GT6 Engine Return Basics

[JohnD]

Aidan, contact your local TSSC Area Group, for local.advice?

John

[AidanT]

2 hours ago, JohnD said:

Aidan, contact your local TSSC Area Group, for local.advice?

John

I will try John

[chrishawley]

Be not defeated! Puts me in mind of when my Mk3 went back together: It took three days of solid work to determine non-starting/poor running issues and the factors were all simple but not obvious to first inspection.

Hopefully some local hands-on help will be available: But in the meantime might it be possible to provide something of a précis of the history of the engine an its ancillaries? For example; before the current round of work was it a 'known runner'? Which components have been renewed/refurbished/replaced or newly added?

Based upon what you've mentioned previously two matters seem to be particular suspect areas, sparking and fuelling.

• Carburettors: Is it still the case the fuel is flooding from the throat of the carburettor(s) on cranking, one or both? If so, this is a matter to fix before anything else and will necessitate some disassembly to (most likely) clean, or replace, the needle valves. If Strombergs (presumably CD150 in thsis case) are saturated in this way then, just because of that, starting and maintaining idle will be very difficult.

• Sparking: There might well be something to be said for reinstalling the points and setting the electromic unit aside for now. At least while troubleshooting points elimate some of the uncertainties associted with electronic units. I've had brand new electronic units in a partial failure condition; producing sparks but erractic, weak and at the wrong time. A rough and ready check for the condition of a coil is to measures resistance across the pos and neg terminals which should be approx 3 ohm for a non-ballasted system and from the HT contact to pos which should be in thousands of ohms (e.g 5000). Worth a try with some points?

[AidanT]

Thanks

All a long story do will type up on thd laptop and not this stupid phone keyboard

Here is a question though. The previous engine started fine, but I have noticed the +ve to yhe cool might still be a resistive wire. Could that be possible?

What symptoms might that cause when cranking over for quite a while I've definitely got a 3ohme coil.

Thinking of swapping it out anyway, but could that cause an intermittent loss of a spark????

[johny]

It wouldnt be good running a 12v coil with 6v. You can check this by connecting the distributor (-ve) side of the coil to earth then turn on ignition and measure voltage at coil +ve terminal. Should be same as battery voltage...

[Pete Lewis]

think of if you halve the input you halve the output

the opposite if you feed a 1.5ohm with 12 v you double the HT 

and double the current (amps) which can burn points and rotors and can blow electronic units 

but with only 6v into a 3 ohm coil will give you a weedy spark 

Pete

 

[AidanT]

OK thanks. Not sure where to go with a potential intermittent spark at the plug then.

Points and condenser I guess, but I'll swap out the pos wire anyway.

Let's see what that does! 

Edited July 14 by AidanT

[chrishawley]

There's opportunity here to do a hot-wire test as a diagnostic procedure. i.e. disconnect the present wire to the pos on the coil and replace with a fly lead directly from battery positive. Turn over engine and observe sparks at end of king lead down to earth.  Desirable outcome is clear, consistent sparks three times per engine revolution.

If a hotwire test gives an improved situation then that would indicate deficiency in the forward feed to the coil the pathway being (AFAIK) brown to ignition switch, white to back of fuse No.1, white from back of fuse No.1 to coil. Investigation of this pathway would include inspection of any pre-insultated spade terminals which, unless artfully fitted, are a common source of malconnection. 

P.S. Not forgetting to disconnect fly lead once test done.

[AidanT]

3 hours ago, chrishawley said:

There's opportunity here to do a hot-wire test as a diagnostic procedure. i.e. disconnect the present wire to the pos on the coil and replace with a fly lead directly from battery positive. Turn over engine and observe sparks at end of king lead down to earth.  Desirable outcome is clear, consistent sparks three times per engine revolution.

If a hotwire test gives an improved situation then that would indicate deficiency in the forward feed to the coil the pathway being (AFAIK) brown to ignition switch, white to back of fuse No.1, white from back of fuse No.1 to coil. Investigation of this pathway would include inspection of any pre-insultated spade terminals which, unless artfully fitted, are a common source of malconnection. 

