1974 Turbocharged MGB GT (MX5 Swapped)

[Nathan]

Mar 10, 2014 19:14:15 GMT bmwv8capri said:

Great work & good luck for the MOT

handheld diagnostic readers are pretty cheap on fleabay these days (or borrow one off a mate, that's what i do ) without the fault codes it could be a lengthy diagnosis

The MK1 MX5 does not have the usual OBD connector, instead you need a hairclip and a LED with resistor. Basically jumper 2 ports on the diag with the paperclip, and put the LED in another 2, then count the flashes and the pauses.

Anyway, last weekend I was determined to get to the bottom of the issue. I re-attached all the non-required stuff (EVAP system) so that a code pull would only show faulty components, we got nothing apart from the power flash. That's a good sign it meant the issue was not with any of the electrical parts, again my thoughts was the Temp sensor or the Lambda but both checked out perfect :-).

This mean only 1 thing...FUEL.
When I started the conversion I tried to make sure we kept the workings of the fuel system as similar as possible in the MG. This meant making sure fuel lines were the same and any rubber hoses, also the return methods.

So armed with a fuel pressure regulator that also had a gauge, I decided to watch the pressure.....Apparently 4.8-6.5psi is ideal (AutoData), so the regulator was set and I let her tickover for a bit. Pressure slowly but surely the pressure started dropping off, and under sudden acceleration it would near enough Zero itself......Promising.

Basically the issue seems to be the new lines, I think they are a little too large for the current "Standard" pump, also the tank not being baffled is causing surge when "Garden" drifting. So I bit the bullet and bought a Facet Race pump (Red Top) I believe, SwirlPot and race regulator....This should sort the issue and I'm ready to MOT it.

[gn3dr]

Mar 21, 2014 15:19:25 GMT Nathan said:

Mar 10, 2014 19:14:15 GMT bmwv8capri said:

Great work & good luck for the MOT

handheld diagnostic readers are pretty cheap on fleabay these days (or borrow one off a mate, that's what i do ) without the fault codes it could be a lengthy diagnosis

The MK1 MX5 does not have the usual OBD connector, instead you need a hairclip and a LED with resistor. Basically jumper 2 ports on the diag with the paperclip, and put the LED in another 2, then count the flashes and the pauses.

Anyway, last weekend I was determined to get to the bottom of the issue. I re-attached all the non-required stuff (EVAP system) so that a code pull would only show faulty components, we got nothing apart from the power flash. That's a good sign it meant the issue was not with any of the electrical parts, again my thoughts was the Temp sensor or the Lambda but both checked out perfect :-).

This mean only 1 thing...FUEL.
When I started the conversion I tried to make sure we kept the workings of the fuel system as similar as possible in the MG. This meant making sure fuel lines were the same and any rubber hoses, also the return methods.

So armed with a fuel pressure regulator that also had a gauge, I decided to watch the pressure.....Apparently 4.8-6.5psi is ideal (AutoData), so the regulator was set and I let her tickover for a bit. Pressure slowly but surely the pressure started dropping off, and under sudden acceleration it would near enough Zero itself......Promising.

Basically the issue seems to be the new lines, I think they are a little too large for the current "Standard" pump, also the tank not being baffled is causing surge when "Garden" drifting. So I bit the bullet and bought a Facet Race pump (Red Top) I believe, SwirlPot and race regulator....This should sort the issue and I'm ready to MOT it.

You sure about those fuel pressure numbers? I would have thought you should have about 3 bar at the fuel rail of an injected car.

[GavinJ]

Got any pics of your new fuel set up mate? i'm using an mx5 pump and having issues.....so will be following your new set up...

[Nathan]

Mar 21, 2014 18:13:02 GMT gn3dr said:

Mar 21, 2014 15:19:25 GMT Nathan said:

The MK1 MX5 does not have the usual OBD connector, instead you need a hairclip and a LED with resistor. Basically jumper 2 ports on the diag with the paperclip, and put the LED in another 2, then count the flashes and the pauses.

Anyway, last weekend I was determined to get to the bottom of the issue. I re-attached all the non-required stuff (EVAP system) so that a code pull would only show faulty components, we got nothing apart from the power flash. That's a good sign it meant the issue was not with any of the electrical parts, again my thoughts was the Temp sensor or the Lambda but both checked out perfect :-).

This mean only 1 thing...FUEL.
When I started the conversion I tried to make sure we kept the workings of the fuel system as similar as possible in the MG. This meant making sure fuel lines were the same and any rubber hoses, also the return methods.

So armed with a fuel pressure regulator that also had a gauge, I decided to watch the pressure.....Apparently 4.8-6.5psi is ideal (AutoData), so the regulator was set and I let her tickover for a bit. Pressure slowly but surely the pressure started dropping off, and under sudden acceleration it would near enough Zero itself......Promising.

Basically the issue seems to be the new lines, I think they are a little too large for the current "Standard" pump, also the tank not being baffled is causing surge when "Garden" drifting. So I bit the bullet and bought a Facet Race pump (Red Top) I believe, SwirlPot and race regulator....This should sort the issue and I'm ready to MOT it.

You sure about those fuel pressure numbers? I would have thought you should have about 3 bar at the fuel rail of an injected car.

