3.5 v8 dies after 10 mins

Hicap phill · Apr 29, 2019

Have you changed the fuel return pipe or made any changes to it?

Muddy goose · Apr 30, 2019

Hicap phill said:
Have you changed the fuel return pipe or made any changes to it?

Hi
No no changes why what’s your thoughts?

Hicap phill · Apr 30, 2019

There is a restrictor in the return. If this was removed 2 carb does not always have enough fuel.

Muddy goose · Apr 30, 2019

Hicap phill said:
There is a restrictor in the return. If this was removed 2 carb does not always have enough fuel.

Hi Thanks for that. No I haven’t removed anything however it run like crap before I rebuilt it so I will check on this to see if that dies the trick
Thank you

Muddy goose · May 1, 2019

Well I’ve put the feed in the middle of the carbs now so they both get a constant supply. Pump is down by fuel tank, Ive removed all filters and cleaned out and rebuilt the carbs again to make sure the dash pots are smooth operation. Removed the large fuel pipes and restricted the pipe size to the return to tank pipe work.
She starts on the button and runs beautiful very smooth and quiet for a rover v8 but still she’s starts to run out of fuel when you put your foot down switch off sit for a min and then up and going again for 5 mins. Losing the will to live on this one. The only thing I didn’t do to the carbs when I replaced them was change the needles, however I can’t think why this would cause an issue? Any more thoughts on this as I don’t have a spare £1000 for a new manifold and Weber 4 barrel

marjon · May 1, 2019

Wow such a clean engine

Can I ask, you have feed too both carbs and return from both carbs yes?

Ok if that’s the case try this no promises mind. Feed to 1 carb then the return goes to other carb fill and then the return from there back to tank effectively 1 return.
To test this thought just block 1 of the returns

don’t need to change any plumbing just yet.

Or is that the way it was plumbed originally, seems strange it all ran good.
J

Muddy goose · May 1, 2019

marjon said:
Wow such a clean engine

Can I ask, you have feed too both carbs and return from both carbs yes?

Ok if that’s the case try this no promises mind. Feed to 1 carb then the return goes to other carb fill and then the return from there back to tank effectively 1 return.
To test this thought just block 1 of the returns don’t need to change any plumbing just yet.

Or is that the way it was plumbed originally, seems strange it all ran good.
J

Hi J
Yes clean mate it’s only done its 500 mile run in. Yes it was plumbed in the usual way and the second carb was empty when it was dying so I tried clamping off the return that made no difference so I then plumber to both to try and stop that issue and yes both the returns go back to tank. I spoke to SU and they couldn’t think of anything other than vapour lock so I took off petrol cap and still it dies not sure what to try next

marjon · May 1, 2019

In one of your earlier pics you mentioned a regulator do you have that in the system?

What psi/ flow is your pump.

J

discool · May 1, 2019

What makes U think it’s fuel, early posts just suggest it’s a maybe, could be or seems.
So are u sure your issue is fuel related, u state u wait 5 minutes and “ then up and going again” so what is the significance of that delay, what’s happening during that period? I’m wondering as so far you done done everything, there’s nothing left, or is there.

Do you have electronic ignition fitted as that can play up and cut the engine, but after a short wait the engine will start like nothing has happened.

Shippers · May 1, 2019

When you say starts on the button and runs smoothly how long after you've let it stand?...mine in my 101 takes a bit of cranking after it's been stood for a while trying to track it down...my point is if it's fuel starvation in yours I wouldn't expect it to start on the button until pump has filled carbs and then run rough till it's fully fueled up...have you checked coil? ballast resister fitted could something in the ignition be breaking down when hot?

Muddy goose · May 1, 2019

marjon said:
In one of your earlier pics you mentioned a regulator do you have that in the system?

What psi/ flow is your pump.

J

Hi it’s a 90-105 LPH and yes still have the regulator in place and set to 4 so quite high. Now I’ve put a t in the fuel line so both carbs get fed at once both bowls are now full even when it’s having an issue.

Muddy goose · May 1, 2019

Shippers said:
When you say starts on the button and runs smoothly how long after you've let it stand?...mine in my 101 takes a bit of cranking after it's been stood for a while trying to track it down...my point is if it's fuel starvation in yours I wouldn't expect it to start on the button until pump has filled carbs and then run rough till it's fully fueled up...have you checked coil? ballast resister fitted could something in the ignition be breaking down when hot?

Hi Yes I’m with you, however I’ve been down the electrics route before the fuel side of things and a complete electronic dizzy with coil (and coil recited away from above the manifold to the front of the engine bay) etc as a kit was fitted and I must say runs even sweeter now and so quiet for a rover v8. Then onto the fuel and with the fuel pump now sited by the tank even more improvements have been made to the system and still having a dying issue

marjon · May 1, 2019

Ok full is good and sorts the fuel problem.
I was actually going to say remove regulator as you have spill lines, but if full now.
I guess you now need to move on to the 2^^^ @discool & @Shippers.

I know you mentioned fitting electronic dizzy and what not but no details.

J

Muddy goose · May 1, 2019

marjon said:
Ok full is good and sorts the fuel problem.
I was actually going to say remove regulator as you have spill lines, but if full now.
I guess you now need to move on to the 2^^^ @discool & @Shippers.

I know you mentioned fitting electronic dizzy and what not but no details.

J

O

marjon · May 1, 2019

Yep posted same time

Muddy goose · May 1, 2019

Hi Here you go I’ve used powerspark products before on a rover v8 and had no problems and of course I had this issue running the standard dizzy and coil set up ‍

I’m baffled

Muddy goose · May 1, 2019

It seems strange that before I put the t piece in the fuel line the offside fuel bowl would empty does that indicate that I have a problem with the SU’s it was me that overhauled them. I did call Southern carbs and they tell me they either work or don’t

Shippers · May 1, 2019

Muddy goose said:
View attachment 176851
Hi Here you go I’ve used powerspark products before on a rover v8 and had no problems and of course I had this issue running the standard dizzy and coil set up ‍ I’m baffled

That's the same one I fitted did you remove ballast resistor? and earth the new distributor...you probably did but asked just in case...

Muddy goose · May 1, 2019

discool said:
What makes U think it’s fuel, early posts just suggest it’s a maybe, could be or seems.
So are u sure your issue is fuel related, u state u wait 5 minutes and “ then up and going again” so what is the significance of that delay, what’s happening during that period? I’m wondering as so far you done done everything, there’s nothing left, or is there.

Do you have electronic ignition fitted as that can play up and cut the engine, but after a short wait the engine will start like nothing has happened.

Hi
I was just trying to do everything I could think of but probably improved things as well from all the help I’ve had on here. However I did wonder about the electrics hence replacing it all

Shippers · May 1, 2019

Can you put a piece of clear pipe in return to tank that's what I did and it shows air in it when it has stood for a while...weeks not days...this would show fuel starvation...

3.5 v8 dies after 10 mins

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