Hi Everyone
I’m certain my car could pull a little better than it does but it may be that the engine is still tight from previous owner’s recon. I’ ve carried out the normal checks and found that the plugs are black and the compression is 125psi on 1&2 , 150psi on 3&4.
I’m going to check the mixture with a couple of colour tunes and recheck the tappers using the information supplied by Keith.
The compression figures do seem odd to me as I would have expected them to be closer.
Any suggestion welcome.
Dave
Compression test
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alexander
- Posts: 139
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- Your interest in the forum: Javelin 1953 That has been off the road for a number of years needing some TLC. Also have a 1959 TR3a and a Francis Barnett 1951Merlin.
- Given Name: Dave
- Location: Warwick
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alexander
- Posts: 139
- Joined: Wed Nov 14, 2018 2:10 pm
- Your interest in the forum: Javelin 1953 That has been off the road for a number of years needing some TLC. Also have a 1959 TR3a and a Francis Barnett 1951Merlin.
- Given Name: Dave
- Location: Warwick
Re: Compression test
Sorry should read tappets not tapers
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Keith Clements
- websitedesign
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Re: Compression test
I like them within 10 psi but there are many reasons they may be different. The combustion chambers should be within a cc which i test with a pipette and some glass over them after the valve seating profiling. But you could do it in situ via the spark plug hole.
If the engine has not been run for a while, the valves may well not be sealing.
There are recons and recons
If the engine has not been run for a while, the valves may well not be sealing.
There are recons and recons
skype = keithaclements ;
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Barry20383
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Re: Compression test
It could be as stated due to not running. Had the same problem 130 on1 2 and 140 on3 4 now all 140 after running for a while. Engine stood outside for long time.
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alexander
- Posts: 139
- Joined: Wed Nov 14, 2018 2:10 pm
- Your interest in the forum: Javelin 1953 That has been off the road for a number of years needing some TLC. Also have a 1959 TR3a and a Francis Barnett 1951Merlin.
- Given Name: Dave
- Location: Warwick
Re: Compression test
Hi Everyone
As I said I was certain my car could pull a little better and once again carried out all the normal checks tappets, ignition timing, carb settings etc. Changed the coil points plugs and condenser with no improvement.( each change was checked before moving to the next so I would know what was the fault).
Took all plugs out and checked to see that I had the leads connected correct and getting a spark in the correct order.
Finally today I had the engine running and took each lead of in turn, this proved the car was running on tickover on four but I did get a jump on removing number 3 plug cap.Closer inspection showed very slight tracking on the plug cap so a quick change of cap and problems solved. What must must have been happening the car was fine on tickover and light load but once I accelerated the tracking would increase and the car would be firing on 3 . Why is it always the stupid things that trip you up ?
Dave
As I said I was certain my car could pull a little better and once again carried out all the normal checks tappets, ignition timing, carb settings etc. Changed the coil points plugs and condenser with no improvement.( each change was checked before moving to the next so I would know what was the fault).
Took all plugs out and checked to see that I had the leads connected correct and getting a spark in the correct order.
Finally today I had the engine running and took each lead of in turn, this proved the car was running on tickover on four but I did get a jump on removing number 3 plug cap.Closer inspection showed very slight tracking on the plug cap so a quick change of cap and problems solved. What must must have been happening the car was fine on tickover and light load but once I accelerated the tracking would increase and the car would be firing on 3 . Why is it always the stupid things that trip you up ?
Dave