924Board.org

[paluck]

Hey - sweet ride.
My team has a '79 toofah that we run on the Lemons circuit. I'll give you some advice based on our experience (we've run it 3x at Lemons and a PCA time trial) and the laundry list of what wasn't up to snuff.

When we first got it we replaced fuel pump, fuel dizzy (with reman unit), clutch, coolant tank leaks glued, vacuum leaks sealed, etc..

First race:
* Sheared the crank pulley roll pin. Spent half a day trying to figure out WTF was up with the engine. (Sometimes acted like it would start, sometimes not due to crank/valvetrain timing changing every time we hit the starter, compression good, fuel, spark). The eventual clue came from cranking it with out hand over the intake. WTF? - Why is air blowing OUT of the intake? That won't work.
Replace pin with snapped end of drill bit - back on track
Thank you non-interference 2.0 litre engine
* We fried the battery and it STANK. Engine power flatlined up in the higher rev's -= we limped it for an hour next to a Mini until the checkered flag
* forgot hi temp fluid in the brakes - brakes sucked and overheated

Second race:
* We broke the stock exhaust like 70 times - there was more weld on it than metal eventually. We now have a flex coupling and its working much better.
* Wheel flew off on track. "What's that vibration"? "Wait - did a lugnut just fly off my wheel?"
* Shredded the rear shifter couplings - difficult to get into any gear
* new hi-temp fluid for the brakes. Still overheated. Still sucked.
After the race, we did the 5 lug conversion. Brakes awesome now

3rd race:
Tried to swap snailshell tranny ( 1st gear gone), but turns out out spare is from a 931 and has a different diameter input shaft.
Put on 944 fenders and qrt panels from parts car - looks badass now
* Aerokit make from school bus sheet metal blocked airlow to radiator. Overheated. Ruptured coolant tank. Replaced - back on track.
* Engine intermittently dying - finally gives up the ghost. We suspect distributor sensor that tells the ECU when to charge the coil. We had a couple of what we thought were spares, but turned out to be for a different car entirely, so we were sidelined for the rest of the event. Now we've got duplicates of all important ignition systems as well.

Pretty much - you name, we've broken it. I'd keep an eye out for a 944 donor - we could NOT get those 924 brakes to work well - even with 660 degree fluid and track compound pads/shoes. I thought same as you - no problem with such little horsepower, but we were wrong. Try your cooling - perhaps it will help

Also - we may have some extra brake calipers... I think we totally junked a parts car with new porterfield shoes - damn - they would have been perfect for you guys.


-Mike[/img]
_________________
paluck(at)hotmail.com
1989 944 S2
1979 924

[KDJones2000]

Great posts, guys.

Thanks a ton for the experiences with a 924 in enduro racing. The part I am most worried about is the radiator, as we don't have a spare, and I heard horror stories.

Thanks also for the info on the brakes. We can't afford a conversion in the budget at this time, but that is in the plans for the future. I fully expect them to suck, but hey what can you do?

We will be testing in some NASA and PCA track days in the PHX area, gearing up for the 2-3 April, full on Chumpcar April Fools 24 hour enduro

Call us fools or not, but that one seems to work best for us. A lot will depend on how the car does in our testing sessions. Adding the oil cooler I am hoping will go a long way towards making the engine reliable, as I have heard that these things are prone to burning up without one.

Alternator is fixed, cage is about ready to be bolted down, after $100 of new, Grade 8 hardware due to 2011 regulation changes. Pictures coming in a future post.

Cheers, Keith
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1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

[924RACR]

Cool... you got what you need for the cooler install?

I'm running a stock rad; with a good oil cooler, doesn't seem to be an issue.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[KDJones2000]

I think I have everything: $25 RX-7 oil cooler, $20 used pancake oil filter adapter, and some AN fittings and oil lines from British American Transfer.

I still need to make up some mounts, but those should not be too much problem. I am looking to put it in front of the radiator, as low as we can. I will take some pictures once I have the details worked out.

