Engine Help 2.7l ?

[CARRERIC]

I just bought a 1975 911 carrera with original 2.7L, engine is strong and runs great. It seems when the engine heats up 220-240 it begins to buck and hesitate a little while accelerating up to 3000 RPM. The engine will idle perfectly steady. This is a CA car with all thermal reactors etc, that will be removed this week.

Brought it up the street to Vertex in Miami. They installed a reman Boshe DME, dropped about $600. Didn't make a bit of difference!

I feel this may be a fuel issue and not ignition as Vertex believed, or should I say made me believe. I now turn to you experts for advice and suggestions.

Regards

[Early_S_Man]

They installed a reman Boshe DME, dropped about $600. Didn't make a bit of difference!

Do you mean they installed a new ignition unit, the Bosch CDI-unit that is bolted to the relay/fuse panel on the left fender in the engine compartment?

DME units did not arrive until the '84 models!!!

[marcesq]

Eric:

Check the basics first. Condition of dist. cap, plugs, and rotor. Check point gap (dwell does not matter because of CDI unit)and timing. If all of the forgoing is ok, plugs wires should be checked for resistance.

Get car hot, loosen gas cap (make sure your tank is not full) and try it out.

If you are still having the problem, someone else on the board will have to chime in, as I have reached the limits of my knowledge.

Good luck

[CARRERIC]

Sorry Warren, it is an ignition control unit bolted on the left rear fender.

I would think they would have checked the basics first like the rotar, cap, wires, etc..

[Early_S_Man]

Eric,

I think you ought to talk to Vertex about a refund on that CDI-unit, since the symptoms stayed ... the repair was not correct, and a test of your old CDI-unit will likely prove it is still good!

OK ... first off ... 230° - 240°F is TOO HOT, especially for a 2.7! I can only imagine what it will run in July thru September ... if it is hitting 240° F in March! Serious plans should be made for a front fender oil coole retrofit ... ASAP.

If you intend to do any work on your car ... now would be a good time to start. and the distributor is as good as any place to start. Read and print the following thread concerning distributor maintenance. All of the data posted in that thread applies to CIS 2.7 engines as well, which use the same distributor as 2.4 'T' engines.

http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=5432&highlight=distributor+lube

[davis911s]

Eric don't ASSUME they checked anything, they want $. I agree with Warren (as always) talk to them about a refund, the CDI would have virtually nothing to do with the overheating. Check to see that your thermostat is working. It could be stuck shut. Once the engine is warm feel under the right side of the car,(the oil lines) if they are cold the oil is not circulating.

Good luck, keep us posted and don't lose faith in your 2.7, people who are jealous will tell you its not the best

AND YES GET RID of those thermals! Do you have a pop-off valve? If not install one.

Shawn

[marcesq]

Eric:

Here is THE cure for the Calif. exhaust system:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1814477361

I changed out my '77 Calif. 2.7 with SSIs from the exact same source. You can keep your current muffler or add a nice aftermarket.

The difference is noticable for performance, and helps slightly lower oil temps (not enough to prevent checking into the items Warren & Shawn pointed out).

If you have further question you can use the PM.

[CARRERIC]

Guys thanks for all your input and support. I love my car and wouldn't give up the 2.7.

I had planned to take the car to Vertex monday morning and install SSI's and updated front oil cooler with a fan. First I will talk to them about checking my old CDI and a refund a refund on the new one.

Warren, I printed out your valuable thread on the distributor. This will be adressed shortly.

Shawn, the oilines in the right rear fender well are very hot while the car is running. I did notice I have less oil pressure when the car heats up as apposed to when cold, is this normal?

[Jim Sims]

I have a 1976 2.7l 911S that started out life in "California trim" with A/C. My thermal reactors have been removed and replaced by "pipes". Before you remove your thermal reactors be sure you won't run afoul of your local smog testing/inspection rules. Save the parts as you or another future owner may need them to pass smog tests/inspections. Next year my entire "pipe"/'76 funky heater box set-up will be replaced with a nice SSI system; hope to gain a few but only a few hp. Ensure you are getting the better SSI units made out in Lovato, California. Even with the thermal reactors installed your car shouldn't be running as hot as you noted unless you're in stop and go traffic with the A/C on and you still have the 5 blade fan.

Some fundamental things to check before installing the external oil cooler system:

Check timimg, if advanced too far this can cause overheating. The problem at 3000 rpm may be ignition related too. Check your distributor as Warren recommends.

Ensure fan produced cooling air is going where it should; check sparkplug wire to intake cover seals, check that all heating air hoses are intact and not leaking and check that rubber seal running around engine sheet metal is intact and sealing the top of the engine from the bottom of the engine.

Remove fan and alternator and clean off any debris (leaves, dirt, mice nests, etc.) you can reach off the top of the engine. Good time to upgrade to 11-blade fan but this will cost ~$250-300.

Drain and remove oil tank and clean exterior of tank of mud, oil and other collected road debris.

Drop engine and transmission, remove and clean engine mounted oil cooler. This is a good time to replace oil cooler seals, oil thermostat sealing o-ring, oil pressure switch and install a new breather cover gasket. You may be able to remove your engine mounted oil cooler without dropping the engine but in 1976 an exhaust gas circulation system line is in the way and it is just easier to drop the entire engine to access things.

