275 GTB4 engine assembly manual

I am in the process of setting up a pair of distributors and doing other engine work on a 275 GTB4 and am hopeful someone may be able to help out with a pdf copy of the 275 GTB4 engine assembly manual.

If anyone has access to this I would be very grateful if they could help out.

 

The 4 Cam Engine Manual has nothing in it about the distributors. It only shows the basic static and max advance settings for the S85A units. These are the same units as used on late 250 and 275 single cam motors. however, a number of 4 Cams were built with S85E distributors. They are 9 degree units instead of the normal 15 degree S85A.

 

technician483
please have a look here: https://www.ferrarichat.com/forum/threads/what-do-you-think-about-filling-out-the-profile-and-introducing.567692/
this will help you and all others here
thank you

 

If you are working on the S85A you may find this useful. Thanks.

john

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Many thanks for all help.

We have S85E distributors so the S85A advance curve doesn't really help.

The distributors are currently not achieving full advance until 8000 RPM (engine) so will need to be adjusted. It seems like there has never been an advance curve printed for these distibutors so I will concentrate on ensuring maximum advance is achieved by a sensible engine RPM.

Once again thanks for all help.

 

Here is the correct theoretical advance curve for S85E distributors:
600 distributor rpm = 0 degrees advance
700 = 0
800= 0
900 = 1.5
1000 = 3
1100 = 3.5
1200 = 4
1300 = 5
1400 = 6
1500 = 6.5
1600 = 6.5
1700 = 7
1800 = 7.5
1900 = 7.5
2000 = 8.5
2500 = 8.5
3000 and up = 9

 

you are sure with this?
only 9° at 3000 rpm from the distributor?. this then would be a max. advance from 18° at the crankshaft. a little less I think?

and simon: thx for filling out your profile

 

Joe: The flywheels on these engines are marked AF24. They use 24 degrees of static advance. This still gets you to 42 degrees total advance. I could write a novel on all this with the 4 Cam engines, but the late 4Cams (about after 10,000) mostly came with S85E distributors. The factory was trying to correct the fact that the 4 Cams made less power than the six Carb 2 Cams. By adding a lot of initial advance, they were trying to make the car accelerate better from low rpm. 4 Cams also had two different carb setups, one with 29mm chokes and one with 32mm chokes. These cars run best with S85A distributors and 32mm chokes.

 

And yes, I have seen 4 Cams with S85E distributors and AF10 flywheels; talk about SLOW! Lamborghini did the same thing for different reasons. Espadas and Jaramas usually run about 20-22 degrees static advance in European form, but use a distributor that calls for 6 degrees static in USA emissions spec. My car came from the factory with a European Distributor and a USA flywheel!! Getting all that set correctly really woke it up!

 

have not known the static advance already has been 24°. you are sure so much? I don´t know any other engine with so much static advance. but then it makes sense only to have those 18° more

 

I can vouch for the 24 degrees static advance. We have the correct AF24 flywheel so will set at 24 degrees static.I will check our carburettor choke sizes as I wasn't aware there were 2 different carb set ups used.