Subaru motor mount

[Hoghead]

What is the best method for mounting the Suby engine - hang off the gearbox (915) like the Beetle or pick up the rear Subaru engine mount from the rear transmission crossmember?

[Steve C]

Hi

I'm using a G50 with a Subaru motor. I don't have any good photos but what I've done is to make a frame that bolts to the end of the frame horns, just like a bug one does and the stock Subaru mounts bolt onto this frame.

Steve

[Turbo Haraune2]

Originally Posted by Hoghead

What is the best method for mounting the Suby engine - hang off the gearbox (915) like the Beetle or pick up the rear Subaru engine mount from the rear transmission crossmember?

Just hang it from the trans. thats the way it is original..
why change something that works?

I have my 280hp subaru just hanging from the four studs in the adapter, has worked so far.

The engine is only producing radial torque, it wants to twist around the crank.

Its the trans thats moving up and down from the torque from the driveshafts.
Just bolt your trans properly in and you'll be fine!
And a "cup-stag"

[Eatoniashoprat]

Originally Posted by Turbo Haraune2

Just hang it from the trans. thats the way it is original..
why change something that works?

I have my 280hp subaru just hanging from the four studs in the adapter, has worked so far.

The engine is only producing radial torque, it wants to twist around the crank.

Its the trans thats moving up and down from the torque from the driveshafts.
Just bolt your trans properly in and you'll be fine!
And a "cup-stag"

Subaru engines don't originally hang off the transaxles nor were they designed to. They also weigh a bit more than the air cooled. This being said, mine is just hanging off the transaxle. Members on some other forums disagree with the hanging method since some have seen cracked frame horns, however most of these were in off road situations as far as I know so they have a vertical shockload causing an increase in bending moment in the frame horns.

Mike

[Turbo Haraune2]

Originally Posted by Eatoniashoprat

Subaru engines don't originally hang off the transaxles nor were they designed to.
No you are right, they also support the original subaru 4wd gearbox with driveshafts. So it is actually designed to take lots nore load to the 6 original mounting bolts. Much more than needed.

They also weigh a bit more than the air cooled. This being said, mine is just hanging off the transaxle. Members on some other forums disagree with the hanging method since some have seen cracked frame horns, however most of these were in off road situations as far as I know so they have a vertical shockload causing an increase in bending moment in the frame horns.

If you manage to bend the frame horns you are doing something wrong!
I guess its in some kind of "redneck" offroad car you can se this
That is why i suggest to use cup-stag between framehorns and damper towers to lessen the load to the frame horns.


Mike

Also the porsche box is designed to hang a boxer 6

[Eatoniashoprat]

-The subaru engine DOESN'T support the gearbox and axles on a subaru car, the transmission has its own mount as well.

-I don't see how it would be surprising if you had a subaru engine in an offroad/baja beetle and just had the engine hanging off the frame horns that the frame horns coud bend/crack. Engine blocks have apparently also broken. If you're jumping a car or hitting serious terrain at speeds there is plenty of force there.


If the frame horns are sufficiently supported (tied into shock mounts, 3-bar kafer style brace at minimum, to at least handle the increased torque) and you use 10-12MM grade 8 bolts to bolt the engine on, I believe this is sufficient. That's my 2 cents... well maybe 3.

Mike

[Turbo Haraune2]

Originally Posted by Eatoniashoprat

-The subaru engine DOESN'T support the gearbox and axles on a subaru car, the transmission has its own mount as well.

-I don't see how it would be surprising if you had a subaru engine in an offroad/baja beetle and just had the engine hanging off the frame horns that the frame horns coud bend/crack. Engine blocks have apparently also broken. If you're jumping a car or hitting serious terrain at speeds there is plenty of force there.


If the frame horns are sufficiently supported (tied into shock mounts, 3-bar kafer style brace at minimum, to at least handle the increased torque) and you use 10-12MM grade 8 bolts to bolt the engine on, I believe this is sufficient. That's my 2 cents... well maybe 3.

Mike

YES! the engine supports the trans in a subaru. look at the construction.
Two mounts under the engine and one mount in the rear end of the transaxle.
That means that the engine supports the heavy front end of the trans. and also takes up torque load from the transaxle.
If you stil dont belive me, try to remove the engine in a subaru and see what happens to the trans.... it falls down in the front end and hangs from the axles. Thats why the subaru manual says: Support transaxle before removing engine.

[Eatoniashoprat]

Yah I know how it works, I've taken several Subaru engines out. However, since the trans has its own mount only half (approx) of its weight needs to be supported. More importantly, the weight, for the most part, is not supported as a bending moment on the block of the engine, as is the case when hanging it off a transaxle, as in a bug. The stresses are mainly torque and some shear. The issue in question is the .. wait what's the issue in question again..? oh yah ,

-I think we both agree that the trans needs to be supported.
-I know some guys at www.vwrx.com and yahoo groups were having trouble breaking engine mount bolts so use good bolts, and possibly even thread the dowel pin holes to help.
-I would only suggest (based on other people's experiences) that if its used for offroad at all to support the engine underneath

What I meant by "doesn't support the gear box" was, "the gearbox doesn't just hang off the engine with no other support", as in: the whole weight of the gearbox isn't on the engine, and doesn't created a significant bending moment. Sorry, its just thats what it sounded like you were suggesting. I probably could have been more clear on that

If we're still in disagreement, than I agree to disagree and Hoghead, good luck with the conversion

[Steve C]

Hi

The reason that I suggested my way using the original mounts is that the 915 has no mounting points under the bell housing so using the stock Subaru mounts over comes this issue.

The other thing to remember is that Subaru designed the motor to have the mounts on the bottom of the case although many converted VWs just use the stock bell housing mounts with no problems.

I also made a top mounted Beg style mount to hold the transmission up when the motor is removed.

Steve

[GS guy]

I used the Small Car mounts. That allows you to support the engine from the pulley end, instead of near the flywheel end.
Well, tried to attack a pic but wouldn't allow the file size, or the web location.

You can check out my Shutterfly pages if you like:
http://jgum.shutterfly.com/action/

Jeff