Episode 34(ish…) Tightening my Belt(s)Happily nothing to do with the economic downturn, this update represents another tiny step forward toward the day the engine might run again.
You might recall from a few pages back I was rather optimistically hoping to have it running (or at least have had it running, there’s a subtle but important difference there!) by the time the 20 year anniversary of the last time the Herald had tax in the window rolled round.
Well clearly we’re ploughing into 2014 like an, erm, plough, and that hasn’t happened.
I should just point out, lest anyone think I’m the slowest worker in the world, ever, that the last 20 years haven’t been solely spent on the Herald. In that time three Vauxhall Chevettes, one Jaguar XJ6, one Austin A55 pick up, one Ford Model A pick up, One VW Caddy pick up, one Ford P100 pick up, one Dodge Dakota pick up, a MKI Granada coupe, a MkI Golf Driver, a MKI Fiesta, a MKIII Escort, another Herald, a Herald Special, an Austin A40, a Sierra estate, a Triumph TR7, a Triumph 2000, a Triumph 2.5S and two speedboats have all required varying degrees of my attention. Having said all that, I am quite a slow worker…
Right, excuses over, where were we? Ah yes, thinking about getting the engine running.
One of the things I need to sort out is the supercharger drive belt and the alternator / fan belt. That’s two things, then. The Sprintex kit I have (which I think is for a Rover SD1) has a modified power steering pump that is driven by the blower belt. I’m going for a manual rack so the pump’s not needed.
The Sprintex kit bolts up something like this with an idler pulley running on the outside of the belt being responsible for tensioning the belt. Clearly, without the power steering pump on there we need a shorter belt.
I’d thought getting hold of the right belt might be tricky. In my very limited experience with cam belts (I’m more of a cam-in-block/pushrod chap) all I’d come across was belts where the teeth have quite a ‘square’ profile, while the teeth on the blower pulleys are all half-round. Happily, I got a lucky break when my Ebay saved search for “Sprintex supercharger” (I’m always on the look out for articles and info for these rare things) turned up a complete kit which mentioned in the description “a new HTD belt”
A spot of Googling and it turns out HTD, or High Torque Driving, is an industry standard for timing belts for industrial machinery and places like RS do them, along with pulleys and stuff. So I measured up and got one ordered from
RS. Not unreasonably, they do them in ‘incremental’ sizes; one looked like it might be around the right sort of length so it seemed like it was worth a punt.
Here it is on the engine, and boy, was it tight! Far too tight in fact; there were a couple of ominous creaks and groans as I wound it on. Hope of not irreversibly broken anything… Happily, I’ve since found a few other suppliers who do HTD belts in a much bigger range of sizes so I’ll get one that’s a tad longer.
The next thing I need is an idler to go with the longer belt, and it’ll need to be toothed to run on the inside of the belt and push it outwards. Again, places like RS do a range of pulleys, but I couldn’t find one with an integral bearing so was thinking about getting a bearing separately.
A quick browse around Ebay to see what sort of timing belt tensionors were available to cut up for their bearing turned up this little fella, listed as Subaru part.
It was the right number of teeth I was after but was is the right pitch and format? I took a punt and hit Buy it Now, reasoning “What are the chances that Subaru would use an almost-imperceptibly different format to the established HTD?”
Seems the chances are good, very good, as despite appearances above…
…it’s not going to happen.
You can see here how snugly the fit is when both parts are the same format. Oh well, at least I’ve got a nice NSK bearing that I know is specified for the right application…
and I’ve got another pulley on order which, if my calculations are correct (and they’re rarely been so far…) should be able to be machined to take the Subaru bearing.
The other belt that needs sorting is the alternator / water pump belt, which needs a new mount ‘cos the pulleys are a good deal further forward than before due to the, erm, unorthodox position of the steering rack…
Seeing as I’m not using it, I though I could save some time by ‘repurposing’ the old power steering pump mount.
I’d got about this far when I realised I was being lazy and buthering an original piece of Dennis Priddle Racing Sprintex kit (that could conceivably be of use to someone else) just to save a few minutes. So I gave myself a good talking to and started again…
Here’s the start of it (un-butcherd DPR plate behind)…
…here’s what I cam up with…
…and here it is on the car. The adjuster is a MkII Jaguar item, as far as I recall…
Also did a spot of work on the exhaust again. I needed some relatively compact way of mounting the pipes where they go through the axle that would allow a little movement but not allow anything to touch. Given the engine and gearbox mounts use urethane bushes rather that rubber, there’s not going to be a great deal of movement anyway, but I wanted to try and keep any ‘clonking’ to a minimum. My first thought was this, an old but unused Metalastix bush, Herald I think this time. Certainly dangled nicely and is rubber-isolated but the whole thing could easily bounce up and down. I was being lazy again…
Another stiff talking to and I’d made this…
…which takes a cut-down ‘pig’s snout’ exhaust rubber…
…and bolts through the chassis like so. (‘Cos I’d already drilled the hole for the Herald bush and I hate using bolts that aren’t a proper fit, we know have the strange situation where the exhaust mounts bolts are thicker than those mounting top coil-over bracket to the crossmember…)
Cheers,
Em.