G22 Turns over but no combustion after CCCG replaced

Hydra-ulic

Hi all I replaced the crank case cover gasket on a yamaha g22 at work today. Sadly, when i pulled the CCC the cam shaft and balancer came out with it

(once the ccc is seperated a few mm I would put a flat head in to prevent this in future... lesson learned)

I put the camshaft back in with the mark lined up with the mark on the crankshaft. And balancer back in with mark lined up with its mark on crankshaft. (crank shaft has two gears fused together one for balancer one for cam shaft)
The balancer gears go around twice for every time the cam shaft spins once, meaning the mark on balancer lines up with its mark on crank shaft when the cam shaft mark is lined up with its crankshaft mark and when cam shaft mark is 180 degrees away from crankshaft.

Is it always fine to line the marks up and go or due to the cam normally being either lined up with its mark when balancer and crank are aligned or 180 degrees away when they are aligned did i take a 50/50 shot?

Both the exhaust and intake tappets the cam shaft moves are in place.

I rotated the primary sheave(clutch?) manually before having starter turn the engine over, and it rotated free enough with some resistance on compression stroke(and completely free when plug was removed) but i did notice it was a bit harder to turn than another g22 and has some air vacum sound internally before refilling with oil.

Now the starter turns it over, I feel compression with my thumb over spark plug hole, and some vacum on down stroke. But from what i can tell no fuel is entering (see no flow in the fuel filters when starters turning it over, and plug is not as soaked as i would expect)

I'm not really sure where to go from here, I have verified spark. Compression verified with thumb on spark plug hole(although i could get a compression gauge on it if desired). There is no attempts at combustion whatsoever, it just turns over and over from starter with no sign of life from engine.

Should i try to start it with starter fluid? Pull the head and look at the valves?


Please help

I can post pictures of the marks on cam and balancer or video of what it sound like or anything required, some guidance would be great but without it I will be checking valves tomorrow or trying starter fluid.

Edit: It ran before the cccg replacement is why I do not suspect fuel issues, I more suspect the valves are not drawing fuel/air sadly :( Will look at valves tomorrow/pour through the service manual and see what i get

BGW

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smallblock450sl

Did the cam/crank and balance marks look loke this with piston at top dead center?

Attached Images

g22 timing marks.jpg (44.9 KB, 0 views)

Hydra-ulic

yes exactly like that, I did not verify TDC of piston however I presumed the crankshaft in that orientation would be tdc was this an incorrect presumption?

It manually turned over by hand before i started it up by if i have to replace valve(s) at this point so be it. Will get a look at valves tomorrow.

Edit: I presume i inadvertantly took a 50% chance of cam shaft being 180 degrees off by not checking TDC, this is due to if the balancer on the right was spun 360 degrees and lines up with crankshaft again the cam on left would be 180 degrees from its mark(balancer on right lines up with crank twice for every one time cam on left lines up with its mark)



Does this sound like what happened? What damage would this do? I did not forcefully turn engine over just rotated primary sheave by hand when reassembled a few full rotations before attempting start(start attempt did not jar or make odd noises either just sounded like a starter turning over a fuelless engine)

Hydra-ulic

yeah i'm guessing I found TDC of the exhuast stroke not combustion.

intake >intake valve open exhuast valve closed
compression > both valves closed
power >both valves closed
exhuast > intake valve closed exuast valve open

Would have become

intake >both valves closed
compression > intake valve closed exuast valve open
power >intake valve open exhuast valve closed
exhuast > both valves open

If it even made it that far before damaging valves. I may be looking at replacing both valves i presume and possibly a piston ring if both valves were closed on the intake stroke?



If this is all true then lesson learned, use the marks on cam/crankshaft AND find TDC of COMPRESSION stroke... will post tomorrow with what valves are looking like

Edit: The tappets visible in crank case are solid tappets that push directly on valves i presume?

Hydra-ulic

I have been busy at work with other tasks but will be delving into this first thing next week. I did have the cam 180 degrees off (lined up with end of exhaust stroke instead of end of compression stroke) and learn from my lesson here that just lining up the marks on cam/crank is not sufficient, you must verify TDC of compression stroke via guage(or putting thumb over plug hole) and line marks up(prob a amateur mistake but won't make it twice). Flipping cam correct still results in no combustion meaning there is likely damage to valves despite me having turned it over by hand prior to starter driven turn over. (My guess is they are delicate enough for even hand turn over to damage?) I will access valves on monday and post results here. Good thing is it's one of 36 beat up g22s our course has not a customers and only one in fleet down, so no urgency. If you ever wondered what a 180degree cam flip on a g22 does stay tuned

Any guesses, info, or blowout of the valve assembly feel free to post here(although I have a g22 service manual at work it calls for removal of engine for cccg replacement is why i was not following it)

Hydra-ulic

Ending: I indeed inadvertantantly took a 5050 flip when I lined up the cam/crank shaft marks of being 0degrees off or 180 and landed on 180 degrees off on first reassembly. The push rods became unseated from rocker arms due to this with very little force(hand turn over) and no damage was caused. Reseating push rods to rocker arms and flipping cam 180 degrees solved problem easy fix. Note the g22 service manual DOES NOT MENTION THIS TO MY DISBELIEF, it just says line the marks up on cam to crank and crank to balancer. But does not note the balancer lines up with crank at both 0 and 180 degrees of cam and crank and does not say to verify tdc of compression stroke to ensure its correct. This can easily be done with a compression gauge, thumb over spark well, or best way just remove the front valve cover and find the upstroke where both rocker arms are inline(compression stroke as both are.closed valves). (On exhaust upstroke rockers are not inline as intake is closed exhaust valve open)

End of story, happy ending, learn from my mistakes here if ever replacing the cccg(A common leak on g22s as I have two more g22s to do this on.

Edit: just ask or pm me if you have a question for the g22 service manual.

SandbaggerYDRA

This really has me sitting here scratching my head. From what I know, the crankshaft rotates through a complete cycle from TDC to BDC and back again in a single revolution. It is the camshaft that makes the distinction between the top of the compression stroke and the transition between exhaust and intake stroke. The timing mark on the crankshaft lines up to the same spot on every revolution. There is no way that it can be anywhere other than TDC if the mark is aligned with the camshaft. In fact, you could theoretically align the camshaft 180 degrees on the other side of the crankshaft mark, and it will still run, because all you've done is swap the compression for exhaust/intake strokes, and a single rotation of the crankshaft will bring the marks into alignment again.
I believe that the push rods coming unseated is why it didn't run the first time through, but that should not have been related to the timing mark alignment.