Shift the Engine Aft?

phantomjock

phantomjock

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While-I'm-At-It #22

Thinking of shifting the engine aft. Car is a '78 C3 - major mod to track car.
Planned new firewall anyway, so might as well move the engine aft too!

ANYONE have experience with this mod?
New Firewall - yep
New floors/tranny tunnel - yep
New/rebuilt Drive Shaft - yep
New cross members - yep
Front Mount - yep
Mid Mount - yep
Soft/Rubber mount for tranny keep from busting case - Yep
New wiring/Plumbing - Yep
Shifting the seat aft and pedals too - Yep

Looking at the Jegs kit -
thum_126950585459ec9de.jpg

Have I missed anything? Other than a WHOLE summer of driving my 'vette?

Cheers - Jim
 
How far back?

I suppose the issue might be a really cramped footwell (more cramped than stock).
 
I thought about it as I had no qualms about cutting up the spare frame. I didn't want to cut up the bodywork though. In my case I only had about 3/4" clearance between the engine and firewall, and similar clearance (UCA, fuelpump) if I wanted to move the engine further to the right. So, I was pretty much SOL unless I wanted to do some serious surgery on the firewall.

Be sure to post some pictures if you move the engine.
 
Move aft - some advantage in fore/aft weight balance (It will be a Track Car). Not Huge - but a benny in any case.

Also I solve a nagging - "Oops that header system is in the way of ___________" (fill in the blank.) But, most notably the Rack and Pinion - the headers are 360 degree Stahl's and join under the engine - front tubes are in the R&P space.

For the engine bay - there is no dizzy -have a crank trigger and coils installed. Main concern will be getting air to the carbs - so don't want to go too far aft. That nagging low pressure area may require a hood scoop to keep them breathing. Fuel pump is aft - a carter feeding the Webers.

I planned on doing "Serious Surgery" the firewall anyway - and maybe only 8-10 inches aft is what I'm going for. Yes a cramping could be a concern. At 6'3" I appreciate that point - but this car won't have a stock interior anyway, and the seat will be as far aft as possible. New aluminum floors and tranny tunnel will be required.

The new Tranny cross-member supports to replace the stock will allow dropping the transmission - rather than pulling it.

Cutting the frame? Not a concern. Shouldn't have to cut up the frame much - compared to what I have done already. The rear frame "horns" are gone and replaced with a new subframe with the dual wishbones coming together this weekend or next. (Yes - I tease!!!! But, YES, real rear suspension progress.)

Debating still of lowering the stock fuel tank or go with fuel cell - but have time to sort that out--and watching that thread with interest.

So, I take it so far no one has used motor plates in lieu of motor mounts. I'll sort it out - pics and reports to follow in time.

Cheers - Jim
 
you could put a porsche 968 power train in the car, and even increase your foot space room.... put the fuel tank in the front for balance :D

I thought about 2 things to change the weight - aluminum LS motor, and C5/6 power train. But someone quickly pointed out that you lose room right where you hips are when you put the transmission in the back.

About moving the motor back. I would really encourage you to look at the "other" stuff that needs to be on a firewall (most notably brakes) when you design the set up. This car:

PA060026.jpg

now has a new powertrain (where the nub is on the side - is where the firewall used to be)

P6280003.jpg

which required moving everything
P6260003.jpg
(funny, I don't have a picture of the mostly completed transmission tunnel)...

anyway, the Spider is a 4 seater car, and I removed the back seats.... and at 6-1, I won't be driving that car a lot because the brakes/clutch set up was by far and away the hardest part to engineer. As it is, it has a less-than-optimal brake master cylinder arrangement
P4240002.jpg
but that was all that would fit

Seriously, put your motor on a diet (aluminum). Redo the front structure in aluminum (cross member/control arms - or simply bolt a Panther platform suspension in), put a fuel cell tank in the back, and I'm willing to bet that you'd achieve a better result than moving the motor back.

Add to this, that firewall behind the driver can't go backwards to give you any more space
 
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phantomjock said:
Move aft - some advantage in fore/aft weight balance (It will be a Track Car). Not Huge - but a benny in any case.

