Essex V6 refuses to start!

Essex V6 refuses to start!

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Discussion

Erich Stahler

Original Poster:

2,878 posts

272 months

Saturday 5th July 2014
quotequote all
Any help much appreciated, its actually an ex Scimitar V6 which I'm trying to fire up for the first time in my 3000m.

Engine is not rebuilt but turns over on starter freely.

Fitted with original 38mm DGAS from TVR engine, distributor in original position on engine so assuming timing is OK.

Mechanical fuel pump drawing fuel from a petrol can and is getting to carb and plugs.

On ignition side of things getting reasonable spark to plugs, although slightly pink not blue. Running new balast coil and have reistor supplying 7 to 8 volts to coil +ve.

Engine has nearly fired a few times and even backfired once. Cranking speed is good as using high torque starter.


madsvlund

345 posts

134 months

Saturday 5th July 2014
quotequote all
Hi Erich

If a engine don't start is one or more of the following 3 things worng. Fuel, ignition or compression.

To check fuel can you take an old cloth and wet it with fuel, and hold it over the carburettor, if this makes the engine ignite do you have a fueling problem.

If spark plugs are wet do you have an ignition problem, either not sparking at all or sparking at the wrong time. To check timing do you need a strobe light, check that cyl 1 is igniting aprox 10deg BTDC (before top dead center)

Compression can be checked with a compression tester or compressed air if you don't haave a compression tester.

In your case, will I guess that your fuling is wrong, try some starter spray or a cloth with gasoline. If that don't do the trick, then check and recheck that the spark sequence is right, and by moving the crank to TDC, lift the lid of the distributor and check that the rotor is at cylinder 1 or 4. (btw cyl 1 is front right / uk driver side)

bluezeeland

1,965 posts

161 months

Saturday 5th July 2014
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when the crank is just before the mark, the rotor in the dizzy points to n° 1 cylinder lead

Sort of guessing the engine makes a sort of 'rumbling' noise on cranking, indicating it is 180° out ....

btw the the rotor turns clockwise....

IIRC 7/8 volts is rather low, should be 9 ?

RCK974X

2,521 posts

151 months

Sunday 6th July 2014
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I've done that on a Triumph straight six, and wasted HOURS trying to figure out why it wouldn't go when it had sparks and fuel, only to realise (after flattening the battery) I'd put the dizzy in 180 degrees out.....

It didn't even cough, which was a surprise to me.

Following day with battery recharged and dizzy reset, it fired up on the first turn !!

It's easier to make this mistake than you might think - if you've had the dizzy apart, it's also easy to put the centre part (which holds the rotor arm) in 180 degrees out as well, and dizzy still looks correct.


Erich Stahler

Original Poster:

2,878 posts

272 months

Sunday 6th July 2014
quotequote all
Thanks guys for you thoughts, sounds like I need to check the the static timing next really, as I hadn't had the distributor out of the engine and it had supposedly been running I ignored it. Definitely first port of call, will let you know how I get on.

kev b

2,717 posts

168 months

Sunday 6th July 2014
quotequote all
Is the coil getting 12 volts when the starter is cranking ie not being fed through the resistor?

Will it fire if you squirt carb cleaner into the carb, to check fuel is reaching the cylinders.

Some carbs have a cut off solenoid on the idle circuit to stop running on, if it is not energised then the mixture will not enter the intakes. If one is fitted you should hear it click when switching on/off.

Timing would need to be way out to stop it firing at all.

Is your coil body earthed properly?

Erich Stahler

Original Poster:

2,878 posts

272 months

Sunday 6th July 2014
quotequote all


[Quote]Is your coil body earthed properly?
[/quote]

I checked negative terminal of the coil is earthed as someone commented a spark that's orange, rather than blue, could be a symptom of a bad earth.

kev b

2,717 posts

168 months

Sunday 6th July 2014
quotequote all
The negative terminal of the coil is not supposed to be earthed, it needs to go to the distributor.

When I say "coil earth" I mean the body of the coil and its bracket should be earthed to the body/chassis of the car.

If you have earthed the coil neg the engine will never spark properly.

