Post Track Day Q's: Rotor Wear, Gearbox Oil, Ps Pump, Manifold Nuts

[V28VX37]

Tbh, I would go option 1) then consider upgrading the brakes if you find out that what you have just absolutely cannot cut the mustard.

It'll either happen eventually and you will want more stop power but getting there and having fun at the track is a good way to find that limit. And if you find you never need to replace them then eh you haven't gone to the track that much and as a result don't really justify a $2k+ brake kit.

Either way, you win out. Its not too hard to sell a set of front GTT brakes when/if you decide to upgrade later, especially if you have a receipt from them being rebuilt at XYZ shop on XYZ date.

Rebuild done, $420 for the fronts, drive in drive out.

Bring on Haunted Hills on Saturday!

[V28VX37]

Ok so Haunted Hills was great fun other than

• the short configuration is too short
• half a day only so too few runs, and lots of waiting
• it's too far from Melbourne.

But then again any track time is better than none, and $50 for come-and-try you can't go wrong

To revisit the issues from March:

Hi all,

I did a track day at Calder Park on Sunday (it was awesome), couple of general maintenance questions from that:

1. I just replaced my front pads before the track day and bedded them in + ran on the street about 150kms to get them ready. They were replaced like for like: Remsa -> Roadhouse, which is the same 650C pad, and I put all the shims etc. back the same way they were before. After the track day I'm seeing what looks like uneven rotor wear on both sides. It looks like the pads are not clamping the centre of the disc as much as the outer. Is this something to worry about?

2. I checked the gearbox oil before the track day and the box was full, which is good. However the oil itself looks a bit bubbly/cloudy, see pic below. It's Redline Lightweight Shockproof and about 16,000 street kms and 3 track days old - is it good to run further or time to replace?

3. I had the PS rack and pump reconditioned recently and it looks like it's sprung a leak near the PS pump, at the top front left corner of the engine/head. I'm not 100% sure but one of the thin rubber lines running right behind the timing cover looks pretty wet, does anyone know what this is? It runs off the PS pump among several other things. The left hand side of the engine is a bit wet but I'm not sure if it's PS fluid, coolant or what. Any suggestions on how to remedy?

4. The turbo-to-manifold nuts came loose at the track with a nice big whistle at high revs/boost. Thanks to the SAU team I managed to tighten the top two and the bottom rear one, however the bottom front one seems like mission impossible. Is there a way to get to it without removing the whole intake system and/or turbo? Some special clever tool perhaps? It's a 17mm nut.

Thanks guys!

1. I had a full brake overhaul done recently: front calipers rebuilt, all rotors machined, all new pads, new fluid (Motul RBF600 312C). The brakes were sweet especially considering all the downhill braking in a heavy car, good pedal feel and no fade.

2. The gearbox oil was changed recently, with a fresh batch of Redline Lightweight Shockproof. However, when inspecting the car yesterday I noticed some gearbox oil on the underbody near the output shaft (opposite to the catalyser) and little on what looked like around the yoke too. I opened the filler and it was down, added about 0.4L in there. I'm trying to work out if this was a spill + underfill at oil change time, or a leak from the output shaft seal, what do you guys think?

3. The cam seals were done recently together with a full service kit (timing belt + all the other belts), which I hoped would have helped with the leak from the front left of timing cover. I think it has, but not 100% - what else could leak at this location, the head gasket??

4. I haven't replaced the turbo-to-manifold nuts as yet, just keep on tightening them. They do work themselves loose over time with the severe temp changes at the turbo. I also noticed that plastic tubing around the O2 sensor wires was melted through, so have added some makeshift metal shielding around it. The turbo doesn't have a heat shield on.

Cheers

[Duncan]

Good to hear the brakes are sorted.

The gearbox is almost certainly just due to breathing. Ever since they changed the formula to remove the carcinogens it has breathed like crazy. I just leave it at whatever level it decides it should be after breathing out the exces....

Cam seals may still be the cause, particulary depending on the quality of the seals and the little rubber pieces under the cam cover bolts (and making sure they are not overtorqued causing pinched seal). Also if its an rb25 head it can leak from the VCT solenoid.

Not sure about the manifold nuts because I've never really had a lot of trouble. I'd guess it is a bit banana shaped...next time it is off put a straight edge along it

[V28VX37]

...

The gearbox is almost certainly just due to breathing. Ever since they changed the formula to remove the carcinogens it has breathed like crazy. I just leave it at whatever level it decides it should be after breathing out the exces....

Cam seals may still be the cause, particulary depending on the quality of the seals and the little rubber pieces under the cam cover bolts (and making sure they are not overtorqued causing pinched seal). Also if its an rb25 head it can leak from the VCT solenoid.

...

Yeah I had a similar issue with the box after the original installation but that was due to no breather hose at all. I added one and it's never chucked up since.

As seen in the earlier photo the box was definitely full of oil in March, but now after recent oil change and track day 5-7mm below the edge or about 0.4L under full. I'll keep an eye on it as I'm concerned about the seal.

