Got a crossflow, cam unknown but twin 40s, luminition ignition with dizzy
Electric pump and filter king regulator, no fueling issues, floats are full when the issue arises
starts fine from cold, gets hot, after 10 mins in traffic and stops and won't restart. once cool will restart and run again until hot when it stops again.
Basically the hotter it gets the slower the tickover gets until it stops, sometimes back firing/popping on the exhaust
Wound the idle mix down 1/4 turn and it is obviously better running a little leaner
My first thoughts were coil, that it was breaking down at temperature.
Swapped the coil for a Lucas Gold Sports coil. But appears to have the same issue.
When it's in the no start 'zone' there is a spark at the king lead
However we noticed the Lucas coil was getting hot, however the ignition had been switched on, would the coil get hot if left with ignition on.? I have no coil temps to hand but too hot to hold your hand on.
My thoughts also are should the coil with a lumintion be a resistor one?

Any ideas appreciated

[Edited on 18/6/14 by philfingers]

Hi

I would put my money on you having a 9 volt coil (ballasted) on a 12 volt supply
as I had exactly the same problem, but took a year to sort out

If I am right, you need a 12volt coil, problem solved

Steve

Are you still using Points? If so, I'd lay odds on the gap has closed up a little...

[Edited on 18/6/14 by stevebubs]

thanks guys
I'll look into the coil resistance
No points, it's the optical eye in the dizzy

It may be worth firing off an email to Luminition to see what they say.

Also try fitting a spare spark plug in the end of one of the plug leads, rest it on a headbolt to earth it and see if you have spark at the plugs.

[Edited on 19/6/14 by DW100]

thanks, I hadn't really considered the dizzy cap. It's quite new and so are the Burton Silicon leads
of course it may well spark at the king lead or the even the plugs when resting on the block but may not spark at the plug under compression.
off outside to try some more with it.

This doesn't imediatly sound like ignition to me. Wouldn't expect the "slower tickover" but either just stopping or missfiring. Have you checked the spark when it won't go?

I'd say from the description it could be valve clearences too tight. That would give the symptoms you describe. Worth checking before you start throwing "parts darts" at it.

thanks Adrian, I hadn't thought of clearances. I don't actually know what cam is in the car so I'll drop a DTI on it at the same same time. what you're saying does sound feasible. I need to check the resistance of the two coils I have too. More later!

I had similar problems with mine, it was running without a thermostat and the carbs on 1&2 used to get hot and the fuel evaporate.
I put a thermostat in and got the carbs set up no more problems.
Now i have fitted Kawasaki zx9.

I dropped a DTI on the head and measured the valve lift
11.01mm EX
10.16mm IL
So the cam isn't a 234 or 244. Not checked clearances but they look open enough, will set to 0.56 and 0.61mm IL and EX as per the Kents 234/244 recommendations

Intermotor coil was 2.7ohms
Lucas Gold was 2.9ohms

So both coils suitable for a non ballast system. So next thought is dizzy cap and rotor arm. Once I've done/checked clearances

thanks for the comments so far

I had a similar problem with mine, turned out to be rotor arm.

well did the valve clearances,they were all a little tight Adrian. Had it running for 30mins on the drive, of which the last 15 mins was probably at 120deg, fan running. Didn't miss or stop at all. then the coolant header tank burst, bugger!
few pics attached of what I've been doing today.
Any suggestions for a replacement for the Ford [Escort MkIV I think] coolant tank?
Wiring to the 'eye' in the dizzy needs addressing, insulation tape breaks down at temperature after a few years. This was as sticky as a baby's bottom after a curry!

Pretty sure it's cured. I think a combination of valve clearances slightly tight [Thanks Adrian!]and more importantly due to the layout of the cooling system in the car [kit car] where the pressurised [MkIV Escort] expansion tank is lower than the XR2 MkI header on the crossflow head. An air lock had developed in the top of the head, so it was running hot anyway, compounded with the out of adjustment valves and when hot the valves were slightly open and it wouldn't run. This would explain the popping/ banging through the intake and exhaust just before it got too hot to run
Previously the header tank hadn't burst, it had vented due to boiling in the head.
Had it running for 30mins last night, with the bonnet on and water temp didn't go over 92-94degC and fan was cutting in and out as required. Only stopped the once as the tickover slowed due to under bonnet temperatures, but restarted fine and upper tickover to about 850rpm
Thought I post the findings for everyone's info, thanks again to all who posted,
Phil

If you have a pressure relief cap on the head outlet then that is the problem, you should only have one pressure cap in the system because this
ensures that pressure is released from the system as the system warms up and then on cooling drawn back in at the same point.
Basically if you have an expansion tank then you should have a dumb (blanking) cap on the headb outlet elbow.

For expansion tanks look at. Renault Clio tanks on eBay, cheap as chips and easy to mount.

[Edited on 20/6/14 by britishtrident]

yes I'm aware of plain cap. I've been using the clio/kangoo tanks for a while on both Phoenix and a Previous Striker, I think they look better than the Escort ones

Well done on getting it fixed. Valve cl is not something that sprang to my mind.

Check the timing too.

timing was where it should be about 14deg before. only thing that was odd was every other xflow I've ever had has the 0-4-8-12 [from memory] mark on the timing cover, this had a single mark. Were assuming a fast road cam from the lift figures so 14deg ish should be ok, with an Aldon FXYS 103 dizzy

The marks cast into the timing cover can be out as well as cam/crank timing which is why a vernier gear set is recommended.

15 degree souns a bit high but is about right if there is no vacuuuuum advance on the distributor.
Note i am quoting from memory so dont take this as gospel.