This page contains a pictoral history of the various connecting rods use during the A65-A70 production, the evolution of the oil pump during the A65 production, and some info on timing side bushes and crankshafts.
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This picture shows the various oil pumps used in the A65's. Starting on the right is an early oil pump from a 65 BSA. There were a few internal modifications of the oil pump internals such as doweling the front housing to the pump body. but this pump which has recessed screw heads has a 2 piece drive between the driven pump side and driven scavenage side, and the fine pitch gears which pump less oil per turn, but could generate higher max pressure (the relief valve blows off before either pump would reach its maximum). The pump next to that one has the newer thru bolts, front dowelled to the body but has the smaller contact area for the nuts/washer mounts. I'm not sure what gears are in it. The next pump is the latest of the alloy pumps and has the coarse tooth gears one piece drive between the feed gears, and wider mounting faces for the nut/washer, to help prevent distortion. The last pump on the left is the cast iron pump. This pump is pretty much identical to the alloy pump next to it except for the housing which is cast iron. This pump will not distort like the alloy pump, however a carefully blueprinted and installed and torqued to spec alloy pump will perform just as well as the iron pump. It will not however tolerate either over tightening of the mounting bolts, or uneven tightening without distorting and binding.
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This is another view of the pumps. Note the different thickness of the mounting bosses.
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This is a photo of the various connecting rods used during the production of the A65/A70's. The two on the left are the A70 rods, these are the same as the later 70 and up rods with the exception of having a steel cap. the rod to the right of the A70 rods is the later 70 and up shot peened alloy rod. The rod on the right was used between 62-69 and is as forged. There was a change around 63-64 to the drive side rod which added the bleed hole to encourage oil flow to the left rod.
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This photo shows the difference between the side beams of the 70 and up rod and the earlier 62-69 rod. The later rods have the parting line smoothed and then the rod was peened to stress relieve and forge a hard layer to help prevent metal fatigue. The earlier rod side beam is also about .100 narrower. The earlier rods do have one advantage in that they are slightly lighter.
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This is a shot comparing the caps of the big end of the rods.
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This is a picture of the various Timing side bushes used in The A-65, A-70 motors. The bottom row of 3 bushes are of the following:
LEFT: OEM# 68-657, 66-72 bush, used in conjunction with drive side roller bearing, and thrust washer between bush and crank.
MIDDLE:OEM# 71-2697 This is a A70 timing side bush. It is narrower than the A65 bush to make room for a special A70 only washer which goes between the crank and the oil pump worm gear. I'm told that the shims on the A70 are on the timing side and the washer is part of that setup to limit end-float. I'll add more to this description as I find out more about it.
RIGHT: OEM# 68-0636 This is similar tho the left bush with the exception of a thicker lip. this bush was used with the ball bearing on the drive side and the bush had no thrustwasher between the crank and bush. I have replaced the ball bearing with the later roller bearings, shimmed end float to .001-.002 and have had no problems even though there was no thrust washer between bush and crank.
The upper two bushes are aftermarket replacement's. The one on the left is similar to the OEM one in that it has a steel outer shell, but it has a solid bronze bearing material rather than the tri metal vandervell bearing of the OEM bearing. The bush on the right is the alloy-tech part and I have not had good luck with these lasting very long.
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This is a shot of the aftermarket bushs. The one on the left has the locating pin flush with the bearing surface. The factory bushes has this locating pin below the surface of the bearing. While I don't think this is a problem as it is almost in the oil grove and right on the edge of the journal it still bothers me.
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This is a OEM bsa bush pressed apart. After removing the little locating pin, you can press out the old bearing. You can see it is is split. I wonder if vandervell still has any of these?? It would be fairly easy to press out the old bearing and press in a new one. Also in this picture is the thrustwasher that goes between the crank and bush lip.
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A shot of a new BSA bush showing the real bearing within the steel shell.
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