My engine has always ran a bit fast on idle,both throttle stops were right back.While checking around, i discover the small vacuum pipe from the left carb,was not connected to the distributor.I have a Lumenition system fitted (did the lecy disconnect it?does it have to be on with Lumenition)Anyhow i'v reconnected the pipe now and the idling has gone down.But what sort of rpm should i be looking for at idle,i'm getting a bit of hunting.The book says turn air screws in then out two turns,which is what i'v done.How much more could i unscrew them to try and stop this bit of hunting?.
Regards
rob.
RPM on Javelin..
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rob needs
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rob needs
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More probs,head gasket?
I'll seal that vacuum pipe up pat,cheers.Now about my water problem,i seem to be putting an awful lot of water in lately.The oil is nice and clean (not milky)i went on a 20mile run this morning and the exhaust is still puffing out white smoke.Cant think where else its going,cant see no leaks,i do get water spitting out the tail pipe,more when starting thou.Can i check this with a compression tester,or one of those testing kits that detect exhuast in the water,which head?.
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Keith Clements
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White smoke
Most likely a head gasket or crack in the head.
Fill radiator right to the top with engine running and see if any bubbles are coming out. Alternatively test with special head gasket leak tester, it checks for CO in the water.
Another test is take out the plugs after leaving the car for a few hours and see if any are wet.
By the way, your fast running may be caused by this water injection.
Fill radiator right to the top with engine running and see if any bubbles are coming out. Alternatively test with special head gasket leak tester, it checks for CO in the water.
Another test is take out the plugs after leaving the car for a few hours and see if any are wet.
By the way, your fast running may be caused by this water injection.
Last edited by Keith Clements on Mon Feb 20, 2006 4:44 pm, edited 1 time in total.
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Keith Clements
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Loss of water
Before taking the heads off you MUST isolate the problem.
Over heating and loss of water can be caused by many things.
But let us cross check.
1. You are getting steam from the exhaust when the engine is at normal working temp, above 75degrees C. Thus it is not normal condensate.
2. When running the engine at 3000rpm there are no bubbles coming from the rad. Probably not a gasket.
3. The engine is not over heating and boiling the water when left for 10 minutes on idle, after a reasonable run up to temp, the temperature does not rise above 90deg C. This is just checking the thermostat is not stuck, the temperature gauge is actually working, the water pump is efficient, the heads or rad are not restricted.
4. The amount of steam increases every time when the throttle is blipped. This checks the water is being sucked in on induction stroke so the crack is into the inlet port.
You should make sure it is a cracked head and not just a gasket as cracks may be hard to find. It is probably possible for a spark analyser to detect which is the offending cylinder. Ask the garage. At the same time ask them to check the rad coolant.
Over heating and loss of water can be caused by many things.
But let us cross check.
1. You are getting steam from the exhaust when the engine is at normal working temp, above 75degrees C. Thus it is not normal condensate.
2. When running the engine at 3000rpm there are no bubbles coming from the rad. Probably not a gasket.
3. The engine is not over heating and boiling the water when left for 10 minutes on idle, after a reasonable run up to temp, the temperature does not rise above 90deg C. This is just checking the thermostat is not stuck, the temperature gauge is actually working, the water pump is efficient, the heads or rad are not restricted.
4. The amount of steam increases every time when the throttle is blipped. This checks the water is being sucked in on induction stroke so the crack is into the inlet port.
You should make sure it is a cracked head and not just a gasket as cracks may be hard to find. It is probably possible for a spark analyser to detect which is the offending cylinder. Ask the garage. At the same time ask them to check the rad coolant.
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rob needs
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I cleared that blockage in the taps with a bit of wire.When i refilled the rad and gave it some revs,i saw some bubbles so i'm taking off the right hand head first.The water transfer pipe would not clear the stud,and touched the body when i tried to remove it.I think i'll have to undo the engine mounting and jack up the other side,thats right isn't it?.
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Keith Clements
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Perhaps those more experienced with fixing Javelins on the road can comment; but I think you will also have problems removing the head in situ. You will need to remove the carburettor; but even then I am not sure the head will extract. I would take the engine out.
What made you think the problem was on one side and not the other?
What made you think the problem was on one side and not the other?
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Keith Clements
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If you are going to have the heads skimmed or even checked, there are lots of things to think about.
This is my suggestion. First go to the old JowettTalk http://keithclements.co.uk/jowetttalk/
and do a search using 'head'. You will see there a number of articles covering liner sinkage and checking for head/block warp.
All you need are feeler guages.
Also check for cracks between the valve seats. polish to a mirror finish and look carefully. Others may suggest ways of finding cracks using various potients and technologies.
If you are skimming you need to balance the combustion chamber volumes using a burette. You can skim at an angle to affect the balance. You must make sure you have enough meat left on the head before skimming. The tuning manual http://jowett.org/jowettnet/dt/tech/JAVELIN-TUNING.pdf shows how to improve combustion chamber gas flow prior to balancing.
