DIFFicult

A long, long time ago in a garage far far away, I started building my car. Well, after a very slow going winter I finally have some progress. If you thought I was going to say that it was finished, have you learned nothing from my previous posts?

Tonight I did some work on the diff, the clue was in the title, I did a play on words thing and changed 'diff' into 'difficult'! You've missed these posts haven't you... I'll get my coat.

Where did I leave off? Oh, I haven't even talked about the engine have I yet... well that was fun.

The car looked very pitiful when thrown on the floor.

Tim and I had great fun getting the engine in place, you see the engine has to come in from under the car, so I took the opportunity to turn the car 180 degrees (not that way! I mean so that it was facing the other way!).

The engine was then hoisted in which was interesting trying to keep it level. We got a couple of mounts in place and called it a night as we hit a slight snag.

Check and check again. Did it your side slip? No, did your
side? No. Up a bit more? Urm... let me check again first.

You may remember that one of the engine mounts was screwed and needed re-tapping. This was a fairly simple affair with thanks to Steve for lending me the taps and Paul for showing me what to do during an hours *ahem* lunch break.

It looks tiny. Hopefully it'll be underestminated ;)

So with the mount sorted, Paul and I decided to get the engine in place. Tip of the day: If you're reading this before you've done it, do the two bottom/rear mounts first, you can then pivot the engine much easier to get it at the right angle for the top/front four.

Millimetres make a big difference in this game. Typical,
the mount that is furthest out is the one I had to re-tap.

Oh if only it were that easy, you see the chassis doesn't exactly line up with the engine mounts. It was a real pig getting the bottom two in as things were so tight, but with the force of some Icelandic strong men, we made it work. The top four don't exactly line up though and I'm going to have to get creative with the holes in the chassis to make it fit.

Never-the-less, with the engine in place, I could crack on. I did some other bits which I'll make separate posts about and fast forward to tonight's work, and the title of tonight's post; the diff.

The diff comes in three parts, two mounts and the diff itself. It's a fairly heavy piece of kit, holdable in one hand but really two's needed to lift it. When all three bits are together it looks a bit like a Tie Fighter.

I originally put the mounts in place and then tried to slide the diff in, but the gap was too tight as part of the diff inserts into the mounts. Fair enough, so I assembled the three parts and then tried to slide it in, but it didn't fit, the gap was still too narrow. Hmm.

So I got out the ol' measuring stick (aka a ruler), and found that the diff with the mounts was 17.7cm wide (that's 177mm for you engineers). The gap however was only 17.0cm, so if my maths can be trusted, the gap is 7mm shy of what it needs to be. Just for completion's sake I measured the gap at the bottom, this was bang on 17.7mm, so it looks like the top is definitely out. As it's part of the chassis this was already assembled by Road Track Race so it wasn't anything I could have done wrong. I was going to drop them an email (they've proven very helpful and responsive in the after sales department, so don't let me lead you into thinking that they're a bunch of cowboys who just sit in the factory counting my money).

Anyway, before emailing them I sat and had a little think and decided I'd try and push the diff in from the bottom rather than slide it in from the top. I knew the bottom was wide enough, so maybe once it was mostly in, I could flex the 5mm aluminium mounts or something.

It probably would have been a long easier with a second pair of hands, but it was still light outside so I wasn't giving up, besides, yesterday's F1 race kicked ass so I was dreaming of getting the damn thing on the track.

It went half way in ok with some jiggery-pokery and the three parts were assembled at this half way stage. After that I tried getting into the gap at the top and it wasn't playing ball, 7mm was too much to flex.

So, so tight. (Stop sniggering)

The chassis is powder coated though which is a couple of mil, so I sanded that back, which still left about 5mm to make up.

Luckily I own a hammer. So doing my best Jeremy Clarkson impression I did some light taps and just about got both sides inside the gap. From there, I could gently tap it further into place until it actually fit. Hurrah!

With a certain sense of accomplishment, I unboxed the drive shafts and temporarily slid those in and everything seems to turn like it's meant to turn and is decidedly more car like now.

Excuse the wonkyness of this picture, I was stood on a chair
with the camera above my head. Believe it or not, this was the
best of three photos.