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MG Midget and Sprite Technical - Fuel line route

Next task is to add a main fuel line to my Frogeye project. So some advice is needed please.
I have a reel of cunifer 1/4" (ext) pipe. Will this be ok to supply my 1098 engine?

And what about the route given I am using a rear mounted electric SU pump rather than the usual frog arrangement of mechanical pump on the engine. Should the fuel pipe follow the seat runner support rail along the right, and then cross over to the nearside chassis rail just behind the gearbox?

Guy
GuyW

Hi Guy
the pipe should be fine diameter wise. I used the same size and I have a 1275.

My pipe runs along the support rail. The u shaped clips fit into holes in the rail. When I took the car apart originally, the pipe ran up the offside and crossed over just in front of the engine pulley clipped to the seams. There are special clips for this. It then comes up by the engine mounting. A 'P' clip is bolted to the front mounting setscrew which holds the pipe. Originally the pipe was coiled to deal with engine movement and then connected to the pump. Like you I have a FACET pump mounted in the rear so dispensed with the coil. I feed the carbs through a pressure regulator and filter
Bob Beaumont

Guy, I've routed my fuel pipe along the RH support rail as shown. Pump will be mechanical so pipe continues over the hump above the rear axle. At the front it follows the "normal" route. I looked through the archive posts for ideas. Note this pipe is from Moss (bought in sale a while back) and o/d is about 7/32".

My rail wasn't drilled initially so I drilled the floor in two places for metal P clips with rubber inserts such that the pipe was snugged into the rail. I'll use a piece of flexible pipe at the pump (engine) end. If the mechanical pump gives trouble I can always revert to a rear electrical pump, like you. Better put a spare wire in the rear loom!



Bill Bretherton

The route you describe Guy is the same as on my 1098 midget MKII, with a rear mounted pump and the pipe secured by a P clip on the one engine mount close to the steering rack.
PN Sellen

Thanks. I have started making it, but stopped for sustenance. So far it starts from the pump and goes forward along the offside dwarves stiffener. I am cogitating over a coffee on whether to make the crossing behind the gearbox as Pete's or at the front cross member.

At the gearbox it always looks to me rather vulnerable, facing oncoming debris and other road obstacles. Tucked in the lee of the front cross member seems more sheltered, although it would be close to that spinning crankshaft pully. Hmm. A coffee refill is needed.
GuyW

Enjoy your coffee Guy.

I would say the front crossmember route was the original routing on my Frogeye. The 1275 has a deeper front pulley and is still well clear of the line
Bob Beaumont

Not sure where the dwarves come into this, except maybe they are better at crawling under the car on a cold concrete floor.
GuyW

Well I decided on the front cross member route. I wss thinking the front pully was closer than it is. But when I checked I see it is well above the top, not the rear edge of the cross member. So plenty of clearance.

I even found I have a packet of the correct edge clips for securing the pipe to the flange of the chassis rails. But that is as far as I got because I got sidetracked.





GuyW

Looks good! On the underside its possible to clip the pipe between the strengthener rail and the floor. The special clips are U shaped . The U goes into holes in the rail and the ends then clamp the fuel pipe. The brake line runs the same way but you have routed it in the tunnel which is better. The U clip is Moss item 23 part no 6k35
Bob Beaumont

I'm unfamiliar with Frogs but I've never seen a brake line that didn't go via the tunnel. When did they change?
David Smith

Thanks Bob. My intention isto get the proper U clips. For now, some zip ties support the pipe withing the reinforcing rail.

It is a Frog, though with various practical modifications, including the routing of the brake pipe.

The diversion I referred to was because I decide to get the carbs out to help identify the best route for the delivery end of the fuel pipe. When I bought this car, it came in boxes. One box contained the set of carbs supplied by Burlen. Not quite sure if they are new or just fully restored. They are very shiny!
GuyW

Although they look nice, there is a problem There isn't any obvious way of getting the inlet manifold correctly aligned with the ports in the head. Not like my 1275 which has insert collars which do the job.

Oddly, looking at the manifold it looks like one port has the recess, (first photo) but the other doesn't, or at least its not been machined out. (second photo)







GuyW

The only thing that might help alignment would be using appropriaate sized washers rather than the usual cast "ear" type spreaders at the manifold studs, but they are pretty imprecise.

I need to research this better


GuyW

Are there no recesses in the head?
Bob Beaumont

No. It's a 1098. Should there be?
GuyW

Yes, if it is a 12G295, I believe.

If your head has no grooves, you should have a manifold with ‘ears’ that locate on the studs.

Dave O'Neill 2

There seems to be a contradiction with this manifold. It doesn't have the "ears" that locate into the head studs. But the recess that would fit into an alignment ring hasn't been used either, at least not in one port. It's not been machined out. So it's neither one thing or the other.

There are however semi circular recesses machined on the manifold that would fit those thick round washers and would roughly align it with the ports, but that's a bit hit and miss.

