Lost compression to #1, but no clue what the issue is

[audiocontr]

Closing this thread out. Fixed the issue with a degloss on the jug and a new set of rings. Has WAYYYYY more power now, starts instantly. Thanks to Jim for diagnosing via photos.

I replaced all the gaskets while i was in there as well. No more exhaust pop!

[Garrycol]

Thats great to hear I am surprised it was that though with a relatively new engine but these happen. I hope you did both cylinders though.

Now go out and enjoy - I just did a 100km drive yesterday out in the country and while slow was a great drive.

Garry

[audiocontr]

and just like that... were gonna yank the engine out again.

Noticed a lot of oil below the filler neck. Checked the oil level and saw it dropped substantially with little mileage. Upon startup, i noticed a strong pressure pushing out the filler neck. Seems i have a ton of blow by. Plugs dont look very good, especially the problematic cyl from before.

I'm going to yank it and tear it down again. Not sure what the issue is

[Heinkeljb]

If the rings and bore are okay, then probably you have a fault in the cylinder head. A crack or a valve(s) not sealing properly. Check by filling the combustion chamber with petrol and see if you are getting any petrol on the other side of things. I.e. in the inlet or exhaust tracts. Also for crack in the head, is there sign of petrol in the valve train area.

Sounds like you are leaking air into the rocker box area which can then go down the oil return tube and pressurise the sump.

John

[Joeri]

Check the oil presure returnvalve in the oilcap ( parts 3-4-9) ...

[audiocontr]

How much pressure should the fill neck have when running? Should I be able to place an empty soda can on the top without it being blown off?

[Joeri]

How much pressure should the fill neck have when running? Should I be able to place an empty soda can on the top without it being blown off?

NO.....when the engine is good , and has a good compression on both cylinders then a empty soda can will be blown of the fill neck...remeber that these 2 cyl dont realy have a oilpan ? A common mistake some make is that they claim that theres no cyl one and two ,but they are wrong....when the mark on the pully is in line with the mark on the fan housing the cyl on the right ( standing behind the haff ) should be number one. This is a 2 cyl boxer engine and not a 2 cyl opposed twin ( like a briggs&stratton or kholer ). Any how....if the pressure release valve in the cap was some how taken apart to clean or somethin else and been assembeled wrong then you get the same problem...oil wil blow out every seal like the rubber gomets that are around the oil return pipes from the cylindercaps...i once had this problem with my ' 74 civilian haf

[audiocontr]

interesting! Thank you very much!!