Lotus Elan

Rev limiter

PostPost by: Robbie693 » Fri Jun 25, 2010 6:10 pm

Hello,

My rev limiting rotor arm is suspect as it seems to be cutting out at around 5500 rpm but varies a bit. I had a look to find the part number and noticed that on it is stamped 3500rpm, which presumably means the cut-out is supposed to operate at 7000 (250rpm too high for a Big Valve engine).

Can anyone tell me if this is the correct part? Part number is 54425701

Thanks

Robbie
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PostPost by: Robbie693 » Mon Jun 28, 2010 8:40 am

Ummm? No one :cry:
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PostPost by: terryp » Mon Jun 28, 2010 9:30 am

Robbie
I'm sure that someone else would know better but I would not want anyone to be :( (I have Lumenition Rev Limiter and standard rotor arm)
I think they can be adjusted slightly
see elan-f14/adjusting-rev-limiter-t20425.html

All the best
Terry
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PostPost by: Robbie693 » Mon Jun 28, 2010 10:50 am

Hi Terry,

Thanks for sparing my :cry: , I did see that post and it was partly what triggered my question; in that it was mentioned that the limiter was 3250 rpm, which sounded correct for the small valve engine and with mine saying 3500 I began to worry that I had a too high a cut-out. As it seems to be cutting out on me I am left with the options of either the cut-out is too soon, or the rev counter is inaccurate. I which case I was hitting 7000rpm which isn't good. Didn't sound that high I have to say though.

So I was wondering if anyone had a rotor arm like mine with 3500rpm stamped on it so I could attempt to find out if I had the right one. The Big valve engine red lines at 6750rpm so presumably the rotor arm should be 3375rpm but I've never seen one like this..

Maybe everyone has standard rotor arms now. With, hopefully, accurate tach's!?

Cheers

Robbie
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PostPost by: oldelanman » Mon Jun 28, 2010 11:02 am

Hi Robbie,
A "standard" one marked 3250rpm sold on ebay recently and the part number is different from yours - 5441216?. Can't see it clearly in the photo but if you zoom in you can definitely see it's not the same as yours.

Link here....http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160442404708&ssPageName=STRK:MEWAX:IT

Doesn't help identifying the correct one for your engine but at least you know which one you don't want I guess.

Regards,
Roger
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PostPost by: billwill » Mon Jun 28, 2010 1:05 pm

Presumably one could reduce the limiting speed by putting small (heavy) washers under the screws?
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PostPost by: terryp » Mon Jun 28, 2010 1:09 pm

Robbie
Just had a walk to the garage and found the old rotor arm I took out of the distributor from my big valve engine a while back
Rotor arm is 54424982 3500RPM

I think that may be the original?

Terry
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PostPost by: Robbie693 » Tue Jun 29, 2010 9:13 am

Hmm, well it looks like I have the wrong part but the correct rpm limit. The plot thickens.

I guess I could always get a standard rotor arm and have the rev counter callibrated to be sure, but that will mean no driving for a bit :(

I have heard about adding/subtracting weight to change the cut-out but how it's done accurately I've no idea.

Thanks for the help guys - much appreciated

Robbie
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PostPost by: oldelanman » Tue Jun 29, 2010 12:56 pm

I have heard about adding/subtracting weight to change the cut-out but how it's done accurately I've no idea.


This bloke might be able to calibrate it.....

http://www.distributordoctor.com/

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Roger
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PostPost by: Robbie693 » Tue Jun 29, 2010 1:06 pm

Thanks Roger, I'll send them an email.

Cheers

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PostPost by: Frank Howard » Tue Jun 29, 2010 2:23 pm

Robbie693 wrote:I guess I could always get a standard rotor arm and have the rev counter callibrated to be sure, but that will mean no driving for a bit :(
Robbie,

If you remove the tach and connect the two white ingition wires to each other (one has a male connector and the other has a female connector), you can keep driving while your tach is being callibrated.
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PostPost by: Robbie693 » Wed Jun 30, 2010 8:43 am

Cool! Thanks Frank

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PostPost by: bob_rich » Wed Jun 30, 2010 7:59 pm

Hi

on the rev limiter on my +2S130/5 factory date of 73 12 the rev limiter has a part num,ber 54412165
3250 rpm. Hope that helps but fee; it may add to the confusion!!

I am not original owner and it does not have he original engine. It has been rebuilt on a 711M tall block twin cam engine

best of luck

Bob
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PostPost by: Robbie693 » Thu Jul 01, 2010 8:53 am

Thanks Bob,

that correlates with the one Roger found on ebay but yes it does add to the confusion! Still wondering why I have a 3500 (7000rpm) cutout.

QED have one with a 3250 cutout, I need to talk to them to see if they know of the other type.

Cheers

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PostPost by: billwill » Thu Jul 01, 2010 12:33 pm

This is a LOTUS we are talking about right?

The factory probably fitted whatever was available and adjusted it to suit.
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