Pelican Parts Forums - Intermediate Shaft Not Enough Backlash Remedy

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Intermediate Shaft Not Enough Backlash Remedy

What is the solution if the backlash is too little?

We are rebuilding our 1970 914-6 (aka 1969 911T) engine. Our original intermediate shaft was out of spec. We replaced it with a new one from Porsche. Crank refurbished by a well known machine shop with excellent reputation. 0 marks on crank gear and intermediate shaft.

There is no perceptible backlash watching, listening, feeling. Best case with dial indicator is it .01mm, but it is hard to be sure I'm not moving the crank to get that. So we're under the published spec. What can you do about it?

As long as there's no interference or binding between the gears, I'd run it.

I'm no expert, but...

Make sure to check your case to see if it's a "0" or "1". Gears can be mixed to provide proper backlash. Also, make sure your bearings are seated when measuring.

This thread might be helpful to you: https://forums.pelicanparts.com/911-engine-rebuilding-forum/1012916-intermediate-shaft-assembly-question.html#post10248955

Quote:

Originally Posted by KTL (Post 10250387)

What Bruce is referring to is in the pictures below. This is taken from the '84-'87 911, 930 Tech Spec book

http://forums.pelicanparts.com/uploa...1542142328.jpg
http://forums.pelicanparts.com/uploa...1542142342.jpg

I disagree with the note that indicates the shaft and bolted gear are one part. People have changed the gear on these shafts over the years. Some like to take the steel gear from the 964 shaft. Also, Pauter and JB Racing make straight cut I-shaft gears and that tells me their gears are being bolted to shafts that have had their original gear removed.