Drive-train in place

As mentioned previously, our chassis had some alignment issues and was sent off to be fixed. We got it back a couple of weeks ago, with some slight chassis modifications and customised wishbones. Those wishbones needed poly-bushes installed, so that was our first task. An important thing to know about the wishbones and poly-bushes is that the metal insert is not meant to move – it should be pinched in the mount by the bolt and the washers.

The wishbone therefore rotates on the poly-bush. This has two implications – firstly you can use bolts with fully threaded shanks, since the insert should not actually be rotating on the bolt. The thread of the bolt will therefore not damage the insert. The second thing is that the bushes need to be properly lubricated. This new set of wishbones gave us the opportunity to really pack in the red rubber grease. (Note – this does not apply to the shock-absorbers, which do rotate about the bolt). Many thanks to Chris for helping out with this sticky, icky job.

We got our engine mount brackets welded – big thanks to Ken of Zodiac Steel for assistance and doing such a good job. As soon as we had those sorted, we were able to properly see how the engine and gearbox would fit in. Needless to say, several adjustments to the bell-housing were needed, and we chopped some more bits off.

To fit the gearbox we needed to drill and fit the gearbox mounting plate. This is an H-shaped piece of steel plate, onto which the rubberised gearbox mount is, well, mounted. With the engine in place and the gearbox supported by a size-14 temporary mount, we could see if the mounting plate lined up with the mount points on the chassis. It was a wonderful moment when we realised that the fit is perfect. We marked and drilled the holes (8mm, although one was a slight miss, so it became a 9mm hole).

Feeling inspired by getting 3 out of 4 holes right, we marked and drilled the engine mount plates. We’d obviously improved our skilz, because we got 8 out of 8 of these right (no cheating here – 8mm holes for 8mm bolts, and they went in smoothly).

Checking the engine again, we realised that there was a risk that the starter would foul against the chassis. So it was another “engine out, attach part, engine in”. Only we realised a slight problem – the starter does not fit. There is a small sticky-outy bit on the sump that gets in the way. A couple of panicked phonecalls to Locost SA, and we confirmed that this needed to be chopped off.

It’s actually quite an easy job, but you don’t want to get all “power-tool” on it. The sump is aluminium, so if you get too aggressive you are likely to chop a hole in it. Another tool you’ll be needing for this job is a torque wrench that can handle 67N.m (thanks JR and Nick). The process is:

1) Remove clutch pressure plate (about 6-8 bolts, fairly easy).

2) Remove the clutch plate, to be left with the flywheel:

3) Remove the fly-wheel (6 bolts, fine thread), resulting in this:

4) Now you can get to the sump, and carefully cut the piece off. See pictures for confirmation.

You might need to remove two of the sump bolts, but we did not. You will not be able to use a normal hacksaw. A junior hacksaw got close enough that the last bit could be snapped off. Then a file neatened it up. One of those blade-only hacksaws will work, as will a dremel tool.

5) Clean off any loose shavings.

6) Put the flywheel back on.

Use a touch of lock-tite (removable) on each bolt, then torque to 67N.m. (Following all the right rules for tightening sequence. I tightened, bit by bit, a triangle of bolts, then chose the next triangle as starting from the opposite bolt that I ended on. Clear as mud?)

Leave the clutch and pressure plate off for now – they’re not needed for a while.

7) The starter motor now fits very nicely:

After this the engine went back in – we’re really getting our money’s worth out of that engine crane. The starter is a tight fit against the chassis, but it does fit. We then tested the bonnet for clearance – the dip stick handle will need to be “lightened”, but the 710 cap is fine (thanks to the bonnet scoop).

While we were fitting heavy things, we decided to balance it all out and fit the diff. It didn’t fit, which is a painful thing to find out while trying to hold that stupidly heavy piece of metal in place. The grinder was called to service again, but not quite vigorously enough. We actually think we might leave it as it is, since with a couple of spacer washers it fits fine.

EDIT 2011-02-25: It’s actually recommended by Locost SA that you rather grind away the webbing on the diff, than the diff mounting bracket. The theory is that the diff is more over-designed than the chassis mount point. We’re holding thumbs that it all stays together.

With the diff in place, it was possible to see how the gearbox and diff lined up. Badly, it turned out. The gearbox was shooting mortars clear over the head of the diff. Undismayed we put some longer bolts in the gearbox mount plate, and dropped it by about a centimeter. This lined it up perfectly, so we’re almost ready to order the prop shaft.

A small miracle happened during the week. We’ve been searching for ages for a solution to our alternator problem. We have a small, awsome little alternator from a toyota forklift. Unfortunately it comes with a v-belt pulley, not a 6PK pulley (which is used on the rest of the Rocam). Also, it doesn’t like high revs, and the test sheet shows its only able to handle about 6000 RPM for any extended time. The crank pulley on the Rocam is quite large, so if you put a small pulley on the alternator it is going to see some pretty high revs. This is NOT good, and others have mentioned burning similar ones out. So we want a big pulley which will fit the thing. The solution is a 6PK water-pump pulley, just like the one on the Rocam. If you attach this to the v-belt pulley, you are sorted. Well, we’ve been to several scrapyards looking for pulleys, with no luck. It seems you very seldom find a water-pump pulley separate from a water pump.

I posted for help on the forum (as I should have done first) and immediately found one pulley, and a suggestion to try Ford for spares. “Maybe they won’t be so expensive” – yeah right. So I got hold of Ford (it’s really worth telling these guys what you are doing, often they are very helpful) and I found out they do supply the pulley on its own. The price: r50 .11 ex VAT. I figured there was a number missing there – surely it’s R500.11? Nope, they ordered the part for me, and it came to R57 incl! Amazing. Even the guys at the parts desk were amazed (they showed me a much worse pulley for R900). The part number is XS6E-8509-AA if you want to find your own. I’ll post more info if it successfully gets attached to the v-belt pulley.

Our engine bay is now getting quite full, and we are becoming more and more convinced that the sequence we did the build in is just wrong. The brake and fuel lines really should only be going in once the immovable objects have had their say. As part of this blog I’ll put together a suggested build sequence.

Phew, long post! Till next time, happy building. Don’t forget, more build pictures here.

B