Cerberus90

1,553 posts

215 months

Sunday 6th July 2014
quotequote all
kev b said:
When I say "coil earth" I mean the body of the coil and its bracket should be earthed to the body/chassis of the car.
Why is that?

Just painted the coil bracket for my mini so there's no bare metal there and it still works.
The coil on the Taimar also has a coating on it so there's no path to earth through the body of the coil.

We also ran the enigne with the coil sitting on the fibreglass wing, so I'm pretty sure there's no need for the coil body to be earthed. What circuit would having the body earthed complete?

Adrian@

4,344 posts

284 months

Sunday 6th July 2014
quotequote all
Don't work Tom/Brian it does not need to have the body earthed.
Adrian@

Erich Stahler

Original Poster:

2,878 posts

272 months

Sunday 6th July 2014
quotequote all
kev b said:
The negative terminal of the coil is not supposed to be earthed, it needs to go to the distributor.

When I say "coil earth" I mean the body of the coil and its bracket should be earthed to the body/chassis of the car.

If you have earthed the coil neg the engine will never spark properly.
The coil I attached to GRP as per the original mounting so definitely not earthed to coil body?

Erich Stahler

Original Poster:

2,878 posts

272 months

Sunday 6th July 2014
quotequote all
Adrian@ said:
Don't work Tom/Brian it does not need to have the body earthed.
Adrian@
Ah, OK.

Adrian@

4,344 posts

284 months

Sunday 6th July 2014
quotequote all
I see no reason not to...attach the coil direct to the battery (with a switch OR even just a twisted together joint, so you can turn the car off!!) to get everything out of the system other than, coil +/- fuel and timing, it will do no harm to the coil just to get the car running.
Adrian@

Erich Stahler

Original Poster:

2,878 posts

272 months

Sunday 6th July 2014
quotequote all
Adrian@ said:
I see no reason not to...attach the coil direct to the battery (with a switch OR even just a twisted together joint, so you can turn the car off!!) to get everything out of the system other than, coil +/- fuel and timing, it will do no harm to the coil just to get the car running.
Adrian@
Definitely worth a shot!

kev b

2,717 posts

168 months

Sunday 6th July 2014
quotequote all
If I can correct myself over the coil body earth, I mis-remembered this from decades ago on a Scimitar.

Earthing the coil bracket was only actually needed to make a radio suppressor work properly, sorry for misleading you.

whitewolf

751 posts

168 months

Sunday 6th July 2014
quotequote all
Ht leads are in the correct order aren't they?


Erich Stahler

Original Poster:

2,878 posts

272 months

Monday 7th July 2014
quotequote all
Right definitely fuel getting into the cylinder head, plugs are wet when pulled.
With the piston of cylinder 1 is at the top of its stroke and the mark on the crank pulley almost aligned to notch on timing cover I am taking where the rotor arm is pointing to as HT lead 1 and have arranged all the other leads accordingly, does this sound correct?

Slow M

2,745 posts

208 months

Tuesday 8th July 2014
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Are you sure it's on compression stroke? If you're not, pull a valve cover, and look at the valve actuation. If the exhaust valve is moving, your distributor is out 180 degrees. You mentioned you would check this, and get back, to the hive mind, with the results. Have you had an opportunity to look at it?

Best,
B.

Erich Stahler

Original Poster:

2,878 posts

272 months

Tuesday 8th July 2014
quotequote all
Slow M said:
Are you sure it's on compression stroke? If you're not, pull a valve cover, and look at the valve actuation. If the exhaust valve is moving, your distributor is out 180 degrees. You mentioned you would check this, and get back, to the hive mind, with the results. Have you had an opportunity to look at it?

Best,
B.
I haven't checked the valve actuation as yet, so No. 1 piston at the top of its stroke does not necessarily indicate the compression stroke?

Adrian@

4,344 posts

284 months

Tuesday 8th July 2014
quotequote all
Erich Stahler said:
I haven't checked the valve actuation as yet, so No. 1 piston at the top of its stroke does not necessarily indicate the compression stroke?
No, it could be the exhaust stroke ..but if you are 180 degrees out then you should know it!
Adrian@