For anyone that hasn't followed my build thread in NA performance, I have a 20B PP that I have slowly been building.

I ran into a strange issue after going to the dyno and making little power (275whp). After some searching i have found an issue with the timing I had set.

I have used the FD front cover with a FFE trigger wheel. Where I went wrong (or misunderstood) was that I bolted that FD trigger wheel to the 20B pulley hub. I did not realise that the 20B pulley hub bolt holes are not at 180/360 deg (like the FD) when the engine is at TDC.

The 20B bolts are are instead at an angle of roughly 165/345deg. I used the oil in chamber method to find TDC and marked the trigger wheel for TDC.

I am not 100% on the angle being 15degree out. What I was hoping is if someone out there with a 20B pulley hub, could measure the angle of the vertical bolt holes when the keyway is at the 9 o'clock position (TDC). It would be much appreciated if someone could either do that, or supply that information.

Cheers.

 

WTF???? I think I did the same thing you did. I currently have the 20b pulley with the 3rd trigger.

 

Hope this helps,

Chris from Banzai took these photo's!

 

Hey mate, thanks for the pic. Unfortunately, it was that picture that clued me onto the bolt holes not being vertical in the first place!
I need someone to actually measure a pulley, or at least take a picture that is perfectly front on, so I could try to measure the angle on screen.
Thanks again though and awesome work with your car!

 

If you can wait a couple of days (till the weekend) I'll dig up an e-shaft and front pulley and do some pictures and a rough angle with a combination square.

 

That would be great! Yeah no rush here. I have adjusted the motor to TDC and marked the pulley, but it would be nice to have the actual measurement.

 

Im lost here I understand you are asking for measurements but all you need to do is put the keyway at the 9oclock position then mark your pulley to match the mark on your cover. Then when you set timing in the ecu just lock it in at 0 and check with the light. If its off then set your offset till your light matches your mark on your pulley to the mark on the cover.

 

Also keep in mind a actual measurement will only work on the hub not on the pulley since the difference in diameter between 2 pulleys will not equal the same measurement for the same mark locations. Hope that makes sense.

 

Gday. The reason I am asking is because the engine is already built and running in the car and I do not want to release the front nut to check the keyway. Also setting the keyway at 9oclock is still a guess. I don't have my original pulley anymore so I can't just use that.

What I have done is found TDC with the oil method and marked the trigger wheel. Then using the Link ECU I have set TDC to that mark. However this still isnt 100% accurate.
What I am asking is someone to actually measure the degrees of offset between the the 12oclock position and the position of a line drawn through the the pulley bolt holes (which on the FD are straight up and down, but are not on the 20B), when the keyway is at the 9oclock position.

I'm not asking for a measurement in mm or inches.

Even a photo of the pulley hub taken directly front on would allow me to measure the angle.

Hope that makes sense.

 

Took some pics that might help. Here is the FD trigger wheel lined up on its TDC mark.
As you can see the bolts line up straight up and down, just like the FD at TDC.



Now here is the actual TDC as measured with the oil in the chamber method.

 

Here you go, also included the stock FD timing wheel with the 20B timing marks

 

Banzai, your a legend thank you very much!

From searching the forums, I hope that a lot of people see this, because there seemed to be a lot of people out there who had made the same error and some didn't even know it!

Thanks again.

 

From measuring that picture I got 14deg. Which is good to know as that is exactly where I marked my pulley at TDC.

 

So 14 deg difference from fd tdc to 20b tdc?

 

Only if bolting a FD pulley onto a 20B pulley hub.

Even though the bolt holes are the same pattern, the FD pulley hub has the bolt holes vertical at TDC.

As in the pics, the 20B pulley hub bolt holes are at 344deg (as best as I could measure).

I don't know if there are any variations, but mine is definately like this.

 

think about how many 20b FD guys didnt get the numbers they expect and just lived with it... or gave up on their work...

dumb question. is this avoidable if you just use the FD hub/ fd pulleys. instead of the 20b hub? i've formed a good habit of leaving the pulleys on the hub for... reasons.

 

^Apparently so. If you decide to run the fd Trigger setup, make sure you also run the fd pulley hub. I made this exact same mistake back in 2009 when I 1st built my 20b by using the 20b hub with the fd Trigger wheel. As soon as I get home from Sevenstock, I'm pulling and changing the hub back to the 13b and re-zero the timming. This may explain why my car hasn't felt as strong as I thought it should have.

