948 convert to 1275 info

[rossco]

Would like info on changing out engines. What do I need to know? (bugeye)

 

[Jerry]

Find a 1275 engine and make the swap. When I did mine, I found engine and transmission. It should be pretty straight forward. I was warned that I needed to upgrade the brakes to Disk on the front. If you are going to go faster, be able to stop.

 

[gfholl]

You will also need to convert to an electic fuel pump. Most electric pumps are "pushers", so it should be mounted close to the gas tank.

 

[rossco]

Have the 1275. Elec. pump is in place. Are there "fitting" issues? Does everything lash up the same? re: braking. I don't want to go faster, just a little quicker. Maybe there is little or no trade off here. Any more comments appreciated.

 

[Pythias]

Smooth case trannys don't mate to 1275s. Other than that everything fits up. .. Oh, tach. No more generator drive tach. You'll need a later one.

 

[Joe Schlosser]

Regarding Tach, just use the generator from the 948 engine. Same generator except for the tach drive back plate.

 

[twas_brillig]

Get yourself a Haynes manual and keep your eye our for an original/reprint BE manual. Make sure that you're happy with the condition of your clutch before installation, as that would be very annoying to discover as a problem, after the fact. Also keep your eyes out for a disc brake set-up for the front (and pickup the corresponding rear drums as well; save some money for resleeving the master cylinder) as I don't think you can ever have too much braking power, and the twin-leading shoes on the BE aren't quite up to today's standards. I'ts been quite a few years since I was swapping out tired 948s in our car and then moving to a 1275, but I don't recollect any problems. Real clearance issues between the bottom front pulley and the frame with our Datsun 5 speed install (still not on the road). Next time that unit is out, we'll be cuting the (hopefully) appropriate sized hole in the top of the Datsun bell housing. Good fortune, and have fun. Doug

 

[Billm]

Actually a 1275 will bolt up to a smooth case transmission. It is a 1098 that won't, the pressure plate on the 1098 is too big.
Billm

 

[rossco]

That simplifies things. Billm. Thanks for the clarification.

 

[Jim_Gruber]

Bill,

My '68 Sprite, Bugsy I, had a 1098 installed with a Smoothcase Tranny. Not sure what was done to make it work but I bought it that way, and I drove it for 12 years and then sold it to Alan Fisher in NH about 4 years ago, and I believe he is still driving Bugsy I. A '68 with a BE Bonnet.

 

[Billm]

Yes, you can clear the bell housing of a smooth case to accept a 1098 pressure plate but it isn't a direct fit. Not hard to do but not real quick either
Bill

 

[Jim_Gruber]

Thanks Bill, hope all is well with you and yours. Take care.

 

[Scargo]

You might also want to use the 1275 exhaust pipe which is larger in diameter than the 948 pipe.

 

[Pat MM]

It's good to hear you already have discs, the most important upgrade, IMO. Are they already on the car and do they function well?
As memory serves, it's much easier to use a complete 1275 (including HS2 carbs versus H1s on a stock bugeye) & ribcase transmission setup as the thin stamped backplate on the 948 doesn't fit the 1275 properly, though it can be modified to "sort of" fit with lots of work.
The ribcase is a stronger transmission and is much easier to source parts for, and to rebuild, than the early transmissions. Using the 1275 exhaust manifold (or a header) & later pipe as mentioned above really helps the 1275 breathe.