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-   -   2.4 timing question (http://forums.pelicanparts.com/porsche-911-technical-forum/558696-2-4-timing-question.html)

72T 08-13-2010 12:01 PM

2.4 timing question
 
My 2.4 is still running hot after a second recent tuning, with my mechanic adjusting the timing (per suggestions here) in an attempt to cool things off. He has it at "28", which he claims is the low end for this engine. The motor is running a bit cooler than before, but still finds 245 or so degrees, when for decades it never saw 230. Can the timing be altered further without any problems, or should I look in another direction?

Trackrash 08-13-2010 12:45 PM

The spec for your engine is 32-38 degs advance at 6000 rpm.
I would check the air fuel mixture.

Maybe others will chime in with more experience but my 71 never gets over 190 on the street. Maybe 210 or so on the track.

245 degs is at the upper limit of what most motor oils can stand. Anything over 230 needs synthetic oil and frequent changes.

Where are you located?

72T 08-13-2010 12:58 PM

I'm in Florida, but have been for 30 years. The car is running full rich. Could that be doing it? My understanding is fuel = cooler.

Trackrash 08-13-2010 01:48 PM

Rich means cooler so that's probably not your problem. Is the motor stock, any mods?

Assuming you still have the MFI those temps sound high to me. Do you have a front cooler? I would sure think about adding one, like a Carrera one with a fan. There have been some recent threads about that.

You may want to check under the fan shroud to see if any debris are blocking the oil cooler.

Maybe others will have additional suggestions.

BK911 08-13-2010 01:55 PM

Maybe pull the alternator and look for a mouse nest on top of the cylinders.

Bob Kontak 08-13-2010 02:20 PM

Yep - was just writing that up.

Do you have a front oil cooler? That will help a lot as Trackrash says. Also Bruce Anderson says (in his first edition Performance Handbook) to change out the plumbing and thermostat to the 74 and later for the front cooler run. That is if you use the Trubotrol cooler which is not the late Carrera cooler.

For checking for debris I don't know if you can just look through the fan. You may have to loosen it and tip the fan/alt assembly back a bit to get access. That would be the first thing I would do. One paper towel, leaves, mouse nest could cause problems. Check way in the back (front actually) on the passenger side where the air is fed to the engine mounted cooler.

The cooler has a nice basket that stuff can settle into. Get back in there somehow and make sure it is debris free.

http://forums.pelicanparts.com/uploa...1281737992.jpg


http://forums.pelicanparts.com/uploa...1281738022.jpg


Maybe a shop vac if you can't reach with your hands?

Bill Verburg 08-13-2010 02:48 PM

generally retarded timing cause an engine to run hot

I'd stick to the spec for your motor which is 5* ATC w/ the dist vacuum hooked up. If the vacuum hose is disconnected the timing should advance to ~0* or TDC.

max advance w/ the vac. disconnected is ~35* BTDC as mentioned above

have you adjusted the MFI rack w/ the adjuster behind the alternator?

also as mentioned check for rodent nests under the shrouds atop the cylinders


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