924Board.org

[Andrew NZ]

Unfortunately we're back already!

We got the car finished late afternoon on Sunday (before the prologue stages started on Monday) so took the car for a bit of a shake down run to run the engine in. It all seemed good until there was a funny noise followed by a total loss of clutch action. We got towed back and the whole team worked through the night and next day (missing the prologue stages) sorting out the problem so that we could start the event on Tuesday morning. It turned out that the spigot bearing had collapsed and welded itself to the input shaft, indicating a probable misalignment problem with the new bellhousing. With no time to correct the problem we ended up making a brass bush to get around the issue as a short term fix to get us to the start line. The plan was to simply see how far we could get through the event at that stage.

We made it to the start and used the first few special stages to run the engine in and get rid of a few more bugs. The starter motor fell apart on the 3rd stage, and we were very lucky to be able to borrow a spare from one of the RX7 teams between pitstops while the crew rebuilt mine.

Next our rally computer started playing up and resetting when ever it felt like it, which made it very difficult to predict the cautions that were coming up. The wipers were the next to go right at the start of a 30km stage in the pouring rain!! Some how we managed to scrape through that stage without coming off the road and carried on to the next service. The problem was diagnosed as a fried alternator, and the hunt started for a replacement for the next day.

The 7th stage became a touring stage, as some poor guy had rolled his escort 4 times before it burst into flames. It was totally unrecognisable as we drove past, but it was great to see them standing unhurt beside the car. I think we count four cars off on that stage as we toured along, and were glad that it had been cancelled before our turn. We did the last couple of hours of the day on the battery alone and just scraped into service at the end of the day before the battery completely died.

We borrowed an alternator for the next day while some of our crew hit the wreckers yards to get a replacement. The first couple of stages went very well as we finally started pushing the engine a bit since it had now covered about 700kms. It absolutely sings at 8000rpm, and the balance is better than ever. This car has so much potential now. We ended up behind the 951 (starting at 1 minute intervals) and caught it about 10k into the stage. The pace was similar on the straights, but we were all over it around the corners. Once they realised we were there they indicated to let us through, and then immediately hit the brakes right in front of us We swerved to the right and over took them on the grass verge at over 160kph, fish tailing the whole way. I have no idea how we got back on the road with out hitting them! Once we got in front of them we were gone, and didn't see them again until the finish control. This car really is a heap of fun to drive now - Porsche really should have put this engine in the car originally.

We flew through the next stage with a new found confidence in the car and pushed harder than ever. A small vibration started at about 8000rpm, and eventually became a large vibration at all revs forcing us to pull over about 4km from the end of the stage. On lifting the bonnet I found the alternator flopping around, so quickly set about reattaching it with bolts from other parts of the car and a bit of tying wire, but when I started it up to carry on the vibration was still there, so we got towed to the service stop once the stage had finished. We came to the conclusion that it was something inside the torque tube (bearings?, balance?) as the vibration wasn't there with the clutch depressed. That was the end of our rally, as we didn't have a spare, and the crew was totally worn out after so many late nights to get the car to the start line, and none of us had the energy to pull it apart to see if we could get it going again.

The end result is a car with huge potential that will be a giant killer when all the bugs are sorted out. We've decided to do lots of small rallies over the next year or so to get it all sorted and then have another go at the big one in the future. Our goal will be first front engined Porsche home, and I really think that we can achieve that once it's all working properly.
_________________
Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[Peter_in_AU]

Wow!! A real baptism by fire. Brings back memories of crewing Group 1, 3 and 4 Escorts in the old days.

Hope you got the whole crew drunk to say thanks for the effort.
_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

[Andrew NZ]

[ideola]

Andrew, thank for sharing, WOW, what a story! I hope you were still able to get some photos...
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erstwhile owner of just about every 924 variant ever made

[924RACR]

Wow, what a rough run. Congrats to everyone, especially your crew for such a hard effort!

Just goes to show, you can never test too much!!!
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[morghen]

Congrats ! get us some photos.
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https://www.the924.com

[Andrew NZ]

The official photos will be up on the Groundsky website in a couple of weeks. We have some in car footage that we may be able to get up on youtube soon for you (i'm not sure if it's digital or not).
_________________
Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[PORSCHEV]

get them loaded
_________________
1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

[Andrew NZ]

The car arrived back on the transporter today, and we pulled the gearbox and torque tube out this afternoon. The driveshaft is bent! I guess it's time to upgrade to the thicker 931/944 one!!
_________________
Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[Peter_in_AU]

Wow, you were running a 924 driveshaft! At least now we know their limitations.

Might be a good opportunity to build one of these and save a little weight;


_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

[Andrew NZ]

Mmmmmmmm..............very tempting! Don't think the budget will stretch to that just yet though.
_________________
Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[ideola]

Peter! Ok, dude, 'fess up, where can I get one of those?! I've already been toying with the idea of a serviceable, multi-piece alu-based torque tube...

Details please!
_________________
erstwhile owner of just about every 924 variant ever made

[Peter_in_AU]

Wish I knew where it came from. I ran across some pics on my computer a couple of days ago while looking for something else. I think it was for sale on US ebay 2 years ago but I can't be sure.

Here's some more pics to perv over (wish I could weld alu like that):




_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

[ideola]

I love the safety wired bearing stays.

So question. What if you took the main tube, and cut it in half. Use 3/8" thick alu tubing. Then, on a lathe, mill out 1/8", let's say 6" or so into the end of each tube. Press your bearings into each end (so you end up with four bearings instead of just three).

Then, in the middle, make a sleeve 12" long less the width of the bearings on either end. Weld a flange to each end of the two pieces of tubing. Put the sleeve into the middle part (to help with rigidity) and then bolt the middle flanges together, and then on the ends you have the normal flanges for bolting up to the bell housings on either side. (Of couse, I'm thinking of a snail shell tube, but on the Audi based, you'd have to weld directly to the bell housing as depicted above on the transaxle side, whereas on the snail shell you just need a flange to mate to the input housing on the transaxle).

See what I mean? Serviceable. Easier to pull the bearings out from each end. More bearings for the driveshaft. Lighter weight due to alu.
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erstwhile owner of just about every 924 variant ever made

[!tom]