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vitesse 6 running on 5


russ
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Hi, I have a 1965 vitesse 6 that is running on 5 cylinders. I have changed plugs, leads, distributor cap and rotor arm. I have done a wet and dry compression test and all is good. The next thing to do is remove the head unless anyone has got any ideas? Would the piston come out top or bottom without removing the engine? Yours hopefully Russ

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If the comp test was good why would want to strip the pistons or head off???

I would look at inlet manifold air leaks, worn distirbutor spindle causing cam, wobble  statr with the easy 

Check the rockers are all ok , no jumped push rods or tight tappet clearances and never forget the   ...... spark plug

Pete

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Never trust new parts to be good, identify bad cylinder as suggested by Poppyman. Then rotate the distributor by at least one cylinders worth of timing move the plug leads to correct the firing order and see if the fault moves, if it does fault is electrical if not mechanical.

Also move plug in duff cylinder and swop its lead object is to move all ignition components.

Regards

Paul

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is this a 'complete'  non fire on no 5  or a  half hearted mis

a ring wont cause a full misfire , and if compressions are all good then the internals should be considered to be basically functional

are the rockers all fully depressing.......like a cam lobe has done a runner 

was the compression test all plugs out and throttles open ???

 

Pete

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"When you have eliminated the impossible whatever remains, however improbable, must be the truth"

Compression test OK (details would be good)

New ignition parts

So what's left?    Fuelling.     Have you looked into the inlet manifold?   Mouse's nest?? Some other reason for the wrong mixture getting to the cylinder?    Which one is it?

John

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One of my former colleagues came along to the Cambridge area meeting in July with a TR3 that was running on three cylinders. Compression all good, sparks apparently good, new points, condenser, leads, disi cap. He'd already checked that swapping leads and plugs left the problem on the same cylinder.

On closer inspection, he'd set the points gap so small that the one ever-so-slightly flat lobe on the distributor shaft was not opening them. Re-set the points and voila! a very happy engine running on all four.

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Same reason as suggesting  dizzy spindle  wear earlier

Delco are more prone to the centre spindle and bush wearing due to lack of lubrication, lucas are less prone but all need a 

Squirt of engine oil down below the base plate to lubricate the top bush, some have a felt pad down in the base , its often ignored in any

Servicing and youmcan end up with a wobbly cam and ever changing point gaps as it rotates

So remove cap and give the rotor spindle a good shove , anym side movement is unacceptable.

Some electronic units can accomodate some wear,  but points cant 

Pete

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Checked the distributor today and there isn't any wear, all plugs firing. Number 6 is oily though but all the valves are seating correctly. Compression test showed slightly higher in number 6. Also did an air leak test on 6 and could hear some leak through the dipstick. What else can I do? Russ

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You'll always get a bit of leakage past the rings.  If the compression is the same as the others, loss of compression is not the reason for not firing (anything over about 50 psi will fire) and the oily looking plug is more likely the result of not firing than the cause.

Worth whipping the rocker box off and checking that the valves are moving about the same amount on no 6 as the others.  Very little lift on the exhaust valve (due to worn cam lobe) won't prevent a decent compression reading but will prevent that cylinder breathing.

Other than that, does no.6 plug get wet with fuel?  Have you tried swapping plugs between cylinders or at least a different plug in 6?

Nick

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Russ,

OK, timing is correct and spark is there. And No.6 has better compression than the rest, the plug should be dripping in fuel.  Why is it not? An air leak on the manifold around No.6 would do this, sucking in air instead of fuel. I would look at the manifold gasket again. How did you check it last time? You can't see the underside?

Doug

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