Help needed with sb 318

[H Monster]

Went to my industrial engine service manual, and it is silent on the subject. It does, however, devote two pages to servicing the exhaust manifold heat control valve? Who among you has one and who services theirs every 4,000 miles of 50 hours? I never knew it existed.

 

[NC Engine Builder]

Those are air injection holes, block them off

 

[mygasser]

most of those heat control valves/flaps i've come across i've removed and welded the shaft holes shut. the bloody things seem to have an annoying rattle when they're a few years/miles old and i'm sure you won't be worried about emissions so......
neil.

 

[Woody500]

So to clarify what I think I'm hearing, when timing chain gears are dot to dot, that corresponds to TDC of the #1 cylinder exhaust stroke. Then, since cam gear is 6 inches, crankshaft gear is 3 inches, that is 2:1 ratio, so if you lined up timing mark on harmonic balancer, then turned crankshaft 1 full turn to line up again, that rotates cam shaft one half turn, or 180 degrees, at which time now TDC for ignition stroke #1 cylinder. #1 plug would fire there. (Normal operation.......not way mine is rigged now)

So on to NEW drama. Went and checked, and with cap and rotor removed, I have roughly 10 inches headspace above the distributor. Above that is a hard deck. If it takes more room than that to pull a distributor, it is staying where it is. Plug wires staying where they are. I'd have to drop the engine to gain more space.

View attachment 1716444864

View attachment 1716444865

But.....engine is running as is. Would be desirable to rig it right, but runs as is. And now for new problem with timing chain. I figured if nothing else, could line up existing gears, dot to dot. Then pull off old and without moving anything install new. Nothing would be changed, except deletion of a worn out timing chain. Not that easy. I can see the dot on the crankshaft gear, the smaller one. I can find NO dot on camshaft gear. Is it even possible to install that inside out?

Green arrow points to crankshaft dot. Cam dot ought to be straight up or straight down. Not one either place.

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Scrape the camshaft gear to be sure th mark is not there, that oil stuff on it looks thick.

 

[Woody500]

I wonder if there is timing marks on the back side the flywheel side? for using a timing light?

Here is what "AI says" in reference to a 318 marine engine (boat engine)

Unlike automotive versions, most 318 marine engines lack a traditional timing tab on the harmonic balancer; instead, an arrow on the bell housing points to the mark on the flywheel

If it is a Marine flywheel, there is a series of marks on the LM318 flywheels. IIRC they are marked to fit both LH & RH rotation, and with the low production numbers that might be the case. Twin engine boats have counter-rotating engines to cancel Torque steer, and make Slow Speed manuvering easier/better.

......continued from just above.....I'm confused how my post happened to get into his quote, sorry!
The Marine Bellhousing is aluminum, and has a large rectangular hole at top(maybe 2-1/2 × 1-1/2 w/a rubber plug), so you can see timing marks.
So turn it, clean all the marks to be sure how it's marked & look closely to find, and then mark proper set of marks with a paint pen, or even nail polish works
Use white or yellow for visibility.
Marks probably hard to see if different bellhousing used w/marine flywheel.
Don't know how I got part of my answer to go into Dartswingers above, so just reread it in his above quote to get my whole post on LM318 flywheels.
At least I was able to separate Dartswingers previous post from my LM318 info, sorry if any confusion.

 

[H Monster]

This is how I went about establishing timing marks. Went to a salvage yard and got a rough old harmonic balancer off an early 80's pickup, with 318. Used timing mark on that to rotate crankshaft to TDC. Then pulled the harmonic balancer and replaced it with the big pulley piece. Then used the TDC marks on the timing cover to put a timing mark back onto the pulley. So this is what it looks like now.

Neighbor dropped by this evening with his timing light and we reset it to about 10 degrees or so before TDC at 1000 RPM idle speed. Engine calmed down and sounded good. Had been closer to 30 degrees......enough advance it may have been causing trouble starting when hot.