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Discussion Starter #1 (Edited)
Greetings,

First off, THANKS to all of those who have taken the time to reply to the many technical posts here. It helps beyond perhaps the perceived scope of this forum as it appears all over the world. Good stuff.

While lurking for quite some time, finally joining, and a member for while now, I offer my first questions that I hope can be answered.

I have a carbureted 1750 Spider. It is time for a rebuild. I also have an 86 Spider 2 litre engine that is cherry.

As the refreshment will likely take me 6 months or so, I would like to install the later Bosch managed 2 litre into the 69 spider while retaining the webers, mechanical tach, and variable cam timing. I know I could change out the gear, etc, and loose the variable cam timing but would prefer not to.

1) It is my understanding that the variable cam timing is solely rpm triggered/managed. Is this correct? If so, any ideas on a cure to use this feature in the car with the webers and a suitable (1750) distributor & coil setup?

2) I know the tach drive is in the 1750 water pump housing. Does the 2 litre have a drive gear in the front of the motor so that I could retain my mechanical tach?

I figured I would ask this time before I spent any (more) time chasing the the little Italian gremlen.

Thanks in advance, Steve
 

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1966-2013
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13,741 Posts
1) It is my understanding that the variable cam timing is solely rpm triggered/managed. Is this correct? If so, any ideas on a cure to use this feature in the car with the webers and a suitable (1750) distributor & coil setup?
By 1984 or 85 the VVT became solinoid activated by the throttle position switch rather than mechanical/rpm activated.
You could put in a trip switch somewhere to activate the VVT, or revert to the older mechanical style.


2) I know the tach drive is in the 1750 water pump housing. Does the 2 litre have a drive gear in the front of the motor so that I could retain my mechanical tach?
1982 and up use an electronic tach that is driven via a wire on the coil.
However, the earlier waterpumps with mechanical drive can be put on without issue AFAIK.


This is all presuming you're working with a EFI version of the 2L of course.
 

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Discussion Starter #3
Thanks, Tifosi. Yes I had planned on switching the water pump over for the tach drive but as I recall, there is an internal drive. I was thinking the 2.0 electronic injection car may not have it. Do you happen to know the amps required to trigger the cam VVT? Thanks
 

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1966-2013
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Right off the top of my head, no. Though it's serviced by an 8amp fuse in its harness if that's of use.

The way the system is set up, 12V gets to the harness plug of the solinoid, (3 wires in), and then comes out of the harness plug (2 contacts) to the solinoid itself at like 8V.

Folks have bypassed the harness all together and rigged manual toggle switches or other systems like aftermarket EFI or linkage operated trip switches directly to the solinoid using straight 12V with no issues though.
(the electric version comes on when the throttle plate moves beyond 57deg rotation from closed)

+/- polarity isn't an issue when done that way BTW. Only if the harness is used as there's a PCB inside that plug end.
 

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Discussion Starter #5
Perfect. Thanks
 
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