Leeroy_25

Hi guy's I cannot seem to find anything online and want to check the ignition timing on my 20B motor. I have swapped over to FD pullies but took the marks off my 20B ones and copied them across so I have that ready. I am just not sure how to go about it as I have never timed a rotary before. Also not sure what timing I should be looking fort as I have read various different things on the info I have found online? I also am not 100% sure what the marks on the 20B pulley relate to so some pointers there would be great too please or if someone has the relevant page of a 20B engine manual that might do the trick!

Thank you
Lee

hsmidy

Factory pulley marks are 5 degrees ATDC and 20 degrees ATDC.
Have you statically timed the engine?

Leeroy_25

I haven't touched the timing. It cane straight out of a donor car as a running engine.. I just want t ok check it out and I am not entirely sure what I am doing it looking for!
Is there only two marks? No TDC? I will double check the pulley later. So am I right in thinking kne will be for leading timing and one for trailing? I read something about 17degrees max timing and 4-5 degree per rotor split. Wasn't sure what that meant. Could just be a translation mix up?

hsmidy

The first mark that comes around when rotating the engine in direction of rotation is the leading mark and the next is the trailing.

Factory timing gives you a 15 degree leading/trailing split.

Correct if its a factory pulley it wont have a TDC mark.

No if you have used an aftermarket ECU you will want to look into their timing instructions. Other wise timing the engine front the CAS is no different to any other.

stickmantijuana

iTrader: (1)

All good points. Here's my take on it. I would first make sure you have 20B main pulley before you look at its marks for timing. Lot of people with 20b use FB, FC, or FD pulley or some franken combination. Marks on those pulley will not give you accurate timing depending on which pulley hub is on the engine. The easiest way I found was take the front nut/pulley off to look at the keyway. It should point toward passenger side at TDC. Put the car in 5th gear with side brake on, and take it off with 32mm socket + breaker bar. There are other ways to do it but imho they are impractical as I tried them all including measuring rotor distance from spark plug holes, etc. The easiest way I found was taking the front pulley off and using the keyway to mark the pulley. Good luck.

Leeroy_25

Thanks for the info guys. Just to clear up. I am using after market pulleys for an FD. But I mounted the FD trigger wheel on the hub with the 20B pulley and transferred the marks across. So the timing marks on my FD pullies should be accurate for the 20b.
So do I connect my timing light to the number 1 leading and trailing plug leads in turn and check the corresponding timing marks?
And to clarify I am looking for timing of 5degs and 20 degs?
When you say about statically timing the engine. Is that just to check the tdc and timing marks on the pulley are correct?

Cheers
Lee

hsmidy

If you have accurately transferred over the timing marks there should be no difference between your current setup and the factory setup.
Statically timing your engine is referring to timing your CAS to your engine.

Correct leading and trailing HT leads with reference to your pulley marks, you may need to put the engine into service mode to lock the ECU out from adjusting the timing while you're making any yours.

stickmantijuana

iTrader: (1)

No that will not work. If you are using 20b Hub, you need 20b pulley. If we are using FD hub, you need FD pulley/wheel. If you're mixing them, they may bolt up fine, but the mark will be off. Either get a matching pulley and hub or take it off to look at the keyway directly.

Leeroy_25

The static timing is the bit I am not sure about. Is there a marking in the CAS somewhere that refers to TDC or L1 or something? I was told I could rotate the engine by hand with L1 plug out and look for a spark. When it sparks see where the pulley is l I need up?
Stickman, I bolted the FD trigger wheel to the pulley hub same time as the 20b pulley and transferred the timing marks from one to the other. The marks have to be in the correct position?

Cheers
Lee

hsmidy

Sorry can you just confirm for me that you are still using the 20b front cover. And that you are still using the factory 20b CAS.
As these two things will make a big difference to the correct information that you're after.

Leeroy_25

Yes.. That is correct. Still have the 20b front cover and CAS.
Thank you
Lee

hsmidy

Unsure as to why you have used the FD trigger wheel though. On the 20b CAS there will be a dimple on the driven gear and a pointer on the CAS body down by the gear...these need to be aligned when installing the CAS. Rotate the engine until the leading mark is in line with the pointer on the front cover and then install the CAS.

Your engine is now statically timed.

I cant stress the importance of the need to have accurate timing marks on the crank pulley. This is what Stickman is talking about, if you just interchange hubs and pulleys they do not align correctly. Because you have transferred marks...if you were accurate then you should have this issue.

Leeroy_25

Thanks for the info.. I will look inside the CAS and see if I am in the ball park tomorrow. Ahh.. That said, I see, I would have to pull the CAS out to check that? Nothing under the CAS cover? I am pretty sure it would have been installed correct. it all runs and starts fine. I just want to check the actual timing. If I get some funny readings then I might look at it further into it.
The reason for the 13b trigger wheel is simple. The FD pullies are smaller that the 20b ones and sit further away from the timing mark. The 13B trigger wheel is however the same size as the 20B pullies and sits right back inline with the pointer on the front cover. So this should make for easier more accurate timing readings! I am pretty confident my marks are bang on.. But I could be wrong. Always wise to check!
There must be a better way than trying to line the keyway up at 90degs to the left? (I presume that was a US passenger side and not a RHD UK one?!) You could easily be a few degrees out lining that up by eye. I assume TDC is like a piston engine. i.e the point where combustion peaks. so how about put a compression tester in one of the plugs. with the valve removed and rotate the engine until the pressure peaks and then starts to drop? There must be an off the shelf TDC finder like that? If not I call copyright on any such design!

Cheers
Lee

hsmidy

UK or US it doesn't matter, as it is setup to the 9 o'clock position when viewed from the front.
There is a thing called a compression whistle that can be screwed into the sparkplug hole and as you come up to TDC the air being forced out causes it to whistle, as soon as it stops your at TDC.

I cant really guide you on what to look for under the CAS cover once installed as this will depend on a couple of things.

1. As you install the CAS the shaft will rotate (because of the helix on the gears) changing its position (mine isn't installed at the moment)
2. The body of the CAS is adjustable in relation to the shaft, this will be vehicle specific as to where you have your timing adjusted too.

I would speculate that once installed and the CAS cover removed the upper most reluctor would be inline with its pick-up.

Also what ECU are you running?

hsmidy

Found this, you may find it of some use.

https://www.bing.com/images/search?q...2o0&ajaxhist=0

Leeroy_25

Thanks for the info mate.. Should give me a starting point. I thought the CAS must move a bit if it was the same as old ones I had seen before. I imagine if you were a tooth out it wouldn't run right at all? But worth checking to be sure.
Then I can check my timing marks. I assume you adjust the CAS to set one of the timing marks and the other is then governed by that until you start messing with the ECU settings? I have a microtech LTX-12 by the way.
Thanks
Lee