getting my 1341cc running.

[LeonBritton123]

The problem ive got is that cylinders 1 and 4 have 0 compression and cylinders 2 and 3 make 9 bar from cold.

Originally I melted a piston in cylinder 3. Since then Ive taken the engine out and replaced the bottom end with a 1341cc with forged pistons. Ive kept the same head but replaced the valve stem seals and reseated the valves plus a 1341cc cam in there.

anyone have any ideas what could cause this?

[hayesey]

valves not reseated properly?  Warped head or something?

I'd do a leak-down test using a compressor to listen to where the air is escaping. 

[LeonBritton123]

I numbered all the valves and used medium and fine paste on them all, i doubt it would be the valves? and i done a compression test on the engine before i took it all apart and cylinder 3 was 0 oviously, but cylinders 1,2 and 4 were low but still had compression, i thought they were low because the head gasket had gone.

[breadman]

Damn Leon, that's a right bastard ain't it? You've been really unlucky with this engine eh?
So assuming the 1341 short engine is all ok (Phil J?) and the head is ok, which it sounds like it should be from what you say you've done - what head gasket did you use? I'm pretty certain you need a different head gasket for the 1341/77 mm bore? 

[hayesey]

no you don't need a different head gasket.  I would do a leak down test as I said as it will tell you where the air is actually leaking from. 

[LeonBritton123]

Yea nothing but bad luck with it, the water pump didnt have any fins on it and the clutch was suprising it still worked but ive been spending out so i got lots of fresh parts on it now!
Yea i really doubt it would be then bottom end as phil had only done 1200miles on it,theirs a possiblity the heads warped but looking at it, it looked flat but you can never tell properly. i used a europarts head gasket, it fitted nicely.

[breadman]

Ok I stand corrected on the head gasket issue. I would've though the fire rings were too near the edge of the bores to seal properly, but obviously not.
If you can't get a leak down test carried out at home, why not remove the cam so all the valves are closed and then spin it over? It'd prove the short engine and head/valves/gasket were all ok?

[breadman]

Actually, thinking about it my last idea is a pretty crap one!

[G-spot]

theirs a possiblity the heads warped but looking at it, it looked flat but you can never tell properly. i used a europarts head gasket, it fitted nicely.

If the head was warped then you'd be loosing water or pressuring your water system with compression air at least, so I'd be more inclined to do a leak down check, and as breadman suggested, loosen of the cam and ensure all the valves are seating properly.

Still to get 0(PSI i assume)compression then something is certainly not right.

[LeonBritton123]

a leak down test will cost me £60 for a kit, i can get hold of a compressor too. But to be honest id rather use that to get a decent head on it, new bolts and a gasket, spend a day on it and then id know it was going to be reliable.

If anyone has a good g40 head, youve got a buyer right here!

[Nick_S]

To check the valves are seating properly, turn the crank by hand so that each cam lobe is 180 degrees away from each tappet. Each tappet should spin freely with your finger tips, if not then the valve won't have full closure.

[LeonBritton123]

cheers for the help so far, soo much more helpful than club polo!

[hayesey]

sod buying a proper leak down leak "kit"  I just smashed out the innards of an old spark plug and welded an air line fitting to it.  Then just pressurise the cylinder and listen to where air is escaping.  It wont tell you how much air like a proper kit would but it doesn't really matter, it'll tell you where the air is getting out which is all you need to know.