Flat Fender Flat Belly

[Mieser]

I'm just about ready to place the engine, transmission, and t-case into my flat fender project. Overall the vehicle is going to be pretty low so I want a nice smooth flat belly.....

Anyone have any tips, tricks, ideas, pictures, etc?

Looking at things so far I only have about 4" of frame height and 1" of body height before the floor pan. The transmission tunnel will be reworked around the raised powertrain but things still look REALLY tight.

Thanks for the help...

[csutton7]

you need to stuff that stuff in there and see where things end up and then go from there--remember most engines slope to the rear 3* or so, so that impacts the bottom of the tranny/t-case in relation to the bottom of the frame and what can be done to create a flat belly....

on my rig(still not finished belly supports) with the same 4" frame I ended up 2" below the frame with my crossmembers and they will be my belly pan supports---but I'm running 40" tires and will be 23-24" at belly...so I got pretty lucky with that....chris

[wilez5150]

the amount of hang down is relitive to the amount sticking out the hood. but you already know this. 30 odd flatties i've built over the years and it always boils down to that

[CRO]

What are you running for a bellhousing?.. seeing as it won't be possible to clock the transfercase up to gain any room there what about redrilling the transmission pattern and clocking the whole package up?
even a couple of degrees will make a big difference and it shouldn't throw off the shifter on the SM420 too much....

[Mieser]

I'm running a buick v6, sm420, D18 combo. I can't really clock anything that I know of...other than just tilting the motor and that is a fairly bad idea I think.

I don't really want the air cleaner sticking out the hood.

I don't mind cutting the floor and rebuilding the tunnel.

What is a 'bad' engine angle? Is level bad?

[CRO]

I used to run a Lakewood stamped bell housing.. I had to modify it to fit the SM420 I used to run, After I had it all done I thought how easy it would have been to drill the mount holes to clock the whole transmission around it's index bore...

[Mieser]

Clocking the transmission is an idea, currently the bottom of the SM420 is the lowest part of the system...



The motor is sitting farily level currently according to the oil pan and valve covers, but the carb is sloped down to the front. The SM420 is currently sitting about 1-1.5" below the frame at the lowest point, the bottom of the D18 sump is slightly less.

I just don't know if its worth lifting the trans/t-case any more? The engine is about as high as I want to go with it I think.

Any ideas?

[MrWillys]

Someone correct if I'm wrong, but the centerline of the crankshaft should set 1 1/4" toward the drivers side, so the Dana 18 sits correctly in the frame. Also, I thought 5 degree tilt was standard, and only important if your not worried about oil going back into the pan. Just kidding a little. Lot's of guys have run them flat.
I'd give it a little tilt and not butcher up the body so bad. Get the back of the head as close to the firewall as you feel comfortable to make room in front.

[Mieser]

I set the engine 1 to 1 1/8 to the drivers side.

The floor on the tub I am using is cut up a lot already, so trimming it even more isn't a big deal. I will be building a new M38 style tunnel cover anyways.

The SM420 is still the lowest part. It hangs just about 1.25" below the frame. The D18 sump is about .75".

I kinda want to raise the engine a little bit, but I think its going to be getting pretty close to the frame.

My grill is getting pushed forward 1.38" so I have a little extra room to play with for the engine. I currently have the back of the engine set 2.5" forward from inset part of the firewall. Since the motor is raised a bit I wanted to get the bellhousing away from the firewall. Even in the old configuration I had a heck of a time getting the top bellhousing bolts out.

[wilez5150]

when i read CRO's comment on clocking i remembered a guy clocking 2 different sm465's in jeeps. the first on he did was a j-10 and he clocked it so it would fit a 258 bell housing. the second one was in his cj7 and he did wind up with a near flat belly pan. i have done as much as 2" offset to clear drive shafts. on the angle the flater you get the more angle in the drive shaft an a cv will take care of that. other than the shifter looking funny i'd say clock away. with that ultra short trans/tcase you have and bumping the wheel base back a tad you will have plenty of drive shaft length. i have been swinging wrench's on flat tenders since the early 60's an have seen a lot. i have say that your frame has probly set the new standard in home built replacement frames. leave it to a machinist to build cool stuff.

