PorschesOnTheCheap
PorschesOnTheCheap New Reader
1/21/09 12:23 p.m.

Help! My 944 is possessed!

It's a 1984 with 73,000 miles on it. I bought it from a repair shop that gave me the following story:

  • they put a timing belt on it for a customer

  • said customer drove it 100 miles and the aforementioned new timing belt broke

  • gray area/fuzzy details that didn't make sense

  • shop ended up owning the car

I had a perfect cylinder head from a 944 that lost oil pressure, so I bought the car and spent last weekend swapping the cylinder head (I hate allen bolts!!)

Erring on the side of caution, when I got it all assembled, I had the Porsche dealer tighten the (new) timing I installed. They called today to tell me that it's all set and it runs.

But it has no oil pressure. Now what?

SVreX
SVreX SuperDork
1/21/09 12:40 p.m.

Are you sure the oil pressure switch is good?

Dr. Hess
Dr. Hess SuperDork
1/21/09 12:52 p.m.

Yeah, make sure the sender is OK. Put a real mechanical pressure guage on it temporarily and crank it to see if you really have any oil pressure.

Could the old motor with the broken timing belt have had zero oil pressure, which caused the cam to bind which caused the belt to break? What drives the oil pump on those motors? Is all that OK?

44Dwarf
44Dwarf Reader
1/21/09 12:58 p.m.

Check for blown oil cooer seal.

Dr. Hess
Dr. Hess SuperDork
1/21/09 1:03 p.m.

And of course, don't run it a single time until you have pressure. Pull the plugs out, put the battery on a charger, diagnose, repair and crank till you have good pressure.

PorschesOnTheCheap
PorschesOnTheCheap New Reader
1/21/09 1:38 p.m.

The Porsche dealer did check it with a mechanical gauge and there is definitely no oil pressure. The cam wasn't seized. The crankshaft drives the oil pump.

My (untested) theory: new timing belt number 1 that broke could have been too tight and it screwed up the oil pump.

Someone else suggested that I may have put the headgasket on upside down and in doing so, blocked an oil passage. I remember installing it and I think it could've only gone on one way.

Dr. Hess
Dr. Hess SuperDork
1/21/09 3:04 p.m.

Depending on where the oil pressure sender is, I don't see how a blocked head passage could show no pressure on the sender if it's in the block. A wide open passage that was supposed to be blocked might.

I guess you have no oil pressure. Maybe the oil cooler seal is blown. Maybe the pickup came off. Pull the pan and look around. I am unfamiliar with your Porch motor, so I don't know how your oil pump is mounted, but you might pull it and inspect it if you can. You had a spare head, do you have a spare oil pump?

I also understand those Porch timing belts need to have the tension set just right. In 4 cylinder Esprit circles to set the timing belt tension, we use a Krikit guage from Gates that costs like ten bucks anywhere and have had them calibrated against the super-special ($$$) Lotus sound based tool. So we all know what a "50 on the Krikit guage" means. If your belt is set correct now, I'd test it with a Krickit guage and reset it to that when you're done. http://www.gates.com/brochure.cfm?brochure=2264&location_id=2742

dean1484
dean1484 GRM+ Memberand HalfDork
1/21/09 4:58 p.m.

It could be as simple s it has lost prime.

Did the shop do the oil pump while they were in doing the TB the first time?

Did they do a Water pump?

I would post this over at Pelican in the 924/944/968 section. I would also take a look around at clarks garage as well. If you get really flustered with this I can get you my cell. There are several things to check starting with priming the motor all the way to a cracked pickup tube to an incorrect oil pump housing.

Ohya the #1 first thing is to check that the crank pulley cog that the T belt is properly seated. If it is not you will get no oil pressure as the bolt that holds the crank pulley on (all of them) puts pressure against the center cog of the oil pump. If this is loose the oil pump will free wheel and you have no oil pressure.

I would suspect that the previous shop that repaired it may have buggered the crank bolt / did not got the thing seated properly. this would explain both the broken belt and no oil pressure.

Shoot me a PM and if you want my Phone # to discuss further. I am "Dean924s" at pelican and Clarks

Ohya another thing it could be is that the oil pressure control valve is stuck / broken. You have to remove it to prime the system anyway so you should give that a try as well. If you pull the oil cooler housing you will need the alignment tool for the OPV to properly install it.

Basically there are several reasons why you have no oil pressure you have to methodically eliminate them.

11110000
11110000 New Reader
1/23/09 5:51 p.m.
dean1484 wrote: It could be as simple s it has lost prime.

Plausible. Definitely check this.

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