This is my suggestion. First go to the old JowettTalk http://keithclements.co.uk/jowetttalk/
and do a search using 'head'. You will see there a number of articles covering liner sinkage and checking for head/block warp.
All you need are feeler guages.
Also check for cracks between the valve seats. polish to a mirror finish and look carefully. Others may suggest ways of finding cracks using various potients and technologies.
If you are skimming you need to balance the combustion chamber volumes using a burette. You can skim at an angle to affect the balance. You must make sure you have enough meat left on the head before skimming. The tuning manual http://jowett.org/jowettnet/dt/tech/JAVELIN-TUNING.pdf shows how to improve combustion chamber gas flow prior to balancing.
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rob needs
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On the right head (looking from the front) this is the one which i'm preety sure is the problem.The locating plate (centre stud) had a washer on it, when i placed a steel rule across this washer it rocks,take washer off and the steel rule lays flat across both cylinders.The other head didn't have a washer.
Keith, could you explain about balancing chamber volumes,whats a burette?.
Keith, could you explain about balancing chamber volumes,whats a burette?.
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Keith Clements
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Read the references in the old JowettTalk first. Then come back to the forum. If you are going to skim the head then you will raise the compression. You may also unbalance the combustion chambers which may cause pinking, hence overheating. So do NOT skim unless you have to.
Perhaps use a dictionary to find out what a burette is,
but see why you need one by looking at the tuning notes? 
Tuning has little to do with competition. It is about having a smooth running engine that is working efficiently.
Clearly the boiling may have been caused by incorrect pinch of the head gasket. The washer may have been the cause or the liners may have sunk, the head or the block may have warped. Replace liner seals with copper and then shim to correct height both available from JCS.
So, yes you have missed something!
Sorry to be so blunt but my rugby team, just lost again!
Perhaps use a dictionary to find out what a burette is,
but see why you need one by looking at the tuning notes? Tuning has little to do with competition. It is about having a smooth running engine that is working efficiently.
Clearly the boiling may have been caused by incorrect pinch of the head gasket. The washer may have been the cause or the liners may have sunk, the head or the block may have warped. Replace liner seals with copper and then shim to correct height both available from JCS.
So, yes you have missed something!
Sorry to be so blunt but my rugby team, just lost again!
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David Morris
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RPM on Javelin
Hi Pat,
Yes, the 0.005" would have been with new copper/asbestos gaskets. As I mentioned, and I believe you also suggest, the alternative is to go for a reduced torque on the stud nuts.
I also liked Keith's suggestion of doing all the tightening down slowly and measuring the gaps as you tighten up, which I believe Keith suggested doing before thinking about fitting the gasket. He also suggested that if the gaps widen after tightening, then you are looking at a suspect crankcase.
Our crankcases are all old now, and need lots of TLC. I seem to recollect reading somewhere that there is a chemical reaction always at work within the cranckcase alloy, which will eventually reduce their inherent strength and probably is the root cause of cracking.
Having heard the sickening 'crack' as a crankcase splits, I am cautious about tightening-down at the factory recommended figures for liner protrusion and stud nut torques. By the way, when this happened to me, I took the whole engine, complete, to a firm of aluminium welders and they welded it up, just as it was. The engine continued to run well afterwards!
All the best,
David Morris
Yes, the 0.005" would have been with new copper/asbestos gaskets. As I mentioned, and I believe you also suggest, the alternative is to go for a reduced torque on the stud nuts.
I also liked Keith's suggestion of doing all the tightening down slowly and measuring the gaps as you tighten up, which I believe Keith suggested doing before thinking about fitting the gasket. He also suggested that if the gaps widen after tightening, then you are looking at a suspect crankcase.
Our crankcases are all old now, and need lots of TLC. I seem to recollect reading somewhere that there is a chemical reaction always at work within the cranckcase alloy, which will eventually reduce their inherent strength and probably is the root cause of cracking.
Having heard the sickening 'crack' as a crankcase splits, I am cautious about tightening-down at the factory recommended figures for liner protrusion and stud nut torques. By the way, when this happened to me, I took the whole engine, complete, to a firm of aluminium welders and they welded it up, just as it was. The engine continued to run well afterwards!
All the best,
David Morris
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David Morris
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RPM on Javelin
Hi again,
Having just re-read Keith's excellent advice on liner sinkage, I should have, of course, said the if the gaps decrease ( not increase! ) after tightening up to Keith's 20lb/ft without a gasket, then this would indicate somthing is amiss.
It's too early in the morning!
All the best,
David
Having just re-read Keith's excellent advice on liner sinkage, I should have, of course, said the if the gaps decrease ( not increase! ) after tightening up to Keith's 20lb/ft without a gasket, then this would indicate somthing is amiss.
It's too early in the morning!
All the best,
David