Adjusting rev limiter

[Heuer]

My rev limiter is cutting in at 5,500 rpm if the tach is to be believed. I tried bending the rotor arm finger contact but it had little effect so I was wondering if removing one of the three screws on the slider would be a better option. It looks like they are there to add mass so I guess less mass means a higher rpm before the centrifugal force causes the slider to move. Anyone had experience with adjusting these. It is a genuine Lucas rotor arm and I notice it has 3750rpm stamped on it.

[gerrym]

Heuer. 3750 RPM for the distributor = 7500 RPM for the crank which sounds a little ambitious for a Twink.

Rather than experimenting (how will you test the setting?), would it not be possible to send it to a distributor overhaul specialist ?

Or if fitting electronic ignition, use one that has a rev limiter in-built. This might also give a soft cut-out.

My own experience is of a cut-out incorrectly calibrated. A gear mis-change caused broken valve springs.

Regards

[curly type 26]

Its prob 3250 = 6500 or 3275 you can still buy these cut outs new from the usual sources. sounds like weak springs allowing early cut i wouldnt mess with it just replace or fit one of many electronic cutouts with standard rotor good luck Curly

[Heuer]

Yep that was a typo, 3275 is the correct number.

OK I am new to all this (only had the car for a week) so where can I get a new (Lucas) cut out rotor? I am used to being able to get E-Type parts from SNG Barratt, Hutsons, M&C Wilkinson, SC Parts via their web sites at the drop of a hat but the only places I can find Elan parts seem to be in the US or Australia.

[Galwaylotus]

There are a number of Lotus specialist suppliers in the UK.
Try Kelsport (Pat Thomas), Fibreglass Services (Miles Wilkins), Paul Matty, Christopher Neil, just to name a few.

[innesw]

SJ Sportscars, Susan Miller (Mick Miller Lotus), Syper Engineering and Tony Thomson Racing to name a few more...

Innes

[Heuer]

Wow - thanks, keep them coming!

However ................... no one seems to list the correct rotor arm. Is this part made of unobtainium?

[bill308]

I have not used or knowingly seen one of these devices, but adding mass would be expected to reduce the rpm cut in.

Over time one would expect the spring to fatigue and the system would cut out sooner. Assuming the action works on centripetal force, adding mass will decrease the centreptal force (strickly speaking works against the spring force) and causes the system to act sooner, i.e. at a lower rpm. A stronger spring rate or lighter mass would have the opposite effect.

Bill

[scottlong1]

I have the same rotor on my elan and the springs do indeed weaken over time. The 3 screws are used for mass, just remove as others have said to increase the cutout rpm. I adjusted mine by this method long ago. The change to the cutout wasn't drastic from what I recall, maybe 3-500 rpm.

[richardcox_lotus]

My understanding was these were no longer available new. They come up on ebay from time to time, but then of course there is no guarantee they will work any better than your current one....


Richard
'72 Sprint

[types26/36]

My understanding was these were no longer available new.Richard
'72 Sprint

S & J list a non limiter and a limiter rotor but it has a "907" part number although I found them with Elans in the search box, probally best to phone first to make sure it fits a TC engine.

ROTOR ARM (For 23/25D type. Not rev limiting) SJ907E0015

REV/LIMITER ROTOR ARM SJ907E0012

[freddy22112211]

I too removed the screws - but it didn't make much difference.
Gordon

[collins_dan]

I've used the pertronix rev limiter with good success.

http://www.pertronix.com/prod/ig/drl/default.aspx

With the value of these engines and the likelihood of inadvertent overrevving quite high, its well worth it to have a rev limiter that you have confidence with do the job when required.

Dan

[ricarbo]

If you are interested, I can test this for you and tell you at what speed it operates. The way they work is that the weight overcomes the springs abruptly, so that the brass part slides out and hits the post. Until it reaches the critical speed, it doesn't move noticeably. When it reaches speed it flips out. So, bending the post won't help. If you posted it to me with a prepaid return envelope, I would do this same day at no charge.
Regards
Richard

[ricarbo]

Just to correct myself before someone else does. The part that moves is not brass, but aluminium colour with three screws in it. My apologies.
Richard