66 motor advice

SethCoffin · 05-11-2009, 01:10 PM

First post.....I just bought a 66 912 that has been sitting for some time...like 10 years. The engine turns over and the previous owner says that it was rebuilt about 25k miles ago. Seems pretty clean but I dont know a whole lot about em (yet). This is my second Porsche, the first being a 77 911 (long gone). ANYWAY, Im dying to give it the juice but Im sure that there is some intelligent way to approach this and was hoping for some advice. Im guessing new oil, new spark plugs and wires, clean gas....but does anyone have any other good advice before I attempt to fire her up.

Thanks a lot

Jaems · 05-11-2009, 02:02 PM

Do everything you would for a major tune-up. Adjust the valves, new points, set the timing, new plugs, new oil and filter, and new gas. Make sure that the engine turns over, by hand, easy with the transaxel in neutral and the plugs removed.

Turn it over with the starter and the coil wire removed to get the oil moving through the engine. The oil pressure light should go off. Then attach the coil wire and fire it up. If it runs like a cylinder or two not firing well. It could mean that the valves are sticking with oil that has been sitting on them for the last tens years. You may have to remove the heads and clean them up.

By the looks of the fan belt, someone may have all ready tried to start it.

SethCoffin · 05-11-2009, 04:24 PM

Thanks. That's kinda what I figured but wanted to be sure I didn't miss anything. I did hit it with the starter once real quick to see if it would even engage...probably shouldn't have. Gas line wasn't connected. I really appreciate the advice.

sabby · 05-11-2009, 05:19 PM

You might want to bypass the gas tank temporarily with a gas can just for starting purposes----no sense sucking up 10 years worth of possible rust and sediment until you can check out the tank more thoroughly......

SethCoffin · 05-11-2009, 06:40 PM

Thats a good idea. The guy I bought it from rebuilt the engine and seemed to know a lot about it. Hes been a mechanic for over thirty years on vw and porsche as well as other german cars. He already has a line running from the fuel pump to do exacly what you advised. He did the same regularly just to keep the engine alive, thank goodness. Hoping for the best and thanks for your input.

Seth

lfausty · lfausty's Garage

hey nice pic of whole car please

SethCoffin · 05-19-2009, 09:52 AM

Here she is...aint she a beaut? Thats 20 years of dust.

912newbie · 05-21-2009, 01:24 PM

Hey Seth,
I just did this about 4 months ago with a 67 that had sat for ~24yrs. I went ahead and did what those above spoke of. I also pulled the sump plate and cleaned it out-it was absolutely FULL of thick oil-replace the gaskets while youre at it. I also pulled the plugs and put some marvel mystery oil in and turned the engine over by hand to make sure it was good and lubed up. I cannot stress enough that you most likely do not want to run any gas that may have been left in the tank through your engine. My car sat for a bit longer than yours, but when I drained the tank it was varnish, sludge, and rust. Be careful. I went ahead while the tank was being rebuilt and connected a small gas container to the inlet in the engine compartment. I also went ahead and pulled the carbs and rebuilt them (at least clean them out as the old gas will be in there too most likely). I would replace all rubber fuel and brake lines before any real operation too. This is definitely a process and dont be too hasty, a lot of damage can be done if youre not careful but a lot of good info can be found on this site and the 912 bbs. Good luck.
J

SethCoffin · 05-26-2009, 04:48 PM

Thanks a lot. I got new points, plugs and wires in the mail today so Im looking forward to giving it some attention this weekend. I'll keep you posted.

Seth

SethCoffin · 06-29-2009, 05:09 AM

Well I finally got a chance to work on the 12 again. I did all of the tune up business as well as flushing the fuel tank, checked that everything was put back on the way it came off and fired it up. It cranked up but ran rough...sputtered...didnt want to idle. So, I took the carbs all apart and cleaned them out REAL good. Put them back on and vvvrooommm! Cranked right up! It runs MUCH better than before but idles kind of high. I'll have to figure out what thats all about. Any ideas??

I did drive it around the block ( I know...probably shouldnt have). I was really surprised at how quick it was. Im excited!

Seth

Jaems · 06-29-2009, 09:51 AM

What is your high? The PO could have had them adjusted higher.

The idle speed should be between 800-900 rpms. Some like it a little higher up to 1100 rpms. That is so the generator light doesn't come on, in the early cars, at night.

I will assume that you also change the transaxle fluid.

SethCoffin · 06-29-2009, 10:06 AM

Higher than 1100....as in up around 1800. Something is definately not right. Think it could be a linkage issue? I know it "could" be a dozen things BUT I can push the linkage back by hand in the engine compartment (as in opposite of throttling the engine) and the rpm will drop. Kind of seems like it may be set wrong or something isnt allowing the linkage to drop back to idle position. I havent really spent much time with it yet.

You know what they say about assumptions....but in this case I would be the only ass. Thanks, I'll change the tranny fluid.

Seth

Jaems · 06-29-2009, 01:36 PM

When you adjust and balance the carbs. You are suppose to remove the linkage. After you are done. You then adjust the linkage ball caps at idle. All the linkage does is to make sure that the two banks of carbs work together.

SethCoffin · 07-02-2009, 06:22 AM

Jaems....thanks. I noticed that one of the throttle linkage rods was set too long and wasnt allowing the carb to return to idle AND was allowing an unbalanced throttling. Runs so much better now. I appreciate everyones help.

Seth