone go 2.7 to 2.9?

I know there were a few 2.9 P&C kits sold by Pelican and Andial. Just fishing here to see if anyone made this upgrade and if so, how it's working out over time.

The ones I'm talking about are the 9.8:1 CIS kit and the 10.5:1 carb/EFI kits.

Thanks,

Jason
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Old 09-27-2004, 05:05 PM
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I wouldnt do that with a mag case. they are barely strong enough for the 2.7 set up. an aluminum case could be a different story...
Old 09-30-2004, 04:24 PM
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Quote:
Originally posted by rover67
I wouldnt do that with a mag case. they are barely strong enough for the 2.7 set up. an aluminum case could be a different story...
If you use the proper hardware, I don't see why it shouldn't work.
I wouldn't be using a stock case, this one is done to the nines.

They're also cheap enough to burn one.

Andial reports that this P&C set does work.

JCM
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Last edited by concentric; 09-30-2004 at 04:55 PM..
Old 09-30-2004, 04:51 PM
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I am sure the pistons and cylinders are great, but thats not what I'd worry about.

All I'm saying is that the early mag cases, even with time-serts, built to 2.8 specs and above, will probably cause problems. You will most likely end up with pulled studs..... It's just what I was taught, and have seen happen in the past. Now if you use a different case, It may work just fine.
Old 10-01-2004, 06:37 AM
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The spigot size is the same for a 2.7 or 2.9 motor. i.e. 97mm. The extra cc's come from enlarging the cylinder bore from 90mm to 93mm. The only downside for the crankcase in this scenario it's seems to me would be the extra heat and torque that is generated.

The heat can be dealt with, and should be whether it's a 2.7 or 2.9, by improved cooling. The torque I don't believe was the culprit in the 2.7 pulled studs syndrome. I believe excessive heat cycles along with unmatched thermal expansion rates between the cylinder and studs were the major contributors. Both can be remedied. So the case isn't really the issue.

From what I've heard, although I have had no first hand experience, is that the main downside to the 2.9 conversion is the thickness of the cylinder wall. 2mm in some areas, give or take a few hundreths, if my math is correct. It starts flexing and doesn't bode well for longevity. Sealing the cylinder where it meets the head becomes an issue.

I've heard from a respected source that 2.8 (92mm bore) is the safe limit for these 2.7 based motors. Now if they made the cylinders out of Ti they could probably handle the thinner walls.

I've also heard from some people who have done the conversion and love it. So there you go.
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Last edited by Bobboloo; 10-01-2004 at 11:31 AM..
Old 10-01-2004, 11:23 AM
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Bobby is SOOO right about these 93mm P/C's.

Their longevity is not great and there are both head sealing and ring sealing issues since the bores do NOT stay round when they are hot.

Stick to 92mm or 90mm P/C's with these engines and you'll be much better off in the long run.
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Old 10-02-2004, 09:39 PM
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