914 Widebody - k24 swap

Nice progress! You are making solid mounts?

In reply to TurboFource :

To the bar yes, but the bar itself has rubber mounts where they fasten to the chassis.

You can see them here in this pic. These are 911 mounts but the factory 914 bolt in similar depending on which year it is.

Cool, I forgot about those from your previous pic!

I had another successful garage session last night. Passenger mount is mostly finished. I plan to drill through bolts so it can be removable. Deciding whether I'll do a crush sleeve or not.

The tubing fit up easily and lands perfect on the angle iron pad.

I made sure it's easy to remove all of the bolts as well.

I've got to remember to clean up the metal more before tacking. I'm so used to flux core not caring about cleanliness it's a difficult transition for me.

It's also really tough to get an "overall" shot of both mounts. You can kinda see I'll need to work on the notched section of the bar more. I need to take a hair off of the passenger side and probably add material back on the driver side.

I also got started on the rear trans mount. The steel spacers are bolted to the mounts. I'll cope some square tubing that will point toward the rear a little on each side and meet a straight section that fits up against a flat plate.

This CAD template is brought to by gushers. I feel like this mount is going to work how I planned it out.

The reason the bar has to go rearward is shifter cable clearance. Here you can kinda see how far back it goes. Just a little past the actual mount so it all has to loop around.

Speaking of clearance. Here's the valve cover to firewall. I'd say it's about 3/8" of room?

From above it looks super tight but I believe has plenty of space for moving around.

Rear trunk lid clearance is great as well.

Tons of space for the water neck.

All in all I'm stoked with the progress. I feel like the trans mount will fall into place and it will be ready for final welding soon enough.

    Great work!

     Just something I saw, something to consider, maybe.  The square tubing motor mounts, one option.  Add a plate front and back of the long cross member, weld those to the plate currently attached to the square tube.  Then add two bolts thru those, thru the long cross member, they would run forward.  This should be easier to remove in the future.   

    You could also insert a flanged bushing into the cross member holes.

        Any welding does prefer clean metal, and it does create less fumes for the welder.  

In reply to TED_fiestaHP :

So the mount on the passenger side will bolt to the bar from above on the outer side and below from the inner due to clearance. Is this what you're talking about? The driver side I planned to keep permanent for simplicity at least for the time being.

Here's a pic that shows the holes I drilled in the angle that sits on the bar for the passenger side. I just haven't drilled the bar yet to match.

I really like that front cross-member engine mount. By moving the flexible bits out to the chassis and solid-mounitng the beam to the engine, you have formed a truss with the engine. So that thin section under the oil pan is (mostly) in tension instead of bending, a very good thing. IF you were worried about the stiffness of that beam, and I don't think you necessarily should be, it would be easy to stiffen it up by adding some members or gussets.

The only other thing I would maybe consider is thickening up the plates that bolts to the engine, maybe 1/4" or 3/8" (looks like 1/8" currently?). Those parts are good candidates for a cheap sendcutsend order if you have the ability to transfer your design to a DXF.

Really cool build, keep it up!

In reply to maschinenbau :

Thanks!

I think I'll do some gusseting/webbing on the driver side plate of the mount. It's 3/16" plate but I think because the span is longer it looks smaller? I also think that side may see at least one extra leg on the inner section to triangulate it a bit.

Initially when I notched the beam and set the engine directly into the notch I could see the flex in the beam. The angle iron helped a bit but as soon as the outer mounts were created there's no longer any deflection. I assumed that the block would help bridge the gap and glad to see and hear that's correct. After I plate up the notch I plan to remove the angle iron and see what kind of deflection can be witnessed.

So here's a quick illustration of what I want to do to the driver side.

On the front of the mount a wedge of square tube connecting the plate to the existing square tube.

Then on the rear part of the mount a tube that connects lower. I need clearance for the bolt and this seems like a good way to tie it all together? Maybe overkill? Too busy and bulky?

The alternative is to plate the top and bottom allowing access to the bolt which is probably good enough and visually more appealing.

I could probably do the same thing for the front section where I plate top and bottom instead of a wedge of tubing.

In reply to captainawesome :

I think the 3rd option (open gussets) looks very elegant. 3/16 gusseted like that should be plenty strong. Looking good!

Is any of that side gusseting really necessary? seems to me that when properly welded it will be strong enough as it?

What's the wall thickness of your tubing?

I made mounts exactly like this for my racecar swap (gm v6 in an rx7).  I did not initially put in the gussets like you suggest in option 3.  Well, after a couple races the tubing cracked right at the intersection (through a weld AND through the adjacent tubing).  After doing the gussets, no issues at all.

I'd add gussets for sure.  Why risk a part failure to save 8oz of weight and an hour of your time? 

The tubing itself is .120 wall so not light duty but these k series engines can be pretty vibe heavy. Shouldn't take long to fashion up the gussets.

As for the passenger side I think it's probably fine without any the way the bolts are located, but I'm willing to explore that idea if others think it makes sense as well.

You could use a square tube like your first picture suggests, but on the right side weld a tube over the bolt holes+longer bolts?

In reply to iansane :

An alternative would be to drill holes large enough for the bolt and socket to pass through on that side. I really don't want to extend the bolts much longer if needed.

One thing I keep forgetting is the bracket has a slope to it so it can pick up the larger rearward bolt. Plating it may end up just being easier than trimming the square tubing to fit up?

   What I was thinking, now you have the mount to cross member bolts vertical.  Drill 2 horizontal holes in the cross member, on each side of the engine.  Then weld a steel tube in each of those holes.  Add a urethane bushing in those holes.  Then add a vertical plate front and back of the cross member, weld those to the motor mount and bolts thru those.  You would then have a solid connection at the motor and a vibration connection at the cross member.  Energy suspension has dimensions of all the bushings on the web site.  For tubing of every size, aircraft spruce.

In reply to TED_fiestaHP :

I already have rubber mounts the bar bolts to from the factory. I don't see a reason to add more vibration resistance or maybe I'm misunderstanding what you mean.