Running problems

[martinminor89]

Hi all,

This may be a long post so please bear with me. I have recently done a lot of work to my 1970 Minor 1098. This started with a new refurb gearbox, new clutch, new coil (it's never the coil - it was this time ) new starter motor, new plugs and new HT leads. I also replaced the radiator and swapped the electronic ignition for points.

After doing all that, the car started and ran well for about a day, next day it ran like a bag of spanners. turned out there was oil on the plugs due to seepage down the valves, so, rocker cover, springs etc off and new top hat seals around the inlet valves. Reset the rocker arm and vlalve clearances and now it's running really lumpy. Wound the fuel mixture adjusting nut all the way up, then down 12 flats and still running terrible, I can only liken the engine sound to something sounding like a 1970's VW Beetle

I did a compression test (wet & dry) and the readings were all very good. There does seem to be a fair bit of bluish smoke (oil burning?) coming from the exhaust and there is a bit of what seems to be steam coming from the oil filler cap.

The only difference made to the car from when it ran really good after the rebuild to running terrible now was removing the rocker arm/valve springs and as I said these have all been reset to the correct specs. I'm really at a loss as to know what's going wrong now and would really appreciate any pointers that you could give to help me resolve this problem.

The car used to run really great until the gearbox failure and had done a run to mid Wales and back without any problems, but since putting the engine back it just seems to be one problem after another. Sorry for the long winded post but I'm totally stuck.

[amgrave]

The plugs oiling up would not be caused by seepage down the inlet stems so it seems you have an oil problem elsewhere. Perhaps the head gasket has failed at an oil way or over filled engine. Check to see if there is any oil in the water under the radiator cap and post back.

[martinminor89]

The plugs oiling up would not be caused by seepage down the inlet stems so it seems you have an oil problem elsewhere. Perhaps the head gasket has failed at an oil way or over filled engine. Check to see if there is any oil in the water under the radiator cap and post back.

I had a mechanic come out and advise me that the seals were in need of replacement. Because of this, there is no longer an oil leak issue. I've also done a compression test, which brought back good readings.

[Trickydicky]

It could simply be you have a dodgy condenser, the best place to buy them is from the distributor doctor as his are the best quailty. A faulty condenser will give the symptoms you described. The plugs oiling up can be caused by rough running.

[biomed32uk]

I am assuming you took the head off to do the valve seals, you don't mention it.

If you left the head on but disturbed the nuts on the rocker pedestals then it is probably a head gasket issue.

[myoldjalopy]

Burning oil, steam from rad cap and uneven/clattery running could well be a head gasket. I think I would get a condensor from Distributer Doc to check Richard's idea (and then you know you got a good condensor that you can rely on for years on end) and , if that fails to cure the problem, take the head off and check the head gasket......as per biomed's thinking.

[kennatt]

bit more info needed.......................did you take the head off to do the valves(Can be done without but not recommended) and can you list the comp test readings wet and dry .this info could make diagnosis easier..

[Trickydicky]

Guys, the reason I suggested to change the condenser is because the op says the car ran well for the first day then the problems appeared. I had an instance myself after replacing a condenser where the car ran fine at first but then started playing up and it was traced to the condenser.

[MikeNash]

Martin,
I've not fitted valve oil seals on my 1098 'cos they often disappeared anyway. (I've got the earlier little ring things.) It's an experiment, but so far after a couple of years running I don't have oily plugs and the engine will idle as long as I like without distress or smoke. And I have a very slow idle of about 550rpm.
So it's not your inlet valve seals, I think. MikeN.

[amgrave]

Mike. He had a mechanic come out and he advised him so it must have been the valve guides

[edd_barker]

I concur with condensor, I have had two of the 'standard' ones fail suddenly and soon after installation, symptoms like a misfire for me. Get a distributor doctor one! I think the major supplies stock them. Just remember to tell your mechanic NOT to swap it at the annual MOT/service or you will be rummaging in a Garage's bins like I have!

[oliver90owner]

Change condenser? Poppycock!

Just look at the colour of the spark to check for a faulty condenser before jumping to an unwarranted, and wrong, conclusion. No need to change a perfectly good item - and it will not sort out the problem, unless it is the reason!

A strong blue spark would indicate condenser is good. A weak yellowish spark, given all other ignition items are in spec, likely indicates a faulty condeser. Points gap at a minimum can also create the same apparent fault. A faulty condenser will also always cause burning at the points.

