1500 spit misfire

[Pete Lewis]

more used to answering than asking  but hey ho here we go

this 1500 spit had bugged me for some time with its erratic unhelpful back fires /spits/ misfires and the ocsional good running

waxstats off , and fitted fixed jets ,these proved hopeless and 2p repair to the waxstats refitted them, it has new point + added an old classic condenser, tappets ok , fuel clear and well supplied,, filters std.  fitted right way up .carbs are fine but need far more richness than std pre run settings  these are ball bearing topped HS4 . correct needles , i dont expect a 421 to need much needle revisions , with std filters .

compressions   all 4 are 110 lbs,  these are all even but below the expected 130+  deterioration since some  guy fitted the 421 manifold, the gasket looks ok and all fixing are in place so air leak is possible ,not done a squirt test over the joint yet

even calibrated the compression gauge and its spot on 

not check cam timing 

but this is all neat tidy everything is as should but runs like a pig  then found no rear brakes and a failed  PDWA valve so no fluid now

and a  coolant bypass tube sealed with filler ,  the list grows but the running is hopeless

not my normal scene ,  im supposed to fix them not grow warts .

any out the box thoughts ???

Pete

[Anglefire]

Points gap was what was wrong with mine when it ran crap after its transplant.

Other than that I would be guessing as I'm clearly no expert!

[dougbgt6]

Pete,

Occasional good running then dodgy running sounds like something in the timing system is slipping, moving, popping back? 

How's the timing chain and/or cogs? 

You haven't mentioned the dizzy? How is it?

Have you checked the flux capacitors? 

Doug

[Pete Lewis]

Will be getting the car back to rebuild the brakes, amd more gremlins will appear on that job, bet the Mcyl needs a rebuild also

Points are new , timing is on the mark , but not checked the cam timing

Just dreaming the firing back out the carbs is internal crossover 

And as for flux  yes I am ..fluxed out 

Pete

[dougbgt6]

Prevarication!

What about the dizzy?!!

Flux capacitors are only on Delorian's and Star Trek, obviously.

db

 

[Nick Jones]

Low compressions (if the gauge used is known to produce normal readings on other engines) and generally poor running suggest the following checks are needed

valve clearances (tight tappets due to seat recession)

Valve lift (worn followers/lobes)

Valve timing.

 

Nick

[Clive]

Cookies GT6 did the backfiring out the carbs etc a few years ago at SEM, and that was cam timing sprockets jumped many teeth (turned out teeth had more or less gone)

Unusual, we were all scratching our heads at the time, and I remember saying how unlikely it would be if the timing had moved that much Wrong again...

 

[Pete Lewis]

Doug  dizzy is as new  points new   did fit an old condenser  no change 

Nick    /Clive cam timing is on the agenda  ,    tappets are fine 

but at times its quite good.. it not fuel  or blockages in the supply , certainly no rubber slivers 

something very odd about whats going on ..maybe me seaweed has dried out in the sunshine ???

its set rich which stops the fire backs out the carbs  the head  has unleaded exhaust seats fitted 

have calibrated the gauge up to 8 bar  ( 120 ish )and its spot on, couldnt go any higher as the fitting wanted to part 

 

Pete

[Nick Jones]

Manifold gasket making marginal contact - sometimes air leaks, sometimes not?  120 psi is a bit low though..... is it known what the cam is?

Nick

[dougbgt6]

13 hours ago, clive said:

Cookies GT6 did the backfiring out the carbs etc a few years ago at SEM

That's what I was thinking about, although I'm sure he told me it was IOW, not that it matters. 

Doug

[Pete Lewis]

Nick  no idea what cam , i expect std, but thats a guess

two things we got worn out and not given up but a days work going nowhere got the better of us (thats Ray ad I)

it did run better on the conversion jets although no matter what you realigned the choke would not return hence back to the 2p repair ,  jet heights all measured and equal .

whay with all the messing about changing the jets , finding no brakes and more time ran out and the ideas about a squirt over the gasket and a cam time check were pencilled in but never concluded , tea and cake was a stronger calling 

she did drive home without any pops or bangs but obviously too rich as i set the jets down to get some running

when the car returns will do the two oustanding ideas  return the needles to a proper setting  and then find a box of matches

as a side the pdwa valve kit from Rb is £19 and  £6.70 from BCS ebay  they say its only for stag,, bit odd as that girling valve  and repair kit  155071  was fitted to a whole plethera of makes   

the suns shining and we have 35 off to.   McAplines Steam trust at Fawley Hill tomorow  

we will see   Hmmmm  !!!!!

pete

[dave.vitesse]

Pete, I guess you have tried the roto arm, dizzy cap and sticking carb piston. 

The problems you have found changing over to standard jets where they stick  when returning the choke is a problem with these repro jets. Changing the angle of the wire link holding the jet in position can help. Though the main cause is likely to be drag on the jet by the fuel pipe. Whatever it's a pain.

Dave

[Pete Lewis]

hi dave  its got a dizzy doc rotor and cap , dont expect lead as this is to variable, if it was just one cyl  missing you could find the culprit

the choke rod was bent /shouted at /cursed  /and  stared at / it was just useless 

tried shortening the bowl feed a few mm to unload the pressure of  the ups and downs ...  the kits take some ingenious trial to get the operting all as should but being a meccano fan it soon sorted which spring went where on what lever.   an expensive mistake 

its got a giant case of rubber slivers  and worse    ..........but without them !!!!

 

Pete