Lotus Elan

Rotor Arm 45 degrees out

PostPost by: ericbushby » Wed Apr 04, 2018 7:01 pm

Well not quite Ted.
It is a four stroke cycle isn`t it. Suck, Squeeze, Bang, Blow during two revolutions as they say.
Yes, that should work OK if you just put the rotor in the correct position. You will notice that as you engage the pinion with the lay shaft gear it rotates clockwise, so you will have to start a little anticlockwise, maybe about one tooth out in order to finish in the correct position. Play with it and see what happens.
Then fit ignition leads in the correct order for firing.
Just check this, but I think the rotor arm runs anticlockwise to fit the leads correctly. I will very soon be corrected if that's wrong.!
best of luck. let us know how you get on.
Eric
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PostPost by: tedtaylor » Wed Apr 04, 2018 10:39 pm

I got it sorted and it runs very well, however what a bear to sort out. I kept checking things, I even have two other Lotus in my garage to compare and EACH was slightly different from the others. distributor position, wiring, etc.
I kept setting up the timing mark on case cover, I even pulled #1 plug to make sure piston was up top, and found the rotor was 180 degrees (3 o'clock) position. I pulled and reset the rotor AGAIN. What was really unclear was which lead on the distributor cap should be #1, the lead "before" or "after" the rotor at 9 o'clock?? hard to explain, but I was really getting very frustrated, but determined to get it right. something so simple should not be so complicated!. Eventually I got it right and she fired right up, smooth, easy and sounded great! I'm happy now, but still a bit critical of the specific timing process with eliminating the guess work with the cap wiring, position, and firing order, clockwise, counter clockwise, and so on.....
hey, but I had fun !!! :lol:
TED
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PostPost by: ericbushby » Wed Apr 04, 2018 11:07 pm

The good thing is that when you get it right , you know it`s right and it feels good. Well done.
You can sort the others out now.!!
Eric
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PostPost by: billwill » Thu Apr 05, 2018 1:24 am

These are the normal positions of the spark leads.
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PostPost by: RogerFrench » Thu Apr 05, 2018 1:41 pm

tedtaylor wrote:i should clarify, that the distributor is pretty close to being in correct position, however it is the rotor that was positioned incorrectly (6 o'clock), so I guess i'll pull the distributor out far enough to turn the rotor to point more at 12 o'clock #1 plug and rewire the cap to the correct plugs via the firing order.

you said 1/2 speed? all I know is every time the crank turns a complete revolution, the pistons travel twice (once for firing and once for expelling), is that correct?


Almost. The next revolution of the crank will be once for intake and once for compression.
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PostPost by: tedtaylor » Thu Apr 05, 2018 3:06 pm

i guess that's my REAL question. How can you tell if the TDC/piston up is the fire stroke or not? I can't see the valves (that would determine - if both were closed)? it seems to me to be a 50/50 guess. Can anyone share the secret?

And I meant to say having the rotor more at 9 o'clock (rear hold down clamp) as opposed to 180 degrees and 3 o'clock. The service manual states to have distributor with low tension lead nearest the block and rotor facing rear most clamp.
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PostPost by: Andy8421 » Thu Apr 05, 2018 4:08 pm

Rest your finger across the plughole. As you turn the engine over, air will escape past your finger when the cylinder is on its compression stroke.
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PostPost by: alan.barker » Thu Apr 05, 2018 4:19 pm

Remove the Oil Filler Cap on the Cam Cover and look at the position of the Cam Lobe.
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PostPost by: tedtaylor » Thu Apr 05, 2018 5:39 pm

two very good suggestions (the first one I should have thought of myself) :D
thanks!
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PostPost by: SENC » Thu Jan 31, 2019 2:29 am

In replacing my distributor, I've found the current leads are inverted from BillWill's picture above (1 and 4 swap places, 2 and 3 swap places). Prior to messing with it, the engine ran ok - does that make sense that it would run? Should I go back to how I found it, or correct it? I have not turned the engine between removing the old distributor and installing the replacement, but if I correct the leads I presume I'll need to start from scratch with timing.
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PostPost by: oldelanman » Thu Jan 31, 2019 9:16 am

SENC wrote:In replacing my distributor, I've found the current leads are inverted from BillWill's picture above (1 and 4 swap places, 2 and 3 swap places). Prior to messing with it, the engine ran ok - does that make sense that it would run? Should I go back to how I found it, or correct it? I have not turned the engine between removing the old distributor and installing the replacement, but if I correct the leads I presume I'll need to start from scratch with timing.

The firing order is 1,3,4,2 so as long as the leads are connected to the cap in that sequence (anticlockwise) .. as yours are .. and your rotor arm points to #1 at TDC on the firing stroke, the engine will run just fine. No need to change it but having replaced the distributor you will need to check/set the timing anyway.
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PostPost by: billwill » Thu Jan 31, 2019 4:34 pm

My car has been renovated at least twice by professional firms and one of those times the distributor was replaced, so I can't be sure that my photo shows the original Lotus setup, but as said in the message above as long as the cables are in the correct sequence and the distributor is inserted so that the rotor is near number 1, it will work OK.
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PostPost by: SENC » Thu Jan 31, 2019 4:57 pm

Thanks for confirming. I was beginning to second guess my original thinking on this the more I read various threads.

Billwill - yours is the same order as what I've found elsewhere, including this article on lotusmarques, so suspect your is correct.

https://www.lotusmarques.com/info/techn ... rientation
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PostPost by: RogerFrench » Thu Jan 31, 2019 9:05 pm

tedtaylor wrote:i should clarify, that the distributor is pretty close to being in correct position, however it is the rotor that was positioned incorrectly (6 o'clock), so I guess i'll pull the distributor out far enough to turn the rotor to point more at 12 o'clock #1 plug and rewire the cap to the correct plugs via the firing order.

you said 1/2 speed? all I know is every time the crank turns a complete revolution, the pistons travel twice (once for firing and once for expelling), is that correct?


No. The crank makes 2 revolutions per cycle in a 4-stroke engine. The pistons go up twice and down twice. The 4 strokes are induction (down), compresssion (up), ignition (down) and exhaust (up again).
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PostPost by: 10kph » Thu Jan 31, 2019 9:40 pm

Make sure that the low voltage terminal on the distributor body is next to the block. You use a side entry distributor cap and you will find that access to the cap leads , clamping bolt are all accessable.Your rotor arm position at No1 firing can be at any lug but the lead then goes to No1 cylinder and the remaining leads follow the firing sequence
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