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Been here a while
 
Join Date: Apr 2004
Location: East coast, west coast, typ. 35,000 ft
Posts: 2,452
Blocking off the hole on the air outlet by the distributor will make a difference. As mentioned above, the majority of the air that the fan is pushing is likely going out that hole. You can find large rubber caps/plugs that the plumbers use to cap off big pipes.

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looking for 1972 911t motor XR584, S/N 6121622
Old 10-04-2025, 04:46 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
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Join Date: Apr 2025
Location: NorCal Foothills
Posts: 247
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My ‘75 wasn’t running hot, but had many of your other symptoms. You may have more than one issue.

Regarding hard starting, back fires, etc… Have you looked at the CIS plastic plenum/intake system- done a smoke check? Do you have one of those ridiculous toilet seats inside your air filter box? I used to find mine laying on its side inside the box after a balked start- if you have a pop off valve, and it is leaking, that’s a big problem. They are glued in with epoxy. Usually not very well.
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Dave
Project: 1985 Porsche 911 Carrera Coupe 3.2 to 3.4L "Carina"
PCA Member- Sacramento Valley region
Old 10-04-2025, 04:49 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
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Join Date: Jul 2018
Location: phoenix az
Posts: 223
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Have you pulled and tested your thermostat?
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Instagram.com/timofthevalley
Old 10-04-2025, 09:30 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
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Join Date: Nov 2021
Location: The Far Side - Chicago
Posts: 1,278
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I think he should do a smoke test. Double check the spark plug wiring is correct order too as well as a visual inspection check for cracks, I’m not a fan of that braided sheathing, also check condition of the spark plugs.


On the oil temp gauge accuracy - maybe disconnect wire and see if dash gauge pegs up or down (no power) and if it has full range.
The other method is where to get an accurate reading with a IR handheld thermometer at the sender or oil return tubes….there were a few pelicans that tried verifying oil temps with a long probe-style thermometer down the oil dipstick to the oil tank. Not sure if this is with engine running or immediately off, but maybe expect a few degrees off and if anyone ever had a respectable reading if it’s possibility to check temp. inside tank.

Regardless, who knows what hidden damage can still exist with an engine fire. Any extreme heat could have warped the diaphragms within several components and that may been overlooked when replacing just charred vac hoses.

Seems to me like the fault was probably in the rebuilding. Finding and trying to “un-do” several mechanics work (too many cooks theory) is a headache especially when it wasn’t just right from the get-go.
If he sorts and eliminates the simple stuff, he can proceed to test the CIS.

Local chapter of PCA membership is a good source if find a qualified tech (or use this reference….https://cis911primer.com/pages/test_pressures.html

The sputtering performance on the low end is being overcome by higher rpm sounds simple enough. Fuel and delivery issue relayed to extended no-run storage may still exist. Once he finds a timing light he can eliminate at least one pressing issue.
Old 10-04-2025, 01:22 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
brianb
 
Join Date: Aug 2022
Location: Cincinnati
Posts: 22
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I do appreciate your patients . I didn't understand that you wanted a specific picture of the
distributor. I did make certain that all of the heat lines were at least going somewhere. I took her out after a 10 minute warm up and got to 250 in less than a 1/4 mile. I took her back and played with the timing and the distributor a bit , but that only changed the idol speed. The burping and sputtering was still there , so I shut her down.. I'm afraid I have a burnt valve or a crack in a cylinder wall. I guess I'm gonna learn about the internal workings of the car.
Old 10-04-2025, 08:02 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)
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Join Date: Jun 2009
Location: St Paul MN
Posts: 5,494
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Hi Brian,

That’s some crazy heat and almost doesn’t sound feasible to get that hot that fast...

At some point you really need to start going after the problem in a systematic fashion. An IR thermometer and timing light can be had for less than $20-30 each and would be a good start.

A leakdown and compression test could eliminate or highlight mechanical issues.

A smoke test can pinpoint any vacuum leaks- CIS doesn’t like vacuum leaks!

A CIS fuel pressure testing kit would be good as you work your way through any fuel delivery problems. The thread on CIS for dummies is great for testing your fuel injection.

Good luck on solving this and hopefully others can chime in on what might be a good order of testing to do.

I’m not sure if you have shared your general location if not it might be a good idea as there could be someone local who could help or loan you some tools.

Rutager

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Rutager West

1977 911S Targa Chocolate Brown
Old 10-05-2025, 08:06 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #26 (permalink)
 
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