The Lotus Grand Tourers

Hi all. This might be a silly question, but I am going to ask it anyway, as I cannot find a post about it elsewhere in the forum. Having put a recon distributor on my Excel SE 912, I am in the process of setting the initial mechanical timing as laid out in the service book (image below), with the crank set to 10 degrees BTDC (timing marks lined up). However, the rotor arm notch is actually facing 180 degrees off from the diagram in the book (blue arrow I have added to image). I tried, removing, flipping and resitting the distributor shaft, but it just wouldn't relocate, so I put it back to the arrowed position. Looks like it only fits one way.

So, my question is... Assuming the reluctor is lined up correctly with the pickup, should I just check the spark plug leads are in the correct firing order, starting from the distributor terminal the rotor arm points to and not panic? This seems like a logical approach, but thought I better put out there and see what response I get, just in case should be persisting with flipping the distributor spindle 180 degrees.

BTW - The engine did work 14 years ago, but had sat still since then. Other than needing to replace the distributor the mechanical timing has not been touched at this point - though I know a timing belt change will be needed.

Thanks for your wisdom!

Sounds to me like someone has put a new cam belt on in the past and got the oil pump / dizzy shaft 180 degrees out.
The drive dog is offset if I recall correct, so my thinking is it has been timed previously as you are now intending.
Your thoughts about timing sound right to me and I'd give it a go. Worst case, engine won't start because it's sparking on the exhaust stokr.

Tony

Yep - sounds like the aux pulley is set on the wrong stroke, as Tony said.

Pete

If you have got it based on camshaft (seemingly unlike the person who put the belt on), then just set the plug leads 180 deg out on the cap, the leads will still reach.

Thanks all - sounds like I was thinking along the right lines. Will see how I get on, and get things the right way round when I change the timing belt. Hoping to get it started so I can work out where a coolant leak is and deal with everything in one go when the bonnet comes off. Duncs

LotusMonkey wrote: ↑

Sun Jan 08, 2023 16:37

..and deal with everything in one go when the bonnet comes off. Duncs

Disconnect the earth lead first, that caught me out the fiirst time

Marten wrote: ↑

Sun Jan 08, 2023 18:03

LotusMonkey wrote: ↑

Sun Jan 08, 2023 16:37

..and deal with everything in one go when the bonnet comes off. Duncs

Disconnect the earth lead first, that caught me out the fiirst time

Chemistry has taken care of that one for me, as the bolt it was connected to had rusted to a point where it sheared on the last attempt anyone went at it

I would forget the distributor for the moment and get the cam belt changed ensuring the dots on the cam pulley's line up at TDC and the Aux pulley is close to the diagram below. The aux pulley doesn't have to be exactly spot on as you can dial out any error with the distributor but the rotor arm should be pointing towards no 1 plug lead.

Yes thanks - have that diagram on my radar from my service book

And don't forget the orientation of the tensioning hub itself.

Pete

Lotus Monkey, I think you are right as I have been caught out by this too. The drawings in the manual are incompatible in that the one for the pulley alignment shows the keyway in such a position that the slot for the dizzy rotor arm is 180 degrees out. As they are on each end of the same shaft you cannot set the shaft to fit both drawings.

It really doesn't matter. Ignore the marks on the auxiliary pulley its only the dizzy end that matters.

.... Good to know someone else has experienced it. As you say, it doesn't really matter as long as the firing order is synched. I have found that the inlet and exhaust cams were slightly off of alignment through doing this change, so good that I am going back to the start and setting initial timing through the dots, rather than marking up the belt method. Just working out a puller to get the v belt cam pulley off - space is tight so might undo some of the oil cooler bolts so I can swing that back slightly. Then I'll be able to see whether then tensioner bearing just needs cleaning up or replacing.

I know a very late reply. Are the camshafts in alignment. Remember 2x crank rotation for 1x cam rotation. You may not be at 10deg on compression on no.1 cylinder which would make you exactly 180deg out.

mac2 wrote: ↑

Wed Aug 16, 2023 10:00

I know a very late reply. Are the camshafts in alignment. Remember 2x crank rotation for 1x cam rotation. You may not be at 10deg on compression on no.1 cylinder which would make you exactly 180deg out.

Thanks. As of last weekend, the belt is on and the timing reset, including repositioning the auxiliary cam, so that it is 'textbook' Great to have her running and left her going for a good hour, where she got to 90 degrees and sat tight. Carb balancing next, so I can get the f-pipes back on and test the advance properly.