Inlet manifold for 1725?

SantaHul

SantaHul

0
I’m looking at twin carb inlet manifolds for my 69 model with a 1725. Most of the 1725 manifolds I find online seem to have the inlet ports in a slightly different layout. I’m not sure how best to describe this, the two on the left are close together, then the two on the right are close together, with a gap in the middle. Most online seem to have the two in the middle closer together.

Attempted diagram:

O O - O O < mine
O - O O - O < everyone else’s

Does anybody know what I need to look for to find a twin carb manifold?

Also interested to hear opinions of anyone who has upgraded to twin carbs re performance and noise.
 
The twin carbs were only fitted to alloy head engines hence the different port pattern, if yours is an iron head 1725 then you won't be able to fit the twin carbs without serious modification to the manifold. Much easier (and cheaper) to get a single SU conversion done and the performance will be similar to the twins.
 
Great thanks Panky. I was kind of hoping to hear that, now I won’t feel like I’m cheaping out if I go single carb.
 
Well tbh I’m looking at going EFI. No particular reason, I’ve just been looking for an excuse to fit a Speeduino to something for years. Can get a throttle body for about £100 and I’m pretty good with electronics.
 
Now that's a very worthwhile project. You've just got to do it and share - you might get a few commissions if it works :)
 
If anybody knows the best way to attach a camshaft trigger wheel then I’m all ears. Probably the camshaft pulley if there’s clearance, then need to figure out the best way to fit the sensor (I.e. where to drill the timing chain cover).
 
Is it the crank or cam you need to fit the trigger wheel to? The crank would be fairly easy assess but the cam sprocket is a bit awkward.
 
Can probably get the crank position from the distributor. Full sequential injection requires cam and crank position.

If you don’t want fully sequential then it gets a lot simpler, you just need crank position in the distributor and no cam sensor at all. And only one injector that can be fitted using of the shelf throttle body.

I’ve had too much free time lately.
 
I think maybe the simpler conversion first as it would probably be cheaper and quicker to develop - unless it's just a matter of another sensor and a bit more programming (easy if you say it quickly). I know Tim commeracer has done a system for his Austin J2 fitted with a highly tuned MGB engine, not sure if it's full sequential though - way over my ancient head ;)
 
SantaHul said:
I’m looking at twin carb inlet manifolds for my 69 model with a 1725. Most of the 1725 manifolds I find online seem to have the inlet ports in a slightly different layout. I’m not sure how best to describe this, the two on the left are close together, then the two on the right are close together, with a gap in the middle. Most online seem to have the two in the middle closer together.

Attempted diagram:

O O - O O < mine
O - O O - O < everyone else’s

Does anybody know what I need to look for to find a twin carb manifold?

Also interested to hear opinions of anyone who has upgraded to twin carbs re performance and noise.
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Yes I think that’s what I’m going to do now. Can be upgraded to MPFI later with mostly the same parts and then just some extra. Keep It Simple Stupid. I’ll let you know how I do but it will probably be a while.

The big problem seems to finding a throttle body which I thought would be easy but it isn’t.
 
There’s a company called Sherryberg that makes throttle bodies to replace carburettors. They include somewhere to put the injector. Problem is they only seem to make twin choke versions, can’t find one to replace my Weber ICT.

There’s lots on AliExpress for around £100. A lot of UK companies seem to rebrand them then charge £500.
 
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