I do have another couple of heads, both 1275 ones which as far as I recall do have collar recesses, but are they interchangeable into a 1098 block? I will have to dig them out and check condition. I would also need to check combustion volumes and do some calculations.

Complications! I have had that set of shiny carbs wrapped in industrial cling film and sealed in an unopened bag, from Burlen for over 10 years believing them to be new and just ready to fit straight on. There's even a receipted invoice for £389 which at the time represented 80% of the whole car project price!
GuyW

It is possible to use a 1275 head, with 1275 gasket, although the combustion chambers are actually smaller than the 1098 head, assuming that you have a 1098 Midget head, not a Morris Minor.

You also need to be careful that the fire rings don't overlap any corrosion around a couple of the waterways on the top of the block. Don't ask me how I know.

Do you know which engine you have?
Dave O'Neill 2

The 1275 head will fit a 1098 block however it has a much smaller combustion chamber capacity. The standard 1098 one is 29CC whereas the 1275 is 19CC. this would give a significantly higher CR around 11:1 using the standard pistons.
Bob Beaumont

Guy,
The float chambers appear to be the wrong way round as supply is normally on Spridgets with 1 1/4" at the front carb - with the petrol pipe routing on the engine side.

That manifold looks poorly machined - worth asking Burlen ! yes need the large washers !

In the old days of 'Car and Car Conversions' - Clive Trickey detailed drilling locating pins through the manifold into the head - I have a copy of his 'Workshop practice' if you want a read.

R.
richard b

I think the 12G940 is 21.4cc and the 295 is alleged to be about 28.3cc
Dave O'Neill 2

Sorry yes Dave the standard 1275 is 21.4. I was looking up the stage 1 ST head capacity!! DOOH
Bob Beaumont

Interestingly, there's a 10CC engine, complete with 295 head, carbs, etc., which keeps failing to sell on ebay.

https://www.ebay.co.uk/itm/303527865431


A bit of a bargain for someone, only it's up near Aberdeen! Not much chance of picking that up at the moment.
Dave O'Neill 2

Sorry, I have been socially distancing at the top of a 5 metre ladder. (fixing gutters)
This engine is a 10CG variant. not ideal but if possible I would rather not start swapping bits around and wouldn't want to run it at a much increased compression ratio. I will be quite happy to potter around with this car as I still have my "enhanced performance" 1275 and don't want this to be a duplicate.

The engine was built by Nick Veuger, for those here who may remember him. He was going to use it himself but then found a replacement 1275 to recondition instead. So I bought this one, or rather, I exchanged it for a set of high lift roller rockers. I cannot really check the specification with him, but believe it to be pretty standard.
GuyW

The head swap with a 1275 head does not sound the option you want. I have seen the manifold with the recess for the large washers and the alignment may not be that bad. I guess its a case of fitting it and see what its like. If not then it may therefore be better to either locate the manifold on suitable pins as described by Clive Trickey or find a manifold with 'ears'
Bob Beaumont

Ahh there's nothing like a good rummage! Found the correct style of thick locating washers for the head studs. A full set of 4 as well! They fit reasonably well into the machined recesses in the inlet and the exhaust manifold. So the carbs are at least located now although until I remove them again and inspect the crush marks on the gasket I won't know how near to alignment they are.

I have also swapped over the float chamber tops so the fuel lines will now be correct, at least for a 1098 engine. Aesthetically, they are not as pretty as the earlier style with brass dashpot damper caps and the domed float chamber lids. But they look OK. Must get some deep brass manifold nuts to replace those steel ones.

I am anticipating I may need to play around with springs and needles. As they came, these have AN needles but the springs are unmarked - no colour dabs on them. I am also going to need fuel pipe between the carbs, heat shield, springs and air filters. I should already have cables - somwhere. Its quite nice fiddling around with these parts as its all so clean and new, but its back underneath onto cold concrete now, to finish bending and routing that fuel line!






GuyW

Ashley Hinton does the shield, either in Mild or Stainless steel. He also makes the P clips to hold the fuel line between the carbs.
Bob Beaumont

Yes Bob, I plan ordering the heat shield from Ashley Hinton. The P clips I will make as I have suitable SS sheet.
How does one identify if fuel hose is Ethanol compatable?
GuyW

I believe its fuel hose meeting SAE J30R9 spec. Moss and other suppliers sell it in various sizes.
Bob Beaumont

Guy,

Maybe you want to get one of these if you don't already have one https://www.ebay.co.uk/itm/Waterproof-USB-Inspection-Camera-Boroscope-Snake-Scope-Endoscope-6-LED-7mm-8mm/114110731859 , plenty of sellers on ebay. That would allow you to see the manifold and port alignment internally. I have a couple and they've proved handy to have but I don't have a smart phone so just use it on the PC as so far I've been able to bring the item to the PC.
David Billington

Smart idea David! Particularly as I have one already but had forgotten and not thought of using one anyway!
GuyW

Plenty of scope, no pun intended, for posting pics of your port alignment from the inside.
David Billington

