HOW TO DO AN ADVANCED SEARCH.

Mon Jul 08, 2013 3:56 pm by Admin


For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.

When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).

After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …

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Drive shaft too short to reach pilot bearning

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Drive shaft too short to reach pilot bearning

Post  carbonarc on Fri Dec 04, 2015 4:42 pm

Hi Guys,

Hoping someone can steer us in the right direction. We have a 1988 944 and 350 sbc. The bellhousing height plus the adapter equals 6.5". The drive shaft extends past the front of the torque-tube about 5.75". In other words it doesn't reach the pilot bearing - help! We're using the 12554980 bellhousing as recommended by Eric earlier this year. Crying or Very sad

Does anyone know if there is a different belhousing that is shorter or maybe a different torque-tube / driveshaft that has a longer snout?

Thanks

carbonarc

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Shaft dimensions etc.

Post  simon123 on Fri Dec 04, 2015 5:31 pm

If you PM me I can email you a pdf of the procedure.

[You must be registered and logged in to see this image.]

simon123

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Shaft alignment

Post  simon123 on Fri Dec 04, 2015 5:36 pm

You may have to tap the drive shaft from the rear to get the correct dimensions.
When you refit the transmission you will have to drill the shaft to refit the pinch bolt.

See this info Info from elsewhere:

I've yet to find anyone who's stripped the splines with a properly installed drive shaft, regardless of hub length. Here is an old (but VERY good) post from Marc A on the old hybrid board:

The position of the drive shaft in the torque tube is set by the factory. At the rear end of the torque tube the drive shaft is notched, as is the main shaft of the transmission, and the two joined by a coupler. The gap between the drive shaft and main shaft from the factory is less than a match book cover wide. I originally installed the clutch and pressure plate on the flywheel of the LS1 without even thinking to check whether the drive shaft was going to be positioned properly into the pilot bearing. This was my first mistake and caused the clutch hub/drive shaft failure mentioned above.

LESSON #1 - Install engine WITHOUT clutch and pressure plate FIRST and then bolt up bell housing with torque tube connected. This way you can see the position of the drive shaft "nose" as it relates to the pilot bearing. If you find the same thing that I did the drive shaft will have to be gently tapped forward (from the rear of the torque tube) until the nose of the drive shaft is fully engaged in the pilot bearing. I had to move my drive shaft about 1/4" forward. Moving the drive shaft forward requires the drive shaft to be "notched" so that the coupler can be installed with the new location of the drive shaft. The drive shaft is not hardened so a drill can be used to make the notch.

At this point connect the transmission to the bell housing, properly tightening the four mounting bolts. Slide the collar onto the drive shaft until the notch in the main shaft is aligned with the rear through hole of the coupler and install the allen head bolt all the way. Now check the position of the drive shaft nose to make sure it is still in the proper location. MAKE SURE THE CAMFER BEHIND THE NOSE DOES NOT TOUCH THE PILOT BEARING.

If all is in order, drill the drive shaft using the coupler as the die. Do not drill too far as you will hit the threads on the top side of the coupler. Once drilled install the allen head and check the nose one more time.

Now remove the transmission and back the torque tube out of the bell housing. Install the clutch and pressure plate and then re-attach the torque tube and transmission.

simon123

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Re: Drive shaft too short to reach pilot bearning

Post  carbonarc on Fri Dec 04, 2015 6:09 pm

Thanks Simon123. I don't have enough posts to PM you, so thanks for posting the procedure. We'll give it a go, but not sure the drive shaft will move forward the 1-1/4" we've calculated we're short and still be visible from the trans-axle end. I notice on the drawing that the T.O. bearing sits in a recess on the adapter. Curious, but our adapter doesn't have the machined recess and instead mounts it flush to the adapter. Which is the second problem we've identified - the T.O. is too close to the clutch. We were going to work on solving this after we get the DS into the pilot bearing. I wonder if Eric sold us the wrong adapter, or an unfinished adapter? Either way we were planning on having our machinist mill out a recess, so it's interesting to see it on the drawing. I'll let you know how it goes with moving the drive-shaft forward.

simon123 wrote:You may have to tap the drive shaft from the rear to get the correct dimensions.
When you refit the transmission you will have to drill the shaft to refit the pinch bolt.

See this info Info from elsewhere:

I've yet to find anyone who's stripped the splines with a properly installed drive shaft, regardless of hub length. Here is an old (but VERY good) post from Marc A on the old hybrid board:

The position of the drive shaft in the torque tube is set by the factory. At the rear end of the torque tube the drive shaft is notched, as is the main shaft of the transmission, and the two joined by a coupler. The gap between the drive shaft and main shaft from the factory is less than a match book cover wide. I originally installed the clutch and pressure plate on the flywheel of the LS1 without even thinking to check whether the drive shaft was going to be positioned properly into the pilot bearing. This was my first mistake and caused the clutch hub/drive shaft failure mentioned above.