 

That will be interesting to see the result t-von. So I guess the 20B and 13B-REW pulley hubs are interchangeable then? (Not withstanding the pulley bolt pattern obviously)

 

The hubs are also different thicknesses. The 20b is thicker thus offsetting the pulley so keep that in mind also

 

There is no difference in hub thickness, dimensionally the FC, 20B & FD are the same, FD just has alignment pins.



Here is the FD timing wheel on each of the hubs

 

So I pulled off my hub and this is what I find!


Pulley on the right is what came off my engine. So apparently I did reuse the fd hub. It was back in 2009 when I 1st built the engine. While it was off I decided to line up the key way to 9'oclock and mark TDC on the wheel. The mark I put on the wheel matches the red mark on Banzai's above pic. So Banzai, what is the yellow mark for? My pulley only has the notch on the far left. The red and yellow marks don't exist on mine. I have a Haltech E11. When I zeroed my timing, I used that factory notch and locked timing at -5.0 BTDC

The info I used to zero my timing came from this thread here:

see #5 in the 1st post for the trigger info I used.
https://www.rx7club.com/haltech-foru...p-tips-850059/

During the zeroing process timing was locked at -5.0 BTDC
Split was locked at 15.0
Trigger angle BTDC was 64.0

Now I'm wondering if I used the wrong mark to zero my timing?

 

I added the 20B timing marks to the FD wheel. Leading and Trailing.

 

Is this picture using the 20B or FD hub? To recap the timing difference is only when running 20B hub + FD timing wheel correct?

Thanks in advance

 

Sorry to drag this back to the top.. But I have a timing issue I have my own thread running on and this has most of the pictures to discuss around. Really hoping Banzai Racing can respond to clear up some things.
So quick recap. My engine is in and running and seems fine. Just gets a bit warmer than I expected and turbo spool was a bit slow. So I was advised to check the timing. I have never moved the CAS. The only thing I have done is swap the 20B pulley for a 13B trigger wheel. On to the hub that was already on the engine.
The marks were copied from one pulley to the other by bolting them together on a hub so I am confident the marks are right. at the end of the day this could be done off a hub as long as they are lined up and bolted together through the 4 bolt M6 holes. That said I notice my marks are not in the same place on my trigger wheel as the image that banzai show. I would say they are around 7-10 degree further clockwise from the 13B timing notch. So it would be good to confirm how those marks were derived and what pulley/hub combo that is based on.

So When I check my timing it comes up at 15-20 degrees advanced on L1. CAS seems to line up fine if I can rely on the timing marks and there is not quite enough adjustment to pull the timing back in. I have tried two timing lights and they both show the same thing. Also when you adjust it back it starts to sound a bit rough like it doesn't like it.

I wonder if maybe I have an FC 13B hub on the engine that was fitted by a previous owner as looking up the page the bolt to keyway position looks similar to the 13B FD? Can someone confirm if that is the case or is the 13B FC a different hole pattern again compared to the keyway.

It seems to work out the 13B holes and 20B holes are around 15 degrees off from one of the posts. So that could tie in with my timing maybe? although I cannot get my head around if the 20B pulley on a 13B hub would make the marks show advanced or further retarded timing?

Point to note is if I align my timing marks and then turn the engine by hand and feel for the peak compression-exhaust point I get pretty much the bolt alignment shown in F1pilots post. i.e TDC on my pulley is with the bolts near vertical and engine feels like this is about 15-20degrees away. I know not super accurate but a guide at least. and I found the images after doing the test.

So the other query is the post from Monsterbox shows the 20B hub on an e-shaft and presumably a 20B hub. The Trailing and leading marks highlighted are say around 15-20 degrees before vertical with the keyway at 9 o'clock. This is supposed to be how you find TDC on the 20B right. However the timing pointer on the front cover is something like 5-10degrees after vertical so there is no way the timing marks would be in the correct place? What am I missing? To note also the TDC I can feel by hand would put my marks where Monsterbox E-shaft assembly shows if you imagine that in an engine.

So what is going on? Is there a different front cover. Is the 9 o'clock keyway position not related to the timing pointer on the cover and only for stabbing in the CAS. That really doesn't make any sense though!

As my engine is in the last thing I want to do is undo the hub bolt as I have heard horror stories about damaged bearings and things.

Please help me get to the bottom of this and help our future fellow 20B owners!

Thanks
Lee

 

Pictures are worth 1000 words., my guess is that you marked the FD trigger wheel incorrectly, probably held the main pulley against it incorrectly, since the 20B is inverted.