7 replies to this topic

[SuperDeLuxeNick]

Hello,

 

Rebuilding my engine currently, all going well.

 

I have triple checked part numbers etc and currently have a 998 A+ block, 998 A+ crank going onto a early 1963 gearbox. The original engine was a 1963 A series 850cc original to the car.

 

Gone to fit the primary gear (the early one so that it meshes with the early box). I was led to believe this was all that was required?

 

However the primary gear is tiny vs the later one, it barely goes over the nose of the crank? I thought it was only 1275s that had a different size? Very confused!

 

Hoping someone can assist?

 

thank you

[SuperDeLuxeNick]

a-ha - just read on mk1 forum that in 1963/1964 the diameter changed - mine is an early 1963...

 

So assume i just need a post 1964 A Series 850/998 primary gear... anyone got one lurking!?

[DeadSquare]

a-ha - just read on mk1 forum that in 1963/1964 the diameter changed - mine is an early 1963...

 

So assume i just need a post 1964 A Series 850/998 primary gear... anyone got one lurking!?

There are lots on ebay, if you type in "Classic Mini Primary Gear".

 

Pick one that hasn't got a worn groove made by the oil seal.

[Spider]

Yes, the early 850 and 997 cranks had a 1-3/8" Tail on them, it was about 1963 they changed to a 1-1/2" Tail.

You'll want a 24 tooth primary gear. If buying used, ideally, take your crank with you along with feeler gauges so you can check the bushes for wear 0.003 to 0.005" clearance is what you're looking for here.

[SuperDeLuxeNick]

Thank you all!

I’ve ordered a couple of used ones, hopefully one is good, if not I’ll go for a new old stock item.

[GraemeC]

I have a few of these if you get stuck

[SuperDeLuxeNick]

Unrelated but while I wait for it… my 295 head had double valve springs fitted previously. Given it’s a pretty standard 998 engine now, Minispares EVO1 cam, are the doubles a bit much? Can’t see it producing a lot of power so wondering if a new set of singles will be better? Thank you

[Lplus]

Are they to original spec for the 295 head?  Does the cam have a particlularly high lift profile?