Also I solve a nagging - "Oops that header system is in the way of ___________" (fill in the blank.) But, most notably the Rack and Pinion - the headers are 360 degree Stahl's and join under the engine - front tubes are in the R&P space.

For the engine bay - there is no dizzy -have a crank trigger and coils installed. Main concern will be getting air to the carbs - so don't want to go too far aft. That nagging low pressure area may require a hood scoop to keep them breathing. Fuel pump is aft - a carter feeding the Webers.

I planned on doing "Serious Surgery" the firewall anyway - and maybe only 8-10 inches aft is what I'm going for. Yes a cramping could be a concern. At 6'3" I appreciate that point - but this car won't have a stock interior anyway, and the seat will be as far aft as possible. New aluminum floors and tranny tunnel will be required.

The new Tranny cross-member supports to replace the stock will allow dropping the transmission - rather than pulling it.

Cutting the frame? Not a concern. Shouldn't have to cut up the frame much - compared to what I have done already. The rear frame "horns" are gone and replaced with a new subframe with the dual wishbones coming together this weekend or next. (Yes - I tease!!!! But, YES, real rear suspension progress.)

Debating still of lowering the stock fuel tank or go with fuel cell - but have time to sort that out--and watching that thread with interest.

So, I take it so far no one has used motor plates in lieu of motor mounts. I'll sort it out - pics and reports to follow in time.

Cheers - Jim
Click to expand...

Jim, I have no problems with headers on my L98 setup, used Schoenfeld #151 headers....they called 'Chassis headers' in their site/catalog I went to ceramic plug boots to cure the 'too close' melting/arcing problems....

as being 6' 5" I cut the floorboard/firewall all across the bottom, and up the sides to height of steering column flange, forced it forward about 3" and glassed it in again, then bent the pedals forward/down a similar amount, that got my knees off the steering wheel, Back in '95 when I bought the car one of the first changes was a later shark column and smaller wheel, that old '72 buss driver wheel was just toooooo large, but it was a shorter column, so it got pulled back by 3/4 inches off the firewall, I also dropped the seat about 2" in the rear by removing the rear mount flanges, seat belt cover and used old foam in the recovering that way I get more headroom....

:bump:
 
SuperBuickGuy said:
Seriously, put your motor on a diet (aluminum). Redo the front structure in aluminum (cross member/control arms - or simply bolt a Panther platform suspension in), put a fuel cell tank in the back, and I'm willing to bet that you'd achieve a better result than moving the motor back.
Click to expand...

Nice work on the Spider!

By "Panther platform", do you mean a Lincoln Town Car? Not familiar with the suspension in that car.
 
BBShark said:
SuperBuickGuy said:
Seriously, put your motor on a diet (aluminum). Redo the front structure in aluminum (cross member/control arms - or simply bolt a Panther platform suspension in), put a fuel cell tank in the back, and I'm willing to bet that you'd achieve a better result than moving the motor back.
Click to expand...

Nice work on the Spider!

By "Panther platform", do you mean a Lincoln Town Car? Not familiar with the suspension in that car.
Click to expand...

the final generation of the Ford cop car.
 
Thanks for all the ahmm positve encouragement! I may not pursue - but looking at it still. The Greenwoods pushed back 12 inches and made do quite well. I'm pretty far down the track on some of the othe bits - and here are the headers - you'll note the forward tubes are the problem area for the R&P.
thum_1269505a16e2ab2e1.jpg

We'll see how it plays out - pics will be included for sure.

Cheers - Jim

BTW - cool mod on the Spyder. A buddy and I traveled much of northern Spain in a 128 with 2 hot spanish chicks -- not much room - but a heap of fun...
 
Another idea would be to move it back just a few inches so that the balancer clears the crossmember and then lower it.. Dry sump oil pan, one of those super small diameter clutch/flywheels and a custom bellhousing. Theres got to be a few inches of room to bring it down without sacrificing ground clearance compared to a wet sump motor.
I would think enough aluminum up front could achieve similar weight bias results to moving the motor back a significant amount.
 
This gives a good perspective of, 12" back, 5" over, 2" down. Check the a-arms to the front of the engine. Looks like its back to the edge of the windshield.


1969-chevrolet-corve-8w_zpsa7f1658e.jpg
 
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