[Mieser]

But I am an engineer....but I started in the machine shop

I did a lot of thinking last night.....who wakes up at 5am because they can't stop thinking about jeep stuff

Clocking the transmission at this point won't get me much more clearance. The D18 already is higher than the bottom of the SM420. Currently the SM420 is sitting at a point where a 1.25" drop will clear the sump/drain plug area. The D18 is only about 0.75 below the frame. If I where to clock the transmission it would make the driveshaft clearance problem at the bellhousing/starter worse. As I currently have it set the driveshaft will clear the bellhousing with the axle fully stuffed to the frame rail.

The rear driveshaft should be pretty dang long.....for a flat fender. The motor is pushed forward 1" from where it was and the rear axle is pushed back a few inches also. With the short transmission and t-case it is pretty long anyways.....I think the old one was like 20". I hope I will be able to get away with just a normal non-CV shaft. A high pinion rear D44 with D50 gears is in the future a little ways.

[wilez5150]

an engineer in a machine shop, that figures, and the wake up thing, everyday. i'm stuck 2500miles from my herd of flatties and the shop playin granpa. i think i'm going thru withdrawls like a junkie. take your time with this, do all the little nit-pickie things while you have it apart. i can't tell you how many times i wanted to kick my own ass for rushing things so i could go wheel it. 1 more month build time, a few more $$$ won't kill you. enjoy the process, you won't get to do it often unless your a tard like me. my latest creation.

[Mieser]

Thanks.....I do have to get it done by EJS this year though. I would like to get it 'done' by mid-march for a shake down.

[euroford]

personally, if it was my flattie, i'd be thrilled with the tranny only 1.25" below the frame, and build a belly around that without tweaking anything else.

in fact, where i'm at with mine, i have a desire to build some new engine mounts and cross members that would let me probably drop the engine and drivetrain an inch to improve the driveline angles and center of gravity.

with the short wheelbase, i'm pretty happy to give up some belly height for a low center of gravity.

[Mieser]

Mine is only going to be lifted with 1" springs still SUA. Its low enough that I need to do something for a little more belly clearance.

[b4wscrambler]

Do the extra work. The flat belly is worth it!

[kirbybuilt]

Not sure if you want to go thos way but it is an option. Raise the whole set up an 1.5". Instead of cutting a hole in the hood, raise the cowl an 1.5", extend the grill as needed. You can still do your high line fenders but they wont be as deep in the hood or as high onthe grill. Do a little chop on the window frame to keep it low and give it a rat rod look. This is the directipn my build will go once i collect the neeeded running gear. Bty i really like the direction your build is going, low and short.

[Mieser]

Originally Posted by kirbybuilt

Not sure if you want to go thos way but it is an option. Raise the whole set up an 1.5". Instead of cutting a hole in the hood, raise the cowl an 1.5", extend the grill as needed. You can still do your high line fenders but they wont be as deep in the hood or as high onthe grill. Do a little chop on the window frame to keep it low and give it a rat rod look. This is the directipn my build will go once i collect the neeeded running gear. Bty i really like the direction your build is going, low and short.

That is a cool idea for sure!

There is an update in the Rango thread, but basically I think I have it where I want it now. It all a compromise for sure.

[CRO]

Meiser.. just had another crazy idea... seeing as how the bump on the bottom of the 420 is the lowest point.. And that you have a spare 420 case.. Why not shave it?.. people do it to differentials all the time ..A Zip blade, a couple of nickel rods and some 1/8" plate.. done

[wilez5150]

or throw it upside down on the mill, i don't remember there being a lot of room under the cluster gear. i cut 4" out of my 42 windshield to keep it low(74"). you mite think about a 1" body lift. that gave me more room in the 51 to keep the air cleaner under the hood and not have so much of a tranny tunnel. it also helped so i could flatten the floor under the seats to fit a 20gl fuel tank there

[Mieser]

No body lift for me. The current setup is only hanging down 1-1.5" just at the back of the SM420 by the drain plug. The crossmember will then slope up towards the engine oil pan. The front driveshaft with the low pinion front is going to hang down no matter what. There just isn't room for a high pinion either with the buick starter ( on the passenger side ).

