Swapping crankcases

["Slack Alice" Simon]

Good evening all

I have a late rubber mounted high frame crankcase.

I need,for a short while, an engine to fit a low frame car.

I assume the fore - and - aft positions of the relevant crankcases are the same - both having 4 speed gearboxes.

Do I need to raise the earlier 'case a bit, on spacers, to match the vertical positionof the later one?

If so, by how much?

Thanks

Simon

[Bob Culver]

Someone must have a case or cases they can measure. Does not have to be the same person. I have the figures somewhere but cannot find. The plane of the top as reference and the other presumably the roof of the recess where the rubber pad fits
I have run a late engine in hgh frame without realising the error but the reverse may be less practicable.

[Geoff101]

Edit: Sorry - on re-reading the OP, I realise I did this the other way round. Ruby crankcase into a box saloon.

To answer one question though, the front to back position is the same.

[Reckless Rat]

My RP has a rubber mounted low frame crankcase (n° 238100 so 1935) and the only issue is the bulkhead to flywheel cover interface. There are no issues regarding the starter shaft/rad position. At some time prior to my ownership someone had " modified" the bulkhead to allow the engine to fit, raising the aperture a little to allow the slightly higher engine position to pass. Subsequent engine remova/replacement requires removal of the flywheel cover but apart from that everything goes in and out OK. (I don't even have to remove the throttle shaft). There are no mods to body mountings, cow horns etc., and it's been like this since time mint imperial with no issues whatsoever. Standard rubber mounts used.

[Hedd_Jones]

there was a solid mounted high frame crankcase in that farm trucked 37 Ruby I had. looked like it had gone straight in to me. No spacers

[Ivor Hawkins]

I put a three bearing in my chummy, I used rubber mounts too...I had to have a bit of a nibble at the bulkhead and the throttle linkage had to come off, together with the flywheel cover, but it went in without any other issues.

As Hedd said solid mounting it could provide all the clearance you need.

[Nick Lettington]

I have recently discovered that the engine in my '35 ORT is almost certainly a late high frame rubber mounted one... no rib above the starter motor? It sits on rubber mounts.

["Slack Alice" Simon]

Thanks for the replies.

I am a little surprised that no-one has come on to give exact dimensions.

Maybe starting from an early solid mount, ant then detailing the changes plus or minus from that.

That was one of the things I have always meant to do but have never had the requisite selection of crankcases in the same place at the same time.


One of the club websites talks of a quarter inch vertical difference, I think.


When measuring, do the rubber mounts count as a nominal one eighth thick? 

The sort of question to which I think we like to know the answer.


If the engine was going in my car the mods required to the bulkhead clearance wouldn't matter - but it isn't.

[Rory Nicol]

For the first time in 9 months of regular browsing on this forum I think I might be able to make a useful contribution. In spite of having an Austin 7 for 40+ years I only became vaguely aware of there being two types of 2 bearing rubber mounted crankcases a couple of years ago. To my surprise a rummage in my garage has produced one of each. I think both have been in my car (a Nippy) at sometime in the past.

Re the attached photo: The crankcase on the left is the lowframe one. They are sitting on a level base. The angle of the camera does give the illusion of differences which are not there. In each the distance between the top of the crankcase at the upper edge of the hole for the rear bearing is identical. One can see that when sitting in the same chassis the top of the left hand (lowframe) crankcase will sit about 1cm higher than the right one.
If it stops raining I'm happy to provide further measurements if required.

---

Here's the photo

[JonE]

That's a good photo. Trying to get head around the differences in the front pieces - does this c. 1cm also thus equate to the differences in the high and low frame nosepieces? Incidentally, saw yesterday that late 65 (190-something engine number) has rubber mounted; high frame obv.