SJ410 1.6 conversion front prop

[Tommyboyblitz]

I have a B reg SJ410 which has a 1.6 conversion which is about 90% finished. The engine manifold leaked and hoses where going left right and centre with no real purpose. The guy I bought it from had a mate do the work so wasn't 100% sure what parts had been changed. He believed the gearbox, transfer box, clutch and flywheel were from a 413. The rear prop is the only one attached and is of the skinny type. The diff ratio's are 4:1 (I think) and are the same as my brothers standard later F reg 410 with the thicker drive shafts and flanges.

So I have sorted out the engine which pulls like a train, compared to my brothers 1litre, but my question is what do i do about the drive train, The biggest problem is the front prop doesn't fit, the owner muttered something about welding it up. one end fits on the smaller flange for the diff fine but the other end doesn't fit the transfer box. Also with the extra power of the engine the skinny props don't look strong enough.

I will be putting this SJ on the road with maybe 30's / 31's for my and my brother to use greenlaning and some fairly easy offroading as i want to keep it straight and looking nice. My brothers SJ is too rusty to put on the road and only used for more extreme offroading. Now what should I do about the drive train, do I change out the 2 drive shafts for the fatter type and change the flanges for the diffs? are these easy enough to find and will they swap straight over? If i change the rear prop do i change the handbrake drum part as it has the smaller bolt size holes. Or will cutting and welding 2 diffs together to make the front prop fit work fine? Is there anything else i should change?

Cheers

[ScottieJ]

Skinny props are just as strong as fat props, if not stronger as they are solid, not hollow.

You can fit a later flange on a skinny prop using a UJ with a combo of end caps.

[Tommyboyblitz]

Ah so the larger hole diameter flange still fits to the UJ. That's handy to know.

As for strength the solids are probably stronger for impact but torque forces turning it I would still bet the fatter ones are stronger. Like gearing, the fatter one is less likely to twist.

[ScottieJ]

I've seen fat props twist, they twist at the narrow splined section

Honestly there is such a minimal difference in strength that I would happily run skinny props

[Tommyboyblitz]

Anyway, so far i have found there is 3 different sized prop/flanges my sj410 B reg 1985 has a skinny prop with 55/56mm spacing between the bolts. My brothers 87 E reg 410 has a staggered 56mm and 60mm rectangle spaced holes. My transfer box for some reason has a square spaced 60mm spaced holes.

A flange with the 56mm spacing wont fit the the transfer box flange.

I think my transfer box may have come from a 413

[ScottieJ]

That doesn't sound quite right? Never known any Sj's to have rectangle bolt patterns on the flanges and I've got loads of diffs, flanges and props. I've had a few 87 410s and they've all been 56x56

Late 410 (fat prop) and 413 / samurai should be 56x56
However Late samurai (93+ ish) should be 60x60

Lj80 and skinny prop 410 are slightly smaller so the 56x56 doesn't bolt up.

Flanges will only swap between later style transfer boxes that have a 4wd light switch.