The t-case is flush to the frame rail once the belly crossmember runs up to the bottom of the frame.



-I can't raise just the trans/t-case now because the driveshaft will hit the starter
-I can't lower the engine any, driveshaft goes into starter.
-I can raise the engine AND the transmission/t-case, but I am already into the area where the air cleaner is going to have a HARD time staying under the hood with a normal carb setup. The HEI on the buick is also going to get really friendly with the hood soon.

I think it is set at about the best point unless I do something drastic like a body lift ( no thanks ), shave the transmission, or lower the bottom of the frame rail. If I was going to build another frame I might make the belly section 5" tall instead of 4" tall.

I don't know what is 'better' though, having a totally flat and smooth belly, or having just the middle of the belly be 1-1.5" lower than than the rail while still having that extra inch of clearance at the bottom of the frame rail?

With the low pinion diff even if the belly is flat the driveshaft is going to hang down. I am looking at building a high pinion D44 rear with D50 gears to get the rear driveshaft up above the frame all the way in the future.

[b4wscrambler]

Just a few half thought out ideas..

Figure out what air cleaner you are going to run. My vote is a carb hat and a conical filter where ever it will fit. Something like this.
http://www.spectreperformance.com/#CATALOG.98499
I think V8 ZJ's use something similar.

If you are think about going to a TBI setup now would be the time. It may be shorter or taller than what you have now.

Can you raise just the Passenger side of the motor?

Smaller started?

Two piece front driveshaft?

I know you plan to mount the motor to the driver side as far as passable, what about mount the drive line diagonal in the chassis. Motor to the left, t-case to the right

Having the motor tilted up or down a bit is not going to hurt anything.

I have made the compromise of building a bowl style skidplate (smooth with a drop in the middle) and every time I hit the skid it reminds me of its shortcoming.

[b4wscrambler]

Some pictures to give you some insperation.

[Mieser]

I need to measure the choke hat in the carb. That might be almost into the hood also. I could probably shave the intake down and fab a flange instead of run the carb adapter. That would save about 1/2" or more.

I could raise the passenger side of the motor, but the valve cover would probably rotate into the area for the brake master cylinder.

The driveshaft hits the 'cone' of the starter at the bellhousing. I have already clearanced it a decent amount.

Two-piece driveline could help but things are VERY tight and the front driveshaft is already pretty dang short...maybe 24-30"

The motor is currently almost flat. I'm not too worried about keeping it at some ideal angle. Its an off-road vehicle that won't be 'level' most of the time anyways.

No TBI for this engine, the odd-fire makes it a pain in the butt.

I don't think its going to get much better than it is. I would have to raise the entire mess up and at that point the distribtor wouldn't really fit under the hood anymore I can't imagine having a 1-1.5" drop below the frame is going to be that bad. I didn't really notice that the belly hung me up THAT much before and it was probably a 3-4" drop below the frame and wasn't smooth at all.

I should have about 5" of extra clearance under the belly compared to the old 'stock' setup.

The main bummer is that the 'drop' of the skidplate is almost exactly between the front and rear spring hangers. I am going to try and make a lip at the rear of the belly skidplate past the transmission crossmember that will extend up into the frame at least to the bottom of the frame rail.

One upside. My oil pan doesn't hang down at all, even the bellhousing is totally above the bottom of the frame.

[Mieser]

One other thing....

I don't know if I can clear a normal external clutch fork

I did a little rough measuring and I think the fork will be into the 'gas pedal' area of the floor where the tub angles up from the flat floor.

I think I am going to have to run and internal style hydraulic throwout bearing. I'm not the biggest fan of these, but its not the end of the world.

I won't know for sure till I get the tub on and trimmed to sit down on the frame.

The back edge of the motor is currently 2.5" ahead of the 'dip' in the firewall. I don't think I can push the motor any farther forward.

The shifter for the SM420 may also get a little bit friendly with the dash. I have been thinking about making one of those 'gearbanger' style remote mount shifters with the new low seating position anyways.