Engine setback

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Engine setback

Post  69BOSS on August 4th 2017, 8:05 pm

I have a 69 Mustang, I have cut the firewall out and will replace it with a flat piece. The trans tunnel will be replaced as well. I am trying to figure out the best placement of the engine. I am using motor plates. If I set the engine back as far as I can, that would be best for weight transfer, but then I would have to pull the engine when I need to service the clutch. If I set it forward enough so I can access the clutch without pulling the engine, then I lose the benefit of better weight distribution.
I leaning towards setting it back as far as I can, but before I commit, I am looking for advice form those that have been there and done that.

A little about the car:69 fastback, R&C Mustang II coilover suspension kit, modified for a Stiletto rack (top of the rack is 3/4" above the x-member), full mild steel cage & frame connectors thru the floor. Mini tubs are in and soon will convert to ladder bar /coil overs. The engine is a 557 dove block with Milodon 4bolt caps and P51 heads. Trans is a Lenco ST1200.

Thanks in advance

Staci
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Re: Engine setback

Post  jasonf on August 5th 2017, 9:11 am

Unless you are running a remote oil pump your oil pan is going decide where it can be unless you get back far enough to be behind the front x member.
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Re: Engine setback

Post  69BOSS on August 5th 2017, 10:23 am

I get what you are saying, that's part of the struggle people have with the Mustang II suspension. The Mustang II rack was 2'' above the X-member. The Stilleto rack I have is only 3/4" above the X-member, so as the engine sits now, the crank centerline is 1" above the frame rail. If I moved the engine rearward enough to clear the rack, the engine would be about 3+ inches into the cowl area. The height of the motor isn't ideal, but I can live with it. The alternative would be to scrap the Mustang II stuff and start over. If I had to start over from scratch, I would go with a full tube chassis without compromise.
Staci:)

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Re: Engine setback

Post  DILLIGASDAVE on August 6th 2017, 4:00 am

Having a decent amount of engine setback in a car that's not a purpose built full chassis car can be a PITA deal full of headaches to deal with.

(1) Making the hood & cowl a one piece deal makes the engine easier to work on.

(2) Having a clutch/Lenco combo pretty much dictates needing a removable trans tunnel. But having a removable trans tunnel means the car won't be as stiff/rigid as it would be with a fixed/welded trans tunnel. Adding a full 8.50 cage helps, but adding a double frame rail helps even more. A SFI cage & double frame rails is even better.

(3) Depending on how much power the combo has to work with having a bunch of engine setback might actually be a bad thing (excessive wheelstands, 100% dead-hooking a conventional slick, etc).

(4) And depending on what the car's intended use is (like say racing in a specific class) there might be specified limits to the max amount of engine setback that they allow.
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