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Replacement Half Engine


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#1 bigfish

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Posted 08 August 2019 - 04:50 PM

     I have an 89 1275 mini and are looking for a half engine replacement due to the cranksaft nose being destroyed by the clutch coming loose.

I was thinking of the mini spares replacement unit and was wondering if anyone has had an experience with these units, and which would be the best one to get.  Also does it matter if the replacement is a 92 and later with the larger oil pipe?  or is that just a bonus.

 

        thanks in advance for the insight

 

                  Paul

 

       Ontario Canada.



#2 cal844

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Posted 08 August 2019 - 05:14 PM

You could just get the existing engine measured to check tolerances.

I'd recommend whilst the engine is stripped and within tolerance to check the head and then go from there.

If the motor didnt smoke, You may only need new crank thrust washers and new bearing shells and a new keyed washer.

If you could post some pictures someone will give you advice on the best approach.

#3 bigfish

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Posted 08 August 2019 - 05:26 PM

    The car did not smoke and i was told the engine was rebuilt when i purchased the car..  I have no way of confirming this.  Would the new crank that mini spares sell do the job? do i need to balance or is it ready to install?   I am looking at adding a mild cam and gas flowed head to get the completed package in the 80 ft Lb  torque area.

 

      Thanks for the insight

 

              Paul.



#4 cal844

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Posted 08 August 2019 - 06:16 PM

The car did not smoke and i was told the engine was rebuilt when i purchased the car.. I have no way of confirming this. Would the new crank that mini spares sell do the job? do i need to balance or is it ready to install? I am looking at adding a mild cam and gas flowed head to get the completed package in the 80 ft Lb torque area.

Thanks for the insight

Paul.


Sounds like you will have a great little engine. I know it's probably a pointless addition but consider a centre main strap, especially if you want to rev over 6000 rpm regularly.

I can't comment on cam or crank suitability as I've never dealt with an 850 engine

#5 grizzler73

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Posted 08 August 2019 - 07:48 PM

Don't bother with a centre main strap, they aren't necessary and costly to fit. Get a good SH crank if the nose is knackered on your's if you are changing cam and modifying the head you might as well do a full rebuild.

#6 cal844

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Posted 08 August 2019 - 07:51 PM

Don't bother with a centre main strap, they aren't necessary and costly to fit. Get a good SH crank if the nose is knackered on your's if you are changing cam and modifying the head you might as well do a full rebuild.


Costly to fit? The holes are already there, all that's needed is 2 longer bolts and then some machining to get the shell sizes

#7 bigfish

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Posted 08 August 2019 - 09:07 PM

the engine is a 1275. i was thinking of the MED modified crankshaft as a replacement thinking alittle better than stock but they no longer do this crank.
would a stock crank such as the mini spares new 1275 crank do the job? again looking for 80ish ft lbs torque.

#8 unburntfuelinthemorning

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Posted 08 August 2019 - 09:30 PM

If it's just the nose of the crankshaft which was damaged and the rest of the engine is OK then the replacement crankshaft from Minispares or a good secondhand replacement is all you need.  Obviously you'll need things like crank bearings, gaskets etc. too.



#9 grizzler73

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Posted 08 August 2019 - 09:57 PM

To put the strap on you need to machine the cap flat on top, that is the cost. On a road engine it is a just waste of money IMHO.




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