What have I done? Two N00bs Try to Resurrect a 7

[YourEconProf]

My car buddy & I do or have owned 4 Miatas. He's a high-end body restoration guy, working mostly with classic Porsches. His shop shares space with a trackside support/race shop. A few months ago, a Caterham came into the race shop that was owned by a long-time client's widow. Though it was running up through a couple of years ago, now it wasn't. The mechanic/owner futzed with it some but lost interest in trying to get it running. I made a threw out a low offer and lo and behold I own a Caterham. 

 

Now, I've owned a couple of Miatas, and I'm pretty good with wrenching. My buddy has owned everything from an early E type to a couple of Miatas to 60's Firebird, and he can weld your butt crack together so smoothly its looks like you were born that way. He also builds motorsports harnesses for Porsches. We know a combined diddly squat about Caterhams.

 

I've put high quality pictures of the car in a google album at the link below. If anyone can help us learn more about the car or solve problems or just wants to see more pics, LMK and I'll add them. https://photos.app.goo.gl/6qKo4TBgRanR2VUN6

 

So far, I can see it's a 1983. The Caterham plaque is missing, and I haven't been able to locate the Caterham chassis number. I see references to "under the pedal box cover" but I have no idea what that means or where to look. The mount of the windshield wiper motor is a black piece of metal with no apparent stampings (both pics in the gallery). So any advice would be appreciated.

 

The current ECU is a Simple Digital Systems that is no longer supported. I'm planning on replacing with a Megasquirt 3Pro Mini. I've installed 5 or so Megasquirts on Miatas, so I'm reasonably familiar with them.

 

Anyway, any help in knowing more about the car, etc., is greatly appreciated.

 

 

This thread started over here:

 

 

[YourEconProf]

I finally got the car up on stands today, and got pictures of the diff. I know its got 3.75" BCD on all four corners.

Can anyone see what this is (sorry the pictures are upside down...not sure what that's about, but are normal in the Google gallery)

 

 

 

Edited January 19 by JohnCh
Image rotated

[YourEconProf]

So, as I'm starting to take apart the car, I have so many questions. Another new one...there is a hose that runs from the exhaust just behind the headers to what appears to be a large black catch can, when then has a hose going to a large stamped part on the side of the block just below the headers. Does anyone know what that might be? 

[JohnCh]

7 minutes ago, YourEconProf said:

He also builds motorsports harnesses for Porsches.

Based on the wiring you inherited with the Caterham, that will come in handy  

 

I fixed your upside down image.  See this help guide to understand how to fix it yourself and why it happens.  Short version is your camera was upside down when you took the photo.  

 

 

[JohnCh]

I went through the photos.  This car has a lot of things I haven't seen before.  What are you plans for it?  Do you want something streetable or are you keeping it as a dedicated track car?  I've seen double silencers before to meet strict track noise regulations, but I've never seen a setup where the exhaust ends at the rear of the scuttle.  I'd think that location would pump exhaust into the cabin.

 

Is this the throttle return spring or just a helper?  It looks like the loop at the end is intended to attach to the bolt next to it.  

 

 

[MV8]

7 hours ago, YourEconProf said:

I finally got the car up on stands today, and got pictures of the diff. I know its got 3.75" BCD on all four corners.

Can anyone see what this is (sorry the pictures are upside down...not sure what that's about, but are normal in the Google gallery)

 

 

 

That is the lower control arm (A frame) balljoint/heim/spherical/rod end, etc.

[MV8]

7 hours ago, YourEconProf said:

So, as I'm starting to take apart the car, I have so many questions. Another new one...there is a hose that runs from the exhaust just behind the headers to what appears to be a large black catch can, when then has a hose going to a large stamped part on the side of the block just below the headers. Does anyone know what that might be? 

That is a check valve for crankcase evacuation from the zetec breather in the side of the block. It pulls air into the engine from the right side valve cover hose from the red bottle. Strange combo but I guess it works.

 

I saw a pic of the oil pan which looks to be an oem steel unit modded for ground clearance. The 250hp version is supposed to have an aluminum pan. Also noticed extra material added to the chassis cross member under the transmission, making it square and reducing ground clearance but not the lowest thing.

 

The pedal box is an oddity to me as well but well designed for the brake and clutch. The two bolts and tabs should be free to swivel. If there is no positive stop on the two bolts, they need to be left a little loose to allow the rotation, which prevents the clutch cable end from bending back and forth, eventually breaking the wires at the fitting. The clevis on the throttle pedal should also be free to rotate for the same reason as the clutch cable.

 

The fuel tank vent is capped. A quick fix is to use brake line to make a loop up to the upper frame rail/coilover top, then drop down to the lower rail but above the air stream to prevent syphoning or slant cut on the aft side.

