What sort of X-flow am I?

[MikeK]

I was looking to get a Weber Alpha 3D mapped electronic ignition fitted to my 1700 Supersprint but:

 

When I pointed out to the supplier that the engine was fitted with twin Dellorto 40s, I was asked whether I was sure that the engine was a “standard Caterham Supersprint engine” or whether it had a different specification (e.g. camshafts) as this could affect the suitability of the installation. Well:

 

1. The engine is a 711M60158 crossflow fitted in a 1990 live axle car.

2. It doesn’t have “Supersprint” cast into the rocker cover.

3. According to the V5, the capacity is 1675cc.

4. The engine number is MC18606.

5. Based on the engine number, Caterham have advised that they don’t believe that they supplied the engine.

6. In 1990, the car was advertised as a 1700 Supersprint with about 100 miles on the clock by Christow Carriage Company in Exeter (a Lotus dealer at the time). However, Christows no longer seems to be open and I can’t trace the first owner of the car.

 

Whilst the engine goes very well (or so it seems to me!), I wonder whether it is a “genuine” Supersprint engine, whether it has been built up to Supersprint specification by an engine builder, or whether it is to some alternative specification.

 

Other than stripping the thing down when it seems to be in rude health, has anyone any ideas about how I can determine the engine’s specification and/or provenance?

 

If nothing else, the specification can affect the ignition timing and valve clearances, so any ideas what I should set these to in the absence of any further information?

 

Also, should this affect my choice of 3D mapped electronic ignition system?

 

Congratulations if you’ve got to the bottom of this essay, and thanks for any advice you can provide!

MikeK

 

 

Edited by - MikeK on 29 Jun 2003 10:16:46

[SiGainey]

If you're having problems tracing the first owner of the car, email me and I'll do what I can to help by checking the voters roll for you

[Joe 90]

Mike,

AFAIK Caterham never fitted Dellorto carburetors, so it's probably not a factory engine. Anyone can fit any rocker cover and the capacity on the V5 would have been taken on trust, so that doesn't help much. Setting the valve clearances will be a bit of a problem if you don't know what camshaft you've got. If you measure the valve timing and lift (which only requires taking the rocker cover off) you can have a guess at the cam spec.

 

As far as the 3D ignition goes, it doesn't matter what spec the engine is because you map the ignition to the engine. If you intend to run with an "off the shelf" map, then the more info you have, the better the results would be. Most XFlows are built to a similar spec, a "standard" map may work better than points anyway.

 

Crash team to the Upgradeitis ward, the withdrawal symptons are getting worse ❗

[Graham Perry]

Agree with Oliver, it shouldn't make any difference regardless of the engines provenence. The only difficulty may be the throttle pot. It fits easily onto the central spindle of a weber carb. Not sure how easily it will fit onto a dellorto. No doubt someone here has fitted one on one of these carbs and can advise.

[MikeK]

Judging from the engine's peformance (it is quite flexible), I don't think it can have a very "hairy" cam in it. On the basis that it is better to have valve clearance a little too large than too tight, I'll try the standard Supersprint clearances (as they are about two thou larger than the 1600 Sprint).

 

Thanks for the comments so far. I was hoping to use an "off the shelf map" to save money.

 

Mike

 

 

[Big Brother]

Hope this helps...

1700 Supersprint Engine Specification

 

Base unit

Ford ohv 2265E Kent crossflow

 

Bore Stroke

83.27mm 77.62mm

 

Capacity Compression Ratio

1690cc 9.75:1

 

Cylinder Head

Gas flowed and enlarged ports

 

Valves

Oversize, gas flowed design manufactured in 21-4N steel.

 

Valve springs

Heavy duty, Duplex with retainers to suit.

 

Camshaft

Caterham BCD with high lift short duration profile

(Kent 234 is commonly used)

 

Pistons

Cast aluminium modified to give valve to piston clearance.

 

Crankshaft bearings

Uprated competition type main and big end shell bearings.

 

Flywheel

Lightened and balanced

 

Clutch

Uprated competition cover assembly and drive plate.

 

Ignition

Caterham distributor with special side entry cap with optional Lucas electronic ignition. NGK B8ECS spark plugs.

 

Valve cover

Caterham cast alloy with "1700 Supersprint" script.

 

Lubrication

High-pressure oil pump with standard wet sump.

 

Inlet manifold

Caterham cast alloy.

 

Carburation

Two Weber 40 DCOE 151

 

Air filtration

Two K&N high performance air filters.

 

Performance Data.

Maximum power 135 BHP (99KW) @ 6000 rpm

Maximum torque 122/lb/ft @ 4500 rpm

 

Servicing Data

* Static ignition timing 10 degrees at BTDC

Valve clearances (cold) inlet 0.22" Exhaust 0.24"

Spark plugs NGK B8ECS

Spark plug gap 0.25"

Firing order 1-2-4-3

*Fuel 97 octane (4 star) leaded

Oil pressure (normal temp) 3-4 BAR

Contact breaker points gap 0.025"

 

Engines numbered with the suffix "UL" can be run on unleaded 95-octane fuel with static ignition timing of 14 degrees BTDC.

 

I cannot guarantee any of the above as this info was passed to me from a friend.

 

Steve

Se7en-Up!

Less is more!

Eagles may soar, but weasels don't get sucked into jet engines!

[MikeK]

Thanks Steve for all the info. Steve.

In the absence of any other information, I'm going to use the Supersprint settings. Don't imagine that they will be too far off the mark!

Mike