welding new engine mounts - opinions please

[stidnam]

Hi,

I'm just about to make up some new mounts for 1j into the ra28. I'm using a ae71 crossmember and attempting to reuse the original mounts in some form. I have two issues at the moment

The first is that the mount position sits the mount 1/2 on the crossmember so I have to make some kind of support to compensate for the overhang of the mount on the front of the crossmember. My ideas on this have been

1. Weld 4-6mm plate steel to the top of the crossmember so it overhangs the front then make a brace underneath to triangulate and then weld the mount onto the overhang.

2. Weld some thinner right angle steel to the front of the crossmember and then weld another piece from edge to edge of the right angle to form a triangular piece at the front. Then weld the mount onto this.

Second thing I'm undecided about is how do to the actual mounts.

While the chaser mounts can sit in the ae71 crossmember mounts I think its going to be difficult to get a spanner underneath to do the nut up. The original mounts that came in the chaser had a plate bolted to them that had two holes on each side that were outside the mount. (Like the original ra28 ones). Should I create a plate and weld this onto the ae71 mount and weld the ae71 mount onto the crossmember so I can use the original chaser mounts?

[SillyCarS]

1. makes sense. just make sure you get the maximum area for the welded area so the stresses in the thinner x-member are spread out. welding a gusset plate to the overhang is more than likely unessessarry and it will create a water trap and weaken the thinner steel

2. i think i know what you mean, bit unclear (diagram & pic confirmed below now)

use 6mm plate, check out that blokes in NZ he's done a really god job of it

finally whatever you do, document it. and if you have enough time i'll even pay you to make me a set and im sure many other would as well

edit: +rep, also if you want to send me dimensions and weld types to me i'd be happy to work the stresses for you, even put it in ansys desgin workbench if you like

[oldcorollas]

i'd suggest talking to your gingerbeer as they will have to sign off on it at the end.. they will advise steel thickness, where to weld and what type of reinforcing is needed... or they should anyway...

[stidnam]

Ok heres a picture of my actual crossmember so everyone gets the real picture



Now my paint effort



The green is the outline of the crossmember mounts. The white sections are the parts that need something there to weld the crossmember too.

I've drawn a copy of a mount maybe I should make thus getting the exact right heights etc. Now not sure if to put tabs on either side for the bolt points or to remove that plate all together and just let the rubber mounts sit on the mount directly like 77gze did.

stidnam

[SillyCarS]

go perpendicular to the x-member so that the majorty of the moments arent hinged on the principle welds

like this

-----i----i------------------------i----i-----
-----i----i------------------------i----i-----
-----i----i------------------------i----i-----
-----L---i 000000000000 L---i-----

if that makes any sense

theres supposed to be space where the 0's are but v-bulletin doesnt like it

[stidnam]

Yeah I understand what your saying. Put a steel plate on each side from back to the front of the crossmember and cover the portion I need to weld the mount to. Thats what I was thinking.

I'll put the gearbox on tomorrow night and do another dummy fit. Gotta get this motor high enough off that damn steering rack but the back low enough to fit the gearbox in the transmission tunnel. I beat the crap out of trans tunnel today .

[takai]

Remember there are two bolt holes for the JZ mounts, make sure you are utilising the forward holes in this case.

[stidnam]

My mounts are bolted to the front position. I had just assumed that the mounts only fitted the front location. Can they also be moved to the rear as well? Hmmm interesting.

Either way at the front or the rear neither position will place the mount directly centre over the crossmember but your saying use the front anyway?

stidnam

[takai]

Its more likely to shift it over the xmember. That said, experiment with the different mounts, there are 4 different styles. JZA80, JZZ30, JZX81 and JZA70.

[hypo23]

check out toy77 members ride thread we mounted a 1j on a ke70 crossmember in his car im sure he has pics if it in his thread

[stidnam]

Hmm interesting. I note that toy77 has lowered his crossmember quite a lot more than me with those spacers. Do you know if that was done for steering or clearance reasons?

His mounts position looks similar to mine though. I didn't think I could go that low though and still have the sump clear the rack :S. Maybe his box is higher than mine. I'm going to go attach my box now and try and shoe horn the damn thing in.

stidnam

[stidnam]

Ok well motor and gearbox are dummy fitted in there now and the motor is as far back as I can push it. Everything looks fine except the damn steering rack!!

Pictures to come soon to show what I mean but sump is now fouling on the steering rack. The only way I can think to get it off is to elevate the whole motor and gearbox. To do that without going actually higher I think I'm not going to have to space down my crossmember.

Also on another note the bolts on my mounts are just on the crossmember. When I'm spacing the crossmember down should I considering moving it forward another 20mm?

stidnam

[1JZ-Rolla]

Shame you chopped the mounts off the crossmember, i'd say they would have lined up quite nicely for you to just replace the alloy mounts on the block with a set of fabricated 5-6mm plate steel mounts.

Lowering the xmember may be necessary to give enough clearance between the top of the g/box and trans tunnel. Remember doing this will require roll centre adjusters (RCA's) to maintain control arm geometry.

If you space the crossmember forward also, wont it completely fark up the positioning of the inner control arm bushes & angle of the steering arms from the rack? Not to mention the length of the radius rods etc.

Cheers
Phil

[stidnam]

Yeah I was thinking about that now that I actually had the possibility to replace the mounts on the motor instead of the crossmember but went on my merry way doing what everyone else had done.

Anyway done now so I'll keep on perservering. I've bashed the transmission tunnel out at the front and played around with it a little more. Pushed the gearbox up as high as possible but you can only go so high at the back before the tailshaft starts becoming a problem. Anyway without lifting the motor quite close to the bonnet I can't clear that rack with enough room to make me happy. Its the actual sump as well not one of the bolts. Will have to price some roll centre adjusters me thinks.

Looking at all these ke70 steering conversions and 1j's everyone seems to space them down and for good reason it seems

Oh yeah I'm not touching the crossmember position. Its lined up with the original control arm position and it can stay there. My thoughts at the moment are to make some mounts that the top runs parallel to the same angle of the crossmember. The Height I think I've worked out is 70mm. Chuck those on some plates welded to the crossmember and triangulate the front.

stidnam

[takai]

RCAs are fairly cheap, about AU$100 at our current exchange rate:
http://www.technotoytuning.com/productdetail.php?p=693