Now you are challenging! I will need to work out how to record from the scope and then save in a format that can be displayed here. Spannering I am ok with, but these new fangled methods where one cannot feel and hold the substance are definitely a whole new world!
GuyW

Guy,

I use a webcam app in Linux called Cheese that allows me view the output and capture video and images. I presume you're using Windows though and I understand there should be a camera app that ships with Windows depending on version and can also capture video and images, you just need to find it, maybe in somewhere like programs->accessories or whatever they call it now. Last version of Windows I worked with was mainly XP and a bit of Vista before I got out of writing software.
David Billington

Thanks David. The endoscope I have is the same as that one you linked to. I tracked down the software app that goes with the camera, plugged it in and am getting video on screen in my laptop! There are various options for different file formats but I don't know how to choose the most appropriate. I will have a go with it in the morning and see what I get.

As I don't think there's any way of uploading video to the BBS, I could used the option I have discovered, of taking still shots off the video. So if I can get a photo of the manifold to head connection that may be an alternative that works here.
GuyW

David,
For your enternainment I have now made an endoscope video of the inside of the manifold. It shows the alignment, or mis-alignment, quite clearly. Actually its not at all bad at least for a standard road car. The manifold is fairly well centred on the port, with the port being very slightly smaller diameter. It looks like a slight flare to the port of about 2mm all round would fix that. But maybe I need to pin it as well first to keep the same positions.

I have found some video editing software and shortened the original 2 minutes down to 45 seconds. I am not sure what to do with it now. It was an avi file format but has now saved as an MP4 file, whatever they are! I don't want to even attempt to upload it here as it will presumably take up valuable space on the server. What next?
GuyW

Youtube or another video posting site, I can't recommend anything as I haven't used any but maybe some others will chime in who have experience. Can you get images out of the video or take images directly from the webcam.
David Billington

Now worked out how to take a still from the video. Front port and rear port.

Given I just bolted the manifold on and aligned it using the thick washers by eye, I am quite pleased with that!





GuyW

Guy, MP4 is a "compressed" file format which derives from MPEG4 (Motion Picture Expert Group 4), in effect an algorithm designed to compress sound and video files. AVI format files are not compressed, meaning they are higher quality but occupy more storage space.

So MP4 is ideal for what you are doing. I hope that's not too much information!
Bill Bretherton

Thanks Bill. Still don't know what to do with it! T
The two stills I managed to get from it tell the story anyway.
GuyW

Guy,

Looks pretty decent from the images, now you just need to photoshop the engineering crew in there blending in the transition.
David Billington

David, thanks. I tried sending the gang in though it was difficult maintaining 2 metre separation as it's only a small 1098 engine. They shimmied under the choke piston and got past the butterfly but then retreated in panic!


GuyW

You running snake oil in that engine?
David Billington

When balancing the carbs the instruction notes say to listen for the hissing noises
GuyW

It looks like a miniature cobra!
Bill Bretherton

No Bill, it's just a long way away.
https://m.youtube.com/watch?v=MMiKyfd6hA0

GuyW

You can set the alignment by eye. If you leave the carbs off and fit the inlet and exhaust manifolds and nip up the nuts a bit. Then with a wood or plastic hammer tap it into alignment while looking into the inlet manifold ports, then torque up the nuts. You might get a bit of a performance drop due to the step change but I doubt you would be able to feel it on a 1098.
Rob
MG Moneypit

Good tip Rob, though I doubt I could improve it much from my first sttempt, as in the 2 photos posted earlier. Not unless I just flare the ports very slightly first, and maybe take out that ridge at the upper portion of the rear manifold port. But if I do that, then I will try your method of sighting through the manifold with the carbs removed. Thanks.
GuyW

Main fuel line now installed up to just next to the front carb. I took the route around by the front cross member. Not that easy to get the bends correct - it would have been much easier done before I put the engine in!

Next fuel line question then.
I have a NOS su electric fuel pump. Are they polarity sensitive? I cannot see why they should be. I haven't quite decided whether to keep this car positive earth as original or to change to negative earth.
GuyW

Don't think the points ones are but the electronic ones are polarity sensitive.
richard b

I believe Midget pumps aren't polarity sensitive, but MGBs are...or were, the latest ones aren't, apparently.
Dave O'Neill 2

I thought I would put together an Ashley Hinton order but I am struggling with this. Has anyone a link to a current website? The one that keeps coming up seems very dated and doesnt have any sort of viewable product lists or search engine. I think it's an old page intended for trade only contacts.

I have bought from them before, but only when parts have come up on ebay which is a bit random. I have found the heat shield I want listed on ebay and hoped to scroll through a list of other parts to see if there is anything else to add to the order.
GuyW

Guy if you view the heatshield ebay listing, then use the Visit Shop hotlink (upper right on the item page) you'll see there are almost 500 different items listed. HTH.
David Smith

Thanks David. That worked.
Not the route to their shop I would have expected!
Order placed now.
GuyW

This thread was discussed between 29/03/2020 and 03/04/2020

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.