Techincal Advise please???

Guest · May 5, 2008

Without divulging into too much detail, my oil pressure sender unit had died and was left to my mechanic to fit a new one whilst MOTing and servicing my car. Unfortunately my cars been returned with a new sender unit and an oil leak from the mounting block caused by threads being stripped from the engine block and the unit not tightening up enough to form a seal under pressure.......Anyway, my engineer brother is fairly hopeful we can fix the problem without having to remove the engine to tap a new thread in.....so my questions are please:

a) The sender unit scres into an alloy square block carrier. This is secured by a large nut - does anybody know the factory torque setting for tightening the sender unit to this alloy block?

b) The above mentioned alloy block that carry's the sender unit is hollow through its middle and has a threaded bolt running through it that screws into the crank case (my damamged part) with the other end connecting to an oil pipe that feeds the righthand cam. Does anybody know the factory torque setting for this bolt where it screws into the block?

c) The above mentioned alloy block that carry's the sender unit is not a true "cube" One of the bottom corners has a flat on it. When you stand at the back of the car looking at the sender unit, should this flat be on the corner facing my feet or facing the front of the car?

Any help would be great as I'm currently living in a state of palpatations at the moment as if my re-assembly doesn't work, I'm looking at an engine out job to fix properly.

Rgds
Antony

Guest · May 6, 2008

Thanks Phil, thats a help for starters. Could you, or possibly anybody else reading this help with my last question by looking at your own car. If anybody could just pop there bonnet lid and look at their pressure sender for me you can probaly help. If you run your hand underneath the sender where the unit screws into the square alloy block, can you tell me which of the two bottom corners as the flat on it. I know which way my came off, but I'm not sure it was re-assembled correctly by my mechanic in the first place. You'll be able to feel that one of the bottom corners is not a right angle as its got a 45 degree flat machined into it. I just need to know whether this flat faces the front or back of the car as the block can go back on the car either way round - buit Porsche must have machined the flat corner for a reason so their must be a correct way round???

Ps, My mechanics a female who obviously doesn't know her own strength.....

Rgds
Antony

l2015 · May 6, 2008

The angled corner faces to the rear of the car just checked mine two minutes ago.

Guest · May 6, 2008

That's great thanks and as I suspected it should be - mine was re-assembled with the angle towards the front by my mechanic who also managed to strip the threads out......

Fingers crossed my brother can fix things, otherwise its an engine strip down just to get a new thread tapped in!

Rgds
Antony

Guest · May 6, 2008

Another question. Can anybody tell me the torque setting for the feeder pipe connection into the right hand cam cover. The Haines manual is rubbish and tells you nothing useful and I don't have a Bentley manual as yet. I'm scared now of over tightening and causing a similiar problem to the one I have at the other end of the pipe / crank case. Thanks.

Rgds
Antony

l2015 · May 6, 2008

Antony,I renewed this pipe recently on mine as it was sweating oil, and to be honest i rarely use torque settings for stuff like this.As long as you dont go overboard you will be ok, The key is tighten it moderately and keep an eye on it , if it leaks give it another nip . I know your erring on the side of caution because of whats already happened butt whoever done the work clearly didnt know what they were doing.

Guest · May 7, 2008

Ok, thanks Liam. Re-assembley tonight although won't be able to test for 24hours until the titanium thread paste has set properly. Fingers crossed.....

Rgds
Antony

l2015 · May 7, 2008

Let us know how it goes.

Guest · May 9, 2008

Well re-assembled Wed night and left for 24hrs for the Titanium paste to fully set. Started her this evening and just let the engine tick over so I had minimal oil pressure. Slowly increased rpm till I had 4bar on the gauge and no leaks. Took her out for a blast and ran her at high rpm for a few mile and gave her full throttle round to the red line - and no leaks. Hopefully not tempting fate, but I reckon she's fixed - at no expense to me at all. Basically, my brother machined 2mm off either side of the block that the pressure sender screws into to allow another 4mm thread length to screw into the crank case. This picked up virgin threads deeper in the crank case. Coupled with this, high pressure hydraulic seals rather than crushed alloy seals, high temp sealing paste and the titanium thread paste, it looks to have worked. 1400 miles to the Leman classic and back will tell for sure I guess but I'm now confident that my mechanics diagnoses of having to remove and strip the engine won't come to fruitition!!

Thanks for your advise

Rgds
Antony

bones · May 9, 2008

I'm glad that all worked out for you but for god sake don't go anywhere near that mechanic again with even a roller skate, ask around and find a respected Porsche independant.