A65 crank shim cup

[Gary S]

Advise please. I am re building a 1965 A65 Lightning Rocket engine. I have replaced the drive side roller bearing with a new one also fit a new plain timing side bush which I still need to bore to size. When I stripped the engine down there was no shim cup fitted to the drive side just a shim. When I ordered the new bearings I was advised that a 1965 engine did not have a shim cup fitted!! Looking at various manuals they all show a shim cup fitted. Any advice would be very much appreciated.
Thanks. Gary

[JulianS]

Shim cup certainly shown in the parts book. But the original drive side bearing for pre 1966 models was a ball rather than roller.

The shim cup for roller bearing was changed for the late models due to a change in the diameter of the centre spool of the bearing.

The 1966 on roller was used with a different bush and used a thrust washer.

[Gary S]

Thanks for your response. Not sure now why I was advised to fit a roller bearing on a 1965 motor if it should have been a ball bearing. It might explain why when I did an initial set up to check the end float measurement using the old timing side bush the end float was about .028" with a .003" shim fitted behind the new roller bearing. The new timing side bush is a solid type not two piece like the one I will replace but the flange on the new bush is much thicker than the old steel one. So to achieve the correct end float I will have to machine the flange down then shim for the final adjustment. Am I right in thinking that the thicker flange on the new solid bush makes up for not having a shim cup fitted or am I totally off the mark with this?
Cheers, Gary

[chaz]

As far as I can remember from two A65 rebuilds, I used Hoffman or RHP bearings , old style good quality.  todays quality of bearings is not as good. a customer had me rebuild a square 4 motor and parts supplied fell out initially other bearings I refused to fit as cheap Chinese ones which were supplied by a make specialist. at least there is the option to rebore the bimetal bush, the B40 only use a single size. I would think the oversize flange was either to manage machining allowance to suit (preferred) or a lack of control on dimension during manufacture (more likely).

[JulianS]

Two types of timing side bushes - pre 1966 and 1966 on.

If you were advised to fit a roller maybe the wrong bush was supplied? You should not need to machine the flange of a new bush.

I presume the engine a 1965 type and not the 1966 season type which were produced from October/November 1965 number prefix A65L?

You are in uncharted territory with the roller bearing in earlier engine. The ball bearing gives positive location of the crankshaft, the roller has movement and as far as I can see the A65 oil pump worm tends to draw the crank over to the timing side hence the use of a thrust washer between the bush and crank at this point.

[Gary S]

Ok, the engine prefix is A65D so therefor from what has been said it should have a ball bearing drive side bearing fitted. The engine is unknown to me so what's been done by anyone else may be right or not. When I stripped it down the drive side bearing fitted is a roller type with one .003" shim fitted behind the bearing against the crank. No shim retaining cup or timing side thrust washer. The timing side plain bush is the two piece type but is worn. the sludge trap tube has no provision for an end plug to be fitted as shown for a 1965 version.
My question now is how can I identify if this motor has the correct crank fitted? What's the difference between a 1965 and 1966 on crank?
Once I know I can then select the correct bearings etc.
Cheers
Gary

[JulianS]

I think the 1965 type is slightly narrower.

[Nanonevol]

Good article explains all here:
https://www.classicbritishspares.com/blogs/news/early-vs-late-cranks

[Gary S]

Excellent, the plot thickens now. Looks like I have early cases with a later crank possibly. Not home at the moment to do any checks but from memory the left case has not been machined. In addition if I am correct the later crank sludge trap plug has a fine thread and the early crank a course thread. My crank has a fine thread which suggest a later crank!
Will update my findings later.
Cheers, Gary

[Mike Farmer]

 

I'm in the same position. Cases and crank from different years. If I fit the thrust washer the cases won't bolt up and if I don't I have about 3 miles of end float. So it is actually outside my skills and I shall have to take it to my local engineering guru. Actually considering sending it to SRM to try to get a definitive answer.

One answer is to have a timing side bearing made specific to this engine, but I shall seek professional advice before going down this line.
This was discussed a while ago and I think the answer was that the crank width differrerd by a few thou.

Mike

[JulianS]

The A65 crank plug was changed to single fine thread in late 1964. See below.

The engine was modified to use a timing plug later in the 1965 season. See below parts service bulletin G31 from March 1965.

[Gary S]

Hi,
Thanks for all your comments and advice.  I have machined the engine cases as described in the link that Nanonevol provided, assembled the engine cases & crank with the correct crank end float. All looking good so thanks again.