3.5 v8 dies after 10 mins

HT components can be perfectly fine when cool, then start to break down once hot
I think i read the points had been replaced with electronic ignition, so if you're sure the carbs are getting good amounts of fuel, then I'd be looking at the coil, including the 12v side of the wiring

It could be the amplifier on the side of the dizzy at fault.

wireman said:

It could be the amplifier on the side of the dizzy at fault.

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New electronic dizzy

J

Just to get my head round this and re-cap...does it cut out dead or stutter and falter when it stalls...have you checked all the wiring not just connections...I had ballast resister on mine that was fitted by coil went faulty but not needed with elec dizzy but have you checked there's not one in your wiring you havn't seen...
Personally I think carbs are not your problem they are simple and you can adjust while the engine runs and if even unbalanced twin carbs will still allow engine to run a bit rough...but electrical will shut down...if it starts up without cranking straight away when cold then I don't think it's carb related...

Also as an after thought not sure if you know each carb supply fuel to 2 cylinders on each bank...but you probably know that...

Hicap phill said:

Just re cap.
Have you got oil in the dampers?
Have you balanced the carbs?

Your doing well.

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Hi I will check again on the oil in the dampers and yes had them balanced not sure how well

marjon said:

New electronic dizzy

J

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Yes, I read that, but I had a failing amplifier on a V8 electronic dizzy just thought it would be worth checking (don't guess - test). Just because its new doesn't mean its not faulty

Balancing is very easy to do yourself without buying specialist tools.
It won't cause an engine to stall though, just run really rough

marjon said:

That is some nice wrapping

Sounds now like an electrical breakdown.
I think your carbs are good, we’ll enough to run and shouldn’t just cut out and restart if they were the problem.(as we have been over the fuel issue) SUs are pretty bulletproof if clean and setup even close.

Still can’t get away from “new coil and dis it’s got to be ok” needs a test sorry and wiring to.
Got anything to swap it with?

J

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Cheers dude wrapping took about four attempts to get it right and wrapped in the right direction.
I have as you know just replaced the whole dizzy side with electronic inc coil etc no ballast anymore, this is my third replacement of dizzy set up. I re wired the whole loom (no I’m no expert so might need checking) so I wonder what it could be on electrical as all new wires and a thicker core in most places not sure what parts to recheck? Remember when I first finished the Landy I ran in the fresh engine for 500 miles with no issues when I got to 700 miles it did the same thing sat on side of road for 5 mins then it would start up again but then break down on shorter and shorter runs on the way back home. It now has become a very short period I will time it today.

kermit_rr said:

SU carbs are brilliant! Wouldn't have anything else given a choice.

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My next port of call I was looking at a new inlet manifold and I self learning FiTech 400hp electronic carb?

marjon said:

I think you maybe need to started checking everything again.
As above start with a look at the plugs color, are they correct/good?
Ruff running when cold and hot, fueling/timing/vacuum hoses?
Not being able to stamp on the loud pedal, again fueling/timing.
Vacuum advance? New dizzy and hose looks good in your pics, and same problem with old dizzy.
Coil? Believe you said new so unlikely.

You need to check all the electrical connections are good/clean.

Most off that is really thinking out loud let’s see the plugs

J

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The plugs are black soot after cleaning them all but it only sat on drive and 2000rpm so not a run hot enough to clean them.

kermit_rr said:

HT components can be perfectly fine when cool, then start to break down once hot
I think i read the points had been replaced with electronic ignition, so if you're sure the carbs are getting good amounts of fuel, then I'd be looking at the coil, including the 12v side of the wiring

Click to expand...

All new ht side and electronic dizzy and matching coil. When she first runs she runs really sweet

wireman said:

It could be the amplifier on the side of the dizzy at fault.

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Well this is all new and the thirds dizzy and always changed related parts ie coil cap and rotor

Shippers said:

Just to get my head round this and re-cap...does it cut out dead or stutter and falter when it stalls...have you checked all the wiring not just connections...I had ballast resister on mine that was fitted by coil went faulty but not needed with elec dizzy but have you checked there's not one in your wiring you havn't seen...
Personally I think carbs are not your problem they are simple and you can adjust while the engine runs and if even unbalanced twin carbs will still allow engine to run a bit rough...but electrical will shut down...if it starts up without cranking straight away when cold then I don't think it's carb related...

Click to expand...

Yes that’s the issue when it’s running it’s lovely I will check again today but I think it’s almost like fuel runs out kind of stop but I will recheck just to make sure but I’m sure it’s getting a shorter cut off if that makes sense

Do you have a relay for ignition feed ?

J

Shippers said:

Also as an after thought not sure if you know each carb supply fuel to 2 cylinders on each bank...but you probably know that...

Click to expand...

No I didn’t

marjon said:

Do you have a relay for ignition feed ?

J

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No I didn’t fit any relays as bigger wiring so didn’t think it needed it. Just to recap on wiring.
Battery then cut off switch. Up to feed fuse board. Each component has a fuse. To start engine arming switch to on and then push button start.
I will take photos today

I thought a relay was to take smaller wires upto the dash. How will that effect the Landy running? Being a Sparks by trade has not helped me with 12 volt lol

Can this problem be replicated every time while you are just sat in the garage?
You say it stops like it’s been turned off electrical?
When you restart do you just push your start button again or turn things off/on first?
Any immobiliser (I don’t think so)?
Any wires chaffed?
I can’t think of any sensor on that engine that would stop it running. (Not sure)

If you can make it do it I would be tempted to start running new test wires bypassing stuff, perhaps even with test bulbs, then sit and watch.
Do you have a timing light? Or a clamp lead to check ht.

It just sounds like a teething issue from the rebuild after your first 500 mile shakedown.

Good luck you’ll find it and probably kick yourself

J