Chapter 7 with a Caterham SVT

[redursidae]

Yes I did mean Celsius. Roughly 96-98 Fahrenheit at the track yesterday.

 

Good to have confirmation on this, thanks. I'll run a 5w-40 first, and then a 50 if the pressure still drops too low.

 

Were your Zetecs dry-sump or wet-sump? Man that's kind of a bummer, as I was planning to do a couple of trackdays this year with the local group of Caterhams. Well, only one of the near tracks has long corners, while the others are more like a big autocross with straights. Think it'll be fine for the latter? At any rate, my Miata will continue to be the dedicated trackcar, and the Cat is more of the 4-wheel motorcycle for me.

 

The thermostat is either 90 or 95C, but I don't know for certain. I think the thermostat is working because on the street and for those first 4 sessions it stayed right at 90C, which is near the thermostat temperature. The fan is on a thermoswitch that runs at 90C, and shuts off at 84C. Those may not be the exact numbers but is close. I saw it printed on the switch when I did the radiator but failed to take a photo. But the fan does work, and it starts near the 80C mark on the gauge (which is why I know it reads low), and it was running the whole time at autocross. One thought I had was that there is no baffling between the radiator and the bodywork, so a lot of the air is going around it, and the fan may not be doing much. The new radiator also pushed the fan away compared to the original, which I have to imagine also reduces the efficiency of pulling air through it without baffling. But yes, I'll investigate further, and use the OBD scanner next time to check the real readings too.

[KnifeySpoony]

What is the oil cooling setup on that?

[Croc]

8 hours ago, redursidae said:

 

Were your Zetecs dry-sump or wet-sump? Man that's kind of a bummer, as I was planning to do a couple of trackdays this year with the local group of Caterhams. Well, only one of the near tracks has long corners, while the others are more like a big autocross with straights. Think it'll be fine for the latter? At any rate, my Miata will continue to be the dedicated trackcar, and the Cat is more of the 4-wheel motorcycle for me.

 

 

Mine were wet sump with baffling - Raceline pan.  

 

If you want to try give it a go but keep close watch on the oil pressure gauge and adjust your driving accordingly.  Long rights do have a tendency to force oil into combustion and you end up with a smoke screen out the back as you add throttle back for a straight - no harm unless you are following and getting second hand smoke.    

[redursidae]

8 hours ago, KnifeySpoony said:

What is the oil cooling setup on that?

No oil cooler on mine.

 

3 hours ago, Croc said:

 

Mine were wet sump with baffling - Raceline pan.  

 

If you want to try give it a go but keep close watch on the oil pressure gauge and adjust your driving accordingly.  Long rights do have a tendency to force oil into combustion and you end up with a smoke screen out the back as you add throttle back for a straight - no harm unless you are following and getting second hand smoke.    

Alright, same setup as this one.

 

I’ll think about it. What’s considered a long right in this context? It should be fine in my local track and at Grand Junction, as those are like a big autocross. My concern is Pueblo Motorsports Park and La Junta. Those have longer corners.

[pethier]

1 hour ago, redursidae said:

 

I’ll think about it. What’s considered a long right in this context? 

The Carrousel at Road America?  

[KnifeySpoony]

Ah ok without any oil cooling it makes perfect sense. You may be able to get by doing autox with heavier oil, but i think you will definitely need a cooler for track work. 

[redursidae]

If Road America’s carousel is the bar, then I’ll be fine. I don’t plan on taking the Cat to a big track like that.

 

One of the local Caterham peers lent me his spare set of Apollos to test fit and measure clearances. It’s scary. 2.5” of ground clearance at the lowest point of the oil pan with Apollos and well worn Avon ZZRs. I may still get a set, but it may only be a track setup as it will certainly hit things around here.

 

As far as fitment, the rear section of the exhaust is in the way. I’ve been wanting a side exit anyways, so this is a good excuse:

 

 

I also re-weighted the car on this setup since I had added the lights and passenger seat. This is with 1/4 tank of fuel and 13s.

