Paul (Notts)
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| posted on 26/6/07 at 05:26 PM |
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Help - cant start engine for first time v8
Having problems starting the engine for the first time…
I have checked that I get a spark at the plugs when cranking the engine over.
I think – will double check later – that all the plugs are connected correctly to the dizzy.
Good news is when cranked for 2-3 seconds the oil pressure light goes out.
When I press the accelerator peddle down I get a LARGE blue flame heading up towards the bedroom above the garage from the carb. ( no filter fitted
yet )
Battery is slightly flat so now on charge.
What if any is the significance of the large flame from the carb.
If not a flat battery what is next to check.
Paul
This is the part of the build that I know least about.
[Edited on 26/6/07 by Paul (Notts)]
[Edited on 26/6/07 by Paul (Notts)]
For some strange reason the blue flame coming from the carb was very pleasing.
[Edited on 26/6/07 by Paul (Notts)]
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scottc
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| posted on 26/6/07 at 05:35 PM |
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Sounds like you're sparking while the inlet valve is still open. try retarding the ignition a bit???
Plugs could be in the wrong order of course. 
[Edited on 26/6/07 by scottc]
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David Jenkins
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| posted on 26/6/07 at 05:36 PM |
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That does sound like plug leads crossed - or valve timing way out - you're getting a spark when an inlet valve is open, methinks! 
Purely IMHO, of course, as I know three-fifths of sod-all about V8s! 
(Damn - Scott beat me by 10 seconds!)
[Edited on 26/6/07 by David Jenkins]
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Paradoxia0
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| posted on 26/6/07 at 05:39 PM |
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I got some nice big blue falmes from mine when I fitted the dizzy on the wrong cycle... (Still got no hairs on one leg!)
Have you checked that you haven't got it fitted 180º out?
Mark
There is no replacement for displacement...
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Paul (Notts)
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| posted on 26/6/07 at 05:44 PM |
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What do you mean by 180deg out. -how do I check
as I said this is one area I am a bit unsure of ..
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scottc
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| posted on 26/6/07 at 05:51 PM |
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Have you got a timing light?
If not, turn the engine over, till its at TDC. then check which terminal of the dizzy cap, the rotor is pointing too. This should be cylinder 1
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Paradoxia0
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| posted on 26/6/07 at 05:56 PM |
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OK. I am not good at this either, so here is my basic understanding of a 4 stroke engine...
The engine works on 2 rotations of the engine for 1 "bang", each rotation having 2 parts (pistopn down and up). THis makes the 4
strokes.
Stroke 1: fuel and air is sucked into the cylender as the the piston goes down.
Stroke 2: the piston comes up causing compression and as it the top of the storke the spark is added causing an explosion which causes
Stroke 3: the piston down with the explosive gasses created. once the piston hits the bottom of this storke
Stroke 4: pushes all off the gasses out of the exhuast valve and when it gets to the top you go back to 1.
This means that if you add the spark at the top of the exhaust cycle (rather than the compression cycle) you will have forced the fuel into the
exhaust manifold and you will cause an explosion in the manifold resluting in a plume of flames from the exhaust. If you had done this you would have
the rotor arm in the dizzy pointing the opposite way to which it should, i.e. 180º out.
Does that make sense?
Did I explain that right anyone?
Mark
[Edited on 26/6/07 by Paradoxia0]
There is no replacement for displacement...
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jollygreengiant
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| posted on 26/6/07 at 06:22 PM |
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Yep spot on.
Easiest way to check that you are timed up on No1 cylinder is to remove the plug from that cylinder, insert a finger tight into hole and turn engine
by hand with spanner or ratchet until you can feel the compression on your digit. Then remove digit and turn crank until timing marks line up and then
check plug leads fitted in correct order. Refit plug refit lead to plug and start engine.
Oh firing order is usually marked on the inlet manifold and the cylinder no's are usually marked on the adjacent inlet tract. (when using std
manifolds)
Edit - motor techs are usually taught the simple 4 stoke cycle, - Suck, Squeeze, Bang, Blow.
[Edited on 26/6/07 by jollygreengiant]
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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darrens
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| posted on 26/6/07 at 06:28 PM |
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dito the dizzy being 180 deg out, for some reason I have a knack of doing this everytime I refit.
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Paul (Notts)
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| posted on 26/6/07 at 06:28 PM |
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looks like I am 180 deg out s will set up again and try to start in wed.
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mark chandler
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| posted on 26/6/07 at 06:28 PM |
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Firing order is 1,8,4,3,6,5,7,2.
Blue flame is a good sign, petrol and sparks.
Sounds like it is 180 degree's out, have you had the distributor out, bit of a stange statement, to explain the distributor turns once for every
two turns of the crank so although the rotor arm may point at the lead the engine could be on a compression or induction stroke.
Regards Mark
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Dave J
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| posted on 26/6/07 at 07:56 PM |
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Amazing isn't it, I too had my timing 180 degs out on first start. Huge pop and flame out the carb gave me a fright.
Great when it comes right though.
Cheers
Dave
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