LESSON #1 - Install engine WITHOUT clutch and pressure plate FIRST and then bolt up bell housing with torque tube connected. This way you can see the position of the drive shaft "nose" as it relates to the pilot bearing. If you find the same thing that I did the drive shaft will have to be gently tapped forward (from the rear of the torque tube) until the nose of the drive shaft is fully engaged in the pilot bearing. I had to move my drive shaft about 1/4" forward. Moving the drive shaft forward requires the drive shaft to be "notched" so that the coupler can be installed with the new location of the drive shaft. The drive shaft is not hardened so a drill can be used to make the notch.

At this point connect the transmission to the bell housing, properly tightening the four mounting bolts. Slide the collar onto the drive shaft until the notch in the main shaft is aligned with the rear through hole of the coupler and install the allen head bolt all the way. Now check the position of the drive shaft nose to make sure it is still in the proper location. MAKE SURE THE CAMFER BEHIND THE NOSE DOES NOT TOUCH THE PILOT BEARING.

If all is in order, drill the drive shaft using the coupler as the die. Do not drill too far as you will hit the threads on the top side of the coupler. Once drilled install the allen head and check the nose one more time.

Now remove the transmission and back the torque tube out of the bell housing. Install the clutch and pressure plate and then re-attach the torque tube and transmission.

carbonarc

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Correction

Post  simon123 on Fri Dec 04, 2015 6:58 pm

Just realised that you are using a Small Block, the info I posted is for a LS1, perhaps someone with SBC experience can help here.

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It's all good!

Post  carbonarc on Fri Dec 04, 2015 7:43 pm

Simon, on the rear of the engine I believe they are dimensional the same. I followed the procedure and it's now good - the pilot bearing is engaged. Many thanks for your reply. Curt

carbonarc

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Great

Post  simon123 on Fri Dec 04, 2015 7:49 pm

Curt,
What clutch plate have you used? I used a Dodge plate that I got from the Vegas people.
I did the engagement thing properly but now have a bad vibration. Will be pulling everything soon and expect to see the shaft spline wrecked. Hope you use a clutch plate with true "Porsche" splines.

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Not Great

Post  carbonarc on Fri Dec 04, 2015 10:13 pm

We were told the Dodge with 23 splines is the ticket. I fitted it on the splines separately before putting everything together. It seemed to fit well without any extra slop or tightness. What makes you think the plate is wrong? Have you just completed the conversion or have you been running it for a while? We run our car in Lemons races and all of the races are a long haul for us in Arizona. So we want to get everything correct before hauling to a race. Everything is out now so this is the time to get everything right. Thanks for your help and advise.

simon123 wrote:Curt,
What clutch plate have you used? I used a Dodge plate that I got from the Vegas people.
I did the engagement thing properly but now have a bad vibration. Will be pulling everything soon and expect to see the shaft spline wrecked. Hope you use a clutch plate with true "Porsche" splines.

carbonarc

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Clutch

Post  simon123 on Sat Dec 05, 2015 8:11 am

I would suggest you do an advanced search (read instructions on left side of the page) and study the various posts on clutches. I believe that the "Spec" clutches which are made for these swaps have the correct spline. Its more about the length of the spline I believe but also the spline profile is important.

I have been driving my car for 3 years and the vibrations slowly got worse, I could never do a standing start in second gear without judder. My Torque tube was OK when fitted as it was rebuilt by Constantine.
My TT was correctly installed and engaged in the pilot bearing.

Here is a page from the Spec web site indicating their range of clutches for 944 conversions.

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Re: Drive shaft too short to reach pilot bearning

Post  944convert on Sun Dec 06, 2015 2:45 pm

carbonarc wrote:  I followed the procedure and  it's now good - the pilot bearing is engaged.  Many thanks for your reply.  Curt

btw...did your '88 come without the engine/transmission? Pulling the driveshaft back several inches makes it a lot easier for someone to pull the 2.5L engine out of the car. I've done it myself.

944convert

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Re: Drive shaft too short to reach pilot bearning

Post  carbonarc on Sun Dec 06, 2015 3:02 pm

Many thanks for the tip. We've removed the Porsche engine oh so many months ago it's just a distant memory, at best for us old guys. We've moved the torque tube back and forth so many times we slightly trimmed the anti-collision tabs so it can be rotated to get it back as far as possible. Anti-collision tabs are useless with one of our Lemons drivers: he's going to have a collision no matter what measures we take!
944convert wrote:
carbonarc wrote:  I followed the procedure and  it's now good - the pilot bearing is engaged.  Many thanks for your reply.  Curt

btw...did your '88 come without the engine/transmission? Pulling the driveshaft back several inches makes it a lot easier for someone to pull the 2.5L engine out of the car. I've done it myself.

carbonarc

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Re: Drive shaft too short to reach pilot bearning

Post  carbonarc on Mon Dec 07, 2015 2:01 pm

The drawing shows a machined area in the adapter plate where the T.O. bearing mounts. Our adapter is flat both sides so maybe it's unfinished? Can you tell me how deep is the machined out area? Thanks again for you help.

simon123 wrote:If you PM me I can email you a pdf of the procedure.