Lots of work to do all around.

Edited January 19 by MV8

[Croc]

 

So a 1983 Caterham.  Originally was a crossflow based on how they installed the current zetec.  Looks original chassis - no evidence of short of long front.  Original rear basket.  Rear end looks original live axle.  AM 83 27 frame number stamped where I expect it to be seen - produced in 1983 by Arch Motors on jig 27 (so no you cannot identify this as a unique number to this car).  Front suspension looks to be updated - not the original from what I can tell.   Firewall shelf has the original round hole for the early style heater. 

 

Its a 1983 chassis so no pedal box cover.  Here's where I expect the Caterham chassis number would be found:

- alloy plate riveted into the alloy skin roughly in line with the brake master cylinder.

- alloy plate - anywhere around the firewall in the case the original US kit builder got random compared to the factory. 

- Bar in lower front of pedal box area was stamped with Caterham chassis number - under the rubber boots - look front side.  May be obscured as it looks like something was modified there at some point - odd join on shelf of the ali panel and the panel wraps over the shelf bar there. 

- Base of wiper motor - but you looked there unless it is under thick paint?

 

Number would look something like:

CS3/XXXX/YYLS

 

CS3 refers to Caterham Series Three. 

XXXX = Chassis number (it was a sequenced number based on production).  Should start with a 4 for an 1983 car

YY = This is engine code.  16 would be 1600cc Crossflow.  17 would be 1700cc crossflow.  May even not be coded since it is a US kit car? 

L = Left hand drive

S = RS axle

 

If not present then no loss as you have the state identification plate which acts as a VIN. 

 

You could reach out to the Caterham archivist and see how many left drive cars for export with AM83 27 frame number?  I cannot believe there is more than one.  Unfortunately the archivist may not have cross referenced the frame numbers with chassis numbers.

 

Looks like an excellent project to rehabilitate for some backroads fun. 

 

 

 

[YourEconProf]

12 hours ago, JohnCh said:

I went through the photos.  This car has a lot of things I haven't seen before.  What are you plans for it?  Do you want something streetable or are you keeping it as a dedicated track car?  I've seen double silencers before to meet strict track noise regulations, but I've never seen a setup where the exhaust ends at the rear of the scuttle.  I'd think that location would pump exhaust into the cabin.

 

Is this the throttle return spring or just a helper?  It looks like the loop at the end is intended to attach to the bolt next to it.  

Thank you so much for your reply. There are a lot of things I haven't see here before, either! 

 

Honestly, I'm not sure long-term plans. I already have a track car, in fact I totaled my old one this year, and just bought the replacement a week before the Caterham. In a perfect world, I'd like to get the Cat running by track season (really starts up in April, as I live in Ohio) and at least see what it's like on track. Then probably will decide which to keep unless I land some big contracts this year and keep both. So for now, I'm building as a street/track-curious?

 

I had the same thought about the exhaust going into the cabin. I figure at this point, its not broke, so I'm not going to fix it, but yes, odd.

 

That is the throttle return spring, and the loop is just to take up some slack in the wire.

 

 

[MV8]

It looks like this fuel pump, return, and fuel filler combo may bolt on to the existing opening in the tank. You could also add a one inch tall ring or bucket (with a small hole) around the bottom to help keep the return flow at the pump pickup. Hard to beat $110. 3003H14, .080" and rivets would work fine.

 

https://www.speedwaymotors.com/RCI-7080A-Universal-12-Bolt-Fuel-Pump-Hanger,394949.html?utm_matchtype={match_type}&msclkid=1bb64d3ebc12168cbcfd2ab03d0f33fa&utm_source=bing&utm_medium=cpc&utm_campaign=SMI - Shopping (CSE) (Bing) (Brand Hybrid)&utm_term=1100310019383&utm_content=RCI (A7)

 

Also it looks like some sort of vacuum canister in the right rear of the engine bay for the crankcase breather instead of a remote oil filter.

Edited January 20 by MV8

[YourEconProf]

On 1/20/2025 at 12:23 PM, MV8 said:

It looks like this fuel pump, return, and fuel filler combo may bolt on to the existing opening in the tank. You could also add a one inch tall ring or bucket (with a small hole) around the bottom to help keep the return flow at the pump pickup. Hard to beat $110. 3003H14, .080" and rivets would work fine.

So...the tank in this 7 doesn't sit flat, it tilts from back to front by about 2" or so. I'm assuming just need to make sure the sock is adequate? That link is just for the hanger and bracket but not the pump, but I have a 165lph in tank pump for a Miata that I think I can just use and make sure any in tank plumbing is right to deal with differing depths/slopes? Does that sound right?

[YourEconProf]

Okay, a combination of work travel, flu and pneumonia has kept this project from going anywhere, but I'm grateful for everyone's help above.

