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2GRFE Crank trigger offset


CDNMR2V6

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I'm having a bit of trouble setting this, although I'm pretty sure I've got it. The timing marks on this engine are in a very awkward spot once you put it into an SW20 MR2 chassis. As I mentioned, I think I've got it, but I was curious as I've been reading all the 2gr related threads in this forum and it seems like different people all have a slightly different trigger offset at the same reference timing (usually of 10°, which is the hardest mark to see).

 

Now, shouldn't all 2gr engines have exactly the same trigger offset? Further to that idea, shouldn't they all have the same cam offset as well?

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As for trigger offset I would expect most to be quite similar but a manufacturing tolerance of about +/-4 deg is pretty average in my experience.  If you see more than that then I would be checking crank sensor polarity and spark edge etc.  You really need to confirm on every engine.  Sometimes that means painting a new mark somewhere that is easier to see or using a mechanics mirror or snake cam to see the marks.  GT40's are real fun. 

Cam offset is a different story as there is much more stacked error involved.  Deck height has a tolerance, cam belt length has a tolerance, cam pulley and camshaft keyway indexing, cam trigger wheel indexing, cam tunnel placement relative to deck height, idler pulley and tensioner placement, etc.  Even just skimming the heads or deck surface during a rebuild changes the cam offset. 

 

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to do the timing on my 2GR we bolted a pointy piece of aluminium onto the timing chain cover behind the crank pulley so we could time it by looking at it from a different angle. This did mean we had to make a different mark on the crank pulley to suit based off of cylinder 4 (was easier to get to than cylinder 1) top dead center. 

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I found top dead center for cylinder 1 using a dial indicator (with the intake manifold off). Then i made a new mark on the crank pulley near where the oil level sensor would go. I tapped one of those holes and put a bolt in it and put a notch in the bolt to act as the new "0" location for a new timing mark. 

I read the the other threads as well and it seems like there is a major difference between where people's trigger offsets end up. A few threads said theirs fired perfectly around 200 offset. That was 360 degrees (exhaust stroke) for me. So my offset ended up being -160. I can post a picture of the setup tomorrow. Hopefully this helps other people who search this info later.

 

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