At the rail it should be 2.65-3.14. The gauge on the rail end never gets above 2, and drops to 0 mostly.
I should have said we put a Pressure gauge (bit traveller) on the pump end so we knew its not flowing enough.

I will be able to show you tomorrow as that's when I'm fitting it all ;-)

[Nathan]

We have success :-)

Using a Slave high pump from the original outlet on the tank feeding a Swirl pot seems to have sorted the issue, this of course required a High pressure out of tank pump to pressurise the system.

Backyard drifting also proved the fuel surge is sorted (well not truly but now its not noticable).
Facet Silvertop, 8.5 Bar high pressure pump, filters and various unions sees the little GT running perfectly.








Didn't take any pictures of the finished product, this was the test run setup.

I do need to remove it all again to paint the boot floor.

Once the fuel systems were proven I moved onto the small jobs, mainly lights and horn plus cable tie the old wiring out the way.
She is now ready for the MOT, however it wont happen I don't think till at least May as the Capri is back on the road as of tomorrow. The Capri is my main Season show car and has its MOT on the 25th, so I need to step on it to get that ready, These past few months only having my Daily to roll around in have actually been horrid (wont drive the Capri in winter weather), so I am excited to be rolling around in that again.

The idea was passed around to just take the GT and Capri to the MOT centre and do them both, so this may be the idea....I'll see later on.

[Nathan]

Forgot, the rear arches are now fitted but will probably be removed again as I want to deck the car.

[Nathan]

Well it passed the MOT, First time round and NO advisories!!!!

Since then (2 days ago) I have been modifying the engine mounts a little as I was just not happy with them.

Apart from that, it will be Taxed tomorrow and tested/Broke/Fixed then tested again :-)




This means that I have ideas for the next project, in actual fact it's a current project (Midget). An engine transplant was thrown out long ago, but I am now thinking Ford Zetec power :-)

[flyingphil]

Nice work on getting the B sorted.

[qwerty]

Well done. Looks fantastic!

[adam73bgt]

Congrats on the MOT, the B looks great hows the performance with the MX5 engine in there?

[Nathan]

Sorry I forgot to reply to this.
This weekend saw the first outing in it's current guise (Sunday Morning meet), however on Saturday afternoon I spent some time pottering around and decided I was bored of the "Bumperless" look.
It must have been round 8 years since they were removed, so quite a bit of searching around (house moves) was needed.

Bit of a buff and new brackets made she looks like this!




Sunday Morning...



As for the drive.....AMAZING.
The Original B series was at Stage 2 spec, so as Pig lumps go it was nippy......But with this in it feels like a rocket :-) Even though it's not alot of power it's more than enough to propel the old girl down the road, better still the note of the MX lump is practically identical to that of the B Series.

60 MPH was about as far as I dared take it, the only test runs were at about 30.
The only issue I have now is the Speedo is way out...35 is 45 :-) I am getting that calibrated later on.

Cheers.

[mhuk]

This is the type of MG my Triumph would like to do some friendly jousting with on the roads! Your MG looks ace!

[adam73bgt]

Great to see this on the road I really like the look of it with the bumpers on and the front rake is cool, I need to sort out the plans for my MG as I want to get rid of the boat anchor up front also

[MrSpeedy]

Not seen this for a while, but looks like good progress.

Really looking nice now, and probably one of the best looking MGB's around imo

[Nathan]

Cheers guys.
My mate who took the last "Driving" photo did ask what's it like.
To be honest I wish I had done it years ago, it's transformed the car, I think during these summer months I'll press her into some Daily duties to stress test the whole setup.

[MrSpeedy]

And then over the Winter months you'll be looking at forced induction. Won't you?!!

[Nathan]

;-) I have been looking at Eatons.

[7M.elody]

Jul 7, 2014 11:05:53 GMT Nathan said:

As for the drive.....AMAZING.
The Original B series was at Stage 2 spec, so as Pig lumps go it was nippy......But with this in it feels like a rocket :-)

That's brilliant news for me. I'm putting an MX5 lump in my Volvo Amazon and I've been advised on more than one occasion that it will be no different/slower!
But I've driven a standard MGB and it shifts faster than the Amazon...a lot faster. So this is really good to hear

Awesome build!

[Mike]

love this project! considered this swap for my B, still thinking about it for a midget looks awesome great work

[Nathan]

Jul 7, 2014 20:45:39 GMT 7M.elody said:

Jul 7, 2014 11:05:53 GMT Nathan said:

As for the drive.....AMAZING.
The Original B series was at Stage 2 spec, so as Pig lumps go it was nippy......But with this in it feels like a rocket :-)

That's brilliant news for me. I'm putting an MX5 lump in my Volvo Amazon and I've been advised on more than one occasion that it will be no different/slower!
But I've driven a standard MGB and it shifts faster than the Amazon...a lot faster. So this is really good to hear

Awesome build!

I am sure you will be happy with the choice, it's never going to tear the tarmac up but it does make a big difference.

Its funny you say that Mike, My Midget is sitting in the queue to be put back on the road. My thoughts have turned to Zetec or K series for that, just to add another engine type to my transplant bow.