Having written all this and given your climate and if you're going to be running A/C I would also recommend installing the external oil cooler system. I am currently adding one to my '76 2.7l as I intend to reinstall the A/C sometime in the future. I have the factory parts manuals for 74 through 77 911's so if you need a part number send me a meassage. Good luck, Jim

[CARRERIC]

Originally posted by Jim Sims
Ensure you are getting the better SSI units made out in Lovato, California.

Jim thanks for the tips. As you mentioned is there any other SSI rather than the ones made in Lovato California?

I do have the eleven blade fan update, and driving without the A/C on. However it is very hot in Miami. I though that 210 would be normal for engine temperature and not 220 - 240.

regards

[Early_S_Man]

Eric,

Regarding the spark plug air seals ... if shriveled or cracked, they need to be replaced with VW part 111.905.449 from an independent VW or foreign parts supplier ... NOT a VW dealer, as VW supperceded the part with an 'A' suffix, and it does NOT work on an OEM 911 Beru connector! The aftermarket parts are still being made in Mexico and Brazil, and are cheap ... but make sure the ones you get are soft and flexible, because you need to get a minimum of 12 and keep the spares in your glove compartment! They need to be checked at every oil change, and at least every six months.

[CARRERIC]

Warren, thanks I just put that tech note in my service book.

At the moment I'm studying the thread you sent me on the distributor before I go to sleep.

[Wayne 962]

I would make sure you get the old CDI unit back. Used ones are worth a lot of money too...

-Wayne

[porsche74]

Eric:

I'd also chime in here and tell you to have your CIS fuel pressures checked.

If your warm control pressure is at the high end of spec, this will make the engine run leaner than it ought to. This can be adjusted with shims on the side of the Fuel Distributor by someone competant.

BTW, make sure that your idle CO is set on the rich side, too. 3-3.5% is good.

[Jim Sims]

Eric, I only have experience with the SSI's out of Lovato, California. They are nice looking (works of art really), well made and have the least fit up problems so I've been told. I've installed 2 sets (one set on a '73T and one set on a 73S) with no significant problems I have been warned that there are other stainless steel heater box units for sale of inferior quality (fit up problems and inferior grade materials) but I can't quote you any names. Also, note that to install the SSI's one of the engine oil lines will likely require replacing and the air injection system will probably have to come off. This means the air injection lines to the heads must be removed and the ports in the heads plugged. There is the element of risk of additional work in all of this as there likely could be problems with the head exhaust studs/nuts (which will connect to the SSI's) or the air injection port fittings. These parts can be corroded or seized making removal difficult. This can result in broken off studs or stripped head ports/stud holes. These can be repaired but it means more labor and parts and hence time and money. Not trying to scare you but make sure you are aware of the possibilities. Hoping for the best but planning for the worst. Jim

[724doorE]

Eric,

I used to live in WPB not far from you. Have a 72 with 2.4 and 2.7 euro p/c's. I don't have an external oil cooler, and mine would heat up to about 210 on a warm day. Although the car wasn't driven everyday and was kept out of traffic.

I've always read as others have stated that a normal temp range is 180-210 F. Anything more deserves an external oil cooler, either front or fender mounted. Of course my car has none of the evil smog junk you are burdened by.

If your not useing the AC and there is a coil under the rear lid grill... remove it if you haven't already. and do the ignition stuff too.

Good luck

Dennis H.

72 911E

[marcesq]

Eric:

You will not need to change any of the oil lines to accomodate the SSIs if you have the CA exhaust/heat exchanger system. BTW there is only one "SSI" heat exchanger, the others made out of stainless are not associated with John Daniels, et al.

Later.

[Jim Sims]

My information shows that there are two different oil lines (and two different Porsche part numbers) for use with a factory external oil cooler system on a '76 California vintage 2.7l engine. One is for the California heater box set-up and one is for the pre-74 (or pre-75?) SSI's. I have both lines and there are differences. Perhaps the California heater box version of the oil line will work with the SSI's after some modification. Cheers, Jim

[marcesq]

Jim:

I replaced the stock CA version of the heat exhangers/thermal reactor replacement pipes with SSIs and did not have to replace or modify the oil lines. This because the rear oil line runs across the engine/transmission joint and then to the block to clear the duel outlet heat exchangers rather than go around the cross over pipe on the non-CA version systems.

My 1 cent.

[CARRERIC]

Hey guys,

thanks agian for all your tech support and comments.

To let you know the outcome of the situation.... It is excellent!!

Brought my babe into Vertex Monday morning for the new equipment. First order of business was to inquire about my old CDI. They were actually very helpful and brought it to me. I know it was the same one because it was sitting in the exact same place on roll cart from Saturday afternoon. They plugged it in and absolutely nothing!! Now what are the odds of this happenig?

Just got my car back this afternoon with the new SSI's and front-oilcooler with fan. Oh boy what a difference the SSi's make over the thermal reactors. Very nice acceleration and great performance . The car sounds fantastic. The SSI's make a very distinct sound. In the Miami heat the car now runs between 180 and 195, big diffrence from thermal reactor meltdown!!!

In all I feel I really got my money's worth. And I can honestly say Vertex gave me a great deal on the parts and installation with no bumps in the bill. It was a very big job with the reactors and smog pump. They were complete gentlemen.

I would love to post a picture of my car but I can't figure it out. Any pointers.

Thanks