I want to give up Smoking
Discussion
Hello all,
Could I ask a question about my engine, which is smoking?
I have a 1293cc A+ with a Stage III head running twin 1 ¾ Su’s. The Engine has been built and put together by a very well known engine builder and the workman ship is second to none, but she has always smoked!
It doesn’t tend to do it on acceleration only really after I come off the throttle after a long run on a duel carriageway, its when I put my foot on the throttle again that it starts to smoke (big bloom of blue smoke). I use the car every day for my 70-mile trip to work and I have noticed that the back of the car on the side of the car where the exhaust is really dirty and black.
Any ideas? Its 8000 mile since total rebuild and I am running 20W50, I have overhauld the head with all new rubbers and gaskets.
Could I ask a question about my engine, which is smoking?
I have a 1293cc A+ with a Stage III head running twin 1 ¾ Su’s. The Engine has been built and put together by a very well known engine builder and the workman ship is second to none, but she has always smoked!
It doesn’t tend to do it on acceleration only really after I come off the throttle after a long run on a duel carriageway, its when I put my foot on the throttle again that it starts to smoke (big bloom of blue smoke). I use the car every day for my 70-mile trip to work and I have noticed that the back of the car on the side of the car where the exhaust is really dirty and black.
Any ideas? Its 8000 mile since total rebuild and I am running 20W50, I have overhauld the head with all new rubbers and gaskets.
It's strange how some re-built engines smoke and others don't. Oil consumption also seems higher on some engines with an identical build standard to others.
My 1964 car, which is 1293 with Karl Schmidt pistons and 'Total-Seal' rings never gives much better than about 120 miles/pint in competition, but my newly built Enduro car, at 1330 cc and with Hepolite 21253 pistons and standard rings uses almost no oil.
However, it does sound as though it's a piston ring problem here. Maybe one of them is broken. That can happen with even the best built engines and could have happened at the time of build. Show me a good engine builder who has never, ever, broken a ring on assembly - such a person doesn't exist.
My tip, if fitting new rings, is to go for 'Total-Seal' rings. They're made in the USA but can be acquired in the UK from Lowman-Jones of Dagenham, Essex. Coat about £130 a set, but well worth it.
Make sure you hone the bores really well when fitting the new rings.
My 1964 car, which is 1293 with Karl Schmidt pistons and 'Total-Seal' rings never gives much better than about 120 miles/pint in competition, but my newly built Enduro car, at 1330 cc and with Hepolite 21253 pistons and standard rings uses almost no oil.
However, it does sound as though it's a piston ring problem here. Maybe one of them is broken. That can happen with even the best built engines and could have happened at the time of build. Show me a good engine builder who has never, ever, broken a ring on assembly - such a person doesn't exist.
My tip, if fitting new rings, is to go for 'Total-Seal' rings. They're made in the USA but can be acquired in the UK from Lowman-Jones of Dagenham, Essex. Coat about £130 a set, but well worth it.
Make sure you hone the bores really well when fitting the new rings.
vasi said:
Pop the dipstick out with the engine running, if theres any oil getting thrown up then tis rebuild time I'm sure. Mine does that :O
Careful with this. On later engines with fully enclosed breathing systems it won't apply due to induction vacuum being applied to the crankcase.
Earlier cars will always chuck oil out of the dipstick hole if you remove the dipstick with the engine running. A better way on earlier cars is to remove the oil filler cap when the engine is hot and see it it smokes at tickover. That's a sure sign of bore wear or broken ring(s). Better still, do a compression check and cylinder leakage check, or just take the head off and have a really good look inside.
Funny you should say this.
I have noticed that I am getting a lot of oil on the front of the engine. The dipstick is not tight in the hole and I just assumed that it was vibrating about and oil was escaping. But even with it firmly held in place oil is still getting out, it appears to be coming out with some force in that case.
As for the breather system, it has a catch tank so I take it that its an open system.
The engine sounds great and is not really missing a beat other than this occasional blue smoke.
What do you suggest? I think if I go back to the builder they will tell me to get knotted no chance of a rebuild.
I have noticed that I am getting a lot of oil on the front of the engine. The dipstick is not tight in the hole and I just assumed that it was vibrating about and oil was escaping. But even with it firmly held in place oil is still getting out, it appears to be coming out with some force in that case.
As for the breather system, it has a catch tank so I take it that its an open system.
The engine sounds great and is not really missing a beat other than this occasional blue smoke.
