4 cylinder issues

Regarding the use of feeler guages, I elected to set up a dial guage when I rebuilt ny 2000TC. Using the guage you set it on the cap, zero the guage, lift the cap by hand, and get the clearance reading.This is especially handy when you have serviced the head and your clearances are way off from the original settings.
 
This seems to have gone on for what seems ages.

I've got my engine back together, having had the valves shims ground down.

It's now reassembled and all back together yet still seems to run like a pig.

It appears to be running on three cylinders, which I've found by unplugging cylinder 1 spark plug and there being no difference to the running of the car. There is, however, a spark at the end of the lead and a spark at the plug also.

So why would a car with valve clearance in tolerance, new plugs and timed to what appears to be the smoothest it can run still run on three cylinders?

I was thinking about the carbs, however, if the front carb can allow cylinder 2 to run then why would 1 not run.

Oh, and today I broke my colourtune.

Help would be appreciated, as I'm starting to run out of ideas.
 
Fraserp6 said:
It's now reassembled and all back together yet still seems to run like a pig.

It appears to be running on three cylinders, which I've found by unplugging cylinder 1 spark plug and there being no difference to the running of the car. There is, however, a spark at the end of the lead and a spark at the plug also.
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Interchange leads and plugs between cylinders to see if you can get the misfire to move. Check the distributor cap for cracks around No1 post. Check the distributor cam as well, as well as play in the shaft. Do a compression check. Compare the spark at the end of No1 lead with one of the others. If you have concerns that it's the carb, then check the plug colours, and if N01 is excessively weak (or rich) then look at the inlet manifold gasket. On 3 cylinders it will run like a pig, and until you can get it back on to 4 it will continue to do so. It may seem like rocket science to you at the moment, but it isn't.
 
Hi Harvey,

I've had a change about plugs, 2,3 and 4 have a light/medium grey colour to them, which would suggest to me they're ok. Cylinder 1 has a grey colour, however, it's slightly darker.

The plugs have the same strength of spark, having changed plugs and leads around they all seem to be good.

...as does the dizzy cap, however, I've swapped it around with the spare caps I have available also. I've also swapped the rotor arm.... this is to no avail...

The dizzy cam looks fine, though it's fitted with an electronic ignition, so I'd have thought this wasn't too much of an issue.

There is slight play in the shaft, however, it's barely noticeable.

Compression in cylinder 1 is 164/163 psi, cylinder 2 is 164, cylinder 3 165, cylinder 4 163(possibily 162) Gunson hi-gauge dial is a little vague.

It spitting back through the carb, usually on sharp, heavy throttle opening. Could it be something with the manifold? Gaskets are about 6 weeks old, could there be something blocking it?
 
Fraser, is it using any coolant at all?
Perhaps the inlet manifold allows some coolant down the port of the No 1 cylinder.
You'd have to remove the manifold to investigate.
 
Fraserp6 said:
It spitting back through the carb, usually on sharp, heavy throttle opening. Could it be something with the manifold? Gaskets are about 6 weeks old, could there be something blocking it?
Click to expand...

I assume that's the carb that supplies the affected cylinder, and that kind if spitting back is usually a sign of a weak mixture, and so as it's only one of the cylinders that's supplied by that carb, and not both, you need to find what's causing that weak mixture, which could be a crack in the manifold to that port, or the inlet gasket. It will be something that is only affecting that cylinder, not that carb
 
If I snap one of the brass fuel fixings on top of the float on a HS8 carb, can the remains of the fixing be removed, or do I need to replace the whole top of the float.

Thanks, Fraser.
 
Do you mean the brass pipes into the float chamber lid? They're obviously two different parts, but even if you got it out, I doubt you'd get one out of another carb to replace it without damaging it, and even if you did I think you'd have problems with it leaking afterwards. Must be easier, quicker and cheaper to replace with good used.
 
Must be easier, quicker and cheaper to replace with good used.
Click to expand...

worth checking out redrover's thread on replacing HS8s with smaller carbs - meant to be a big improvement!

Rich
 
rockdemon said:
Must be easier, quicker and cheaper to replace with good used.
Click to expand...

worth checking out redrover's thread on replacing HS8s with smaller carbs - meant to be a big improvement!

Rich
Click to expand...


That's my line! I only refrained from saying it for fear of being seen as sounding like a broken record..... (As long as those smaller carbs are HIF6's, not those other horrible things.)
 
Getting very frustrating for you Fraser!