P.S. Not forgetting to disconnect fly lead once test done.

Sounds like a plan. I did wonder why quick start had no impact, unless the cylinders were already drowned in petrol. Spark plug inspection did not look wet.

Aidan

[AidanT]

3 hours ago, chrishawley said:

There's opportunity here to do a hot-wire test as a diagnostic procedure. i.e. disconnect the present wire to the pos on the coil and replace with a fly lead directly from battery positive. Turn over engine and observe sparks at end of king lead down to earth.  Desirable outcome is clear, consistent sparks three times per engine revolution.

If a hotwire test gives an improved situation then that would indicate deficiency in the forward feed to the coil the pathway being (AFAIK) brown to ignition switch, white to back of fuse No.1, white from back of fuse No.1 to coil. Investigation of this pathway would include inspection of any pre-insultated spade terminals which, unless artfully fitted, are a common source of malconnection. 

P.S. Not forgetting to disconnect fly lead once test done.

Sounds like a plan. I did wonder why quick start had no impact, unless the cylinders were already drowned in petrol. Spark plug inspection did not look wet.

Aidan

 

Engine Rebuild Story so far!

Purchased a mk2 Vitesse engine Head and block for Rebuild. I took the engine apart to do a visual inspection of what I had. The Cam had some damage and after a picture posted on the TSSC forum, it was suggested that I replace Which was done.  

Both Bottom and top ends were sent separately off to be rebuilt and skimmed.

I then, slowly put the engine back together with the help and advice of others using new gaskets everywhere and replacement bolts nuts and washers where needed (Head bolts for instance)

Gearbox and clutch put back on (Clutch was replaced not long ago) engine refitted in the car and all ancillaries apart from the radiator re-fitted

Engine turns over freely, tries to fire up but then stops trying to fire. Easy Start at this point has no impact.

[Pete Lewis]

Aidan  ,cant remember but did it have recessed fire rings having had a nightmare  with a duff  payen gasket 

i still wake up at night dreaming about the thing 

Pete

[AidanT]

1 hour ago, Pete Lewis said:

Aidan  ,cant remember but did it have recessed fire rings having had a nightmare  with a duff  payen gasket 

i still wake up at night dreaming about the thing 

Pete

Hi Pete, no it was a completely flat block so no worries there. Head gasket from Canleys so hopefully reasonably good quality 

Pic below is from the strip down

 

 

Aidan

 

Edited July 15 by AidanT

[Pete Lewis]

yes  sorry we have done this before .earlier 

its an age thing  Ha 

maybe recheck you valve timing as thats all been stripped out 

Pete

[AidanT]

All

Recommendations for a decent distributor coil please?

Prices seem to vary wildly, I'd like a decent quality one

TIA

 

Aidan 

[Iain T]

Aidan, buy from The Distributor Doctor. Their parts are good quality.

Iain

[Pete Lewis]

I have never had a duff coil in all my years  

guess there is a first time 

for no ballasted  i suppose  lucas DLB105  is the one to try or cheaper  DLB101

[johny]

agree Pete, pretty sure mines the original 50yr old one! Nothing moving on it to wear out...

[AidanT]

43 minutes ago, Pete Lewis said:

I have never had a duff coil in all my years  

guess there is a first time 

for no ballasted  i suppose  lucas DLB105  is the one to try or cheaper  DLB101

It's a just in case really - If I run out of every other component between the Battery (new) and the spark plugs being the problem!

Aidan

[AidanT]

Quick question all all those who have had the dreaded rubber slivers in the carbs. Started to remove the float chamber, is there anything but the six bolts I have to undo to remove?? It's still firmly attached 

 

[johny]

No thats it but it will be stuck on by the gasket and of course the o ring round the jet holder at the bottom, both of which will need replacing. A little gentle tapping on corners should free it but dont go mad as the floats inside are quite delicate...