What do you suggest? I think if I go back to the builder they will tell me to get knotted no chance of a rebuild.
Check out the catch tank. Is it half full with grotty and smelly oil?
I was going to suggest that you check for blocked breather passages. the mini engine, in up-rated form, does need to breath properly and if it can't you can get a bit of smoking.
From what you say, though, my money would be on a broken piston ring. Now, that's not the end of the world and new rings are relatively inexpensive. If the engine has only done a low mileage, just whip the unit out, split it from the box, leaving all the ancilliaries on (dizzy, water pump, etc., remove the head, take out the rods and pistons and check it all. If a ring is broken you'll see straight away. Alternatively, just renew all the rings anyway (about £50 for a full set for Hepolites). Don't forget to hone the bores thoroughly when re-fitting and take care not to break the new rings. Make sure the top of each bore has a small chamfer to help the rings to go in.
I was going to suggest that you check for blocked breather passages. the mini engine, in up-rated form, does need to breath properly and if it can't you can get a bit of smoking.
From what you say, though, my money would be on a broken piston ring. Now, that's not the end of the world and new rings are relatively inexpensive. If the engine has only done a low mileage, just whip the unit out, split it from the box, leaving all the ancilliaries on (dizzy, water pump, etc., remove the head, take out the rods and pistons and check it all. If a ring is broken you'll see straight away. Alternatively, just renew all the rings anyway (about £50 for a full set for Hepolites). Don't forget to hone the bores thoroughly when re-fitting and take care not to break the new rings. Make sure the top of each bore has a small chamfer to help the rings to go in.
Thanks Cooperman.
Its a Turbo block and I am running a Facet pump, so the people that built the unit made the fuel pump blanking plate into a breather but didnt seal it very well and I got a leak. For a quick fix i fitted a new blamking plate but with all this going on i may go back to having a breather there.
But I am now on the look out for a 1275 to stick in to keep me mobile while I change the rings.
Its a Turbo block and I am running a Facet pump, so the people that built the unit made the fuel pump blanking plate into a breather but didnt seal it very well and I got a leak. For a quick fix i fitted a new blamking plate but with all this going on i may go back to having a breather there.
But I am now on the look out for a 1275 to stick in to keep me mobile while I change the rings.
I don't think I like the idea of using the fuel pump aperture as a breather. I've never seen this done, but it seems a bit low down on the block and it must me in an area of high oil splash.
Ideally a breather should be as high up the block as possible, which is why the venting is usually done from the rocker cover, the cam chest, but via a pot-type catch unit, and the top of the flywheel housing.
I may be wrong, but if you vent from the back of the block without a catch-pot (you may well have one), then you could get a lot of oil loss into the catch tank.
Ideally a breather should be as high up the block as possible, which is why the venting is usually done from the rocker cover, the cam chest, but via a pot-type catch unit, and the top of the flywheel housing.
I may be wrong, but if you vent from the back of the block without a catch-pot (you may well have one), then you could get a lot of oil loss into the catch tank.
If I were you I would do a compression check first whilst the engine is hot. That will tell you whether it's a general problem or specific to one cylinder. It always helps to have an idea of what you are looking to find. Of course, low cylinder compression can be a sign of bad valve seating, but in your case, with the engie recently re-built, this is a bit unlikely. If all the compressions come up at between 140 psi and 150 psi, then maybe we all need to think some more and it would be unlikely to be a ring.
If the comp is low on just one cylinder, then take the head off and look for a bore wear pattern which might indicate a broken ring (you might not see anything, but it's worth a look).
Then take the engine out and strip it all down. We are all here to offer advice and assistance.
Peter
If the comp is low on just one cylinder, then take the head off and look for a bore wear pattern which might indicate a broken ring (you might not see anything, but it's worth a look).
Then take the engine out and strip it all down. We are all here to offer advice and assistance.
Peter
That does seem incredibly high (is this a road car or trac only?), and also very even. Usualy you get a few PSI difference between cylinders even on a good engine.
If compressions are all OK, it's more likely the valve guides that are leaking. Possibly the stem to guide clearance is excessive? Just a thought, have the ports been ground out enough that they have broken into the pushrod holes and had to be sleeved?
If compressions are all OK, it's more likely the valve guides that are leaking. Possibly the stem to guide clearance is excessive? Just a thought, have the ports been ground out enough that they have broken into the pushrod holes and had to be sleeved?
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