jester_s1

Did a search and didn't get much. I'm converting a 30cc weedeater reed valve engine. The head gasket was toast when I took it apart. Is the gasket material at the auto parts store the best stuff to use or is there something better?

Also, on trimming away the weight- the engine was mounted where the shaft comes out but there are screw holes that hold the back plate on. Can I grind away all of that material where it was mounted and use the back plate mounting holes or do I need to keep it and rig up something else?

arobatx

Yamabond gasket sealer/maker works great on most utility engines, no gasket at all. Extra case bosses can be machined off.

Chad

av8tor1977

My Feedback: (6)

Yes, you can mount using the backplate mounting holes, and that's how I do it. You can use the cardboard from the front or back of a spiral notebook for gasket material, or you can use auto gasket material; your choice.

I use nothing but Yamabond on my engines, and this lowers the cylinder a bit and raises compression. However, you need to check the piston to head clearance without the gasket and make sure you have at least .015" minimum clearance if you decide to go this route.

AV8TOR

arobatx

Thanks Av8tor, i forgot to talk about squish

av8tor1977

My Feedback: (6)

Yeah, it depends on manufacturing tolerances. I've had some engines I could leave the gasket out with no problems, and I've had others of the same size and make that when I left the gasket out and tested for clearance, the piston smacked the head.

AV8TOR

waterloged

I have also suscessfully used a pepsi or pop can, just cut it out and don't bent it. It has held up for 3 years with no problems just check you piston cleara[:-]nce.

rangerfredbob

My Feedback: (13)

one thing about weight loss, spending a lot of time cutting off aluminum isn't going to significantly lower the weight of the engine, a good portion of the weight is the flywheel and crankshaft...

jester_s1

I neglected to mention that I milled roughly 1/32 off the head and I still have about .040 clearance in the squish with no gasket so thickness is not a problem for that. I considered going farther, but I don't have a compression gauge and didn't want to overdo it. I was worried about the gasket because I had to lap the head surface flat with sandpaper and I figure I'll need a gasket to get it to seal well.

On weight- I'm figuring on a gas/glow setup with no ignition so I can ditch the stock flywheel. Grinding off all that extra material will be nice for saving bulk though.

NikolayTT

One thing more for the "weight loss" is to make the piston ligther and that seems the most efficient way to improve Power-to-Weight ratio. I did some "brutal" tuning when the piston reached the head - then I erased that part of the piston a bit and compression got higher; for less than 0.5 mm I believe those pistons are not going to get crashed, i.e. so far so good. What do you think ?