c.h.i.e.f 's 110 Isuzu county

Quote:

---

Originally Posted by c.h.i.e.f

Thank guys I will go over your previous post when I get some time to comprehend what was said :D I was thinking about modifying a output shaft from say a r380 etc etc and mounting that to the Isuzu box output flange the rest is obvious but I need to figure a way out how to do it with minimal welding and maximum alignment which may pose a problem...I shal take some more photos and post some measurements of my box :angel: the sarvo ...
As for drilling the block for oil return I am asuming by looking at the housing that bolts to the matching surface on the block I need to drill a hole on the top left quadrant ? Any idea on hole size ?

---

Better shaft to modify is the spud shaft from a disco ZF auto (use the one with longer spline.

Then only need to fit a flange. Shrink fit the flange onto the end of the spud shaft and circumferential weld at the front end only (for weld prep make a chamfer at the end of the shaft and end of the bore in the flange. Weld at that position will not cause any problems as long as the parts have suitable pre-heat before welding and low hydrogen electrodes are used (or good wire).

Quote:

---

Originally Posted by Dougal

I'm wondering if one of these:
https://www.aulro.com/afvb/images/im...012/05/762.jpg off road race transfer box motorsport
and some ingenuity attached to the Isuzu driveflange will sort the power transmission out. Then you just need to build attachment for the casings.

I'm getting annoyed with my current setup leaking (porous cast aluminium adapter) and am considering a variation on the above. This way I can keep the leak free Isuzu box rear end and get a decent seal into the lt230.

John, my 5 speed box also had no spring support but from gears 1-2 and 3-4. I took the top cover off and welded in a steel leaf-spring to give enough centering action that 3-4 was easier to find. It was a very ugly modification at the time, but it's still in there and working 9 years later.

---

What you say abuot the top lever makes sense - the only difference for 6 speed is addition of a 4th position on right side for 6th.

Quote:

---

Originally Posted by c.h.i.e.f

<snip>....
As for drilling the block for oil return I am asuming by looking at the housing that bolts to the matching surface on the block I need to drill a hole on the top left quadrant ? Any idea on hole size ?

---

From memory I drilled mine 13mm.
There are some photos on here somewhere that show where to drill the hole, but I dont recall which thread they are in.
I know I looked long and hard at exactly where to drill it, and checked on the inside of the block, and made sure the conrod wasn't behind the hole etc etc before I fired up the drill on mine.

Steve

[QUOTE=Bush65;1683661]Better shaft to modify is the spud shaft from a disco ZF auto (use the one with longer spline.

Then only need to fit a flange. Shrink fit the flange onto the end of the spud shaft and circumferential weld at the front end only (for weld prep make a chamfer at the end of the shaft and end of the bore in the flange. Weld at that position will not cause any problems as long as the parts have suitable pre-heat before welding and low hydrogen electrodes are used (or good wire).

Thanks I will take that into consideration.. As this may be an option for this project if not Grubbs shaft or the one dougal just posted will be high on the list...

Quote:

---

Because of the length of the 6 speed box I looked at close coupling an LT230 by resplining the LT230 input gear, but the gear case was too fat and the front drive extension of the LT230 wouldn't clear by a large margin. The extra length of grubb's kit, which involves an extension from the gearbox output flange, might be enough to squeeze it in. But the LT230 will be shifted further back from stock.

---

Interesting about the gear case fatness. In the picture there doesn't look to be all that much hanging out there. On the MSA box if I were to have no extension and pushed the LT230 face to the rear MSA face, the fill plug on the MSA would just hit the casing on the front output on the LT230, otherwise would all clear. Diverging, I looked at a MBG-6 of a 6BG1 motor to get a 6 speed but the same fatness was an issue. We unbolted the flywheel housing and flywheel from the 6BG1 and bolted it straight up to the 4BD1 to fit the MBG-6. Some may be interested to know that the 6BG1 flywheel is 20mm thicker than the 4BD1 for extra inertia (50mm commpared to 30mm)

Quote:

---

Originally Posted by the_grubb

Interesting about the gear case fatness. In the picture there doesn't look to be all that much hanging out there. On the MSA box if I were to have no extension and pushed the LT230 face to the rear MSA face, the fill plug on the MSA would just hit the casing on the front output on the LT230, otherwise would all clear. Diverging, I looked at a MBG-6 of a 6BG1 motor to get a 6 speed but the same fatness was an issue. We unbolted the flywheel housing and flywheel from the 6BG1 and bolted it straight up to the 4BD1 to fit the MBG-6. Some may be interested to know that the 6BG1 flywheel is 20mm thicker than the 4BD1 for extra inertia (50mm commpared to 30mm)

---

This is interesting!!
So the 6bg1 flywheel bolts to our motors but does the pressure plates we use bolt to the flywheel ? Wonder if a 6bb1 will have this same flywheel ? This may be the answer to the torsional vibrations that dougal has been reffering to !!

Quote:

---

Originally Posted by the_grubb

Some may be interested to know that the 6BG1 flywheel is 20mm thicker than the 4BD1 for extra inertia (50mm commpared to 30mm)

---

Very interested to hear that. Don't suppose you took any pictures?

Just thinking about the adaptor to go on the flywheel to house the spigot... This would mean longer bolts will need to be used so I was wondering if having longer bolts would mean it would be weaker ? Wouldn't really want a flywheel flying off :eek: I may be looking into it all wrong and a "extension or spacer" may not be used ...

Quote:

---

Originally Posted by c.h.i.e.f

This is interesting!!
So the 6bg1 flywheel bolts to our motors but does the pressure plates we use bolt to the flywheel ? Wonder if a 6bb1 will have this same flywheel ? This may be the answer to the torsional vibrations that dougal has been reffering to !!

---

Pretty sure the standard clutch on a 6BG1 is 325mm - so bigger than the standard Rover/Isuzu 4BD1 N/A 275mm and Turboed 4BD1 300mm. The clutches on these were air assisted as well.... I dare say the 6BD1/6BB1 will have bigger flywheels as well.

Quote:

---

Originally Posted by Dougal

Very interested to hear that. Don't suppose you took any pictures?

---

No :(

But i did take a few rough measurements.

Flywheel housing thickness

6BG1 155mm
4BD1 (Truck) 105mm
4BD1 (Rover) 80mm

Flywheel inside dia. (these are real rough)

6BG1 410mm (SAE 3, I beleive)
4BD1 (Truck) 405mm

Can't recall now, I should of measured, if the two flywheel dia. where the same. It looked like the 6BG1 flywheel would fit in the 4BD1 flywheel housing, as to whether the ring gear aligns with the starter... also leaves the dilemma of the flywheel protruding 20mm further out if using the 4BD1 housing...

Anyway back to the MXA-6R!!

But the bolt holes have the same pcd as the 4bd1 ? (bolts to the crank) a larger clutch will be good but the main concern would be the outside diameter as you said.
Crap don't mention mxa i am avoiding looking at it at the moment :D
If the larger flywheel fits and has a 325mm pressure plate it will depend what diameter clutch plate can be found to suit the mxa-6r input shaft I would suspect ?