My new car...

concentric · 03-30-2004, 09:07 AM

So I picked up my 1974 911 from the shop yesterday, they finally fixed most of the little interior issues and were comfortable turning over the car to me....

There are a couple issues I need to address that I've found out about the car. I'd like to get some advice on what could be causing these issues:

1. The car is running quite hot. Maybe 230 degrees when I was really pushing it on the freeway in 90ish degree weather yesterday.
2. There is a burble in the acceleration of the car. From about 1k to 3K rpms, it hesitates slightly in kind of a pumping, bubbling fashion. I hope this description makes sense.
3. When I come to a stop, the idle sticks at 2K rpm until I let out the clutch a little to creep the car forward, then the idle drops to it's regular rate.

Despite this stuff, I have been having a hell of a blast tearing around in this car. It handles amazingly, everybody loves the look, and for such a low HP engine, it really goes. What a fun car!

And it's all mine!

I'll be posting some pics after I clean it up a little over the weekend.

Jason

IROC · IROC's Garage

Something to check regarding the sticking idle. My car did this a couple of years ago and I checked everything in the world and it ended up that the throttle linkage was catching on one of the vacuum lines to the WUR (I think) and not allowing it to return all the way. Simple fix...

Congrats on the car. I'd get those oil temps down.

Mike

concentric · 03-30-2004, 09:18 AM

Quote:

Originally posted by IROC

Congrats on the car. I'd get those oil temps down.

Mike

Thanks. Don't worry, I'm on it. I know how important a cool-running air-cooled car is.

When I drove to work this morning, the temps were only about 180, according to the gauge. I'm not even sure the gauge is right at this point.

JCM

targa911man · targa911man's Garage

Congrats on the new car. Concerning the 1-3k hesitation, it sounds like typical lugging to me--you shouldn't be in the 1-3k range.
These engines were made to rev. Try to keep it at least at 3k, prefereably higher except when its warming up. Some recommend keeping it under 3k during warm up. I go 3-4k with mine.

GrindingGears · 03-30-2004, 09:30 AM

My SC would burble at 1k to 3K rpms also, until I replaced the plugs, wire set, cap, rotor. Pull the plugs and give 'em a looksy.

My 911 was running hot yesterday too, hanging right below 250. Stuck in 405 traffic.

vash · vash's Garage

my throttle did the exact thing your's is doing. my throttle cable was not moving freely. i checked the springs (two) both good. the problem was the bushings were dry at the attachment point coming off the tranny. some sanding, cleaning, and greasing gave me a snappy throttle again. i agree with the low rpm lug dan describes. temps? what cooler do you have?

concentric · 03-30-2004, 09:48 AM

Quote:

Originally posted by unfixed
my throttle did the exact thing your's is doing. my throttle cable was not moving freely. i checked the springs (two) both good. the problem was the bushings were dry at the attachment point coming off the tranny. some sanding, cleaning, and greasing gave me a snappy throttle again. i agree with the low rpm lug dan describes. temps? what cooler do you have?

Cool. I'll definitely check that out, although I have noticed that it stays at 2K rpm even if I blip the throttle/move it around. It's only when I put some strain on the engine via engaging the clutch slightly that it will fall to normal.

My car doesn't have an external oil cooler, the trombone was an option for this year but the original owner didn't get it. I will be installing a Carerra cooler for the future 3.2 conversion.

Another cool little thing that I forgot to mention about the car, is that I was able to trace it's history back to the original owner. There was some information in the owners manual that listed a name and a license plate of "Music 9" This, coupled with the fact that the car was purchased in Beverly Hills led me to think that the owner might be associated with the music industry. After doing a google search and putting two and two together, it turns out the car was originally owned by one of the most famous entertainment lawyers in LA. I e-mailed him and we chatted about the car a little bit. Turns out he replaced the '74 in '79 with an SC, which he still owns to this day.

JCM

vash · vash's Garage

you have a hand throttle? mine sometimes goes to 2k at the red light when i leave the throttle up. i dont think the hand throttle does anything more special than hold the gas pedal partially down. i bet your cable is hanging a tiny bit somewhere. your car will be really temperature dependent on ambient temps without an external cooler. start looking for one now, they are a pain to find used. it will take awhile.

DanTheCat · 03-30-2004, 10:08 AM

Potentially useless post, but does your 74 have anything like the deceleration valve on my SC? I'm having the exact same idle problem, and although I haven't had a chance to look into it, I'm pretty convinced this valve is the problem. Wiggling the throttle does nothing.

Is your car MFI, or carb? They didn't have CIS in 74, did they? My old carbureted fiat had a similar device that I removed, but that was a 79 so they might not have had them back in 74. It's an emissions related device.

Dan

concentric · 03-30-2004, 10:09 AM

Quote:

Originally posted by unfixed
you have a hand throttle? mine sometimes goes to 2k at the red light when i leave the throttle up. i dont think the hand throttle does anything more special than hold the gas pedal partially down. i bet your cable is hanging a tiny bit somewhere. your car will be really temperature dependent on ambient temps without an external cooler. start looking for one now, they are a pain to find used. it will take awhile.

Yup, got the hand throttle, but I don't leave it up while driving.

I'm just going to bite the bullet and get a cooler kit from Pelican. I have a 930S chin-spoiler that will go on this weekend, it will have a Setrab in it as well.

Jason

concentric · 03-30-2004, 10:11 AM

Quote:

Originally posted by DanTheCat
Potentially useless post, but does your 74 have anything like the deceleration valve on my SC? I'm having the exact same idle problem, and although I haven't had a chance to look into it, I'm pretty convinced this valve is the problem. Wiggling the throttle does nothing.

Is your car MFI, or carb? They didn't have CIS in 74, did they? My old carbureted fiat had a similar device that I removed, but that was a 79 so they might not have had them back in 74. It's an emissions related device.

Dan

It probably does, I think the CIS system is pretty much the same. CIS started in 73.5, IIRC. My car is CIS.

Thanks for the idea, I'll check it out.

Jason