Re cam seals, that would suck if it still leaks there, heaps of labor to get them changed... I'll see if it keeps leaking if it could be addressed under warranty or something.

Good idea about the VCT, it's a stock Neo so that could be it too.

[V28VX37]

Another track day, another issue. First time I had to tilt tray it back #carlife

I took the car to Sandown yesterday, third session it started overheating badly. Normally when I back off it corrects immediately, not this time, just kept climbing. I crawled off the track and the water hit 120-125, spitting heaps of boiling coolant out of the overflow. I shut it down and let it cool down, still starts well but temps start climbing quickly. Btw oil temp was high but not outrageous during this.

Some theories thrown around the track were:
- Blocked rad
- Dead thermostat
- Air pocket in coolant
- Issue with turbo lines

Thoughts?

[Duncan]

Crappy way to end a day, eh? Too hard to guess on an overheating issue, too many potential causes.  Most likely some sort of leak which you can tell by pressure testing the system.

[admS15]

Has the turbo been removed recently?

If not, I would take, issue with turbo lines off your list. All the others sound possible.

You may also want to try replacing the rad cap in hope that its something simple.

Good luck man, hope its a quick easy fix.

[KiwiRS4T]

On 5/9/2016 at 9:18 PM, V28VX37 said:

Yeah I had a similar issue with the box after the original installation but that was due to no breather hose at all. I added one and it's never chucked up since.

As seen in the earlier photo the box was definitely full of oil in March, but now after recent oil change and track day 5-7mm below the edge or about 0.4L under full. I'll keep an eye on it as I'm concerned about the seal.

Re cam seals, that would suck if it still leaks there, heaps of labor to get them changed... I'll see if it keeps leaking if it could be addressed under warranty or something.

Good idea about the VCT, it's a stock Neo so that could be it too.

I think Redline is more likely to foam than something like Motul. Cam seals need to be installed with silicone or other sealant on the half moons to seal properly.

Do you have a stock radiator? Had it cleaned out? Try replacing your stock thermostat and radiator caps with new OEM items. A pressure test may show up a leak or worst case compression test for head gasket. What was your maximum oil temperature? 

[V28VX37]

Crappy way to end a day, eh? Too hard to guess on an overheating issue, too many potential causes.  Most likely some sort of leak which you can tell by pressure testing the system.

Has the turbo been removed recently?

If not, I would take, issue with turbo lines off your list. All the others sound possible.

You may also want to try replacing the rad cap in hope that its something simple.

Good luck man, hope its a quick easy fix.

Thanks guys! It's already at the shop being diagnosed by people much more mechanically savvy than me. I was lucky to be able to drop it straight there on a Sunday to save the cost and hassle of a second tow.

What do they say again, Run it, Break it, Fix it

[V28VX37]

Ok some updates, the workshop had a good look over the car that the main problem they found was a leak near the Defi water temp sensor which is at the radiator top hose. Pressure test is fine, car starts and runs well, no temp issues during short test drives.

My working theory is that it may have leaked coolant from the temp sensor for a bit, run a little low and/or taken in some air, and then overheated when pushed hard. I also checked the Defi peak reading and it hit 125C at the highest, which is not good. This said the highest I saw on the OEM gauge was the 'hot' mark, the notch one down from the top end of the scale, so not off the chart.

There's still a chance that I've damaged the head gasket or warped the head but I suppose I'll just need to drive it more to find out.

Learning for next time is to take the warning signs more seriously – I saw a bit of coolant under the steering rack and near the overflow after session 2 but didn't investigate properly before heading off for session 3. Foolish.

---

Couple of other things on the list to investigate:

1. The hose connecting the turbo coolant return line to the block always appears as if it's 'sweating' a little. Is it possible that there's a minor coolant leak at the turbo?

2. There's a sensor and bracket in front of the AC/rad that I've bent down to make space for the IC, what's this for? Does it need airflow on it i.e. is the current placement behind the IC end tank a bad idea?

3. I can see some pretty substantial cracks forming in the clutch fan plastic blade assembly, is this due for replacement?  

4. There's this really curious little box in what I thought was the brake line running alongside the passenger side chassis rail, what's this for? Looks strange.

5. I've got beautifully glazed brake pads now and a crappy pedal feel with lots of travel. I'm assuming the pads will return once the glazing wears off, however the pedal is a little disconcerting – I'm guessing mildly boiled brake fluid and requires a bleed, or?

 

Thanks again!

[Duncan]

Yeah that's why I suggested a leak "somewhere", it works exactly like you said....slowly disappears without you noticing until there isn't enough coolant left to circulate and temps suddenly go ballistic (because no coolant is actually circulating). I've had the head to 132o and got away with it, I guess you'll be fine.  You can always do a compression test if you are worried.

On the others

1. No real sign of a leak, discolouring is normal. In any case pressure test the coolant system to about 1.2 bar to make sure there are no other issues. That first pic is the oil return.

