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ael911's Avatar
 
Join Date: Dec 2005
Location: Rancho Cucamonga Ca
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Carb conversion without motor drop

A question for the engine experts: I am considering doing a PMO carb conversion from my CIS and I have read all the old posts in this fourm. I have one question that I could not find an answer and that is can this conversion be done with the engine in the car if I am just swapping out CIS for carbs? I
have no a/c and the heater system is already backdated so there is quite
a bit of room in the engine bay. I thought I read somewhere in Wayne's book
that the CIS system can be removed as a whole from the engine with careful maneuvering. Also, are there any major issues that others have faced when doing this conversion besides the usual suspects such as re-curving the distributor and adding a pressure regulator to drop the fuel pressure from the CIS pump.

Any input is greatly appreciated.

Andy

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'75 911S Silver Anniversary #164(Formerly JTO's)
Rebuilt 2.7 with full ARP, 9:1 CR.
SSI, GHL, ER polybronze bushings, finned oil lines.
Lowered and corner balanced. CIS retired, now PMOs!
'65 912 slate gray sunroof (driving project)
Old 02-06-2008, 09:22 AM
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Hi Andy,

No worries, Sir. This conversion can be done without dropping the engine although its easier if you lower it a little to help you remove the CIS intake.

You will need the PMO fuel pressure regulator (its included in the kit) to lower the pressure from 72 psi to 3.5 psi.
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Old 02-06-2008, 09:52 AM
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As always, thank you for your worthy advice Steve.
Andy
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'75 911S Silver Anniversary #164(Formerly JTO's)
Rebuilt 2.7 with full ARP, 9:1 CR.
SSI, GHL, ER polybronze bushings, finned oil lines.
Lowered and corner balanced. CIS retired, now PMOs!
'65 912 slate gray sunroof (driving project)
Old 02-07-2008, 08:28 AM
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You might not need to re-curve the distributor. I think the 75 has enough centrifugal advance to get you to 30-35 degrees without a re-curve.

-Andy
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Old 02-07-2008, 09:45 AM
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I got my CIS out without even having to lower the motor. The trick was to disconnect the intake runners from the airbox. As an aside, I was shocked at how heavy the complete system was.
Old 02-07-2008, 10:16 AM
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Mr. Weiner:

Can you believe Andrew wants to remove the CIS from that sweet running motor we worked so hard on!?
Just kidding Andrew. You know I think its just one of the steps in creating the right power plant for that sweet car.
Actually, I'll probably be doing the same thing to my 3.6 some day.
Troy
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Past: 1975 911S Silver Anniversary-rebuilt and sublime.
Past: 1988 Carrera-backdated with a 3.6 and all the goodies.
Present: 2011 GMC 2500HD with the 6.0 & 4x4!, 2004 Toyota Sequoia (wife's)
Old 02-07-2008, 10:41 AM
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Thanks everyone for all the advice, I can't wait to get started. Does anyone have any experience with pulling out the intake studs and the swap for longer studs? I assume some PB Blaster, heat, and a stud puller will persuade the studs to back out.
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'75 911S Silver Anniversary #164(Formerly JTO's)
Rebuilt 2.7 with full ARP, 9:1 CR.
SSI, GHL, ER polybronze bushings, finned oil lines.
Lowered and corner balanced. CIS retired, now PMOs!
'65 912 slate gray sunroof (driving project)
Old 02-07-2008, 01:21 PM
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Quote:
Originally Posted by ael911 View Post
Does anyone have any experience with pulling out the intake studs and the swap for longer studs? I assume some PB Blaster, heat, and a stud puller will persuade the studs to back out.
I used the double nut technique to remove my intake studs and they came out no problem; no heat, PB blaster, etc. I had been through exhaust stud removal (and broke a few), so I was concerned. I was advised that it's the intense heat on the exhaust side of the head that creates the problem with the exhaust studs.
Old 02-07-2008, 01:38 PM
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Quote:
Originally Posted by JP911 View Post
I used the double nut technique to remove my intake studs and they came out no problem; no heat, PB blaster, etc. I had been through exhaust stud removal (and broke a few), so I was concerned. I was advised that it's the intense heat on the exhaust side of the head that creates the problem with the exhaust studs.
Great, I hope mine will be just as simple.
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'75 911S Silver Anniversary #164(Formerly JTO's)
Rebuilt 2.7 with full ARP, 9:1 CR.
SSI, GHL, ER polybronze bushings, finned oil lines.
Lowered and corner balanced. CIS retired, now PMOs!
'65 912 slate gray sunroof (driving project)
Old 02-07-2008, 01:46 PM
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If the double-nut technique gives you any problems, buy a stud remover from the Snap-on, or Matco guy. They're relatively inexpensive and make the job much easier.
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Old 02-07-2008, 03:24 PM
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Can someone clarify the double nut method for me, I think I have an idea but I need some confirmation. Thanks for the tips everyone, this forum is awesome.
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'75 911S Silver Anniversary #164(Formerly JTO's)
Rebuilt 2.7 with full ARP, 9:1 CR.
SSI, GHL, ER polybronze bushings, finned oil lines.
Lowered and corner balanced. CIS retired, now PMOs!
'65 912 slate gray sunroof (driving project)
Old 02-07-2008, 08:25 PM
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Thread two nuts down the stud. Lock them together by turning one against the other. Use the one closest to the head to remove the stud. As you try to unscrew the bottom nut, being locked against the one on top, you remove the stud. Heat can be your friend here. Don't go crazy and break the stud. That opens a whole other can of worms.
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Old 02-08-2008, 07:28 AM
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I thought the "Double Nut" method involved you and your buddy a hammer and chisel and a case of libations??

Old 02-12-2008, 11:41 AM
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