Mark, where did you put the flex connection in the exhaust? We may want to do this now, as we had to remove that useless shock absorber on the engine to fit the oil cooler. The engine now bounces around more, and we will likely have similar issues.

The spare engine we have is newer than '78, but most of the things should swap, as we already are using the fuel dizzy from that one. Good point about the ignition - we will look into that part as well.
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1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

[paluck]

Wish I taken soem pictures, but we put the flex coupling early in the exhaust line. I think the first thing is a resonator - we eliminated that and put the flex coupling there. We could have probably also benefitted by having another hanger in there - our break spot was pretty much half way between the front and rear hangers - we think that's where the motion was greatest during vibration and that contributed.
FYI - other than our blocking the airflow, we've had no issues with the engine cooling.
Brake conversion was cheap (although you may be talking about it being too expensive per $ rule limit). We got everything we needed from an '83 944 roller donor which cost us $300 (half that if you offset the other stuff we sold off it).
If you keep the stock brakes - get high temp fluid (duh) and really work your cooling airflow. I'd probably recommend ducting and also some 968 style scoops.
_________________
paluck(at)hotmail.com
1989 944 S2
1979 924

[924guy]

ive got a hundred pounds worth of 4 bolt brake and suspension parts, and at least 5 4 bolt wheels, though i wouldn't trust the tires, if you need spares.
id much rather donate them to your cause then scrap them...just pay shipping from 34983 and buy me a cup of coffee if you want them.
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Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

[J1NX3D]

very cool!!

but, i recall my old '78 4 bolt having ventilated front discs? can you not find secondhand or even a new pair of these? and get them slotted? (if allowed to under your regs)

ptno 477405083A
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'86 944

[paluck]

we did some looking for ventilated front rotors for 4 lug, but couldn't find any. The p/n referenced also fits 944's, so that must be for the 5 lug system optional on the early 924's.
_________________
paluck(at)hotmail.com
1989 944 S2
1979 924

[J1NX3D]

yeah i did see the conflict between applicable models and i know the 5 and 4 stud would have different discs. ive been searching PET and the usual parts sites... maybe my '78 did have solid discs...
_________________
'86 944

[KDJones2000]

As far as I know, the only vented options are for the 5 lug setups....

Well, much progress has been made recently, as I am off work for the rest of the year

Chumpcar rules for 2011 state that all bolt-in cages requre Grade 8 hardware, with the same required for both the seat mounting and harness. Nylock type nuts are also required. Here is $100 worth of Grade 8 nuts and bolts to meet tech:



The oil cooler was also an interesting install, with several problems needing to be overcome. We purchased a pancake type oil filter adapter from Fleabay, along with an RX-7 oil cooler, as this was supposed to be a very good cooler, plus we got it for like $20. When we first tried to install it, we found (As many of you have I am sure) that the oil filter would interfere with the exhaust manifold. Hunting around our FLAPS we were able to find a shorter version of the oil filter that allowed us to install the pancake with no further issues. The oil filter is for a circa 1980's Ford or Mazda engine, FRAM part number: PH8316.





You can see that there is enough clearance to the exhaust header:



The oil cooler install was a bit trickier than expected, due to the length of the unit. A banjo fitting for the upper line protruded out, preventing the cooler from easily fitting between the radiator supports. The only way it would only fit was to have the banjo fitting wedged into a detent, placing the oil cooler high up:





The brackets were made such that the top hole of the cooler was 3-3/4" from the bend in the bracket, that put the banjo fitting at the proper location for everything to fit:





The cooler could then be wedged into place, and secured with a couple of sheet metal bolts with fender washers from the top:





A picture of the final mounting:



Some NPT to AN-8 fittings from British American Transfer/Mocal, along with oil cooler hose connected everything together. The sheet metal around the radiator was bent up to prevent sharp edges from cutting into the oil lines:





So the oil cooler is installed, the cage is now bolted into the car, the seat is mounted and working, along with the seat back brace. The A/C bracket and Air Pump for emissions have been deleted, the brakes are as good as we are going to get for now, the engine runs well when it is warmed up, but we are still fighting a cold start issue. EDIT: Cold start issue fixed with different WUR

Still remaining are the headlights, various electricals and a quick-disconnect for the steering wheel, adding a second bar on the driver's side of the cage, fire extinguisher bracket, and some communication stuff.

