99 Caterham tires 205/45r16

[Reiver]

Firstly, hello from Arizona and my first post...long time sports car owner (longer than I like to admit) but just purchased this but not yet in hand.

 

Gents, a car that is enroute to me has the original Caterham 16" wheels with 205/45r16 tires.  This will be a street car only and I am concerned about ground clearance where I live so was wondering if anyone has run a higher profile for that reason?  I understand the speedo will be off some, but I am more concerned about the sump.

As the width would be the same would there be a clearance problem with the wings?  

[Reiver]

Say a 50 or 55...the first would gain about 1/2" and the later 1"

[CarlB]

Taller tires will have an effect on how quickly the car will turn, and they will also give a smoother ride. You might also consider putting a skid plate on the car. I am not familiar with your engine's sump, but I have a very simple skid plate on my car. It is nothing more than a piece of aluminum attached with hose clamps that goes under the front of my oil sump. Message me if you would like to see pictures.

[Reiver]

Thanks Carl and I sent you a message..... I have been looking for a sump plate for the Vauxhall but anything I can modify will do...

[Croc]

14 hours ago, CarlB said:

You might also consider putting a skid plate on the car. I am not familiar with your engine's sump, but I have a very simple skid plate on my car. It is nothing more than a piece of aluminum attached with hose clamps that goes under the front of my oil sump.

 

Carl - your sump guard came from George Alderman - he sold them when he was a dealer.  I used the same sump guard on my old yellow SVT Zetec and it saved me many times.  Its a simple design that works well and can be easily copied for a VX Caterham. 

[Reiver]

I sent Carl a msg.... but can you post a picture of your sump guard?

[CarlB]

Here are some pictures of the skid plate on my car. The fist picture is under the car and shows the hose clamps used to attach it to the car in front. Not visible in the picture are two more hose clamps just before the skid plate bends down to go over the oil sump. The second picture shows the second set of hose clamps from the top, and the black part is what goes under the oil sump if the engine was in the car. The skid plate is made out of 1/8th or 3/16th aluminum diamond plate. From experience I can tell you it works. The last picture is the from the top and shows how the skid plate attaches to the front of the car. If anyone who has looked at my post on alignments is looking at this, look closely at the last picture. You will see a small hole located between the clamps holding the steering rack. That is the center point Arch Motors used when they built the frame. 

 

 

 

 

 

[Reiver]

Thanks...I'll do something similar as I want to block off that whole area as I'll be running without a cam belt cover (can't use one with the aftermarket pully system from SBD) and want to keep dust/debris from contaminating the belt. Looks like an effective and simple solution....

Edited December 15, 2024 by Reiver

[Reiver]

Off topic but have you tried POR15 black chassis paint..... just paint over that rust and no issues...I've used it on older car resto's when I wanted to save a floorboard etc. and it held up great.

[SCse7en]

CarlB thanks for posting photos of your skid plate as I have been thinking about adding one to my car.  How much ground clearance do you have with it in place?

[CarlB]

4 hours ago, SCse7en said:

CarlB thanks for posting photos of your skid plate as I have been thinking about adding one to my car.  How much ground clearance do you have with it in place?

Sorry I do not remember what the ground clearance is. I set the ride height with some droop in the lower control arm. Mike Beachman suggested that. Doing that gives more camber gain than having the control arm flat or pointed up. I would measure it for you, but the car is on stands with the engine out.

[Reiver]

Thanks Carl.... I'll figure it out but appreciate everyone's input.... I will go with a higher aspect 16" tire tho as that is easy to do.  The same make I am looking at makes them in 45/50/55 aspect.  I will copy that guard too..... too bad the ind. making those steel welded jobbies quit doing so, those looked nuclear capable.

Edited December 15, 2024 by Reiver

[Reiver]

Speaking of tires/wheels.... I find that the wheel nut torque is 55 Ft Lbs....seems a tad light to me but what do I know...for fun...the C8 Corvette is 140 ft. lbs. 

[theDreamer]

I replaced the 20 year old tires on my HPC with the same recommended size 205/45 16. My speedometer reads about 10% higher than actual when compared to GPS or road side radar.

As for the sump guard, it will have a beneficial side effect. Speaking to Peter Marie earlier this year (he now owns the HPC that I first drove back in in the 90’s) he told me of an over cooling issue the C20xe Sevens are known for. He supplied this answer to his “shroud” in the latest issue of the Lotus Club of Canada’s newsletter which I’ve included.

When Caterham shoehorned the tall 2L Vauxhall engine into the Seven they replaced the original oil pan with a bespoke long, shallow, heavily-finned aluminum sump. Additionally they removed the oil to water heat exchanger that was fitted between the oil filter and oil pump. This was all done to provide adequate ground clearance. Unfortunately these changes made for a very cold running engine.

The heavily finned sump is really a non-thermostatically controlled oil cooler. It kept the oil temperature at an ideal maximum of 95°C when hammering the car on the track on a warm summer day—but on the street even on a hot 35°C summer day the oil temperature rarely got above 80°C. On a cooler 20°C day I'd be lucky to see 65°C, and on a cold day the oil would struggle to get above 50°. That of course is way too cold for a long engine life.

So I made a ‘Shroud’. [Thermal Blanket] It prevents air flow under the sump and retains engine heat. I now get the oil up over 80°C on a 10° to 25° day which is at least okay. One advantage of the low oil temperature in the carb'ed engine, with no starting choke, is that I can run a light 0W-20 engine oil which greatly improves the car's starting and driveability when cold. Plus proper oil flow at 80°C oil temperature. Plus at the track the shroud can be removed to maximize oil cooling.

Note: My car was ordered with an oil cooler. However, it was removed at some point probably because it was overkill.

Edited December 17, 2024 by theDreamer

[Reiver]

Thanks, very interesting on the oil issue.... everyone has cooler weather as we do now, and I'd be more apt to run the car in our winters than the dead of summer.

I plan on a full shroud from the nose past the oil pan on the sides to keep debris from the open belt/cam sprockets and then a sump protector plate similar to the one shown here lately.  Looks rather easy to put in place and I have a drive on lift in the garage.  

Thin alloy for the shroud and similar 1/8 in. for the sump shield.

 

I'd be nervous running that low a weight of oil tho...presently has 10/40..otoh 0w40 might be the ticket.

 

Appreciate your time and info....now all I have to do is convert those temps to 'Merican....

Edited December 17, 2024 by Reiver