Engine work continues

[Andydesperado]

Hi, my work continues with some poor running. After doing some checks the below images. The wet plug is on 1, dry on 4. Min compression on 1 blew off my compression gauge on 4, it’s a hand held on one. I have to put s little oil in 1 cyclinder to see if there is a difference. Hopefully not but possibly valve stem seal gone....any comments. It likely then the heads coming off. Might as well do head gasket and rocker cover gasket too. The cover Allen bolts are a little tight so will have to work on cracking them off. Nice clean in there too.

Doh nevermind

Cheers andy

[triton28]

Andy;
In my opinion, which more often than not is incomplete, if after you put oil in cylinder #1 the reading went up then you probably already know you may be headed for rings and/or a deglazing of the cylinder walls. If no change then either a stuck/burnt or poorly seated valve/s.
The stem seal has no bearing on compression BUT could explain the wet deposits on the plug as the oil in the valve spring area is bypassing the seal by piston travel vacuum and being mixed with fuel in the combustion chamber. OR,
you have oil bypassing worn oil control rings along a smooth cylinder wall and that could be the oily deposit on the plug.
If you are certain of your procedure on testing compression and you get the same low compression on #1 it will probably mean an engine R&R and top end rebuild. Not cheap as each set of rings, 4 required, costs a minimum of $46.00 USD per piston, not to mention the cost of head, head cover, base gaskets and cost of a deglazing.
As Carl Leo told me about removing the engine, "Make sure you have a heavy towel/tarp on the rear vertical face of the front fender as the motor will usually tip forward and gouge the plastic". I used a piece of plywood and sure enough the exhaust studs left a gouge on the plywood.
If you do a top end rebuild pay particular attention to the 3 piece oil control ring during the cylinder reinstall as the top and bottom rings of the 3 piece oil control ring are VERY thin and especially the top ring is easy to displace from it's designed location above the corrugated, oil rings separator, the bottom ring not so much. Failure to pay attention here can be unforgiving.
AND, make sure to have a thorough understanding of the cam timing as these are interference engines and the piston will contact the valve face if the timing is off.
Other than that it is pretty easy except for the long laborious task of lapping 16 valves. I use a 1/4" length of steel rod inserted into a longer length of 1/4" poly tubing and the protruding stub of the rod I put in the chuck of a variable speed drill and the poly tubing presses onto the valve stem. Then it is slow RPM and steady in/out of the valve but it is easier than hand lapping. (Hand valve lapping purists can shudder here!)
I hope you find some easy solution to your compression reading on #1 and that the oily deposit clears up.

[Andydesperado]

Thanks for the reply, wow.

I’m only going to be doing a few hundred this year, till nov time. I’ll run it as is, with a stroke of luck it may sort itself out?... I can then tear into it. On the plus I got the carb balanced....slowly slowly .....

Cheers Andy