Diagnose, not guess, is my recommendation. But as always, you can choose to change most or all of the engine components for a single minor faulty item.

[martinminor89]

Hi all

Sorry it took so long to reply, been working nights . To give a bit more info, I'm beginning to think this may after all be a head gasket problem. when I looked into the oil filler cap I noticed there was some lovely greyish mayonnaise around the neck. When we did the valve seals this same stuff was coating the inside of the rocker cover, but as the comp readings had been good I discounted the head gasket.

As I said, this moggy has had LOADS of new parts, one of them being a new rad as the fins on the old one were shot, I'm beginning to wonder if the gasket was on it's way out and because of the new rad, increased pressure through the system has blown what was already a weakened head gasket.

I'm about to go out now and take a new comp reading and will post the new numbers. If it's as I suspect, I'll remove the head and take it to a local engineering works who specialize in classic cars and have them re-machine it.

I've not had much experience with car engines and have only got deeply involved with them since starting on the moggy (and a '78 Land Rover Series 3 ) around 6 months ago so this has been a huge learning experience for me. I'm very grateful for all the help you've given me and really appreciate it.

[philthehill]

Just because you have mayonnaise around the rocker cover does not mean that the head gasket has gone.
Some oils create more mayonnaise than others.
I have seen new Morris Minors plagued with mayonnaise in the rocker cover if certain engine oils were used.
Using Castrol GTX 20w/50 seemed to get rid of the problem.
I would suggest that you re-check the compressions both hot and cold with the throttle held wide open then report back on here and go forward from there.
The problem could be anything but what ever you do - do it systematically. Proving or disproving the item or process before moving on to another item or process.
The price of a condenser is not that expensive and for the sake of confirming or excluding the item it is well worth the money.
It always pays to carry a spare condenser and points in the tool box just in case.
Check the lead from the condenser to the points to ensure that there is no breakdown in the insulation.

[martinminor89]

Cheers Phil, I've done a dry comp test and the readings are

Cyl 1 150

Cyl 2 158

Cyl 3 160

Cyl 4 155

One thing that happened was, as I removed the plugs to do the test, Champion N9YC, two of the plugs shattered at the middle, do you think these could have been a dodgy batch and have caused misfiring leading to bad running? I'd rather not remove the head if there isn't a problem with it. Also, in answer to an earlier post, I did the valves with the head on using a Bergen compression tool and only undid the four nuts on the rocker arm posts. I've also checked the dipstick and the oil is a greyish colour. The engine oil we used is Halfords 20w50 classic motor oil.

[liammonty]

Those compressions sound good enough, but unfortunately, grey oil on the dipstick doesn't. That rather suggests the head gasket is gone, with water getting into the oil, and you'll need to get the head off and investigate. It's not a tough job though. Out of interest, which 4 of the 8 rocker pedestal bolts did you undo? You probably know this, but I ask as 4 of them are of course head bolts, and loosening them would have disturbed the head gasket.

[martinminor89]

Sounds like I may have done that, I'm afraid I undid all eight and removed the rocker arm assembly

[liammonty]

Oh fiddlesticks - you removed half the head bolts! At least you know the likely cause and how to fix it now Off with the head it is - new head gasket time.

[oliver90owner]

Condensation within an engine can be caused by excessive blow-by, too. Also, if the engine never reaches proper operating temperature any water will not be evaporated and scavenged by the engine breather system (which may be another possible area for checking).

Don't assume, until diagnosed properly, is my advice. Removing several head bolts is not a good omen, mind. But if retightened and then retorqued in the correct order, the likelihood of not sealing around thd water jacket is reduced. Loosening head bolts with the cooling system under pressure is a bad idea, too, so hope that is not a contributing factor as well.

[philthehill]

A tip for future removal of the rockers/rockershaft without disturbing the head:-
Cut the rocker shaft locking peg locking plate so that the head bolt section is dispensed with (later 'A' Series engines had this modification incorporated in the form of a modified rocker shaft locking plate).
Doing the above modification allows the rocker shaft and rockers to be removed without disturbing any head bolts - only the rocker pedestal stud nut holding the locking plate, the rocker shaft locking peg (remove) and rocker adjusting screws have to be undone with the pushrods disconnected from the rockers.
The rocker shaft can then be slid forwards out of the rocker shaft pedestals noting where the washers and rockers fitted so that they can reassembled in the same position/order - full reassembly is the reverse.