Nuke Em wrote:
Piston is actually in forward(correct), hard to tell from the pictures. That is a port window in the piston and the intake side has a extra port in the sleeve. Miss that in the photos? hehehe New to me too! I am getting the dremel out tonight and start "fixing" things.
I am heading to Cheyenne tomorrow night to get my 420 Leckich oddy and bring her up here to Minot for...tuning up????
Guy that last assembled that
Engine must have thought he was caulking a window or storm door?
It looks like that head was meant to be sealed with O rings, if the head and the top of the cylinder is flat then all you need to seal it is the Orings no sealers, most the heads I have seen that seal like that including OEM engines just use a soft steal washer under the head nuts this usually seals up and coolant leaking around the studs concerns, after market heads like my Pro Design for the Pilot used copper washers under the head nuts, never a leak, my ROTAX 440 sled Engine that has Orings from the factory they use a silicone sealer just around the studs to keep coolant from creeping up and leaking out between the washer and the head and then you only need to put a little bit around the studs only.
Coating the whole surface like see was done in the pictures is just plan stupid, jackassery, shows the complete lack of understanding about mating up of Engine parts.
Let me draw a mental picture for everybody about sealing up engines, FIRST if the parts are clean and flat they should seal WITHOUT any gaskets or sealers just bolt them up metal to metal and they would seal how ever these are production machines their is not enough precision in the castings that you could rely on every one begin the same, the parts are machined in a high production environment, so to reduce the chances of a Engine leaking its gaskets for everybody turn up production speed balls out
WOT (Wide Open Throttle) lets make MONEY shoving the parts out the door.
The crank cases on SOME engines are only sealed with sealer their is no gaskets, special care is taken when these parts are cast and machined, they will actually seal without any sealer but over time will weep a little if no sealer is used.
Normally all the parts mate up almost perfectly, if anybody has read a service manual for a ATV Engine they all give great details on checking parts to ensure they are flat enough to properly seal under average conditions, all the parts should be clean and flat free from any defects if they are then all you need to do is apply a light coat of oil on both sides of the gaskets and assemble and torque to specs all will be fine, no gobs of silicone required, you ONLY use sealers where the manual says its required!!!!!!
You don't ( I never do) use grease or oil on the head gaskets just install them dry some gaskets has a temp coating that bonds to the metal surfaces once heat cycled a few times, you probably have seen the residue left on the parts when you took the Engine apart.
When you get parts like Nukems cylinder spacer most guys like us here on this site don't have a machine shop like
Speedchaser and the skills to ensure that spacer the crank cases and the bottom of the cylinder is perfectly flat, we can lap the spacer and the top of the crank cases but can only half ass check the bottom of the cylinder like shown in the service manual, so this is where a exception to the no sealer rule comes into play, I would never use silicone because its not as good at withstanding pressures as other sealers like threebond, yamabond, hondabond type sealers.
The minor imperfections your trying to seal when no gasket is used is almost nothing, if their is any measurable GAP between the parts STOP and correct this problem sealers are not designed to fill or seal GAPS a paper type gasket CAN seal up minor gaps, so when you apply the sealer keep in mind 99% of its going to be squeezed out, when you take the Engine apart you wont find a thick layer of the sealer you will be lucky to find a layer less than the thickness of a sheet of news paper, fact is if you find a layer 1/2 the thickness of a sheet of news paper you need to fix the mating surfaces.
On metal to metal connections a layer of sealer about 1/2 the thickness of a sheet of news paper is all you need but this is hard to apply, if I was going to install a space plate with no gasket I would try using that spray on copper coat gasket sealer on both sides of the spacer plate, spray it on (again real thin coat) let it dry then flip over spray the other side.
If using threebond yammabond or hondabond type sealers just apply a thin layer then only apply it close to the outside edges of the surfaces so when torqued any that tries to squeeze between parts wont squeeze inside and block flow like seen in the above pics.
Hope this helps.
I am sure we will see more engines like this in the future with sealants oozing out all over the place lmao