My 1954 803cc has a problem. The middle two plugs on the engine have started to oil up and the engine is 'hoppping' when you put your foot down. It feels as if the engine is almost 'flooding' and on a flat spot when accelerating. Compression is good as is oli pressure. There was some top end rattles today but they sounded like noisy tappets, or possibly valves? There is no blue trail when driving.
Could this be due to valves burned out? The engine is original and unconverted. I do not really want to swap the engine for a 948 unless essential. Trying to keep originality so would a leadfree head be an answer? I do not have garage facilities but could have a go at the job at a friends workshop under supervision! Would the oil be valves or possibly something more serious? I am not sure what I am looking for to diagnose the problem but do want to try and keep the old 803cc if I can.
Don't worry about an unleaded head!! You won't drive an 803 hard enough to warrant that. You say compressions are good - if so - can't be burned valves - or blown head gasket! Can you report back the actual compressions ? Possibly just bad plugs/cross arcing in the dizzy - something like that. You should check the valve gaps - but again - they can't be bad IF the compressions really are good ? When the engine is hot and idling - take the oil filler cap off. Is there a plume of smoke/fume ? If so - engine is 'past it's best' !
Many thanks for the info,
The plugs are brand new, I have had to replace the middle two within the last 200 miles. The cap, rota and contacts are also new as are the leads.
I am going to get a compression test done this afternoon and will report back I was hoping to drive to the National this year (230 miles from me !!) An adventure I know but up to now the engine has been fine..... I will also check the dash pot on the carb. The engine has 20w50 in it, would 10w40 help as this is obviously slightly thinner. I went for the thicker stuff as I thought thinner may 'leak' through more. Thanks
Paul
bmcecosse wrote:Don't worry about an unleaded head!! You won't drive an 803 hard enough to warrant that. You say compressions are good - if so - can't be burned valves - or blown head gasket! Can you report back the actual compressions ? Possibly just bad plugs/cross arcing in the dizzy - something like that. You should check the valve gaps - but again - they can't be bad IF the compressions really are good ? When the engine is hot and idling - take the oil filler cap off. Is there a plume of smoke/fume ? If so - engine is 'past it's best' !
Well the latest is as follows. The compression is fine I am informed , there are no rattles from the engine, no smoke from the back or from the filler cap. The valve clearances have all been reset and the car ran home fine.
I got to the driveway and all power went again. Its almost as if the engine is flooded when you put your foot down. Nothing! I had a look at the distributor and the plate the points are set to is rocking about. The two small screws that secure it have worked loose. I think there is a fault in the distributor as this would explain the sudden loss of power. If it is not working correctly I am guessing this could cause intermitent firing of the plugs, this may account for the oil on one of the plugs.
I have had a look about and a complete distributor for an 803 looks quite a rare thing. I may be constructing a new one from donor parts if I cant find one!
Bung in a 1098 dizzy, at least it will get you running.
If the plate is moving about pehaps the thin wire from the terminal to the points is not connected properly.
Thanks for that good news, I did not think that the 948 and 1098 were interchangable with the 803cc distributors. If they are it will certainly make the job easier to get a new one
The advance curve won't be as per original but then they would originally be designed for very low octane fuels compared to todays standards, so, a later dizzy may even make it run a little better
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I think I am going to hunt about and see if I can find an original side entry distributor before going down the 1098 route. I have a spare one but am not sure if it is complete or working! I see that some of the dealers do replacement ones recon etc for the 948 and 1098 but have yet to find a recon 803 one. If anyone spots one please feel free to point me in the right direction
mike.perry wrote:You would probably have to fit a plastic vacuum pipe with push fit connections
I have just ordered from Bull Motif a brand new Lucas (not recon) 948 complete disti. This should be with me tomorrow and hopefully the problem will be solved Is there anything I need to do when fitting that is different or will it be a straight exchange? Would a 948 disti improve the engine running?
With the new disti on I am hoping the plug oil issue will resolve. If everything is running ok this could mean that the drive to the National is back on!! (Althought I will need to leave in about 2 days in an 803cc to get there for June!)
Chances are that you will see an improvement in running - if nothing else because now you will have a correctly functioning dizzy and not one that is slopping about and altering the timing all the time ! The only thing I can think of different is as Mike already mentioned in that the vac pipe may be a push fit rather than a screw fit - easily overcome though....
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Sounds great thanks The new one comes with a screw fix vac and is a side entry cap so it will not look to different from the original which is good for an originality freak like me....I can live with it being a 948 disti on an 803 block though so maybe I am mellowing
On further investigation the weights and springs were all over the place. I was going to try and build a disti from two old ones but as the drive to the National is over 200 miles I did not really want to trust my 'mechanic' skills that much I have owned the car for 17 years and thought I might treat him to something new .
Well the good news is that the new disti has solved all the 'lumping' engine problems. The old disti was very worn and the spindle was rocking a fair bit.
I will see how the engine runs and then check the plugs again to see if the oil reapears in the plug.
