Have he tranny's input shaft machined down shorter?
Jim Stuart wrote:
> Well, an update on what has become an interesting, if somewhat
> frustrating problem:
>
> Not satisfied with disassembly/ reassemble to eliminate the problem, I
> dug into it again this weekend. Boy am I tired of r & r'ing the clutch,
> flywheel, bell housing, tranny!
>
> This is what I have discovered- smarter ones on this list probably new
> the answer, I just didn't ask correctly. The engine I have is approx.
> 1994 4.2 L from a Land Rover, originally with a serpentine drive front
> cover. As such, it has a slightly different crank than the Buick/Olds
> that I am more familiar with. The rear of the crank has a tubular
> extension that holds the pilot bush. On the Rover, this extends approx.
> 3/4" beyond the flywheel mounting flange. On the Buick/Olds, the
> extension is 5/16". This is something I had not noticed until yesterday.
> It does not present any obvious problems, the flywheel & clutch assembly
> bolt up just fine. Apparently, some Rover engines have a spacer, solid
> chunk of steel, that slides over the end of the crank, spacing the
> flywheel further to the rear, so it looks like the end of the GM unit. I
> don't know when this is used, manual or automatic? or why. I assume it
> is to space the flex plate or flywheel to align with the starter drive.
>
> The transmission is a Chevy T-5, not a Rover, & the bell housing is a
> 3/4 speed Buick. The flywheel is an after market Buick/Rover replacement
> item, clutch is a Chevy S-10, 10.5".
>
> This extra 3/4" of crank length is my real problem. Everything bolts up
> just fine until you finally snug up the tranny. When this is done, the
> splined section of the tranny input shaft comes to rest on the end of
> the crank, forcing the crank forward in the engine, until it locks the
> engine due to the pressure against the thrust washers, or some other
> internal part. I could only see this by removing the clutch assembly and
> then installing the trans. As I tightened the trans to bell housing
> bolts, the input shaft became harder & harder to turn, until it stopped.
>
> To prove my observation, I installed 1, 1/2" flat washer on each bolt,
> between the tranny & bell housing. when tightened down, everything was
> free.
>
> Now, 2 questions. How much space is really required, how/where to space.
> Observation shows that the small end of the input shaft resides entirely
> within the pilot bearing. I do not see this as a problem. More of the
> shaft is supported by the bush than is normal, but is this bad? I am
> using a hydraulic throwout bearing that is adjustable for length, so the
> distance from the face of the tranny to the clutch (or flywheel) is not
> a problem. There are 2 obvious places to add a spacer, between the block
> & bell housing, or between the bell housing & tranny. There is plenty of
> space within the bell housing for the clutch, so no need to space here
> for that reason.
>
> I am not comfortable with just leaving washers between the tranny & bell
> housing, as it seems that it will put all the stress on the ears of the
> trans. Any contrary opinions are welcome, as this is the simplest
> solution. Alternately, anyone capable of providing a spacer, please let
> me know. This is the last item keeping the car off the road.
>
> As usual, I am counting upon the magic of this list for advice.
>
> Jim Stuart
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