New Purchase Advice Pls

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PSL184
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New Purchase Advice Pls

Post by PSL184 »

Hi All
Just purchased an early 60's Minor 1000 which has been fitted with a 1098 motor and I have a couple of questions....
Firstly, at an indicated 50mph it sounds like its revving very high. What would be my diff ratio (assuming its not been changed) and what would be my best option to change it to?
Secondly, the crank is knocking quite badly. In your experiance, can I get away with changing the shells or would I need to rebuild the bottom end? I have a good used 1098 twin carb in the garage so this might also be an option but what else would I need to change, ie gearbox or gear ratio's etc....
Thx in advance....Image
Willie
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diff ratios

Post by Willie »

the standard diff ratio for your car would be 4.555-1 whereas the 1098
ratio is 4.22-1. The correct gearbox for the 1098 has a ribbed outer casing instead of the smooth case of the 948. If you uprated to complete 1098 running gear then you would need the correct speedo which, in order to retain the present look would be from a 1962-64 1098
which retained the bronze coloured face.
Willie
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Post by Welung666 »

Ooooo look, it's Phoebe's cousin!

Image

She was registered at the start of Sept. 1963.
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Post by Kevin »

As willie has said check to see if the gearbox is ribbed if so you will just need to change the diff for a later 4.22 to reduce the revs.
As for the engine you may get away with just changing the shells it depends on if the crank is marked, it can be done with the engine in situ as the sump does come off with no problems, but personally as you dont know the history of the engine I would want to give everthing a full check over.
Cheers

Kevin
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PSL184
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Post by PSL184 »

Thanks Guys and Hi to Phoebe :-)
I've had a look and if I'm looking at the right things it does look like the gearbox casing is ribbed, so its just a diff change needed. Any one have any experience / thoughts on a 3.9 or 3.7 diff??
I think I'll drop the sump off and have a good look around and see if shells will sort the problem - if not I'll dust off the spare lump for now....
I'm sure there will be more questions in the future so thanks again for your help...
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rayofleamington
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Post by rayofleamington »

The 4.22 diff gives good driveability unless you spend most of your time on motorways. The 3.9 is a nice option if you do a lot of long distance main road driving, but you will notice it on hills.
A 3.7 diff with a 1098 will feel far too high ratio (to most people) and be very poor on hills but it can be used (but I wouldn't recomend it over a 3.9)
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Post by ASL642 »

And Vikki's cousin, Hi and welcome to the Board! :D ASL 642 not so clear in pic.

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PSL184
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Post by PSL184 »

Maybe we should start an exclusive relatives club :-) Not far from either of "Jenny's" cousins here in Nuneaton !!!

Thanks Ray for the ratio advice - so, I guess my next question is.... Does any one have a decent 4.22 or 3.9 diff going spare and just begging to be used?

Fingers crossed :wink:
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Post by bmcecosse »

3.9 and 3.7 diffs are expensive! Check your ratio before rushing in to changing the diff. If the crank has been 'knocking' for any time at all - new shells will be money down the drain. It needs crank grind and a new oil-pump. If the other engine is in good order - use it. You should probbaly use the flywheel and clutch you have now - and of course you don't 'have' to run it on twin carbs unless you want the extra power and petrol consumption!
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PSL184
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Post by PSL184 »

Thanks BMC, that's sound advice - Are there any markings on the diff case to tell me the ratio of is it a case of counting the turns?
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bmcecosse
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Post by bmcecosse »

Dunno about markings - I would count turns. But 4.22 diff has oil filler hole in the casing - and 4.55 filler is on the diff itself. Hence later 4.22 diff in early casing = no filler hole !!
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PSL184
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Post by PSL184 »

Hmmmmm, interesting - I will check it tomorrow in day light!
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bigginger
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Post by bigginger »

It's marked on the diff gear itself, not the casing, so you probably don't want to pop the diff out to check. Happy turn counting :D
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Post by PSL184 »

OK, so now I'm confused!!!

Filler is on the diff casing at the rear - not on the diff itself... I marked the prop and the wheel and carefully counted the number of turns and for 8 full wheel revs I got 17 turns of the prop - so that makes it something like a 2.22:1 ratio (I think not). So I guess I'm measuring wrong somewhere - any ideas??
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Post by alex_holden »

I make that 17/(8/2) = 4.25, so it will be a 4.22 diff.
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PSL184
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Post by PSL184 »

OK, thanks Alex.... Silly question I guess but why divide the 8 by 2 ?
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Post by alex_holden »

When one wheel is fixed, the diff makes the free one turn twice as fast.
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Post by PSL184 »

Ah yes, of course - I was forgetting that part of its job!
So anyway - still think it's revving too high and I seem to have the correct box and diff in so I will try to rig uo a rev counter and see what it actually is doing.... or maybe its been too long since I drove an old car and am forgetting what they are like???
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Post by alex_holden »

I suspect it's just a matter of getting used to the sound. I have the same setup and I often cruise at about 60-65 for several hours at a time. It might be worth checking the speedometer against a GPS though in case it is reading low.
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Post by PSL184 »

Yes I will defo check the speedo. Am I right in assuming that 50mph should be at 3000rpm ((155 R14 tyres)) ??
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