Sunday, 29 May 2011

Preparations for the IAE

Been busy with all sorts of smaller jobs on ‘t Kreng since fitting the coil over’s two weeks ago. As she’ll be used for next week’s International Auto Ecosse it was time for a full service. First thing to tackle was to change the original spark plug tubes for some proper engineered ones ...


Took slightly longer to fit them, as I had to remove quite a lot of old sealant from the cylinder head, which was needed to keep the oil away from the spark plugs. But after an hour and a half all of the old sealant was removed from the spark plug holes. So time to fit the spark plug tubes, needless to say that they fit perfectly ...


As I found a set of brand new NGK BP6EFS spark plugs which I had completely forgotten, these were also fitted. The old ones had covered almost 20.000 kilometres, so they had seen more than enough action. The same could be said of the hydraulic fluids, I usually flush them every one or two years, depending on the car’s use. This is to get rid of any moisture and rubber particles from the seals that gets trapped in the fluid. Flushing the clutch system clearly was necessary, the fluid that came out was very murky indeed. The old brake fluid looked much cleaner, but that only tells something about lack of rubber contamination, nothing about trapped moisture.

Next on the to do list was changing the left hand front wheel bearings. When I fitted the front struts in 2009 I over tightened these bearings. As a result of which it was an MOT failure one year later. I fitted new bearings to that side from a front wheel bearing kit supplied by one of the TR7 specialists. But it turned out that the quality of the supplied bearings wasn’t very good. Till date I had to retighten the left hand bearing every 500 kilometres, which isn’t as it should be (other side still hasn’t been touched and still is OK). So it was time to contact a friend to find me some proper quality bearings ...


While removing the old bearings I found something strange. The spring of the hub’s oil seal was badly damaged, while the rest of the seal was in good condition. Luckily I found an old seal with a good spring ...


The bearings that came out didn’t look to bad, but the overall impression of these wasn’t very impressive. Although not very clear in the pictures, there were already clear signs of wear on the bearing’s outer races. And they have covered less than 3000 kilometres so far! ...



With the front sorted I changed my attention to the rear suspension. When driving the car last weekend under certain conditions, there was a very light but clear knock from one of the rear upper links (felt like the right hand one). So just to be sure I removed all of the bolts on the body side of the rear suspension, fitted new (and thicker) washers and re-torqued them. Have a test drive planned for early Monday morning to see how she behaves. And to end a weekends work on the car I checked all fluid levels, as expected no surprises there.

Will check ignition timing and carburettors balance after the test run tomorrow. And re-check the right hand front wheel bearing of course.

Sunday, 22 May 2011

Time for a little test-drive

Took slightly longer to tidy up everything after fitting the rear coil over’s last Saturday. This was caused mainly by other commitments and work. But early this morning I found a few spare hours to go for a little test drive. As it had just stopped raining, and there were still some showers around, it was rather slippery. At least this kept most of the Sunday morning cyclists and walkers at home, so I had most of the country lanes to myself.

To be honest I didn’t really know what to expect from this first drive. First thing which was a bit of an unknown was the fact that the springs are now situated behind the rear axle. This results in an effective spring rate of ±34 kg/cm (190 lbf/in). So they have the same effective spring rate as 43kg/cm (241lbf/in) springs mounted in the original location. But sitting behind the axle also means that the upper links will be loaded differently. I needn’t have worried.

Although the improvement wasn’t as pronounced as when I fitted the front, the overall behaviour of the car has clearly improved. First thing I noticed was the fact that the ride was smoother over bumps. This can be explained by the fact that I have the shock absorbers at their softest setting. The AVO’s I had on the rear of the car needed to be set pretty hard to prevent them from bottoming out. But most important improvement was the balance. With the old set up the car’s handling was biased towards understeer, but it’s more neutral now.

To sum it up, it was rather good fun steering it on the throttle, helped quite a lot by the slippery road surface left by the rain showers. But most important it feels much more balanced and thus more confidence inspiring.

Everything fine? No! Will have to experiment with the shock absorber settings a bit, as under certain conditions the outgoing stroke is slightly under damped at the softest setting. Also the fact that the springs sit just behind the axle now has highlighted the fact that I need to re-torque the rear upper links. But those are minor points.

Looking forward to see how she behaves in Scotland in two weeks time, but before that I need to sort a few other small issues ...

Saturday, 14 May 2011

Suspension upgrade 't Kreng (part 5)

With the International Auto Ecosse only a few weeks away, it was about time to get the rear suspension from ‘t Kreng sorted at last, as I want to use that car for the event (I have already scheduled two long trips to the Alps with the DHC ...)
For those who have been following my ramblings, know that I had a complete coil over set made for ‘t Kreng by AST a few years ago. I fitted the front coil over’s early in 2009, but due to other commitments (including a makeover of my DHC) I didn’t get round to fitting the rear coil over’s. Until today that is ...


But before I could fit them I first had to (re)drill a few holes in the rear suspension turrets, this to accommodate the new top mountings. I wanted the coil over’s mounted as much in the centre line of the turrets as possible. But as British Leyland thought it a good idea to mount the rear shock absorbers of centre in the turrets (slightly leaning backwards) it wasn’t simply a matter of enlarging the current hole and drill a few smaller new ones for the mounting studs. Initial plan was to weld a plate in the original hole and drill a centre hole in there, but in the end I opted for a drilling template made from a piece of 3mm steel plate I had lying around ....


This template was first used it to drill the mounting holes for the top mounts. After which it was cut up and fitted to the top of the rear turrets to act as guide for the hole saw centre drill. Was all a bit fiddly in the rather cramped spade in the boot underneath the rear deck, but with the assistance of Robbie that wasn’t a big problem. And with the template in place it was time to attack the holes (I really have to invest in a better drill). Luckily the hole saw was of good quality, so soon we had two nice large holes through which the top bearing can poke out ...



And after which it was only a matter of removing the rear springs from their original location and fit the coil over’s.





Only need to refit the rear parcel shelf and the seats tomorrow (these were removed to help access to the rear suspension turrets tops). Hopefully I will have some time left afterwards for a test drive ...