 

I have since found out that this is a 1983 LHD long cockpit based on the AM chassis number. I still haven't uncovered any Caterham chassis numbers, though I haven't actually taken the windshield wiper motor mount off to look at the top of it.

 

Over the weekend, I found the combination of time and energy to put a few hours in, and removed the old computer and have started removing and labelling everything for the engine harness. My current plan is to remove and replace the engine harness, ECU is being replaced with MS3Pro Mini, fuel pump/filter, and relocate the battery from behind the passenger seat to the engine bay. At that point, should be able to focus on getting it running, and then worrying about things like seats & belts, chassis harness, and other bits & bobs.

 

1. (Pic 1) As was mentioned above, in the passenger side rear of the engine bay were two catch cans, one plumbed to the PCV, one to the valve cover. Both set up cheesy and trashed. I'll run both to a single smaller (each had to be 1-1.5L) vent to atmosphere catch can.
2. Anybody know what *originally* went here in this location (rear passenger side of engine bay)
3. So far identified & labeled the headlight, fan, and fuel pump relays. Still 3 more relays to go.
4. Relocating battery to the bay will clean up a lot of wiring due to the lack of a distribution point for +. Someone decided to make that the starter motor (Pic 2) and there are at least 6 extra wires coming off the positive terminal that then proceed to lallygag through the car.
5. I know that lack of spark was the issue, and I'm replacing the ECU, and the coils were already replaced, so I'm going to replace the ignition module, too, with one made by ECU maker to keep settings and compatibility easy, even if it will cost me a few extra bucks. Pic 3 is the ignition module that was in it. 
6. Pic 4. So this guy was just flopping about under the intake.
7. Pic 5. The brake lights in this car are actuated by a pressure sensor on a dedicated brake line instead of a mechanical switch at the pedal. Is this a Lotus/Caterham thing?

Some requests/questions:

1. Any thoughts suggestions on battery size/where to locate and good solutions for attaching? I've always liked the look of the base-mounted Optima batteries. 
2. Pic 6, if I remove the windshield and the two bolts under each side where it attaches to the frame, can I lift off the cowl cover and leave the dash in place? I can't really see anywhere else it attaches. If so, would be much easier to work on backside of dash.

 

 

[MV8]

Right? No. Will it work in the driveway and for a few months of not too aggressive cornering? Probably as long as you keep the tank 3/4 full.

 

Yes, the link is just for a hanger so the pump does not flop around in the tank.

A tank that is tilted only affects the diy baffle arrangement.

When efi pumps pickup air when the fuel sloshes away, they are damaged.

 

A miata tank has baffles inside and is shaped to aid fuel return to the sock. A Caterham tank is like an '80s ford pickup truck tank only worse, because it is very wide where a pickup truck tank is narrow, so fuel can slosh further away. The pickup truck doesn't have issue because it has a small sump tank that feeds the external efi pump and has a low pressure lift pump inside the tank that is not damaged by picking up air on occasion.

 

If you want two pumps with an external tank, that can be done. There are also the multi-sock arrangements that could work for you and some members have used that.

 

The simplest arrangement is what I suggested but takes some fabrication.

 

 

Edited Monday at 05:33 PM by MV8

[YourEconProf]

1 minute ago, MV8 said:

Right? No. Will it work in the driveway and for a few months of not too aggressive cornering? Probably as long as you keep the tank 3/4 full.

 

<...>

 

The simplest arrangement is what I suggested but takes some fabrication.

 

 

Okay, now re-reading your earlier post, I understand what you are saying. I mentally whiffed on the 1" tall ring or bucket. Thank you.

[MV8]

I've heard that optima quality has gone down hill in the last few years. I'd use a lead acid side post with about 450-500 cca, then make cables with copper lugs and terminals from 3/8x1/2" bolts and washers. The hydraulic switch is standard caterham. You can split the power taps between the alt stud, batt terminal, and starter stud or run a remote stud off any of these things.

Edited Monday at 05:43 PM by MV8

[CBuff]

On newer cars scuttle removal is usually done by drilling out the rivets and taking off the scuttle (leaving the firewall ) as lots of electronics attached and heater. Some older cars folks remove the scuttle and fire wall together disconnecting what’s needed. 
 

https://www.caterhamlotus7.club/forums/topic/186815-scuttle-removal/

if you drill out all the rivets you can replace with rivnuts for future removal 

Edited yesterday at 12:42 AM by CBuff

[7Westfield]

that brake light switch is like 60s+70s MGs Healeys etc

a lot of westy owners wire in a pedal switch in parallel, gets lights on sooner

the pedal switch acts first   pressure one is backup

 

I'd extend that exhaust back to lessen hearing loss