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Problem After Trackday
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Mon Mar 20, 2017 8:04 am    Post subject: Problem After Trackday Reply with quote

Today after trackday on Monza track I risk to loose a wheel!
I installed 20 mm spacers on rear with longer bolts (no double bolt) , during trackday I have no problems, but on street for go to home bolts of rear wheel have unscrewed and luckyly my speed was low, how is possibile this?
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Ian89C4  



Joined: 01 Apr 2011
Posts: 443
Location: North Carolina

PostPosted: Mon Mar 20, 2017 9:34 am    Post subject: Reply with quote

Did you torque them down during the event? I know even during auto crosses I retorque between each run. It is especially critical during high speed and g force track events...Especially one like Monza! I bet it was amazing.

Ever think about studs instead of bolts?

Cheers!
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Ian Edgerly
Spiveys Corner, North Carolina

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1981 924 Weissach Race Car ("Serenity")
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daniel  



Joined: 18 Jun 2009
Posts: 594
Location: Sydney, Australia

PostPosted: Mon Mar 20, 2017 10:07 am    Post subject: Reply with quote

+1 to the above, I retorque my wheels to 100ft/lb after every race
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Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Mon Mar 20, 2017 5:38 pm    Post subject: Reply with quote

what a fright! I did not know that it was necessary to tighten the nuts after trackday. Now I buy immediately spacers with double bolts.
Luckyly I have no damage to wheels or others suspension parts.
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CÚdric  



Joined: 27 Aug 2004
Posts: 1513
Location: Sweden

PostPosted: Mon Mar 20, 2017 6:11 pm    Post subject: Reply with quote

It isn't necessary, but of course not bad to do on any car you track drive, i seldom recheck torque for track duty and have never had any nut or bolt getting loose, but i often use a torque wrench when I tighten them, and clean slightly lubed threads.

But sure, bolted spacers is simpler to have. But I would definitely look at a possible stud conversion, it makes life so much easier when you do a lot of wheel swapping!
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morghen  



Joined: 21 Jan 2005
Posts: 7376
Location: Romania

PostPosted: Mon Mar 20, 2017 6:47 pm    Post subject: Reply with quote

how about your engine? is it now ok? you were saying there is something wrong with it and you took it for a track day?
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Mon Mar 20, 2017 9:18 pm    Post subject: Reply with quote

Engine on street was ok, the only problem was white smog on startup.

On track my car after thwoo lap don't go at high rpm and I noticed metallic noise.

After trackday engine perfect even at high rpm.
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morghen  



Joined: 21 Jan 2005
Posts: 7376
Location: Romania

PostPosted: Mon Mar 20, 2017 10:04 pm    Post subject: Reply with quote

What oil are you using? how hard did you push it on the track? Did you check how much oil you have in the engine before going on the track? You may have starved the engine of oil. Next time you start it cold listen for knock / metallic noise....you now may need a complete rebuild of the engine if the headgasket is leaking and you blew the mains or whatever got a lack of lubrication while you were pushing it on the track.
Also...did you check that the camshaft oiler is working properly? if not...you may need a new camshaft and tappets as well.

I'm not sure what are your intentions with this car but the way I see it you're destroying it.
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924RACR  



Joined: 29 Jul 2001
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Location: Royal Oak, MI, USA

PostPosted: Mon Mar 20, 2017 10:55 pm    Post subject: Reply with quote

We always check lug nut torque before going on track, every session. Most important, do not check while hot, only after things cool off.

Fuel level, fluid levels (oil, coolant, and brake fluid) air pressures, torque wheels, those are the most important basics.
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Tue Mar 21, 2017 1:29 am    Post subject: Reply with quote

Lack of lubrification is possibile, even because I noticed the problem after parabolic corner during acceleration, in this point roll of car is very high and for a lot of time.
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Alfa Romeo Spider "Duetto" 1.6 104hp (1986) european, weber with trumpets and exhaust no muffler
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924RACR  



Joined: 29 Jul 2001
Posts: 7964
Location: Royal Oak, MI, USA

PostPosted: Tue Mar 21, 2017 2:27 am    Post subject: Reply with quote

Strange, I wouldn't expect the Parabolica to be a problem with the 924; while the lateral G's are high for a long time, they're in the "right" direction, since the engine is slanted into the corner... the problem is usually going the other direction, turning left for a longer time.

Still - sounds like you'd better change your oil and inspect your filter very soon, immediately. With such noises, I would be very concerned to catch anything before it gets worse.
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CÚdric  



Joined: 27 Aug 2004
Posts: 1513
Location: Sweden

PostPosted: Tue Mar 21, 2017 2:59 am    Post subject: Reply with quote

Oiling should be of no concern, especially on such a std car. Unless you have too little oil in the sump, if it is close to the bottom you could see the oil pressure warning light flicker, then you should slow down instantly !

Unless something in the oiling system is broken, oil pick up, pump etc.
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Tue Mar 21, 2017 3:55 am    Post subject: Reply with quote

My car at first corner:


https://plus.google.com/106493825386573398385/posts/T9qzo9Wq617


But I never noticed this problem of metallic noise, only on track and after only thwoo laps, it's strange. On street usually I run engine at maximum rpm without problems.

About wheel, the problem is in rear left , the one charged in this track, I think exclude vandalism (I leaved my car unattended after trackday)
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Porsche 924 2.0 na 125hp (1979) european, exhaust no muffler
------------------------------------------------------
Alfa Romeo Spider "Duetto" 1.6 104hp (1986) european, weber with trumpets and exhaust no muffler
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daniel  



Joined: 18 Jun 2009
Posts: 594
Location: Sydney, Australia

PostPosted: Tue Mar 21, 2017 9:43 am    Post subject: Reply with quote

Do you still use the standard drums on the rear? If so I had the thread on the drums start to crack with the pressure of racing. I upgraded to Kombi rear drums that use a separate adaptor plate and have no problems since.

And yes you must re torque your wheel nuts after every session, not every track day. Takes less than one minute with a tension rench.
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Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet
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chris79  



Joined: 29 Jan 2014
Posts: 489
Location: milan

PostPosted: Tue Mar 21, 2017 5:17 pm    Post subject: Reply with quote

Yes, I have to improve rear brakes and install front racing brakepads, do you have some advice ?

Can you link your thread for replace drums?

For now I don't convert my car from 4-lug to 5-lug.
_________________
Porsche 924 2.0 na 125hp (1979) european, exhaust no muffler
------------------------------------------------------
Alfa Romeo Spider "Duetto" 1.6 104hp (1986) european, weber with trumpets and exhaust no muffler
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View user's profile Send private message
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