2.No idea what that is, but its not necessarily a sensor...could also be a diode or resistor.  Could also be the ambient temp sensor for the A/C but I have NFI

3. I'd replace the fan. Looks like the viscous coupling may have been overtightened to the fan leading to cracks there. You dont want it to let go at 7000rpm. 

4. Not sure what that is either but unlikely to be brakes (that will run down driver's side I think).  Maybe part of the fuel breathing system. No need to touch it if there's no problem

5. They wont really unglaze on their own, more likely to damage the discs running them like that. Give them a good rub on rough concrete then bed them in again.  The pedal is probably fluid; bleed it through with good quality fluid like motul RBF

[admS15]

Well, that sounds like good news. There does seem to be evidence of a wheep at that turbo line. Possibly from the crush washers. You could try tightening it a bit more or remove the banjo and replace the washers, make sure you anneal them.

Definitely replace that fan before it lets go. Is that a stock radiator? If so, maybe time to upgrade to something bigger.

The brakes would need a bleed for sure and could probably even do with fresh fluid.

I have no idea about the other stuff. Cheers.

[V28VX37]

Thanks Duncan and Bill, talk about helpful and speedy responses!!

Duncan re comp test, the guys at the shop pulled out the plug at cylinder 1 and were happy with it, also the system pressure tested and bled fine. Not sure what pressure they tested at though. The thermostat was also removed and checked to be working.

Bill yes it's a the stock rad, also originally being an auto I'm not sure if it's slightly smaller capacity than the manual unit given that the bottom part of if was originally connected to the auto gearbox.

I'll look into replacing the fan.

[Dose Pipe Sutututu]

See if there's friction with your stock fan.. the OEM viscous hub leaks/wears out after time and stops spinning the fan at the rate it should thus causing the water temps to sky rocket.

Also re-bleed your system, totally worth it.

front sensor is for A/C
side sensor thing, no idea.. could be a crash sensor.. I have one too but never bothered to trace it back

also I see you have a R34, replace the OEM themostat with a R33 one.. will lower the running temp from 88 to 82.. don't worry it won't affect your tune.. most tuners/oem maps/after market base maps, etc.. remove all fuel compensation after 70 degrees.

[KiwiRS4T]

3 hours ago, Dose Pipe Sutututu said:

 

also I see you have a R34, replace the OEM themostat with a R33 one.. will lower the running temp from 88 to 82.. don't worry it won't affect your tune.. most tuners/oem maps/after market base maps, etc.. remove all fuel compensation after 70 degrees.

We are talking about track days here. Within a very short time the (any) thermostat will be wide open so I can't see the point in getting one that opens a few degrees earlier - it will certainly make no difference to running temps on the track.

[Dose Pipe Sutututu]

5 minutes ago, KiwiRS4T said:

We are talking about track days here. Within a very short time the (any) thermostat will be wide open so I can't see the point in getting one that opens a few degrees earlier - it will certainly make no difference to running temps on the track.

if you can maintain your coolant temp always around 80 instead of 90 that means if it does get super hot you have about 20 degrees before it boils instead of 10.

Does that make sense?

[KiwiRS4T]

3 hours ago, Dose Pipe Sutututu said:

if you can maintain your coolant temp always around 80 instead of 90 that means if it does get super hot you have about 20 degrees before it boils instead of 10.

Does that make sense?

I follow your reasoning but:

in your example we are talking about a difference of 6 degrees which will take less than half a lap to make up (even the Nismo thermostats do not help in track work)

and with a stock radiator cap boiling point is around 120 deg C

[V28VX37]

8 hours ago, Dose Pipe Sutututu said:

See if there's friction with your stock fan.. the OEM viscous hub leaks/wears out after time and stops spinning the fan at the rate it should thus causing the water temps to sky rocket.

...

Thanks mate, I'll definitely check that.

I just priced the OEM parts with Kudos, it's $176 for the fan blades, and $385 for the cooling fan hub / viscous coupling, eek.

[V28VX37]

10 hours ago, Dose Pipe Sutututu said:

See if there's friction with your stock fan.. the OEM viscous hub leaks/wears out after time and stops spinning the fan at the rate it should thus causing the water temps to sky rocket.

I just checked this then, it certainly doesn't spin freely but I'm not sure what the friction level is meant to be. If you spin it by hand it rotates maybe 2 blades' distance (is that like 30 degrees?) then stops. Not sure if this is within spec or not?

Also somehow I would have thought the fan would make less difference on the track at higher speeds where there's more natural airflow through the rad?

Edit: Just sanded back all glazing from front and rear pads, slightly improved pedal feel but still need to change the fluid. Mental note: Remember the cool down laps!

[KiwiRS4T]

9 hours ago, V28VX37 said:

 

Also somehow I would have thought the fan would make less difference on the track at higher speeds where there's more natural airflow through the rad?

Edit: Just sanded back all glazing from front and rear pads, slightly improved pedal feel but still need to change the fluid. Mental note: Remember the cool down laps!

Fan makes no difference at speed - needed for traffic and idle only.