[You must be registered and logged in to see this image.]

carbonarc

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Can xschop help?

Post  simon123 on Mon Dec 07, 2015 5:34 pm

Rob,
Can you answer this question please?
It's your drawing.
Mike

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Re: Drive shaft too short to reach pilot bearning

Post  xschop on Mon Dec 07, 2015 7:30 pm

For a factory FW/clutch the C5 adapter has to be machined/recessed to allow the T56 throwout bearing inner surface to set on the adapter surface which is the exact plane at 5.80"
The little blue extra spacer is only needed if you are using an 11mm depth pilot bearing so as whatever clutch disc you use does not allow its rear hub to touch the pilot bearing. If a 14mm depth bearing works, then use it.
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Yellow part on diagram

Post  mred2nice on Sat Jul 07, 2018 10:44 pm

carbonarc wrote:The drawing shows a machined area in the adapter plate where the T.O. bearing mounts.  Our adapter is flat both sides so maybe it's unfinished?  Can you tell me how deep is the machined out area?  Thanks again for you help.

simon123 wrote:If you PM me I can email you a pdf of the procedure.

[You must be registered and logged in to see this image.]

Hello. I am having the same issue. There is only about 1/4inch engagement in the bearing.
What is the yellow part in the diagram?

I put a bearing in the back of the crank like you would when running a GM 4speed. I have the adapter/corvette bellhousing combination.

Thanks,
Ed

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Re: Drive shaft too short to reach pilot bearning

Post  Arthropraxis on Sun Jul 08, 2018 2:20 pm

Did you use a pilot bearing adapter? That would be the yellow in the diagram. The adapter relocates the pilot bearing toward the drive shaft. If the pilot bearing is put directly in the crankshaft it will be too deep for the driveshaft to reach.

The drive shaft can push toward the rear if the trans axle is not installed. Check how far the driveshaft is sticking out of the back. I don't remember how much should be sticking out but it is on here somewhere.
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You solved the mystery

Post  mred2nice on Sun Jul 08, 2018 9:47 pm

Hello

Well, that solves the mystery I have been trying to figure out for a long time. I don't have an adapter the bearing is in the crank.

Do you sell the adapters?

Thanks,
Ed

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Re: Drive shaft too short to reach pilot bearning

Post  spence on Mon Jul 09, 2018 4:23 am

If you use gm bearing number 12557583 you won't need an adapter (LT1 and SBC only).

Also, if you ended up using that spacer plate / shield. That only made matters worse by adding a 1/8".

On my swap I had to move the shaft forward and redrill the pinch bolt coupler bolt on the transaxle.
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Re: Drive shaft too short to reach pilot bearning

Post  Arthropraxis on Mon Jul 09, 2018 7:00 am

Sorry, didn't notice it was an SBC.
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Re: Drive shaft too short to reach pilot bearning

Post  mred2nice on Wed Jul 11, 2018 10:35 pm

Does anyone know if there is a guide on how to move the driveshaft forward? I can't even find a picture of where this access panel thingy is to gain access to the area.

Thanks,
Ed

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Re: Drive shaft too short to reach pilot bearning

Post  spence on Thu Jul 12, 2018 4:48 am

There should be lots of info here if you search.

On the front of the transaxle there is a rubber inspection cover. Pull that cover and you'll see the torque tube coupler. Unbolt the coupler and pry the shaft forward a little bit at a time each time checking the depth of the tip in the bearing (note: clutch should not be installed while checking all this)
The tip of the shaft should not be inserted past the chamfer on the back of the tip.
When you have the insertion depth correct you can then redrill the pinch bolt on the transaxle coupler.
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coupler

Post  mred2nice on Wed Jul 18, 2018 9:33 pm

Hello there

I have another question if you don't mind.

If the driveshaft is inside the coupler, how are you prying it forward?
Are you loosening the transmission end and hitting the clamp on the driveshaft end?

Thanks,
Ed

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Re: Drive shaft too short to reach pilot bearning

Post  spence on Wed Jul 18, 2018 10:28 pm

Unbolt the coupler and slide it all the way back.
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Driveshaft space

Post  mred2nice on Wed Aug 08, 2018 10:15 pm

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I found the coupler had an allen  bolt on one end and hex head on the other.

Is this space normal?

Sorry about the picture size. I couldn't fig out how to shrink it in photobucket.

Ed

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Re: Drive shaft too short to reach pilot bearning

Post  chrenan on Thu Aug 09, 2018 9:31 am

Usually allen bolts on both ends to secure the coupler. Over the years a lot of gorillas have overtightened them and stripped the allen bolts. They require very little torque to stay put, something like 30 foot lbs.

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Re: Drive shaft too short to reach pilot bearning

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