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SE5 stalling at junctions

Posted: Sun Jul 14, 2019 1:17 pm
by housemartin
Good afternoon guys.
I was hoping you might be able to assist me in solving a stalling problem with my rebuilt engine.
The car starts quickly but idles roughly and feels strong from 2000 rpm upwards, but stalls when I get to a junction or press the clutch down when above 200 rpm.

I have set the timing to 10 degrees with a strobe, fitted a new coil, rotor, cap, points and condenser.
Engine temp seems steady 100 degrees and no water loss.

Fitting a colourtune plug to engine I have set the idle to a nice blue.
However the colourtune spark seems to miss a spark every so often.

Could this be an air leak, or fueling issue?
Is there a fuel circuit stops the car stalling on the overrun?

There car has been off the road for 12 months.
Cheers
Dan

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 2:48 pm
by rebel alliance
New head gaskets fitted ?

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 4:22 pm
by scimjim
Confirm that you’re losing spark by putting the strobe onto each lead in turn. I had a dodgy distributor cap (no visible faults at all) that was causing intermittent spark on several cylinders.

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 5:19 pm
by housemartin
rebel alliance wrote:
Sun Jul 14, 2019 2:48 pm
New head gaskets fitted ?
Good shout.

I purchased new gaskets and reassembled to find I had oil leaking through the new head gasket, so had the heads skimmed.
However I did reuse the same new head gaskets as they had not seen any action.
I will do a compression test, should they be about 120 psi?
I do hope the block is not warped!

Cheers
Dan

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 5:34 pm
by rebel alliance
After you had the heads skimmed how was the fit of the inlet manifold before you tighened up the bolts...Also this may be a problem some head gaskets leave a bit sticking out which needs trimming off or the inlet wont seal
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SE5 stalling at junctions

Posted: Sun Jul 14, 2019 6:03 pm
by housemartin
Yes I saw this and trimmed the head gaskets.
Pressure test give 110psi on all cylinders but the cheap compression gauge shows it flicking up to 140 before dropping down.
Could this be the leaky gasket?
Thanks for your assistance
Dan

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 6:48 pm
by rebel alliance
150 psi is normal on a good engine..compression test won't show up any inlet manifold leak...i had poor running at idle and low speed on my 5a. After it started leaking water into the sump i found the inlet manifold was not seated correctly...this may not be related to your problem but if you skim the heads you alter the fit of the inlet manifold

SE5 stalling at junctions

Posted: Sun Jul 14, 2019 9:59 pm
by Rev Light
I had a stalling at junctions issue a couple of years ago. Turns out I had dislodged the auto choke housing on the carb, where the water pipes come into the carb. It meant that the choke was effectively on all the time.

Just a thought

Steve

SE5 stalling at junctions

Posted: Mon Jul 15, 2019 10:01 pm
by housemartin
Guys thanks for the advice
I am off for a week holiday, but will borrow a vacuum gauge, alternative DGAS carb and cap/leads from a know running engine and let you know the result.
Cheers
Dan

SE5 stalling at junctions

Posted: Tue Jul 30, 2019 10:32 pm
by housemartin
Update...
Back from holiday to a dripping from the bedroom ceiling, it seems the galvanized header tank fitted in 1950s, even older than the scimitar, had corroded through. Now a nice plastic one, which I suspect will not last as long has replaced it so I can get back to the task of my se5 engine.

I connected a vacuum gauge to the servo inlet manifold take off and watched the needle settle at about 18. All of a sudden it flickered then dropped to zero as the engine stopped. It did this a couple of times. This does point to a cylinder gasket failure.
The fluid level in the header tank has fallen but not my much, could this just be air in the heater matrix being forced out as the engine runs?

Before stripping down the heads I installed a "borrowed' 38dgas from another car. This started and ran at idle with the vacuum at 18 and it does continued to run but opening the throttle cause a large backfire at the carb, but this could be the incorrect jetting/mixture.
Interestingly it did not stall or die.

Further testing was cancelled as the rain arrived.
I will let the engine get up to temp on the borrowed carb to see if it dies off and update

Cheers
Dan

SE5 stalling at junctions

Posted: Tue Jul 30, 2019 10:50 pm
by scimjim
housemartin wrote:
Tue Jul 30, 2019 10:32 pm
I connected a vacuum gauge to the servo inlet manifold take off and watched the needle settle at about 18. All of a sudden it flickered then dropped to zero as the engine stopped. It did this a couple of times. This does point to a cylinder gasket failure.
that depends on whether it’s cause or effect? You’ll quickly lose vacuum if the engine stops :D

The carb swap seems to indicate that’s at fault?

SE5 stalling at junctions

Posted: Sun Aug 18, 2019 3:22 pm
by housemartin
Been for a drive with the borrowed 38dgas and no stalling at junctions.
I need to buy a replacement. Has anyone got a know good carb in their stock they would be willing to sell?
Seems a new one is going to set me back over £200.
Cheers
Dan

SE5 stalling at junctions

Posted: Sun Aug 18, 2019 5:05 pm
by peter freeman
Try a refurbishment kit first - cheaper and it "may" cure your problem.

SE5 stalling at junctions

Posted: Fri Aug 30, 2019 5:36 pm
by housemartin
peter freeman wrote:
Sun Aug 18, 2019 5:05 pm
Try a refurbishment kit first - cheaper and it "may" cure your problem.
Peter,
Good Shout.
I have replaced all the gaskets, washers and fuel valve etc and it has cured the stalling at junctions.

The differences I could see was my carb was missing a washer under the power value in the bowl base, the pipe from the anti-stall was orientated differently to those picture on the the net and possible the reason my float was set too high.

There seems to be a hesitation from idle to mid-range when it just flys.
I have checked the timing and it was about 14 degrees so I have moved it back to about 12 degrees.
So I will see if that helps on my next run out.

Cheers
Dan

SE5 stalling at junctions

Posted: Fri Aug 30, 2019 7:59 pm
by Old and Slow
Here's a thought: if it isn't a timing issue then the changeover from the idle/slow running jet to the main jet is possibly the problem. If a quick pump of the throttle when accelerating overcomes the problem then it might be a lean spot. If pumping doesn't make a difference then it might be too rich at the changeover.
Hope this helps.