240 General: valve cover ticking panic

[calibano]

Originally Posted by Clan

Have you tried your dealer for the idle speed bypass screw and "O" ring ?

This will not fix your lack of power , the brass idle speed screw is redundant as soon as you open the throttle the smallest amount ... are you using your original carburettor or the one from the other engine , Is it the Stromberg or Inferior Pierburg ?

it is the original pierburg. I feared that the screw was going to make no difference. I hope for the better, this journey (and my lack of skills in dealing with it myself) is proving testing. hope I won't have to sell the car in the end...

[Rustyboots]

If it doesn't respond to the throttle, but does to the choke then its seems fairly likely the carb is tuned far too lean.
I think this is where you should be looking and forget the idle screw as people have said this is just for trimming the tickover. I have never known one to seize, if it really is then I'd fill the recess with Wd40 and try it again in a few days.
I think you need to be checking the carb diaphragm is not split and that it has the right needle and jet, also check all hoses/pipes are connected and there's no air leaks anywhere.
After this, get the trusty Haynes manual out and set the throttle position then get tuning. The mixture adjustment is underneath the float chamber, follow the manuals advice, its actually a very straightforward procedure and quite satisfying too.
If you haven't got a Haynes manual then I would advise anyone to do so, cheap enough second hand. Picking up a decent manual is the first thing I do with any car.

[Clan]

Originally Posted by calibano

it is the original pierburg. I feared that the screw was going to make no difference. I hope for the better, this journey (and my lack of skills in dealing with it myself) is proving testing. hope I won't have to sell the car in the end...

I didn't realise it was lpg too ! you have the same problem on LPG and petrol so it seems something fundimental is wrong with the fine tuning , Cam timing? Ignition timing? Air leak is the favourite .
You say when on LPG you pull the choke and it is better ??? you mean the LPG choke or the choke for petrol ? ( yes there was a choke button on the volvo approved landi-Hartog systems fitted by dealers from 1978 to the mid 1980's )

The pierburg is highly unlikely to be in good condition especially when using LPG ! Volvo advised the needle was changed every 24000 miles due to no lubrication with LPG , so the petrol mixture would be getting richer and richer as it wore .
The needle and Jet should be renewed , Needle "PN" if i remember right .

The float level is prone to rising over time due to a weak plastic hinge pin support bridge relaxing it's strength , again fuel mixture would get richer and richer over time and poor hot starting so a new bridge piece would be needed and float level setting would need checking . diaphragm should be changed at 24000 miles to prevent breakdowns and It's plastic retaining ring distorts so replace that too ! It should have a metal support ring to strengthen it but they often went missing years ago .

Having said all that get it running nicely on LPG first , then look into the carburettor ... The Pierburg really is a fuel guzzler if not maintained properly ..

If you are still using your original head have the valve clearances been checked and adjusted ? With LPG the seats can indeed wear reducing the gaps .

[calibano]

Originally Posted by Rustyboots

If it doesn't respond to the throttle, but does to the choke then its seems fairly likely the carb is tuned far too lean.
I think this is where you should be looking and forget the idle screw as people have said this is just for trimming the tickover. I have never known one to seize, if it really is then I'd fill the recess with Wd40 and try it again in a few days.
I think you need to be checking the carb diaphragm is not split and that it has the right needle and jet, also check all hoses/pipes are connected and there's no air leaks anywhere.
After this, get the trusty Haynes manual out and set the throttle position then get tuning. The mixture adjustment is underneath the float chamber, follow the manuals advice, its actually a very straightforward procedure and quite satisfying too.
If you haven't got a Haynes manual then I would advise anyone to do so, cheap enough second hand. Picking up a decent manual is the first thing I do with any car.

thanks for your precious input and suggestions, I also suspect the carb is the culprit, as I have changed several due to the Lpg being decisively unkind to it.

as for the tuning, to use a musical analogy, carb tuning is a bit as piano tuning, and I definitely am tone deaf… being able to do something like that would greatly enhance my experience of life. I have an early haynes manual but it still requires some dexterity and experience in turning those meticulous instructions into reality!

[calibano]

Originally Posted by Clan

I didn't realise it was lpg too ! you have the same problem on LPG and petrol so it seems something fundimental is wrong with the fine tuning , Cam timing? Ignition timing? Air leak is the favourite .
You say when on LPG you pull the choke and it is better ??? you mean the LPG choke or the choke for petrol ? ( yes there was a choke button on the volvo approved landi-Hartog systems fitted by dealers from 1978 to the mid 1980's )

The pierburg is highly unlikely to be in good condition especially when using LPG ! Volvo advised the needle was changed every 24000 miles due to no lubrication with LPG , so the petrol mixture would be getting richer and richer as it wore .
The needle and Jet should be renewed , Needle "PN" if i remember right .

The float level is prone to rising over time due to a weak plastic hinge pin support bridge relaxing it's strength , again fuel mixture would get richer and richer over time and poor hot starting so a new bridge piece would be needed and float level setting would need checking . diaphragm should be changed at 24000 miles to prevent breakdowns and It's plastic retaining ring distorts so replace that too ! It should have a metal support ring to strengthen it but they often went missing years ago .

Having said all that get it running nicely on LPG first , then look into the carburettor ... The Pierburg really is a fuel guzzler if not maintained properly ..

If you are still using your original head have the valve clearances been checked and adjusted ? With LPG the seats can indeed wear reducing the gaps .

of course it is, otherwise I could have never afforded cruising through europe on petrol! I sincerely hope it's an air leak Clan, as my greatest fear is for it to be caused by some cambelt or ignition related issue which would entail reopening a just reassembled engine… yes, it's the original volvo choke adjacent to the left of the wheel. system is an old romano model and I’ve always used the original choke for cold starts.

due to Lpg running being hard on the carb I have been through a selection of strombergs and pierburgs. this existing one had been in service for a short while I got it in great shape but had it installed without inspection as I assumed it was proving to be better that the knackered, previous one. I could not for the life of me find anyone (avail)able to strip it down and renew it as it seems to have became almost like an archeological practice. for a few months until the valve problem surfaced - that eventually led to the can of worms I’m in now - that pier burg was working like a charm, even if the car was slightly less quick than when the previous, bigger stromberg was in place


valves have, yes, been adjusted, oil seals, cambelt also have been dealt with,

thanks for your help clan I keep my fingers nervously crossed

[Rustyboots]

http://www.southerncarbs.co.uk/page_2654188.html

[calibano]

An avenue definitely worth considering, thanks

[Clan]

Originally Posted by Rustyboots

http://www.southerncarbs.co.uk/page_2654188.html

It doesn't look like southern carbs deal with the Pierburg .
However Gower & Lee do

http://www.gowerlee.dircon.co.uk/175CDStype.html

But i feel the main problem is not the carb as it does the same on LPG . although no doubt the Pierburg will need an overhaul after so long .

[calibano]

But i feel the main problem is not the carb as it does the same on LPG . although no doubt the Pierburg will need an overhaul after so long .

I suspect you're perfectly right, as the pierburg worked beautifully before the valve issue emerged. it is a very clean example with likely low mileage and it was installed less than a year ago. I fear it is a timing issue

[CaptainAhab]

Hi Leo, I have just had a read through the thread. I'll post you over the spare carb I have and you can see if it helps. PM me your address mate.