With all the track miles I had done last year and the fact I have a shorter ratio diff in this year, meaning the car will be at the top of the rev range more often I thought it best to get the shells out and have a look at what’s going on and change them for a new set. I had done some research and you can buy coated shells that are supposed to give more longevity and cure the problem, but as it transpires, this could actually make the problem worse. If you’re having the whole engine apart and everything measured and fitted to perfection, then yes this could be a better solution, but to just put a set of off-the-shelf shells in the bottom end whilst the engine is still in the car, the extra thickness of the shells and the fact that the rods and crank aren’t measured and matched up, is what has caused a lot of crank scoring and extra engine failures. This is only an educated guess, but it’s still not a risk I am willing to take.
I saw that a company in the US called Bimmerworld (who I have used before and who race competitively with all kinds of BMWs) sell a cure for this problem which uses standard BMW shells treated, as opposed to coated, so no more material is added to the shell – it’s just treated to make it last longer. The kit also includes a set of ARP con rod bolts to hold the caps better on the rods and stop any extra stretch. It’s just an extra fail safe. Some people argue that the bolts should stretch and others that the rods should be honed and matched to suit the bolts. I’m happy that this kit is a good fix for at least this season. We’ll see what happens later on when I have the bottom end off to have a look again next year.
It was quite a mission to take everything off, but as the car was already up on the ramp it wasn’t too bad. As well as the shells I also got a brand-new set of sump bolts and gasket as well as a new oil filter. I now use Millers Nanodrive race car oil in 10w60, which I have been using since I did my first oil change after I got the car. To start with after every track day the car would use half a litre of oil and I was told this was normal.
As the car had just been serviced when I bought it, I waited about three or four track days before I had had enough of topping up and made the switch. Since putting the Nanodrive in I have never had to add an extra drop between changes. I’m not telling you to run out and buy it, but I do use it in all my cars and even gained 6hp in a 100hp Fiesta race car back-to-back tested on a hub dyno.
Anyway back to the shells, so yes we took the whole bottom end off, had the rack out, took all the suspension arms and the front subframe off and lastly the sump! This took about six hours with a bit of faffing around and we called it a night to let the last of the oil drain completely from the engine ready for the following day.
The next morning we were straight on it starting with the first rod. We did them one at a time so we wouldn’t get confused, oiling them up as we put them in and replacing the bolts and torquing to the ARP spec sheet as we went. Working methodically through the whole crank set, this didn’t take too long and before we knew it, we were bolting the sump back on with the fresh gasket and bolts. While the front end was apart I had some matching front race arms that I got last year from Bimmerworld that are all fully adjustable and rose jointed at both ends, so these went on instead of the standard items. Also the engine mounts were worn and I wanted to replace them anyway, as I thought as everything else is getting a freshen-up and the car’s apart now, it would be sensible to do. So these were changed for a pair of Vibratecnic mounts as well as some underdrive pulleys to free up power and give more feel to the front end. More about them later…
Finally we got everything fitted and bolted up. By the end of the second day, all that was left to do was the geometry, ride height and corner weights – or that’s what we thought…
On the next morning we sat the car on the metal tables Dave had made to make adjusting things on the car easier. He pointed out the angle of the rose joints and that they were almost locked out when the car was back down on the ‘ground’. This had us scratching our heads as you really don’t want to run a car like this as the suspension will potentially lock up on track. We set the car as low as it would go and it was still quite aggressive on the joints, with limited travel before the joints would move no more.
Accordingly, after much nail biting and head scratching, I thought it best to give Bimmerworld a call. Being in America it is obviously in a different time zone, so I had to wait until 2pm to call. By this time we had all four springs off and chopped the helper springs to try and get the car lower to give the joints a bigger range of travel before they locked. Bimmerworld advised us that the car had to be run really low and that they were designed to lower the car’s roll centre to allow the car to run lower without upsetting the geometry.
Because we were so concerned with the position of the rose joints, we unintentionally lowered the car far too much and ended up with the position of the track control arms (TCA) at an undesirable angle. We had spent all day on the car and had a shake down test day at Snetterton the following day, so we decided to go with the tried and tested ‘suck it and see’ and make any changes necessary after the test.
With the car off the ramp we started it up (after cranking the car with no ignition to get the oil pressure up for the new shells) but there was an issue with the gearbox – I couldn’t select any gears. Now I was really worried. As with the wiring for the engine that I reported on last month it turned out to be a case of reconnecting a wire we hadn’t noticed we had disconnected, but there were a few nervous minutes while we sorted it out…
We took the car back home and were looking forward to the following day’s track evening. After a bit more tidying up inside and a few adjustments and the fitting of a full lightweight titanium Akrapovic exhaust, which I had bought second-hand, we took the car along to Snetterton. The car tested at a reasonable 97db at 6000rpm, and having passed the noise check that was another weight off my mind.
I was a bit rusty on track having not driven it in anger for several months and coupled with the completely new setup and being a bit excited I was over-driving the car a little. Initially I set it up soft as the weight removed should have made the springs a bit harder than is ideal – considering they are for a car that was 300kg heavier.
This gave the car a bit of roll on the corners and as I stiffened things up I started to get a bit of understeer. I had anticipated this and thought it was the TCA angles. I had my mind made up before I even drove the car that these would need to be changed. I got carried away with a supercharged Ariel Atom on slicks and after about five laps the power steering fluid boiled! This was very unusual and I have never had it happen before – it wasn’t until I thought about it that maybe the underdrive pulleys were giving it a little bit of a hard time. Not sure, but that would be up for investigation at the ‘Ring and I may change back to the standard pulleys if I start having grief there.
After the third session I was convinced the car needed to be raised up, but unfortunately we couldn’t do anything on the night as our couple of hours were drawing to a close… While I was starting to pack up I noticed the driver’s door lock was missing and I was worried this was going to cause a massive headache when out of the blue a marshal drove up and asked if I had lost a door lock! When I answered in the affirmative, he said jokingly he wanted £10 for it and when I instantly handed over the money he said he was only joking… so we donated the cash to the air ambulance instead.
I have to say that initially I was a bit disappointed with the car as I thought the handling and way the car went was going to be night and day but it’s a completely different car now and it will need tweaking and setting up all over again. All-in-all though, nothing broke, it was pretty fast everywhere and we came home with no major issues – mission accomplished.
The Snetterton shake-down was designed to ensure the car was safe and ready for its inaugural ‘Ring trip in the new evolution. Not being happy with the ride height, the following day it was raised up until the TCAs were completely parallel and at least in my mind I won’t be blaming understeer on the ride height being too low messing with the roll centres. Sunday we loaded the car up and off we went to the Nürburgring…
Sadly the heavens opened up from the minute we left until we arrived at the hotel. En-route we stopped off to have the GTS gearbox map put back on the car after BMW wiped it off on its last warranty visit. We were also supposed to take all the errors off the dash and code them out, but as it was raining and we couldn’t get the car on Ian’s drive due to it being on a trailer, we had to go to a nearby car park and do what we could and at least get the GTS map on.
Once we arrived at the ‘Ring we unloaded the car and settled in with a few well deserved beers. It was still raining when we awoke the following day and while I don’t mind driving in the rain or even the snow as you will have seen from my previous articles, to pay for a private track day with the car not set up and unable to push or get some good feedback as to what is going on, I just wasn’t prepared to put myself or the car in that position. I had waited many months to get to this stage, so another couple of weeks won’t hurt. Let’s just hope this freakish weather sorts itself out or I may be pushed into some wet laps…
For anyone wondering, the final weight with the fuel tank empty but all fluids in the car is 1323kg – not bad for a big bus like this.
