Is this gear toast or can it be saved?

N

Neil Verity

Well-known member
Need some advise... is this gear toast or can it somehow be saved (see pic)? Appears the synchro landing pad has been damaged...If it can be saved (all other gears are fine) by whom?... was a MGB Jack Knight, close ratio, straight cut (3rd gear). Any advise appreciated.. As a limited prep car I need to run the stock transmission... if not salvageable.. anyone know of alternatives?

Neil
#83 HP MGB

 
Not inexpensive however my friend Chuck Leighton who passed away years ago used a readily available Nissan kit (rivergate) in his GP MGB. Then a Z car 4 speed with Houseman close ratio synchro gearset. Was a really nice drive and 0 maintenance last forever kind of reliable.
 
Is this gear toast or can it be saved?

The answer to your question is, I believe, yes it is toast. I am not familiar with MGB stuff, but it looks just like the BMC close ratio gear sets that we used to race before the dog boxes. There is a coating on the synchro cone that used to break off and when it does the spacing between the cone and cup goes off and it no longer works.

I never really ran this to ground, but the coating is probably a plasma spray of some kind that could conceivably be replicated. However, these treatments are not cheap, and unless you were doing a bunch of them would not be cost effective. You could probably buy three gears for the cost of doing one. They use it to build up worn journals on very expensive cylinders for printing, paper, and textile machinery.
 
fwiw, you don't necessarily need to run a stock transmission just because it's a limited prep (L2) car.

You have to run a stock trans with stock ratios fow a zero weight penalty. But if I read your post correctly and this trans is a close ratio, you can run any other "synchronizer" type gearbox with any ratios (but same # of gears) for no additional weight penalty:

There is no weight penalty for the use of a stock transmission
utilizing the stock case, stock gear ratio set (as defined
in the factory workshop manual) and stock synchromesh
style of gear engagement. An alternate transmission that
uses stock type, circular, beveled synchronizers, imposes
a 2.5% weight penalty. An alternate transmission that
uses a gear engagement mechanism different than stock
type, circular, beveled synchronizers imposes a 5% weight
penalty.
 
Thanks everyone... I agree it appears to be toast, and for the price of buying a new set of gears I could possibly go another route and end up with a better box. I'll need to go back and re-read the rules for limited prep. The last I read, I needed to run a stock "case" with various weight penalties for not stock ratios and or dog engagement.

Al, if you are correct it appears I may be able to go over to an alternative case (non-MGB) with various penalties depending on internals. I'll look into this...

Thanks,

Neil
#83 HP MGB
 
Chuck's car that I referenced was Limited prep Neil. I think it was considered "alternate syncro".
 
Neil, have you tried contacting Jack Knight directly? They still have a website and a 2011 price list shows some of the individual parts are not that expensive. http://jackknight.co.uk/

I will mention that a few years ago people had issues with orders from Jack Knight. Not sure if the business was taken over by someone reputable.

You may also want to post on the MG Experience Forum. They have a motorsports forum that a lot of vintage racers are active on. Maybe someone has a good 3rd gear from a set.
 
One of the best options for an MGB is the quaife rocket 4 speed. Shifts like butter and good ratio's with the ultra close set. Taylor has done a lot of these conversions. There's one in the MGB powered Elva I drive. Super sweet transmission. Maybe call my dad to get the info. Good luck!
 
I'm beginning to think its time for a quaife trans. I'll check into it... thanks for all the advise. I assume in an LP2 car I can use a 5-speed box, just lock out one of the gears and have 4 functional forward gears and still be within the rules.... Will also look into repairing my MGB close ratio... more homework to do,,

Neil
#83 HP MGB
 
Neil.. I have one Ford T4 Rocket box and two Taylor Series 26 boxes for my Sprites. Taylor services the Ford and provides great support for the 26s. They all are as good as they get. Calling Taylor wouldn't hurt you one bit.

Bob
 
Gary Wittman":1csrmw1e said:
It just hurts the bank account a little but usually not fatal.
Click to expand...

Neil has had enough trans/clutch related DNF's he would be way ahead of the game upgrading. :wink:
 
Neil, the quaife rocket box is a 4 speed box. Perfect for your application, you just have to add another 2.5% weight to the car.
 
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