 

 

The front 185/55/13 Avon ZZRs on Apollos are 22.6lbs, and the rear 215/55/13 are 27.6lbs. The 15” Caterham wheels with Toyo R888R 195/50/15 weigh 31.2lbs each. Huge difference, but is it worth risking an oil pan for it…

[Austin David]

honestly, full syn 5-50 isn't that hard to source, and is not too expensive either.  Maybe do that first, or "do it anyway"?  I get mine in bulk from O'Reilly, Mobil-1 with free shipping sometimes.  Ends up about $10/qt, which is more than what I put in cars I don't care about, but not a lot more.

[Austin David]

9 minutes ago, redursidae said:

The front 185/55/13 Avon ZZRs on Apollos are 22.6lbs, and the rear 215/55/13 are 27.6lbs. The 15” Caterham wheels with Toyo R888R 195/50/15 weigh 31.2lbs each. Huge difference, but is it worth risking an oil pan for it…

FWIW my pan has touched a few things gently, I'm still on the first one.  I've learned how to better avoid high spots, like the optimal path through a few parking lots to avoid speedbumps altogether.

Do you also have to adjust ride height or rake after swapping to taller wheels?  I assume a speedo recal is required too

[pethier]

21 hours ago, Austin David said:

 I assume a speedo recal is required too

LOL.  On my first 7, a 1600 Caterham with dry sump and live axle, I installed a Quaife LSD and 4.11 gears.  Didn't touch the speedo.  I'd be cruising down the highway at an indicated 90mph being passed by soccer moms in their minivans.

[redursidae]

@Austin David Regarding 5w50, is not so much difficulty finding it, as it is how long it may take to warmup in the colder months here. I’ll order some to try it out anyways, and could go back to 5w30 or 5w40 in the winter. I also wasn’t sure if the 5w50 would make the VVT unhappy, but I have been told it would be fine.

 

@Austin David Any chance you could measure the clearance of your pan to the ground? You also have a Duratec which I have to imagine has a different height.

 

Having rocks, branches and potholes on the road is common here. Bridge junctions in New Mexico are also horrible, and I already scrape on those if I’m not careful. Josh Robbins said I could raise the front further, so maybe I’m overthinking how the geometry may get affected by that. It’ll probably be better anyways because of the drastic unsprung mass difference. And since I do have an affliction, a dry sump is possibly happening at some point in the future.

 

Yes to all of those adjustments, and good point about the rake. The ride height dropped an inch in the front going to 13s. The rear dropped about 1/4 to 1/2 inch. I took measurements after your comment and it will need readjustment for the 13s, as it had too much rake. I didn’t jot down the numbers, but it was around an inch higher rake than the 15s. I’ll take close measurements once I’m able to get my own set, since these are only for test fitting and I don’t want to mess with the current setup.

[Austin David]

< 3".  this is the back of the pan, which afaik is the lower part.  And further behind the wheels, so more likely to caress the odd speed bump.

 

Squirrels and such will catch the front, but for roadkill I worry more about the nosecone.  Note that I once caught a bird on the left cycle wing; that was gross.  Like hitting a waterballoon full of ketchup.

Note also that the bell housing is not much higher than the pan; the bigger difference is that scraping the housing is less likely to drain out all your oil, but you will still scrape.

[IamScotticus]

On 4/19/2026 at 1:54 PM, redursidae said:

I’m waiting for a bead roller

Link?

[redursidae]

Thank you, Austin. That’s good info!

 

8 hours ago, IamScotticus said:

Link?

Unfortunately the bead roller was not the right size and didn’t work. In the end I did not put a bead on the pipe and only used a fuel safe rubber cap and a clamp per the picture. Anyways, here is the link:

 https://www.pegasusautoracing.com/productdetails.asp?RecID=31584