Amc V-8: Mj

[bajacalal]

So it's not really gonna break my heart too much to drain the oil and floor it until :explosion: There will be a vid cam present, anybody host it for me?

I hate to be a big wet blanket but I think most modern computerized motors have an antifire saftey feature that- if theres no oil pressure = cut off the gas. Not sure about the xj but my feeling is yes. Don't know what you can do short of just trying it or maybe hotwiring the fuel pump, offloading the motor on someone else or just junking it. Good luck anyway.

I do think the 'ol 4-0 was a good match for the mj so the big hulkin v8 troubles me but then again everybodys entitled to my opinion

 

[ChicksDigWagons]

TH400 is huge and soaks up a lot of power. I'd stick with the AW4 in your case.

The AW4 flexplate will physically bolt up to an AMC 8's crank, it's just a matter of getting the balance factor right. You could take two flexplates to an engine shop and have them matched up. Or maybe drill some holes for the AW4's converter?

Their respective sizes aren't really that much different, at least not to the point where its going to cause fitment issues as the tranny seems to fit nicely behind the 258. The 360 on the other hand is a majorly tight fit, and I'm either going to have to move the tranny forward or move the firewall back. I'm opting for the latter, going to pocket the firewall for the V8s heads which will move the weight back as well as keep my driveline lengths as equal as possible.

The only thing I don't quite understand is why you say the TH400 soaks up a lot of power? It doesn't have a lock-up TC, but this is going to be far from a highway ride anyhow. Is there some obvious reason an AW4 is more efficient, and is that efficiency worth the reduced strength?

 

[JJacobs]

I hate to be a big wet blanket but I think most modern computerized motors have an antifire saftey feature that- if theres no oil pressure = cut off the gas.

Not so..

I do think the 'ol 4-0 was a good match for the mj so the big hulkin v8 troubles me but then again everybodys entitled to my opinion

[/Napoleon Dynamite] I'll do what I want! GOSH! [Napoleon Dynamite]

 

[JJacobs]

Their respective sizes aren't really that much different, at least not to the point where its going to cause fitment issues as the tranny seems to fit nicely behind the 258. The 360 on the other hand is a majorly tight fit, and I'm either going to have to move the tranny forward or move the firewall back. I'm opting for the latter, going to pocket the firewall for the V8s heads which will move the weight back as well as keep my driveline lengths as equal as possible.

The only thing I don't quite understand is why you say the TH400 soaks up a lot of power? It doesn't have a lock-up TC, but this is going to be far from a highway ride anyhow. Is there some obvious reason an AW4 is more efficient, and is that efficiency worth the reduced strength?

Well besides the 400 not having an overdrive, it's pretty well known in drag racing circles that it sucks a lot of power. Stronger and less efficient than a TH350. Now in a 4x4 application maybe it's a moot point.

I'm with ya on the firewall mod, trick is to make the pockets big enough you can still service the engine in vehicle. I think doing away with the stock gas pedal position comes with this swap too.

 

[alosix]

Its shouldn't be all that bad to make shift. The older AW-4 TCUs only really need power (both bat and ignition) and a 0-4.5 volt TPS signal. If you are using the RENIX style with the 4.5->0 TPS you might want to start looking for a post renix TCU depenting on the TPS that the edlebrok setup has.

Jason

 

[ChicksDigWagons]

Well besides the 400 not having an overdrive, it's pretty well known in drag racing circles that it sucks a lot of power. Stronger and less efficient than a TH350. Now in a 4x4 application maybe it's a moot point.

I'm with ya on the firewall mod, trick is to make the pockets big enough you can still service the engine in vehicle. I think doing away with the stock gas pedal position comes with this swap too.

Hmm...I never looked at the pedals...but it doesn't look like it will be that big of a deal. I'm essentially gutting both the engine bay and interior of all unnecessary wiring, relays, this and that and the other thing. Of course its a limited I'm starting with so I have power everything :-( On the other hand its a two door so half as many wires for the doors... heh.

I'll have to take a closer look at that pedal thing.

 

[JJacobs]

'nother dead 4.0L! Broke two rods, after about 5 minutes with the pedal matted. Got pics and video to come
Kind of disappointing, only a small pinhole appeared in the pan, didn't ventilate the block or anything.

 

[bajacalal]

'nother dead 4.0L!.

You sound like a man on a mission

I was wondering if she would die a violent death or just peacefully sieze up without making any racket.

