Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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Feathers
John Feathers
NY
(3 posts)

Registered:
08/06/2018 03:47PM

Main British Car:


Daimler 2.5 fuel delivery
Posted by: Feathers
Date: August 06, 2018 04:21PM

Hello All
Does anyone know what the best replacement for the Mechanical fuel injection would be?
The motor runs strong, and the top end is really something. It just doesnít want to idle.
The way the fuel system is set up: fuel is taken form the fuel cell in the trunk and pumped from an electric pump in the trunk to a regulator in the engine bay then to the twin SUís if wanted. For the injection system Fuel is pumped the same way but rather than go to the twin SUís flows into a holding tank with a float bowl, this was built by Paul, fuel then flows from the holding tank to the fuel pump on the front of the engine. The fuel pump on the front of the engine runs off the fan belt, the faster the engine turns the more fuel is pumped. From the fuel pump there are 2 lines, one goes back to the holding tank and the second goes to a main shut off on the top of the engine just before the fuel rail. In the return line to the holding tank there is a brass fitting, this fitting has a hole in it, by replacing the fitting with either a smaller hole or larger hole more or less fuel goes to the injectors. small hole more gas to injectors, lager hole less gas to the injectors to shut the car down just close the valve on the top of the engine and gas stops flowing.
I have an SU setup for it, just wondering if there is anything that will give enough gas.
1962 new.jpg


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5657 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Daimler 2.5 fuel delivery
Posted by: BlownMGB-V8
Date: August 07, 2018 11:43AM

Very nice. I think that's actually the first one of those we've seen on this forum. But your description of operation is exactly consistent with that type. What it lacks is any provision for low load operation, as it was designed for racing. As a result it was never expected to operate under high vacuum and idle was more of an afterthought. It may have some provision for idle tuning or it may not.

For street use you can convert to EFI. That will take some work but if you are willing to do it the results are worthwhile.

Jim


Feathers
John Feathers
NY
(3 posts)

Registered:
08/06/2018 03:47PM

Main British Car:


Re: Daimler 2.5 fuel delivery
Posted by: Feathers
Date: August 08, 2018 08:52AM

Hello Jim
Thanks for the input.
Thatís the way I bought the car. The description is the last owners.
I would love to get EFI for it, I just donít have the knowledge to do it.
Carburation would work if I could get enough.
I was told it has 12:1 compression and has an 8500-rpm red line. I know itís is quite thirsty.
It runs so rich it smokes like crazy at 2000-rpm and runs smooth and clean at 7500. The plugs fowl at idle in no time at all. Thatís why I am looking for other alternatives.

John


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5657 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Daimler 2.5 fuel delivery
Posted by: BlownMGB-V8
Date: August 08, 2018 10:35AM

Having someone else convert to EFI for you will be expensive as you would have to install an injector in each throat but beyond that it is pretty straightforward as EFI systems go. However it sounds like you might be better off with a carb. Keep the FI setup in case you sell the car, or sell it on, it is likely quite valuable.

If going to a carb, either a 4bbl or one of the new 4bbl throttle body EFI systems are good choices if you can find a 4bbl intake for that engine.

Jim


88v8
Ivor Duarte
Gloucestershire UK
(609 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Daimler 2.5 fuel delivery
Posted by: 88v8
Date: August 09, 2018 04:14AM

That setup looks way overchoked for a small engine, don't see how you will get any coherent airflow at idle.
Seems to me it's for competition pure and simple and anyone into period drag racing might be very happy to have it.
As you probably know, very bad for the engine to run so rich, it will cause washdown, and contamination of the oil.

Regarding options, the SUs are fine for a road car, beyond that if you post on the DLOC forum someone may direct you into other possibilities. Although they're mainly polishers, there are some people with enthusiasm for pepping things up a little.
[forum.dloc.co.uk]

There is no factory 4bbl intake, you would have to have one fabbed and then get into setting up the carb on a rolling road.
What do you want to do, road use or something more?

What car's the engine in, btw?

In general, this engine was never very strong and in old age is showing design problems with cracking and maintenance issues with corrosion. Unless it has strong historicity, perhaps not one to sink a lot of time and money into.

Ivor


Feathers
John Feathers
NY
(3 posts)

Registered:
08/06/2018 03:47PM

Main British Car:


Re: Daimler 2.5 fuel delivery
Posted by: Feathers
Date: August 11, 2018 10:00AM

Hello Ivor

Its in a Daimler SP250.
I would like to race it when I get the time.
Thanks for the input.
John


88v8
Ivor Duarte
Gloucestershire UK
(609 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Daimler 2.5 fuel delivery
Posted by: 88v8
Date: August 13, 2018 04:10AM

A chap with good knowledge of these engines pointed out to me that an engine with this sort of (Hillborne?) setup has likely been modified, such that the stock SUs and needles might no longer give a good result. An 8,500 redline certainly suggests that it's a little non-standard.
In that case, if you also want to drive it on the road you may as well have a manifold fabbed and go to a small Edelbrock, it will be a lot easier to tune than trying to regrind suitable needles for the SUs.

I believe that there are also electronic systems using repros of the Weber IDA bodies, ah yes here we are [foxinjection.com] but again, there's no stock manifold. However, might be worth talking to Fox as they seem to have a range of manifolds, and see if someone has already gone down this road.

Ivor



donkelly23
Don Kelly
Charleston, SC
(111 posts)

Registered:
07/21/2011 05:13PM

Main British Car:
1980 TR7 V8 Z28 FI ECM 4.0

Re: Daimler 2.5 fuel delivery
Posted by: donkelly23
Date: August 13, 2018 08:42AM

Just for the coolness of it
Id lookin to Squirting it with EFI
Be a fun track car


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