Hi There,

Looking to find out the difference in these 2 flywheels.

986-114-012-05-M37 (for a 99 Boxster)

And

986-114-012-06-M37 (for a 2001 Boxster S)

Is it possible to install the 986-114-012-06-M37 into a 99 boxster?

Will it bolt up to the crank?
Will the 5 speed transmission still be mountable?

If anyone has drawings or pictures or a good discription of the difference I would appreciate if they could post them


Thanks

 

Can't help you with the differences.

All I can offer is in talking to my Porsche tech contacts they tell me when ordering parts to go by the VIN. Porsche connects part numbers to VIN.

In the past I have bought a battery which had a different part number than the one in the car, the original battery. The new part number was for a larger -- in size and capacity -- battery. The new/larger battery dropped right in to the battery box all I had to do was to move the hold down out one hole. There was even a threaded nut behind the hole.

Another time I ordered new windshield washer nozzles. This time the new parts were not just a bolt in replacement for the existing/stock washer nozzles. The new nozzles required a wiring harness extension (they were heated?). I balked at this -- $75/each -- and never bothered to install the new nozzles.

For other parts I order at the parts counter: Plugs, MAF, air filter, cabin filter, oil filter, plugs, anti-freeze, tranny/diff lube, water pump, T-stat, fuel pump, idler rollers, radiators, idler roller bearings, seals, CV boots, rear view mirror, and every thing else the parts manager always goes by the VIN when selecting the part.

My point is that unless the flywheel part number comes up with your car's VIN there is no way of knowing if the flywheel is compatible other than I guess to try it.

However, I would not recommend this as this is dangerous. Even if the unit fits if the spacing of the timing tabs around the flywheel's periphery are not right for your car's engine the fuel injection timing, spark timing, and other things related to engine speed could occur at the wrong time with possibly disastrous results.

 

Macster,

Guess I should of stated that I am still hunting down the no idle issue - Took it to a most recommend shop here in Calgary and after 5 hrs of diagnosis their thought is the fly wheel either has bent teeth, improperly made or is the wrong flywheel. The came to this diagnosis after checking the output of the Crank Position Sensor - They checked to see if it was a bad sensor - it was not - they modified an old sensor to go closer to the teeth on the flywheel and the car fired up but timing is out and car is not drive-able - Loaded up the car brought it home and have just finished pulling everything out of the way to drop the trany on Wed night and take a look at the flywheel.

My question is - if they sent me the incorrect flywheel would it actually fit?

Thanks

 

To directly answer your question, I don't know.

Based on what you posted the wrong flywheel -- or in some way just a bad one -- has to be suspect at this stage of your trying to get to the bottom of the no idle issue.

If this no idle issue appeared right after the flywheel was replaced that points the finger at the flywheel.

While no one wants to go to the trouble of removing the transmission to check the flywheel the shop having narrowed it down to the crankshaft position sensor output and having eliminated the sensor as the possible problem this doesn't leave much room for the problem to not be with the flywheel.

I know it sounds wise after the fact but one has to be careful about what parts he gets. I ordered brake hardware for my Boxster from a large Porsche parts house and it sent me the wrong rear brake hardware. Instead of the rear brake rotors for my base Boxster I got the front rotors for a Boxster S. The rotors obviously were the wrong items and wouldn't have fit even if I had tried to bolt them up.

 

Got everything out of the way and just need to pull the Transmission - will be doing this tomorrow night - going to give it an inspection and comparison to the old one.

Hope they are right - the dang snow is going away here and want to get it on the road soon.

Can one fire up the car without the transmission installed? If I have to I can put the old one in just to test the theory that the new flywheel is the issue if I can not find a difference in the two.

 

You can run the engine with no transmission. To run the engine you will need the proper flywheel installed and secured just as if you preparing to finish putting the car back together. If you have loosened the engine mounts to remove the tranny these must be secure as well. The last thing you want is an engine to come loose from its engine mounts, or the flywheel to come off the end of the crank without the benefit of the transmission bell housing there to catch it.

With the two flywheels side by side and oriented the same as they would bolt on to the end of the crankshaft then observe the spacing between the tabs around the circumference of the flywheel, the tabs that the crankshaft position sensor sense as they rotate past. Not only that they have the same spacing, and there is the same number of tabs, but they have the same width, are of the same material/metal. Also, note the "gap" in this ring of tabs that it as near as you tell starts at the same place and is the same length for both flywheels. The overall diameter of the ring of tabs should be the same too, so the sensor is positioned at just the optimum distance from the tabs to maximize the signal generated by the sensor.

If there is any question regarding the correctness of the replacement flywheel, at this point I'd just buy a new one and I'd buy it from a place that I was sure would supply me with the correct one for my car.

 

Looks like we found the issue.

Correct flywheel - bent teeth

We built a stay for the DMF to keep it in place that worked off the teeth on the starter ring - and also had the pin in on the front to stop any movement while it was tourqued so quite sure this must of happened during shipping.

Just missed the dang thing

Here is a pic - Top is the new - bottom is the old.

Still cant believe I missed this.

 

Why can't you just bend them back?

 

I probably can - but going to ask the supplier for an exchange first before I go that route - There are some on the oppisite side that are also bent in - only about .5mm and seemed to cause fluctuations in the scope also - From what I was told from LUK there is very little tollerance allowed between teeth and sensor

 

Experience is the best teacher. The most expensive teacher. But the best.

Don't kick yourself too hard. (That's our job! J/K.) Just be thankful you found the problem and it did not result in collateral damage. Get a good FW in the car and button everything up again and resume enjoying the car. You've earned it.

 

Flywheel supplier says on occasion the teeth get damaged in transport and asked up to straighten them out and try it first.

Straightened the 3 bent teeth just after the gap. Re installed flywheel, Clutch and Transmission,

Did a test start - Fired up immediately - idled nice - WOOOO HOOOO

Putting the rest of it back together over the weekend - 4 months and $2000 later we got a winner.

What cheesed me is when we called the supplier when this started they had "no ideal what could cause this issue" Then when we pulled the flywheel and noticed the bent teeth and asked them what to do - "They had seen this many times ""Just bend them back in place"" I was so pissed off - Could of saved me a couple grand if they just said - Did you check the teeth on the flywheel as they sometimes get bent in shipping.

Really cheesed about that part - but live and learn and send my $$$$$s else where next time.

Peace Out to all those that put out ideas along the way trying to get the beast back on the street.