92 replies to this topic

[minitomfoolery]

you'r crankcase breathers are connected up properly to the carb i assume? have you checked the oil isnt coming from them?

[camelotr]

Number one cylinder in the picture above still shows the worst. Just look at the inlet valve, its wet, the others are not. Could the machinist have broken into the oil gallery on cylinder 1 and 4 while fitting the liners and when the engine is warm, the oil is working its way up between the block and liner into the chamber?. What size liners are they? What size pistons are fitted?

Its well known that boring to 73.5mm and above can be a hit and miss affair at times. There are two oil galleries to the left of cylinder four, and one to the right of cylinder one. All cylinders have the main gallery run across the front of them.

Pistons are std size, liners are around 74mms.

According to the machibe shop, it is impossible for the oil to work its way up between the liner and the block. (?)

[camelotr]

the only other thing I can think of is valve stem oil seals on inlet valves............

thats what i am thinking,
are the valves oilly in the ports? or are they dry?

The ports itself are oily. Soo do the valves.
But I have tried 3 heads with exactly the same results.

[camelotr]

you'r crankcase breathers are connected up properly to the carb i assume? have you checked the oil isnt coming from them?

Breathers are not connected now to make diagnose easier.

[camelotr]

I have made an intresting observation today. If I run the engine with very low oil level (6-7mms below min), the smoke decreases. I still have normal oil pressure though, and the head still gets oil normaly.

What would You say then?

[CobraV8]

How much oil are you using to fill from empty? Is it possible that you have the wrong dipstick or been overfilling?

[camelotr]

How much oil are you using to fill from empty? Is it possible that you have the wrong dipstick or been overfilling?

I use aprox 4.5-4.7 liters.

[Sprocket]

Its clearly not the hear, that only leaves the block

[camelotr]

After running the engine with very low oil level, I have found the smoke to be better. I think the only thing thats affected by the oil level is the load of oil thrown up on the cylinder wall by the gearbox. Soo I suspect piston-ring-liner problem.
Can incompatible liner-rings cause such a drama?

[camelotr]

One final question:

Is the fitting direction important on an AE piston? It looks simmetric fro me...

[jaydee]

Do they have front markings on them, dont they?

By the way I'd investigate the oil galeries, that a fairly ammount of oil..

[camelotr]

Do they have front markings on them, dont they?

By the way I'd investigate the oil galeries, that a fairly ammount of oil..

Unfortnatly they dont have "front" marking or any other direct direction indicator.

[camelotr]

?

[dklawson]

If I failed to mention this earlier, you may want to put the head back on and perform a leak down test on each cylinder. The leak down test should quickly identify if you are having ring related problems as you mentioned above.

You said earlier that the breathers are currently disconnected. Do you mean the connection points are open or that they are capped/plugged?

[camelotr]

Breathers are now open to the air.