3.5 v8 dies after 10 mins

Well yes it’s all been said a thousand times and I’ve read a thousand threads but I’ve come to a stop.
In my Landrover I have a 3.5 p6 V8 completely rebuilt with SU’s on top all quite standard and facet fuel pump mounted next to the clutch reservoir on the bulkhead, however I do have tubular manifolds (I think I need to wrap them because of the heat).
Whilst running in its first 500 miles all seemed fine and then after a while it broke down a couple of times pull over sit for a while restart then back on route. Gradually it’s got worse to the point where now 5 mins or so, when it starts it’s runs lovely and slowly but surely it runs out of power and if I rev then engine it dies.
The thing that’s throwing me is everything is new and or refurbished to an as new state the things I’ve tried.
Blown out fuel lines to check for blocks and cleaned out tank again just because.
Replaced new facet fuel pump just because.
Replaced alternator just because.
Wrapped the fuel lines with heat wrap.
Replaced the dizzy with an electronic one with resin filled coil, new leads 10mm just because and after timing runs even sweeter. Went for a run within mins had to turn round and still died sat still for a min restarted parked and then died. It’s like a fuel starvation except the fuel is getting through with everything being new as I said I’m not sure what to try next except a new inlet manifold with a Webber on top as it was myself that rebuilt the su’s although when I speak to SU they say that they either work or don’t .......please any guide lines from you rover v8 masters

Is your return line blocked from the SU's to the tank. Are the pots filled okay with oil as the pins could be sticking.

Does sound like starvation of some sort, long shot maybe filler cap/tank vent?

Sounds like fuel is not being replenished quickly enough in float chambers, have you left a restriction in the fuel pipes between the carbs ?

saxavordian said:

Is your return line blocked from the SU's to the tank. Are the pots filled okay with oil as the pins could be sticking.

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Hi Thanks
Yes checked fuel comes back and I’ve checked the pots but I will recheck both today

Kev12 said:

Does sound like starvation of some sort, long shot maybe filler cap/tank vent?

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Hi thanks
Filler cap refurbed so I will check by leaving it off on a run

freelance said:

Sounds like fuel is not being replenished quickly enough in float chambers, have you left a restriction in the fuel pipes between the carbs ?

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Hi Thanks
Fuel seems to be coming out fine and I replaced the fuel line just because. I will run again until stopped and then switch off pump and check the floats.

Hi Guys
I’ve just taken off the two float chamber lids and the near side carb has fuel in the chamber, however the offside is empty is that correct I don’t think so but what would cause that?

It sounds like you are getting closer to the problem.

Is the little gauze filter clear?
Sticking float/lever/needle valve.

J

marjon said:

It sounds like you are getting closer to the problem.

Is the little gauze filter clear?
Sticking float/lever/needle valve.

J

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Hi Thank you
Yes I will check those items today and see what I find

[GALLERY=] Hi Guys
A big thank you so far a great help from you all including a new found energy to get this sorted
Right I checked the pipe connecting the offside second carb and nothing coming out! Pulled the main fuel line really what I would call a fast dribble that then decreases spits then picks back up to a fast dribble, ignore the two fuel pumps I just plumbed in a replacement to see if it was a faulty new pump. I’m going to remove everything including the pressure gauge blow through and check again, one thing I will add is if I increase the flow pressure on the regulator, however if I turn it down less than 4 which I would guess is a little high it reduces still further.


[/GALLERY]

Hi
Right all the way back now to the original new pump and not a lot coming out well maybe for a 50cc moped. So have I mounted the pump too high on the bulkhead the tank is down under the drivers seat?
Or just because I’m using fairly cheap facet style pumps?

Right new electronic dizzy sorted poor running the fact that it had fuel starvation is crap in the tank I can only assume so now doing some more test runs

Hope you got it now

J

@Muddy goose
Them facet pumps have internal filters. Undo that large nut at the bottom of the filter. Clean out & see the crap your getting from the tank.
Hope this helps

i thought the fuel pump needed to be level or beneath the tank?
mine is fixed to the seat box

Hicap phill said:

@Muddy goose
Them facet pumps have internal filters. Undo that large nut at the bottom of the filter. Clean out & see the crap your getting from the tank.
Hope this helps

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Good shout thank you for that I will take apart and check today

Diamond7 said:

i thought the fuel pump needed to be level or beneath the tank?
mine is fixed to the seat box

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Hi I did wonder however when it works and not blocked with crap it works very well I’m not sure what the manufacturer suggests on the placement of the pump?

https://mossmotors.com/media/instructions/377-420.pdf

not your model but i guess they are similar

suggests no more than 12 inch above tank

Hi
Thank you very much for all the help and great for the pump Manuel info.
Right I’ve put the pump level down by the fuel tank attached to the seat box . A massive difference and I felt that it had been sorted so I did a couple of short runs and all seemed well, then buttoned everything up and off for a proper run got about half a mile and started to die so had to keep stopping then back to driving taking about three stops. Not sure what to look at next I will test again at the carbs and see what’s coming through