Compression?

[sihi]

Hi. I want to share with you my new experience...
I finished lapping valves all was checked by leakage test ---all seal good . (I started this job because of worn valve seals- at starts it smokes really much)
I polished piston heads like mirror.
Installed new Oem cylinder head gasket.
Than I checked valve clearances all good and adjusted.
I reassembly cylinder head cover also with new oem gasket.
New exhaust sealing and clamps
I didn't put on carbs
Compression test results:

Before maintenance

cylinder	1	2	3	4
psi	190	170	170	175

Immediately after reassembly after 2 months from last running
[TABLE="align: left"]
[TR]
[TD]cylinder[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]psi[/TD]
[TD]156[/TD]
[TD]140[/TD]
[TD]130[/TD]
[TD]150[/TD]
[/TR]
[/TABLE]



After 1,5 tea spoon of engine oil
[TABLE="align: left"]
[TR]
[TD]cylinder[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]psi[/TD]
[TD]195[/TD]
[TD]180[/TD]
[TD]180[/TD]
[TD]210[/TD]
[/TR]
[/TABLE]





Actual valve clearances
[TABLE="align: left"]
[TR]
[TD]valve[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[/TR]
[TR]
[TD]Ex.[/TD]
[TD]0.04[/TD]
[TD]0.06[/TD]
[TD]0.05
2.60[/TD]
[TD]0.08[/TD]
[/TR]
[TR]
[TD]In.[/TD]
[TD]0.08
2.65[/TD]
[TD]0.05[/TD]
[TD]0.03
2.6[/TD]
[TD]0.06[/TD]
[/TR]
[/TABLE]








Where is truth or how bad is that ? Manual says (142 - 199 psi)

 

[Steve]

After two months of not running, the numbers are not bad. When the numbers come up with a little bit of oil, you can see that the rings were not sealing at first. Running it for a while will take care of that. Those "wet" numbers are rather excellent, considering a cold engine. :encouragement:

You might also consider putting a 2.55 shim in IN3. All the other numbers look really good.

.

 

[sihi]

Thanks Steve. I wasn't sure.

 

[JTGS850GL]

Some drop in those compression numbers might also be associated to having removed a layer of carbon buildup on the piston heads. Those numbers still look very good. I wouldn't worry.

On a side note, I see that you didn't replace the base gasket. Keep an eye out for oil leaks around the base. Very common when you untorque the head and don't replace the base gasket.