Engine compression

[Gizze]

Hi,
I'm finally getting round to putting my +2s onto the road. The plugs are oiling up very quickly so I've checked compression dry and 'wet' with oil dropped into the bores:

Cylinder 1 165 and 215 (wet)
Cylinder 2 155 and 220 (wet)
Cylinder 3 160 and 190 (wet)
Cylinder 4 155 and 205 (wet)

The car came with a cylinder head rebuild invoice for ?1400. This and the results above make me think the head is ok, but the block needs some attention (no documentation of any work on this). I'm a bit concerned about rebuild costs that seem to be quoted but otherwise machining aside, I'm reasonably happy to tackle the rebuild - any thoughts /advice would be welcome.

[twincamman]

i GET 180 ON A REBUILD BUT THAT CAN BE THE DIFFERENCE IN COMPRESSION GAUGES ---Do the rebuild your self if the oil pressure is low or there are any clunk-knocks or bangs . The motor is very sturdy at the bottom end -----ed

[Tonyw]

Hi,

The compressions look to be OK to me, I would have trouble holding the compression tester in the plug hole @ the pressures you are getting wet. The fact that you are getting a large increase in compression pressure wet though would suggest some leak down so you may need to pull your engine down and if the bores and pistons are OK re-ring it, my bet is you have some stuck piston rings.

I would try putting in some Redex or similar and letting that soak for a while ( may work but not likely) or run it for a while longer with hotter plugs to keep them from fouling up so quickly.

Tonyw

[twincamman]

the good thing about Redex is you will solve the mosquito problem for a while -----just drive the thing till you are sure you have a problem because something will fall off of break before too long , then you will have something to do ---ed

[Gizze]

Many thanks for the replies, and er, words of encouragement concerning bits falling off, all part of the Lotus experience I guess!
The compression tester I have is a screw in type hence i don't have to worry about holding it in whilst cranking the engine.
The Head is off already and the strip down is well on its way - I'll start the search for a decent machine shop next week.

[twincamman]

investing in a good spring compressor will pay huge dividends . The head is easy to disassemble and lapping in the valves is a pleasant saturday night pastime for us lotus owners with no life but keeping the bloody thing running right ----ed .

[45bvtc]

Alternatively: make a Schrader tyre valve/spark plug adapter (an old spark plug, a tyre valve, and some initiative works great).

Remove all spark plugs, select 4th gear, and apply the handbrake.

Fit the adapter to the first (whichever) cylinder and, using a tyre pump, or similar, pressurise the cylinder - 20psi is more than sufficient.

Now listen.
1) Air bypassing the inlet valve will be heard via the carburettor choke inlet.
2) Air bypassing the exhaust valve will be heard via the exhaust pipe outlet.
3) Air bypassing the piston rings, and there will always be some (hot or cold) will be heard via the oil filler cap and/or breather tube.

Others can/will disagree and/or have other options, etc., but there you go.

Me, owned and maintained Elans, Europas, etc., for 40-odd years. What do I know?

However, I can supply photographs of my own homemade adapter.

[email protected]

[Foxie]

Alternatively: make a Schrader tyre valve/spark plug adapter (an old spark plug, a tyre valve, and some initiative works great).

Others can/will disagree and/or have other options, etc., but there you go.

Me, owned and maintained Elans, Europas, etc., for 40-odd years. What do I know?

[email protected]

Excellent advice

[twincamman]

I made mine from an air inlet and a pipe with a spark plug -but I use the compressor for constant pressure --ed