Antonio Silva
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Operating with an open heart
In the first test I did for The Escudería it said the following:
[su_quote] “The day was appropriate, a warm, sunny morning in late September. The place could not be better, the Lozoya valley and its winding ports. And what about the company, two beautiful Ferrari from the nineties and a Porsche 965 (964 turbo)… ”[/ su_quote]
Well, that 965 is the one that we bring to our electronic pages today.
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The truth is that, after climbing the Madrid ports of Morcuera, Cotos and Canencia at a good pace, following or setting the pace, depending on the moment, a Ferrari 328 and a Testarossa, that late summer day it didn't end very well for our friend.
After feeling the roar of the engines of those beasts among the pines, always with the windows down; after a great afternoon, surrounded by friends; after having a smile on his face that he thought was infinite ... Yes, after all that, at 23:05 p.m., near the Jarama circuit on the NI in Madrid, the heart of 965 suffered a "heart attack" that It was sudden thanks to the quick intervention of the "doctors" who were nearby.
The patient was transferred by crane to the reference mechanical center. A priori, the subject did not look good at all; Although outwardly nothing could be seen that would mean the total death of the motor, our experience allowed us to know that this failure could only be fixed in two ways: with a transplant or with an open heart operation.
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At the time of the breakdown, I was behind the 965 driving another classic and it was my brother's thumb that indicated its serious problem to me through the window. The most curious thing, and I know it will be difficult for you to believe it, is that we were going down the NI at absolutely legal speeds; the afternoon, without a doubt, had been too demanding with a mechanic with 189.000 kilometers declared.
The following days were spent analyzing the fault. The first day we realized the need to remove the thruster; the second, of disassembling it. By the third we had him out and, in the meantime, we got used to the idea of what happened. An endoscope inserted by the spark plug revealed the momentary scope of the incident, cylinder 6 marked and unrecoverable, with a piston also grated and equally useless.
After a month we had a clear diagnosis, although we still did not know the cause of what happened. The exhaust valve of the fatal cylinder 6 had broken, falling inside the head, hitting the piston and nock and damaging them both permanently. Luckily the rest of the elements had not been affected, and in the checks of the crankshaft, connecting rods, other pistons, etc., it was appreciated that they were in good condition.
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Some surprises
What to do in this case? Replacing damaged elements and fitting others in good condition was the most economical alternative. Preparing the engine with racing parts was another option and we could easily take the car to around 500 hp, by the way more economically than the decision we finally made:
Perform a comprehensive rebuild with original parts. In order not to get wrapped up too much, I will say we bought six pistons and their 6 cylinders new original Mahle Porsche equipment, bushings, valves, seals, gaskets, Turbo, and so on until reaching the chilling figure of € 12.564,00.- only in materials and with discounts of between 15-55%. Many spare parts were purchased directly from Porsche Madrid, and the most expensive from Porsche Germany by moving contacts.
Even so, and in order not to be truthful, I have to admit that some minor modifications have been made of which the most important are the discharge valve spring set at 0,9 Bar instead of the original 0,7, the maintenance of the Cup elbow - since in its day the previous owner eliminated the final silencer and installed this option - and something that caused great discussions at home and that was settled after speaking directly with several German specialists, the abolition of the anti-pollution system.
I am going to explain this last point because in itself it has crumbs, and it is to see to what extent the Stuttgart Engineers gave the bogeyman to circumvent the increasingly restrictive anti-pollution regulations. I explain:
The aforementioned sanitary and ecological standards spoke - and continue to do so - of the number of polluting particles per volume of air (m3). For this reason, manufacturers mount systems aimed at making the only thing that comes out through the exhaust pipe is CO or CO2 depending on the type of engine, or so it should be ...
Well, in those early days, and faced with the difficulty of making a car that ran and did not pollute, Porsche designed, manufactured and assembled in several of its dishes, its "Anti-pollution system", which consisted of an air pump moved by a belt from one of the camshafts, which put air into the exhaust duct in order to increase the amount of clean air and, therefore, reduce the concentration of pollutants.
If gentlemen, read well, a vulgar and simple trick, trap, call it what you want. The number of actual pollutants was the same but disguised as more air came out of the exhaust pipe. In Stuttgart they weren't stupid, of course, and they said it was a system for cooling the exhaust valves. That is why they placed it near these.
Today a large number of 965 have it withdrawn, for two reasons: The main one because it reduces power, and the secondary one but for me more important because these air injectors are made of steel, they receive a lot of direct heat from the exhaust and they break or deteriorate at their tips, leaving the metal debris to stop the turbo shell and can cause breakdowns. In fact, the ones we removed were quite damaged, and for that reason we had to rebuild the turbo.
The restoration of the mechanics took us a year, and it was only possible due to the tenacity, dedication, effort and, above all, knowledge of my father. He had just had a Packard 120 engine fully repaired, having previously taken care of our 308's, and these days it must have felt a bit idle.
The 965 is back to life and is in top shape
The recovery of 3.3 would give itself to another article and if the fans demand it, I will gladly write it. But this time I think I'm going to focus on telling you how today's guest behaves.
To begin with, we will say that, according to various German trainers, the estimated power is between 360 and 390 hp. And that, according to them, this small gain does not compromise the reliability of the vehicle, our primary objective.
