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If the cap fits !!!

PostPosted: Sun Feb 21, 2021 12:57 pm
by persiflage
The car, 1972 Sprint with Dellorto carbs. The problem .... I can not fit the distributor cap correctly.

Way back in the 90s the original 23D4 distributor was replaced with the 43D4 touted as a direct replacement.
When the car was in daily use I obviously had issues with the caps as in my box of bits I have several set ups. Top entry with thinner flexible silicon leads and side entry with slightly thicker leads, both of the simple push in type.
The current setup as used when the car was last on the road is a side entry cap but it is impossible to fit in the correct orientation, leads facing firewall. It has to be fitted 180degrees out with the leads facing the radiator. Even this is is a real task.
On attempting to fit the cap in the correct orientation the cap and rubber push in caps for the leads foul the manifold casting and carb accelerator pump mechanism.
Measuring the old and new setups shows a significant difference in overall height from the mounting flange, some 7 or 8mm.
Has anyone else come across this issue?
Are old style caps (screw secured leads) available to fit the 43D4 distributor?
I’ve had a quick scan on the internet and can’t find any.

I can live with the leads exiting forwards but it doesn’t look good and they do get in the way
in what is already a messy area of the engine bay.

Re: If the cap fits !!!

PostPosted: Sun Feb 21, 2021 2:06 pm
by richardcox_lotus
I run a sprint with Weber’s, 43D dizzy and side entry cap. It’s a tight fit but does fit ok, so will be interested to hear if the dellortos are deeper.

Re: If the cap fits !!!

PostPosted: Sun Feb 21, 2021 3:49 pm
by h20hamelan
persiflage wrote:I can live with the leads exiting forwards but it doesn’t look good and they do get in the way
in what is already a messy area of the engine bay.


I find the forward position is optimal as it gives more space and light for adjustments. When it is off, I can move the cap and wires to the other side of the engine.
Though it is a messy area :?:

Re: If the cap fits !!!

PostPosted: Sun Feb 21, 2021 5:39 pm
by Mazzini
I have a dim recollection of this happening to me in the 80's. I think number 1 plug lead at the cap end rubbed through and shorted out on the inlet manifold. I ended up machining the collar on the distributor where the clamp fastens, it allowed the distributor to seat further into the block and it gave me just enough clearance.

Re: If the cap fits !!!

PostPosted: Sun Feb 21, 2021 7:18 pm
by joe7
From looking at the picture and comparing where the oring is on the shaft is appears that the length of the drive on the left one is shorter than the drive on the right one.

Re: If the cap fits !!!

PostPosted: Sun Feb 21, 2021 9:16 pm
by bdea
May I suggest an alternative cap for your 43D:

https://pertronixbrands.com/products/pe ... 7181448228 This kit has brass terminals not like the aluminum ones on the brown cap!

This is what I used and clears the intake manifold on my stromberg motor.

Brad

Re: If the cap fits !!!

PostPosted: Mon Feb 22, 2021 2:48 pm
by persiflage
joe7 wrote:From looking at the picture and comparing where the oring is on the shaft is appears that the length of the drive on the left one is shorter than the drive on the right one.


Parallax due to my shoddy picture work :|
Standing side by side on a level surface everything lines up nicely.

Re: If the cap fits !!!

PostPosted: Mon Feb 22, 2021 7:43 pm
by davidj
Coincidentally I have been fitting an Aldon TC103 distributor today ( which I believe is a 43d? Can someone confirm?) and have exactly the same problem as persiflage, and with cap fitted, the distributor is the same length. I have a Weber engine and have managed to statically time it with the distributor pointing forward, 180 degrees different from my +2. It fits OK, apart from No 4 lead being a bit tight, but have not yet run the engine.

Re: If the cap fits !!!

PostPosted: Tue Feb 23, 2021 8:23 pm
by davidj
Update. I have gone back to first principles and managed to statically time the tc103 (43d4?) distributor pointing downwards towards the rear of the car. This position allows the cap to be removed and the cables are slack.