lotus Twin Cam distributor

[Guest]

Dear Fellow members

 

I have a Caterham 7 with a Lotus Twin Cam, Tall block running off twin 45's and producing around 150 bhp.

 

I have developed a flat spot above 5,000 rpm, almost like it's hitting a rev limiter. It looks to be a problem with the distributer. I've checked leads spark plugs and they are all good. I have had previous non spark problems.

 

I am looking at ideas on a replacement distributor/ignition replacement.

 

Any suggestions please?

 

Many thanks in advance.

 

 

 

Sent from my iPod

[elan_fan]

QED should have all the springs and weights if you want to diy. A chat with Ken will prob be a good idea as he will tell you who might do a rebuild.

What about electronic. Trigger wheels do a kit using a mega squirt. Or theres an omex.

 

[elie boone]

Aldon Can surely help you, if you give them the cam spec they can adjust the advance curve accordingly.

Do you have a mechanical fuel pump or electric ?

[Golf Juliet Tango]

Quoting elan_fan: 

What about electronic. Trigger wheels do a kit using a mega squirt. Or theres an omex.

It would be a shame to do this to a twink, surely?

[Nigel Fox]

Has the rotor arm got a centrifugal rev limiter that has become faulty?

[Jonathan Kay]

What's your current (!) ignition system?

 

Jonathan

[Roger King]

Ditto the comment about the centrifugal (centripetal?) rotor arm. Twincams used to be fitted with them and they're a bit vague to say the least.

 

What makes you think it's ignition though? A common reason for an engine feeling like it's hit an artificial rev limiter is a broken valve spring. Worth checking if you aren't certain.

[pugwash]

The twin cam in my elan looks stock but it does have an Aldon ignitor hidden under the dizzy cap. Makes life a bit easier.

 

As a quick fix, try changing the rotor arm. I had one where the rivet on the top was too long and when it got hot it would allow the spark to "leak" straight through to earth onto the dizzy spindle. Took a while to figure out as it started intermittent as a lack of power at certain revs (that bogging down feeling) but when hot would just cut the engine. If you left the car to cool down for 30 mins it would start fine, up to the time it did not! A bit of research found there had been a quality problem with them, so I now carry a spare just in case.