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Propshaft angle


DrKai
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Gt6. Engine moved rearward as per usual spitfire front plate process. Type 9 gearbox. Chassis cross brace removed as fouling type 9 mount. Made the new mount at the weekend and tacked in at same height as type 9 was previously mounted keeping engine at same angle (with gearbox slightly downward). Issue is because the combination of rearward mount and type 9 being longer than original gearbox. The prop will be quite short and subsequently the angle will be quite extreme initial mockup suggests almost 15 degrees. Options are to drop the rear mount further but this will put the motor even more rear down, get in the way of the exhaust (can be overcome with side exit) and put the shafts of the gbx and diff even more out of line. Or some kind of propshaft magic as per 4x4s. I've spoken to Bailey Morris and they echo concerns re 15 degrees and I'm going to speak to them fully tomorrow. My questions are

1. How much rear slant will the engine tolerate. I suppose main issues will be fuel and oil supply. Fuel will be overcome with efi. How much of a problem could you forsee in oil?

2. Which would you prioritise: matching the angles of the flanges or reducing propshaft angle?

3. Anyone with any experience of the issue having made the modification/ anyone that did and how did they overcome it?

Long post I know but would appreciate any input 

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My mere penny worth and it is very minor.

If the engine slant might cause an issue with the oil, would a sump baffle(s) be useful ??

Sorry I cannot assist with the other Q's.

Good luck.

Richard.

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The engine slant would need to be quite extreme to cause problems.  Could partly be mitigated (though probably unnecessary) by using a saloon sump as they have more rearwards tip as well as a 6º list to the right which would tend to put the deepest part of the sump under the oil pump.

Fuel could be an issue with carbs but EFI (or PI) won't care at all.

Propshaft-wise it is probably worth trying to get the angles as good as you can as prop vibration is a pest with cars at the best of times.  You could consider using CVs rather than UJs as they can manage larger angles.  Spit 1500 had a CV at one end (odd thing in itself) from the factory.

Fit a Subaru diff as well and you'll almost get away with a single joint......😛

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