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Gareth_C
08-09-14, 09:24 AM
Hi guys this a bit puzzling, I was racing my 14se at the weekend. Previous to racing all four cylinders were equal at 200psi, I check the pressure after it failed and I had 1) 30psi 2) 30psi 3) 200psi 4) 200psi. And there was pressure in the breathers. I've took the head off the gasket is fine, I've poured oil in the bores and there not passing. The only thing I can come up with has the head warped or lifted due to the comp stil being in the oil ways.
Any suggestions please guys.
Benn
08-09-14, 09:28 AM
Valves lifting/leaking?
Gareth_C
08-09-14, 09:36 AM
Valves lifting/leaking?

The valves have been questioned I had a quick look and the there was no obvious bent ones and they looked ok but I sort of rules them out as all the pressure seemed to be oil ways and breathers.
meritlover
08-09-14, 10:55 AM
pressurised breathers would suggest rings.
Stuart
08-09-14, 12:07 PM
and an oil in bore test isnt really conclusive imho as a static test may pass but a dynamic one with the fun of compression can blow past. A leak down test would have been more conclusive.
jimbob-mcgrew
08-09-14, 12:27 PM
A leak down test would have been more conclusive.

^ is that where you fill it, and leave it overnight stu ?

+
you may be able to do a rough-check on the head with a real thin feeler gauge slid underneath a spirit level, and check it all over, although you need a pretty damn accurate steel level to do it properly.

is there oil in the water and water in the oil ?
spot any cracks in the head ?
meritlover
08-09-14, 12:54 PM
a leak-down test is a pressuiresed compression test with an airline, where the pressure applied shows a drop off across a restriction depending on the 'flow' due to leakage in the cylinder.
jimbob-mcgrew
08-09-14, 05:50 PM
ah, i see
Andy
08-09-14, 05:53 PM
Leak down test is the only way without throwing parts at it
Gareth_C
08-09-14, 07:43 PM
Cheers guys hindsight I should of put the leak down tester on it first. Daft as it sounds if I put the head on but didn't time it up that would give the same reading as filling the chamber on the compression stroke am I correct?
Andy
08-09-14, 07:46 PM
As long as the valves are closed on each cylinder that should be ok,hardly much extra work to time it up after all that.but I cant for the life of me believe you cant spot something obvious that's making it run that low compression! Generally that low is no valve/hole in piston!
Gareth_C
08-09-14, 07:59 PM
As long as the valves are closed on each cylinder that should be ok,hardly much extra work to time it up after all that.but I cant for the life of me believe you cant spot something obvious that's making it run that low compression! Generally that low is no valve/hole in piston!

Absolutly nothing mate that's why it's thrown me, there is no play In the pistons, the bore have no marks on them, the valves are all in tact and hold petrol in the chamber.

its baffling that's why I was blaming the gasket and bolts as they had tech been used more than once
Stuart
08-09-14, 08:14 PM
You could bolt the head down with no cam fitted to keep the valves shut but you will write off a head gasket and maybe a set of bolts if you feel anally retentive
Gareth_C
08-09-14, 08:35 PM
You could bolt the head down with no cam fitted to keep the valves shut but you will write off a head gasket and maybe a set of bolts if you feel anally retentive

Tbh Stuart I was thinking of building it back with the gasket and bolts that I took out to try to replicate the engine before a stripped it
tom reid
08-09-14, 08:39 PM
Were the head bolt holes in the block cleaned out properly before you fitted the head?
Gareth_C
08-09-14, 09:05 PM
Were the head bolt holes in the block cleaned out properly before you fitted the head?

No Tom they weren't would that cause a problem
Andy
08-09-14, 09:13 PM
Its unlikely as it would have ran crap to start with
170psi loss is massive.It has to be going somewhere big.
Valves open and close ok?
meritlover
08-09-14, 09:18 PM
Tbh Stuart I was thinking of building it back with the gasket and bolts that I took out to try to replicate the engine before a stripped it

what's the point? clearly something is wrong, and whatever it is the head will likely need to be off to fix it.
Gareth_C
08-09-14, 09:20 PM
what's the point? clearly something is wrong, and whatever it is the head will likely need to be off to fix it.

This is just to carry out a leak down test not to actually run the engine