Is there meant to be a gap between the coupler's when re-installing the SXR engine?

[Bri577]

Guys,

I'm about to re-install my SXR engine and had a question about the couplers.

Per the service manual, you drop the engine back in, then slide it back and insert the engine's coupler into the driveshafts coupler, (with the rubber damper in place).

After you slide the engine all the way back until it stops, are you supposed to pull it forward to create a gap of any particular size, or do you just butt it up against the back and tighten the motor mounts??

 

[yurkanip]

2mm in most circumstances.

 

[Tyler Zane]

It's not a super critical measurement. You don't wanna be metal to metal and you want to have a much contact surface area on the dampener as possible. I just eyeball a few mm's.

 

[Bri577]

This coupler has a rubber damper. I believe the damper prevents the two aluminum couplers from touching each other.

I was questioning if I was supposed to leave a gap between the couplers and the damper. For example, just give it a little play so the "stackup" of the engine coupler, damper, driveshaft coupler is not tight together which would exert some level of pressure on the balls of the crank and pump bearing races.

 

[SUPERJET-113]

Dont worry about the rubber "donut" dampener. Just make sure you have a 2-3mm gap between the couplers and make sure the gap is even all the way around the coupler.
So pull the spark plugs out so you can turn the coupler by hand. You want the gap to be dead even all the way around. This is how you align the engine so that everything is in line/sync with no vibrations and no excessive wear going on.

 

[Vumad]

This coupler has a rubber damper. I believe the damper prevents the two aluminum couplers from touching each other.

I was questioning if I was supposed to leave a gap between the couplers and the damper. For example, just give it a little play so the "stackup" of the engine coupler, damper, driveshaft coupler is not tight together which would exert some level of pressure on the balls of the crank and pump bearing races.

Don't worry about how tight the damper is to the metal. It's not going anywhere. Space the 2 couplers as other have posted. The damper can float a little bit.

If you can't find information on the alignment, look up the superjet process. It's basically the same. In short, shim the pump then shim the motor.

 

[Bri577]

Thanks guys! I've been watching some videos and understand the importance of the two shafts being EXACTLY in line with each other.