Blairm
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| posted on 1/3/09 at 01:16 AM |
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X-flow compression problem
Hello All,
I am hoping someone may be able to point me in the right direction.
My X-flow started running really rough and I decided it was ignition. I fitted a electronic trigger and removed the points. Set the tappents,
checked everything else out and got it running. Still running rough so I borrowed a mates compression tester.
Pot 1 60, Pot 2 65, Pot 3 120 and Pot 4 135.
I have just realised that I forgot to open the throttle. I assume the DOCE's would not cause the compression to be as low as 60 if butterflies
shut? Port 3 and 4 made some pressure in the same state, but not as high as I would have hoped and maybe that can be blamed on the trottle?
Anyway, it was not getting hot and there is no sign of water in the oil tank (drysump) or under the rocker cover. But since both 1 and 2 were low I
figured it must be a head gasket.
I removed the head this morning and I can not for the life of me see any area of the head gasket that looks like it is leaking.
What do people think. Grab a new head gasket and bolt it back together or should I be looking further first?
Thanks Blair
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Paul TigerB6
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| posted on 1/3/09 at 01:59 AM |
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Seeing as its appart then i'd sort a new head gasket and repeat the compression test once it is all back together. Check the head with a steel
ruler / feeler guages etc though to see if it is warped before refitting. Given the evidence i'd agree with your assumption of a leak between
cyl 1 & 2
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britishtrident
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| posted on 1/3/09 at 09:28 AM |
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The xflo dosen't generally blow head gaskets.
The difference in compression readings with the throttles closed may well be due to the front and rear carb butterflies being out of synch. Which
would also explain the rough running.
On cars with twin DCOE carbs always check the carbs ie jetsare clean and the jet holders properly screwed home and the throttles for
synchronisation before stripping anything more major.
[Edited on 1/3/09 by britishtrident]
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thunderace
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| posted on 1/3/09 at 09:54 AM |
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i would take the rocker cover off torque the head and try comp again before you take the head off 
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rusty nuts
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| posted on 1/3/09 at 10:18 AM |
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Before you go any further it may be best to check for valve leakage> With the manifolds off stand the head so that the ports are uppermost ,
carefully pour parrafin, petrol or degreaser into the ports and watch around the head of the valve for any leakage . repeat for all valves , should
only take 5 minutes and won't cost you a gasket set. Any leakage the the head will need stripping , valves lapped in etc. Look for any signs of
piston ring breakage befroe refitting the head . Might be worth repeating compression test , if any cylinders are still low the a little oil down the
plug holes and repeat test. If compression rise by more trhan about 10% the rings/pistons/bores are at fault. As BT says it may be carbs out of
balance.
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Blairm
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| posted on 1/3/09 at 05:53 PM |
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Thanks Rusty Nuts (and every one else who replied),
My brother suggested petrol down the ports last night which I did with the head on its edge on the bench. Leaked like a sieve. So of to get it
lapped. I hope this is all the problem is 
Thanks Blair
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