27-02-2020, 11:47 AM
After 20 years without an Austin Seven, I recently acquired a long-mothballed 1932 3-speed Tourer with little known history. Having removed the engine to fix a clutch issue, to my amazement I discovered not only that it has a Phoenix crank but also that the engine has done virtually no work since (perhaps because of the clutch problems). Needless to say, I am delighted!
Then I noticed that the crank seems to be positioned too far back in the crankcase with two of the little ends only a fag paper away from the rear gudgeon pin bosses in their respective pistons and the other two little ends also heavily biassed towards the rear of the space between their gudgeon pin bosses.
From what I can deduce of the car's history, I guess that the crank was probably fitted around 2005. Is anyone aware of any possible dimensional problems with Phoenix cranks from that period? Could it be that the front main bearing journal should have been machined another 1/16" or so further back to allow the crank to sit further forward?
If is not the crank that is at fault, maybe it is the crankcase which has had the usual lip replacement repair carried out but possibly not in exactly the right place. But the timing gears are perfectly in alignment which suggests that the lip is in the right place.
I have one thing left to try and that is to rotate the conrods 180 degrees to see if the little end moves across the gudgeon pin towards the other boss. That would mean of course that the white metalling on the edges of the big end has not been machined symetrically.
Whatever the final outcome, I have two further questions:
First, is there any reason why I should not put a 1/16' shim behind the outer race of the rear front bearing to move the crank forward, so long as I take 1/16" off the back face of the crankshaft gear?
Second, how important is it that the little end is centred between the piston's gudgeon pin bosses?
Any thoughts or suggestions will be most gratefully received.
Then I noticed that the crank seems to be positioned too far back in the crankcase with two of the little ends only a fag paper away from the rear gudgeon pin bosses in their respective pistons and the other two little ends also heavily biassed towards the rear of the space between their gudgeon pin bosses.
From what I can deduce of the car's history, I guess that the crank was probably fitted around 2005. Is anyone aware of any possible dimensional problems with Phoenix cranks from that period? Could it be that the front main bearing journal should have been machined another 1/16" or so further back to allow the crank to sit further forward?
If is not the crank that is at fault, maybe it is the crankcase which has had the usual lip replacement repair carried out but possibly not in exactly the right place. But the timing gears are perfectly in alignment which suggests that the lip is in the right place.
I have one thing left to try and that is to rotate the conrods 180 degrees to see if the little end moves across the gudgeon pin towards the other boss. That would mean of course that the white metalling on the edges of the big end has not been machined symetrically.
Whatever the final outcome, I have two further questions:
First, is there any reason why I should not put a 1/16' shim behind the outer race of the rear front bearing to move the crank forward, so long as I take 1/16" off the back face of the crankshaft gear?
Second, how important is it that the little end is centred between the piston's gudgeon pin bosses?
Any thoughts or suggestions will be most gratefully received.