The Master Cylinder Porsche 912 Tips

  • Got stuck in two gears at once

    Q – On my way to the Woodward Cruise my 1966 912 got stuck in two gears at the same time! My mechanic got it unstuck but I am worried that it might happen again. Why does this happen? Help! I don’t want to miss the party.

    A – How annoying, all dressed up and no way to go! On the early 901 and 915 transaxles the transmission gear selection has a lot to do with the front shifter adjustment compared to newer transaxles. This is just one of the annoying traits of the early boxes, but the sticking in gear problem is easily corrected. First of all, you do not need to take the transaxle out of the car. The fix is getting the shifter in front correctly adjusted. If the bushings are worn, this would be a good time to do this as well. If you follow the guidelines in the manual and adjust the fore and aft travel, odds are good that it will not happen again. MC

  • 1968 912 is running hot. My mechanic suggested that the oil cooler is clogged

    Q – My 1968 912 is running hot. My mechanic suggested that the oil cooler is clogged since I live on a dirt road and for quite a while, the engine compartment gasket wasn’t doing it’s job. I believe him but wow is it expensive to take it all apart. I guess I should be glad that it is not a 911. Peter

    A – Well I agree with your mechanic. His method is foolproof but expensive. But I have had some success by using a chemical called “Gunk Engine Brite”. I sprayed it into the cooling fan on a cold engine (about ½ can) and then let is sit and soak in for about an hour. Then I started it up and held the engine speed to about 2,000 while spraying hot water into the fan. No, the engine did not stall (I was surprised) and once the process was complete, the engine ran at normal temperature, never exceeding the ½ way mark on the gauge. As you would expect, this was a fairly cheap, “Band Aid” process. My client and I were tickled pink that he could spend his money on other fun projects. Hooray! If this does not work in your case, you better consider avoiding long drives and changing to synthetic oil that can tolerate a lot more heat than regular oil. I have seen oil coolers expanded to the point that the vanes in the cooler were so bloated that air could not pass through them. Oh yeah, and about the question of the faulty gauge…trust the gauge and save your engine. – MC

  • Adding to your comments on the 912 engine compartment seal

    Q – To add to your comments on the 912, where the engine compartment seal was not doing its job (P 4 July, page 30), an easy way to check the gauge is with one of those temperature guns. Get engine surface temperature readings in degrees and see if the gauge is in a similar zone over time for that reading. I have 130,000 miles on a 1964 SC. Maintaining the engine compartment sheet metal and the seal to the body is vital to keeping the engine cool, and not much dirt gets in either. I do a reasonableness test with the temperature gun to the gauge a couple of times a year. Harry

    A – An excellent comment about a tool we use frequently. Another use for the temperature gun (non-contact pyrometer) is determining which cylinder is not producing equal power. If you can gain access to the exhaust ports and you detect a misfire but can’t be sure which cylinder is causing it, pointing the “ray gun” at the header pipe will quickly show you which cylinder is loafing. We also find the tool useful in verifying the source of brakes that pull to the left or right. After a few hard stops, you can measure the heat on the rotor surface and this helps determine where to look first for the problem. An excellent tool and now that they can be purchased for less than $100.00, any motorhead can afford to own one. – MC