Overhauled G-9, Questions

[TheNewGuy]

Thanks for the update Joe, this is interesting.

[Flintrock]

It almost makes sense that the con rod has a specific orientation, per EZG's comment on the VW rods? Can't remember.....

[stricks1]

I have the same problem. Fresh rebuild and knock at mid RPM only. Low RPM and WOT no knock. .50mm over piston, .020 milled head, new bearings everywhere and assembled correctly. One thing to note is that the knock is not terrible, it’s very light, but it’s definitely not supposed to be there. I can even hear it when I rotate the engine over by hand when I get to the spot and rotate it back and fourth. I honestly think my cam bushings or balancer bushings are making the noise. I pulled the engine apart right away and checked everything again. I have actually had the crankcase cover off 3 times checking things out and I can’t find anything wrong. I gave up and started driving the cart with the noise thinking something would show up after a while. I now have approximately 200 miles on the cart and remove the crankcase cover to see if I locate the problem, and of course NO signs of damage, not even strange bearing ware. I give up unless someone has figured this type of problem out.

[qmaziggy]

I have 1994 G8 that I overhauled and heavily modded. The engine was overbored .25mm (.010") with .002" piston to bore clearance. I welded in the combustion chamber and then machined it and installed big seats and valves. I cut the head approximately .050" and added a programmable MSD ignition and bumped the rev limiter to 5000 RPM's. I built a custom long exhaust with a motorcycle muffler to let it breath. It has rattled since day one, I took it apart twice to recheck everything and my guess is that the higher compression may be causing piston slap under light load. I have run it hard, right up against the rev limiter, with no issues. I'm not sure what to offer, except it doesn't seem to get worse, or cause any issues.

[mghave]

I found this thread very interesting as I had very much the same issue. I would describe my noise as more of a click, and it seemed to come from the "flywheel side". I first thought slinger, then rod orientation, then counter balance (why not a "real" timing mark!?) and used that old BGW thread to count teeth and line it up. Still this annoying click. With the crank cover off, I can rotate by hand through bdc and it "clicks". Engine ran fine for quite a while. The engine has since had other issues so it is now a spare, but I will dig into it again trying to locate this mysterious noise.

[Wynelocked]

I found this thread interesting too.I just did some "trade out" deal for a new crank,rings and bearings for my broke G2.I did NOT mark nothing when I pulled it apart...Some pictures would be nice...to know what I do when putting this back together.

[rkggoodman]

well i hate to say it but your gonna have to tear down the engine, i think youll find the balnce shaft hitting the piston skirt ever so slight,just trim down the piston about 0.004 in but do this on both sides of yr g-14 piston,the engine can and will run without the balance shaft, at high rpms then u will notice a vibration, note also, these engines didnt have ballberings in them , they were stock aluminium mounts for the cam and balance shaft on both ends,

[EZ-GOnewild]

Did you ever figure it out joefixit?

[jiminpa]

I don't know if you could hear it when turning it by hand, and you probably checked it, but you did not mention the wrist pins. Did you check to make sure they were tight? at this point, sound like you are looking for any possibility. So, since you changed the piston and probably the rod and rod cap to a G14, is it possible that that rod cap is touching the inside of the case someplace? I don't know if the inside of these are built close enough that it is a possibility, but, I thought I would toss it into the mix since you may have a different rod and cap.