dt3257

sexy car....congrats!!!

I love my Jap import 928s4 as well.

Barry Chan

Nice ride and welcome, i too love to drive it on the highway, it just keeps pulling and going doesn't it?

928mac

I will second and 3rd that. It is very important that the pinch bolt on the flywheel that holds the driveshaft be loosened to relieve pressure on the crankshaft.

If it is under pressure for to long you will have to pull the engine and replace the main bearings, or total engine failure, and good luck finding another engine.

Enjoy your awesome car, it is really nice. BTW do you know Brian Jean MP

Crisis

Welcome to the Shark Tank and let me beat the dead horse some more about checking the flex plate tension to avoid TBF. As the owner of a ex-Japanese 928 that came to Canada with an engine in the early stages of TBF and then received a replacement engine from Japan that now appears to be suffering TBF, I'm a little too worked up about this issue. I wish you nothing but good luck with your car and hope you have many years of enjoyment with it. Now, if you can figure a way to keep diplomatic immunity once you're back here, then you'd have it made.

Hilton

Welcome, and +1 on pictures to explain.

This thread here has an excellent pictorial of the process, thanks to Bill Ball:

https://rennlist.com/forums/928-foru...pictorial.html

perdued

Just wanted to say thanks again for waking me up to the flex plate / TBF problem and for the links to the relevant threads. I have been reading off and on about this over the past few days and have been getting nicely paranoid! With Japan in the middle of the new year holiday there isn't much I can do right now but have vowed to take the car in to get this checked (armed with the pictures) next weekend.

Basic question that is not explained in the threads for those like me that simply don't know: the figures for crank end play like 0.016 - what do they represent? In other words, what is being measured?

The answer to another question: no, I don't know Brian Jean MP.

I'll be sure to report back once the job is done, as a courtesy to the kind advice received.

David

Vilhuer

How far crankshaft can move back and forth before it is stopped by #3 main bearing side surfaces.

Cosmo Kramer

Beautiful car, congrats on your purchase. Follow the others advise and enjoy the car. They are a labor of love but definitely worth it.

axis of evil

Something I have never understood, Why are most of the pre 1990's Japanese 928's left hand drive?
Japan is drive on the left(right hand drive) 928's were available in right hand drive from the beginning, and it is just so dangerous driving with the wheel on the wrong side. (have to put most of the car onto the wrong side to see whats coming when passing trucks and buses, scary times for passengers!)

perdued

Simple answer to that question is status. At the time (in the bubble years when Japan's economy was actually hot) driving an imported car with the steering wheel on the wrong side was totally cool, especially on an exotic car like a Porsche! It is a bit less cool now, but still it is a mark of status to buy the lastest exotic import with the steering wheel on the wrong side. Case in point: all of the Teslas selling like hotcakes from the new Tesla dealership down the street from me have the steering wheel on the left side (and they're selling at the equivalent of 150k US$!).

Yes, it can be scary at times making that turn across the traffic at an intersection when a truck is blocking the view. I either have to trust my passenger who tells me if there is a car coming or not, or simply wait it out!

axis of evil

Having owned a left hand drive Mustang in a right hand drive country, Scary is an understatement,(there are still 2 states of Australia that will allow normal registration, in the others LHD can only be registrered as Vintage or historic, with very restrictive useage.
At least you are in the land of the Kamikazi, could be fun.

namasgt

When your mechanic checks and releases the tension, change the allen bolt with a new one. Note that the 62 ftlb torquing is the new torquing number, I believe the manual says to torque it to about 50 ftlbs.

perdued

By way of follow-up:

I just heard back from the mechanic, and ... whew! I think I'm safe.

I was told there was "3-4mm" of pressure on the flexplate, which was released.

Crank end play figure quoted to me was 0.18mm.

Now I wait for the bill!

Thanks again for first of all alerting me to this, and secondly for pointing me in the direction of Bill Ball's clearly laid out process. Given that I would have trouble explaining the procedure even in English (let alone in Japanese to the Japanese mechanics), the pictures made the communication easy.

I am going to read up on options for the next time such as the superclamp.

In the meantime, the car's going to get some nice exercise this weekend in search of some hot springs in the mountains!

perdued

Mechanic was nice enough to send me pics just now. I think they speak for themselves except note that the dial gauge is in mm not inches.

I'd appreciate any thoughts/feedback, even just to say "looks about right!" ... or not.

Thanks again

Tails

Good pictures from your Nihon-gin mechanic.

New thrust bearing clearance 0.110 to 0.312mm with a maximum wear of 0.40mm, so your clearance at 0.18mm is great, less than half way in the bump clearance allowed.

My inital thrust bearing end play was 0.20mm or 0.008" when I first measured it in Feb 2004 with a flexplate movement of 3.08mm when the clamp was released.

I fully support the installation of a new clamp bolt and tension it up to 85Nm (62 ft lbs), as this is about 10% over the initial Porsche recommended torque on the bolt. Porsche in their Technical Bulletin #9203dated 5th May 1992 recommended torquing up the bolt between 75 to 84Nm, so go to the higher value which is about 10% increase.

There is three methods to stop the migration (draw back) of the drive shaft through the forward flexplate:
1. Locktite 290
2. Pklamp
3. Constantine's Super Clamp.

Note: The rear flexplate clamp will not migrate as there is a recess in the drive shaft where the clamp bolt goes through, so it can only move the amount of the clearance between the bolt and the recess.

Next time you have your forward flexplate migration checked, check the tension on the after flexplate clamp bolt and retension it up the same higher torque value.

I used locktite on mine in Feb 2006 due to continued migration even after I checked and released the clamp and fitted a new clamp bolt, after noting the migration at 2.95mm in September 2005. Since the application of the locktite I have not experience any movement, however locktite is not the most favoured method on this forum, but a few of us have used it, as a matter of fact, in my opinion, the best method of clamping is in the order of 3, 2 & then 1. When I used locktite there was no PKlamp available, as an iterim measure.

The cost of each application run in the order of 1, 2 then 3, with 1 being the cheapest.

When the flexplate migrates over time it causes some wear in the splines of the drive shaft and the flexplate clamp, so the flexplate will probably continue to migrate due to reduced friction even when the new clamp bolt is fitted and tightened to 85Nm,

I would recommend that you paint the back end of the flexplate clamp and the drive shaft with white paint, so if there is any (draw back) migration it can easily be identified/seem, released and reclamped.

If the flexplate continues to migrate, I would recommend that you fit the PKlamp, which can be purchased from Roger at 928srus.com at a very reasonable price and can easily be fitted by removing the lower half of the bell housing.

In the future if you have to remove the torque tube and the drive shaft for new bearing or new torque converter bearing or seals, I would highly recommend the fitting of the Constantine's Super Clamp. You can find the details of the super clamp on this forum by using the "search function".

Every time I check my flexplate clamp at the yearly service I check the measurement similar to how you mechanic has done it and record measured value, release if necessary, check the end play of the crankshaft, resecure the clamp and then enjoy driving your car.

It would be interesting to know what the mechanic charges you in Yen for the job as you have described

Watch out for the weekend car warriors in Japan, you know what I mean!

Tails 1990 928 S4 Auto