 

[GregW]

You sound like a man on a mission

I was wondering if she would die a violent death or just peacefully sieze up without making any racket.

oh it made some racket 6200RPM or WFO (wide F'N open) and it went knocking and banging and we have a 8MEG MPEG Video if anyone wants to host it

Greg

 

[ROBZ95Xj]

oh it made some racket 6200RPM or WFO (wide F'N open) and it went knocking and banging and we have a 8MEG MPEG Video if anyone wants to host it

Greg

load it up onto www.putfile.com

 

[JJacobs]

http://www.putfile.com/media.php?n=TwoRodsBroke

 

[Eagle]

Well besides the 400 not having an overdrive, it's pretty well known in drag racing circles that it sucks a lot of power. Stronger and less efficient than a TH350. Now in a 4x4 application maybe it's a moot point.

I'm with ya on the firewall mod, trick is to make the pockets big enough you can still service the engine in vehicle. I think doing away with the stock gas pedal position comes with this swap too.

Use the stock motor mount locations. It worked for AMC, even in small, light cars like the Rambler American and the Hornet.

AMC did not line up the back end of the engines. They lined up the transmission. The 6-cylinder applications used a 6-1/2" deep bell housing, and the V8s used an 8" deep bellhousing to allow for the fact that the back end of the engine was set farther forward.

 

[IdahoEagle]

Look around, you can find shorty hearers. Look at Performance American Style to start, they are an awesome AMC speed parts source.

 

[JJacobs]

Well the swap looks surprisingly doable, once I lowered a mockup motor into the bay. The nearest engine was a few miles away before, and I had pulled all the wrong types of measurements off it. So it looked like more of a challenge than it really is.

I want the engine back and down as far as I can get it without major work. So exhaust manifolds (that I've seen) and shorty headers will NOT work. The problem lies in the passenger side, the pipe goes right into the firewall. Which could be clearanced I suppose.. on that note the firewall will be getting the torch and BFH clearance for the valve cover recesses. The heater box is the limitation, I may have to move the heater core inside the HVAC box to get more room.

Otherwise the steering shaft isn't an issue, brake booster clears just fine, oil pan clearance should be OK depending on setback.

I think I'm gonna make near-center dump headers out of my new Hedmans. A blockhugger style should be about perfect.

 

[JJacobs]

minor updates. A few pics, nothing earth shattering.






It's down about as low as I can reasonably get it, and won't move back anymore without major metal work. As is the rails have been BFH'd and will be plated. The axle is under the second set of cylinders, not the first like I'd like it. I ordered up some Chevy blockhuggers today with the plan to mate them to the AMC flanges from my other headers. $160 flanges anyone?

Got the 2WD AW4 today, now for some motor mounts after the blockhuggers go in.

Sorry my camera's flash isn't very bright.

 

[ChicksDigWagons]

Looking good. I'm interested to see how you do the motor mounts. I'm going to assume the transmission is going to be further forward than stock? When I was sizing up my 360 to fit in the hole it looked like I'd have to move the TH400 about 8" or more forward...which I don't want to do at all.

I'm also kinda perturbed that nobody sells cheap mild steel cut flanges for AMC headers, or block hugger headers for that matter. Just one more reason to buy a CNC plasma table...

 

[JJacobs]

Forgot to measure where the bell sat in relation to stock. Probably about 4 inches forward.

The motor mounts look tricky, since the portion of the block where the bolt holes reside is actually below the center of the "frame" rails. I need to get an oil pan bolted on then bend a tube around the bottom of the pan, then up and out to the plated rails. The engine will then hang by YJ leaf bushings on tabs off the rails. This will give a skinnier engine mount interface, though still strong, and more room for the blockhuggers.

At least that's what I'm planning as of today. :laugh3:

 

[JJacobs]

Little more progress. I'm taking a break from the heat right now, although I'm sure it's nothing here in Colorado compared to elsewhere. One of the pics is the 'frame' plating, there are two of course, 1/8 plate. The other is the one header I have done so far. AMC blockhugger.

More pics later, I'd like to get to work on the engine mount cradle, just as soon as the other header is done. The air cleaner will clear the hood w/o mods, the TBI unit is very low profile.

 

[JJacobs]

Got the AW4 on. The torque converter was a big issue. I had to weld spacers to the front of the converter lugs, and extend the centering ring on the snout. Along with redrilling the flexplate. There's no chance of extending the flexplate back into the trans enough to keep everything engaged in the pump.

I could have bought an AW4 flexplate instead of using the 727 one, and had that balanced to the 401's spec. If I did it again would be going that route.

 

[JJacobs]

It's in, finishing things up. Don't mind the stock cooling system, it's just temporary. Everything clears.. barely. Even the tall ps pump clears the hood by 3/4 inch. Note how the stock 4.0 lower rad hose fits. Perfectly. Makes me wonder if the stock shaped aluminum radiator would be the way to go, except for the price.