It looks like the inlet manifold will be coming off. Whilst it is off it might be a good idea to check that all the inlet ports on the head are sucking equally when you motor the engine. Just a "start right from the beginning" thought!

Chris
 
Hello,

I'm back out at this again, having had a relatively intense run at work, I've finally got some time to myself for a few days.

I've currently had the carbs off to rebuild them and they're looking clean and free of grease and general crud. I've also made sure there is next to no play in the linkages and the mechanism that moves the jets. For good measure I fitted another set of needles (AAC) I believe.

I STILL HAVE A ROUGH RUNNING CAR!!!

I've got new plugs, new leads, new coil... Rebuild carbs, Re-shimmed valves, Replaced ALL gaskets on the inlet manifold and carbs, re-built the snapped fuel pipe (and it does not leak!) checked the timing, adjusted the mixture and my car is still running like a complete pig!

I've getting a little tired of spending any free time I have out at a car making little to NO progress on it's running issues.

One of my final thoughts were, have I moved the cam timing too far forward?

http://sdrv.ms/OaleVX

This is the cam timing locked, with the fatter end of the locking tab. (Yes, I'm aware I bent that piece of metal, however, I replaced it when the head came off.)

No matter what the ignition timing looks like, I seem to be getting a missfire, either through the carbs, or through the exhaust from what I can gather from Cylinder 1.

I'm at my wits end here guys, I've got a 2000tc I need to have either SOLD of EXPORTED by September and its mid-July with nearly no progress in 8 weeks.


Any suggestions? Cam timing is about all I can think of.
 
Fraserp6 said:
I seem to be getting a missfire, either through the carbs, or through the exhaust from what I can gather from Cylinder 1.

Cam timing is about all I can think of.
Click to expand...


Cam timing will affect all cylinders, not just one.
 
Scrap that "only backfiring through cylinder 1" statement, it is infact firing through both carbs, having just been out to run it again.

This after static timing having been set, then refined with a strobe and then the carbs being tuned...with a colourtune.

Fraser
 
So it's spitting back through both carbs? If that's the case it could be cam timing. At least on a P6 it's nice and easy to check, but if you've pegged the crank and the camshaft already, then it's correct, and if you've checked the timing and that's correct as well then you're fast running out of options. Another thing that can cause it is excessively weak mixture. On V8's the same thing can be caused by the exhaust cam lobes being worn away, which means the charge can't be exhausted from the cylinder, so spits back up the inlet when the inlet valve opens. I've never seen a 4 pot camshaft worn so it cant be that, but it could be a blocked exhaust doing the same thing, but you'd have very poor performance if that were the case, but if you're not actually driving it, only running it, you might not notice that.
 
Yes, it is now spitting back through both carbs, no amount of fiddling seems to be getting it to run on four cylinders either, still seems to be Cylinder 1 that isn't running, even though there is a spark at the plug...

I checked the cam timing about an hour ago, I locked the cam first then flywheel... It would appear when my cam is locked, I can still rotate the flywheel slightly, enough allow the flywheel pin to go from not fitting...to fitting. I assume this is play in the chain, would that be right? should there be enough play in this that you can lock one (either cam or crankshaft) and sufficiently rotate the other to make it fot/not fit?

Fraser
 
There will always be a certain amount of slack in the chains, but ideally with the crank turning in the correct rotation then as the pin slots in the flywheel the peg will slot in on the camshaft as all the slack will be taken out.

If it's spitting back through both carbs, and also misfiring on No1 cylinder you need to sort the misfire first, which ISTR was the point that we got to the last time the topic came up. While it has the misfire you'll never be able to sort anything out, and if you're this far in and still getting nowhere you need to go back to the beginning and start again, because with all due respect you've missed something along the way. If there's a spark at the end of number 1 lead, then you need to be sure that spark is occurring at the right time, and that the plug that's in there is working as it should, that there's compression in the cylinder, and there's fuel in there to ignite. If you have compression, fuel in the cylinder, and a spark at the right time, then it's going to fire. If you still can't get No1 to fire try interchanging things between cylinders to get the misfire to move. When the misfire moves then the last thing you moved is the cause of the problem.
 
Apologies if 1) this has been checked already, 2) my ideas are wrong.

The timing marks on the pulley are known to inaccurate. Not a case of the marks being so far out to cause this? (Unlikely, as that would be a problem before now)

Have 2 HT leads been inadvertently interchanged? (e.g. the leads positioned 1-3-4-2 in the clockwise direction as opposed to the anti-clockwise direction)

Can't help thinking it's either something really serious, or something really obvious that's being overlooked. :evil:
 
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