On the steering wheel quick disconnect I have a question for those of you have already done this. What was your solution? I have looked into the weld-on types and have not been able to find a suitable one for this steering shaft diameter. For buying a hub adapter, I don't see one that will also allow for a quick disconnect. Advice here would be greatly appreciated.

Cheers, Keith
_________________
1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

[924RACR]

Not the ideal location for that cooler; I would push to hang it at the bottom of the rad, if possible with only 50% overlap, as the airflow up that high in the nose can be problematic, at best.

OR - I forget, you're not running to IT rules. You might consider punching additional holes in the front nose badge panel, like the turbo has, to ensure enough air. Make sure that the cardboard baffle in there is long gone, too.

You'll still end up with the result that the oil cooler will act as an "inter-heater" for the radiator, as it'll be dumping hot air onto the rad. But that's not the worst thing possible, and if you're supplementing with more fresh air in the nose, it'll probably work out OK.

Thanks for documenting the filter solution with part #.

Re: the quick release - you're absolutely correct. What we did (note that we are using the el-cheapo $40 hex-style quick release, nothing fancy) is that we sleeved the steering column to get the right size shaft to weld on the steel hub. That is, we procured a correct-size solid steel shaft for the hex, then found a sleeve that would fit that and part of the taper for the shaft.

It's not trivial to weld, as naturally you must ensure throughout the welding that the shafts stay parallel and concentric, not angled, but can do just fine. Added bonus is getting the wheel closer to the driver, for better leg clearance and improved arm geometry.

I hope you've been sure to loctite or use nyloc nuts on that cooler mounting?

Looks like you're getting to the home stretch, and are going to be hitting the point where you'll need more and more support... will PM my cell to get in touch. I have a feeling the right input in a timely fashion will save much time from here out...

Also - cold start - what's the symptoms, and what have you tried?
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[KDJones2000]

Appreciate the help, Vaughn.

The mounting bolts have lock washers on them, and have blue Loctite on them (now)

I was thinking about punching some holes in the nose for additional cooling - we shall see. Tests today showed that the cooling fan was pulling air through both the radiator and oil cooler, so things are looking good so far.

I solved the cold start problem today by replacing the WUR with our spare. I haven't taken the time yet to do all of the CIS fuel pressure tests, but now the car starts reasonably easy and is running well.

Thanks for the info on the quick release. Right now our car is still legal to drive (we registered it for 4 years, so no emissions or anything else required), so we have the turn signals and wiper handles on the steering wheel, which we would like to preserve. It sounds like that is likely not going to be an option, however.
_________________
1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

[Andrew NZ]

I'm using the same oil cooler in mine, but have it mounted on the engine side of the radiator.

For anyone else thinking about RX7 oil coolers, try to find the earlier series 1or2 coolers, as from memory the inlet and outlet are both on the back facing the engine so that you don't have to worry about the banjo fittings.

These are very efficient oil coolers, as a fair chunk of the cooling in a rotary is taken care of by the oil system.
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Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

[fiat22turbo]

Looking good! One thing though: Get rid of that Fram piece of junk on your car, unless you like potentially causing oiling issues in your engine.

http://minimopar.knizefamily.net/oilfilters/
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[924RACR]

You'll have better cooling without the rad fan ducting; we ditched the stock setup (also for weight and space consumed) and installed a single thin aftermarket fan without shroud.

It's not enough to do the job in traffic, no, but is sufficient for a racecar, which needs limited protection while parked. Furthermore, while moving, the airflow for the rad is cleaner, allowing better cooling.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype