4wd engine cross member

[mjensen]

Can anyone explain to me why the engine is set 2" back on 4wd 67-72 trucks? I'm putting in a torque splitter and one of the options presented would be to move the front cross member forward two inches and the rear one back 5-1/2. I'm thinking this would cause clearance issues with the front axle, but wanted some feedback while I plan this out.

Thanks!
mike

[SunSoaked]

Originally Posted by mjensen

Can anyone explain to me why the engine is set 2" back on 4wd 67-72 trucks? I'm putting in a torque splitter and one of the options presented would be to move the front cross member forward two inches and the rear one back 5-1/2. I'm thinking this would cause clearance issues with the front axle, but wanted some feedback while I plan this out.

Thanks!
mike

How do you know that? I have a 2wd and 4wd frame sitting side by side. I could measure them to verify and see if I see anything obvious. What trans are you using. If manual-how are you going to address the z-bar for the clutch since its mounted to both engine and trans? I plan on going with a hydraulic clutch.

I'm curious if the water pump/fan shroud are different in 2wd vs 4wd? I'm using aluminum tank with SPAL dual electric fans. No issue with 2 inches less clearance.

I'm doing the same mod as you, so I'll be following your progress closely. Let me know how I can help with measurements/photos etc.

[mjensen]

Originally Posted by SunSoaked

How do you know that? I have a 2wd and 4wd frame sitting side by side. I could measure them to verify and see if I see anything obvious. What trans are you using. If manual-how are you going to address the z-bar for the clutch since its mounted to both engine and trans? I plan on going with a hydraulic clutch.

I'm curious if the water pump/fan shroud are different in 2wd vs 4wd? I'm using aluminum tank with SPAL dual electric fans. No issue with 2 inches less clearance.

I'm doing the same mod as you, so I'll be following your progress closely. Let me know how I can help with measurements/photos etc.

I don't really know that for sure, but I've read about it a few times on this forum. I'm not sure what the reasoning is, but if I had to guess I would bet it is to provide more clearance for the front axle. Just a thought. If I do end up moving the front x member, I will probably just move that bracket up as well, but if I leave it alone then nothing will need to be done.

As for the water pump and all that, I don't know if there are any differences. I would be surprised if there were any because there is/was a ton of room between the radiator and fan. My guess is that the shroud would be the only difference (and they are listed differently in the LMC catalog).

It would be interesting to see the comparison between the 4wd frame and the 2wd frame.

[kwmech]

The only answer I can come up with on engine placement on the 4x was for the front drive shaft length and angle on full droop. With the stock suspension and the engine 2''rearward the cv won't bind

[SunSoaked]

Originally Posted by kwmech

The only answer I can come up with on engine placement on the 4x was for the front drive shaft length and angle on full droop. With the stock suspension and the engine 2''rearward the cv won't bind

If so, wouldn't it be easier to just rotate the front axle to lessen the pinion angle?

I love a challenge.

[Mr-Jack]

rotating the front axle is no easy task...you have to cut the knuckles off precisely all the way around on both sides, then using angle finders and levels, you'll have to set your pinion angle then re-weld the knuckles back to the axles...you can shim a few degrees, but i definately wouldn't shim it an extreme amount.

I do know that there are differant mounting position on the frame rails for differant motors. V6 V8sbc and V8BBC so 3 differant engine mount positions, with v6 closest to the firewall and the BBC furtherst from the firewall.

[BLAZERMAN]

I've looked my truck over real good and 2" will not be a clearance problem at all..but I'm running a 4" lift also. I've always wanted to do this even before I got my Ranger splitter. It a pain just to replace a distributer cap the way it is..I think the 2" move would make working on the motor much easier.
I know some of the Big Block guys have moved theres forward without problems..maybe one of them will chime in.

[mjensen]

Originally Posted by BLAZERMAN

I've looked my truck over real good and 2" will not be a clearance problem at all..but I'm running a 4" lift also. I've always wanted to do this even before I got my Ranger splitter. It a pain just to replace a distributer cap the way it is..I think the 2" move would make working on the motor much easier.
I know some of the Big Block guys have moved theres forward without problems..maybe one of them will chime in.

Blazer...It's your advice that's got me into this predicament! :LOL: I actually really like the idea of moving it forward for two main reasons 1 - distributor to firewall clearance as you mention, and 2 - may help the shifter clearance.....

Whoa...you're running a splitter on yours?

[BLAZERMAN]

Originally Posted by mjensen

Blazer...It's your advice that's got me into this predicament! :LOL: I actually really like the idea of moving it forward for two main reasons 1 - distributor to firewall clearance as you mention, and 2 - may help the shifter clearance.....

Whoa...you're running a splitter on yours?

I havent installed mine yet...ite one the first versions..cast iron case, with an Eaton electric shift motor..manufactured around 78 I think. I got it still in its original shiping crate...was sent to a dealership in K.C. and was opened but never used.

[Dieselwrencher]

When I put a BBC in my 70 K20, I moved it the SBC cross member ahead 2" and I didn't have clearance issues. IDK why the factory did this because they could have installed BBC's in them from the get go.

[SunSoaked]

Originally Posted by Mr-Jack

rotating the front axle is no easy task...you have to cut the knuckles off precisely all the way around on both sides, then using angle finders and levels, you'll have to set your pinion angle then re-weld the knuckles back to the axles...you can shim a few degrees, but i definately wouldn't shim it an extreme amount.

I do know that there are differant mounting position on the frame rails for differant motors. V6 V8sbc and V8BBC so 3 differant engine mount positions, with v6 closest to the firewall and the BBC furtherst from the firewall.

Guess your right. It's not as easy as the rear with the steering linkage and all..

[jjzepplin]

I did this in my truck (2" forward). And have not run it yet but have a splitter (23/205 ORD) and 700r4 and do not see a problem with clearance. I am running electric fans and a four core with serp set-up though. Was a real challenge getting those lower frame rail holes drilled. Used a rt angle drill. Came up with a close tolerance between my headers and the left front spring though. Bought the headers used off different truck so correct ones may not be so close. Sure is easier to get to the rear header bolts and spark-plugs!

[mjensen]

Okay, I've decided that I will move the front cross member up the 2" then the rear 5-1/2 back. Thank you everyone for the valuable input!!!

[BLAZERMAN]

Here ya go Mike, the electric motor is made by Eaton..not sure if this style will work with yours as they changed the shifter mechanism when the company changed hands.

[mjensen]

Thanks Rob! Yeah, that's totally different than mine. I guess I'm going to have to find something else.