Project 2.

[Errol62]

2000rpm with 3.08 final drive and 235/70 R14 tyres, I work out to be around 78kmh. With 20% overdrive it would be 94kmh. If you have a flat torque curve such as diesels do then the extra 200rpm won't make much difference.

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[Blacky]

I have a grey motor - it has a flat torque curve of just above bugger all

I used a 3.08:1 diff one year with the 205/50/13's and it was okay , left that centre in with 225/60/14's the following year and it was awful - that was the year we went down to Victor Harbor and on the hills heading down there we were stuck on 40kph .....

[Brett027]

Speaking of gearing, a pleasant surprise opening up my M20 today. Even synchro cones are as new. Lay shaft also unworn. I'm tempted to just give everything a wash but think I'll do the kit job anyway. My guess is that it was overhauled shortly before it got to me.

Handbrake mechanism tidy-up day as well. Will have to find a spot for the cable lever mount in amongst the crossmember mods.

[EK283]

Clever man the gearbox designer !!

Looks nice and servicable.

Greg

[Brett027]

Yes, it's not a hard box to go through and tidy up. Figured best do it now and have everything nice and tight for my upcoming burnouts

[Errol62]

Good news mate.

I mounted the pivot to the gearbox crossmember on a short extension offset to driver side. Worked fine although the angle at the lower cable block was slightly askew.

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[Brett027]

Yes, I'm thinking the critical bit is to get the stock front cable right and then engineer whatever is needed to meet up with the HR rear axle and find a pathway through the CRS chassis kit bits. I have a modified EK to HR conversion rear cable connected up to the axle waiting for action. Probably best to attack that job when the engine and box, driveshaft and exhaust are in. I am thnking of making a joining piece for crossmember 1 under the box and the cable arm can attach to that. Good fun this hot rodding stuff: I'm like a pig in @#$% at the moment

[Brett027]

Gearbox back together this morning. Next level degree of difficulty compared to grey three speed.

Word of warning. There is no way you can pull this gearbox apart and put it back together again without having a spare shortened layshaft. This is because while you may fluke holding the needle rollers in with some vaseline, it is impossible to hold the thrust washers in place without a shaft cut to the full width of the opening. To complicate things more, the layshaft shaft is a tight fit and has to be flogged in. As well, the whole assembly has to be in the box but not in place before you put the reverse idler and mainshaft in. If your gearbox is tight to turn after reassembly there is an almost 100% chance that one or both of the layshaft thrust washers is not seated with the locater tab in the housing slot. They can easily turn while you are trying to get the shaft back in. I used a felt pen mark at the bottom side to the tab which you can see as you position them to line up the tab with the slot ( which you cant see). Other thing to note is that while the thrust washers look the same, the ones for the reverse idler have a larger inside hole. It would be easy to put the reverse ones on the layshaft but not vice-verso.
The input shaft lock ring was too big in my kit and I had to re-use the old one to get the holding plate to seat properly. The reverse idler thrust washer in the box needs to be checked for seating before the extension housing goes back on as it tends to slide out while everything else is being installed. It is easy to position.

Take lots of before photos because there are two ways to put everything on - the right way and the wrong way. I had a manual to look at but it's never as good as a photo.

Everything on this one was probably good enough to go back in except the input shaft ball bearing which definitely had a rough feel to it. Seals also were a bit hard.

If anyone has an M20 or M21 and need to borrow my custom layshaft let me know.

[Errol62]

Very comprehensive and insightful thanks Brett.

What would you say the implication is of one of the thrust plate tabs being displaced, other than yhe initial tightness? I suppose it may spin and then wear the housing, but then cease to be an issue.

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[Brett027]

The best case scenario would be if the tab was outside the slot and then it would just move around until the tab hit the housing and then it would stay against it. Not sure if it would rotate back the other way when in reverse gear. Even so it would not be a disaster I guess. The real drama would be if the washer was jammed onto the housing and then it would rapidly wear onto things until it freed up. Dropping bits everywhere in the process. It would probably last until the next overhaul. Just guessing here.
Edit: first bit is nonsence after thinking about it a bit more. It cant move around. it can only jam and wear down until it frees up and then eventually it would spin.

[Errol62]

Thanks Brett


FB ute fixer upper, EK van on rotisserie

[Brett027]

Things are getting serious in Canberra

[Errol62]

Project 3?

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[Blacky]

I hope its electric .......

[Brett027]

I dont think it's electric Blacky. Definitely not mine so not Project 3. Maybe they use it for neighbourhood watch. Its in O'Malley amongst the embassies. House is for sale - not sure if tank goes with it.