Couple of interesting updates:
Looks like the oem trigger wheel on the crank timing gear will work with MS. Despite the 4 teeth being joined, it acts just like a 36-2 tooth setup under an oscilloscope. This is good news because a 36-2 setup is good for wasted spark without a cam position sensor and I do not need to modify anything.
Of course this all depends on if the oil pump and everything from a late afe block fits on the early 4afe block. But it should. I was able to make it down to the junkyard yesterday and pull a 96+ oil pump, crank timing gear and the vr sensor. I will be able to check the fitment of those next weekend.
While I was at the junkyard, I also grabbed a 1zz coil on a plug. I have heard that these are a good option for someone looking to retrofit a COP setup. They should work with the 4afe head if you sand down the outside insulation a little to make it slide in and out a little easier. I think this would be a cool upgrade but doesn’t really make sense right now. It would make wiring a little harder, not much, but a little. I’ve heard they don’t last as long as a separate unit because of the heat and lack of airflow which I kinda believe. It would make it harder to get a timing light on a traditional plug wire. But they also have their advantage as they would only be firing once per 2 revolutions. This allows it to have a better burn at higher rpm. Igniter dwell is something I still don’t totally understand but will look into later. I will probably wait to do this till the quality of burn becomes a limitation.
Also the adjustable cam timing conundrum. I did some research and found 2 possible solutions as an adjustable cam gear is not offered for the late afe. However, there are adjustable cam gears available for the 4ac which is the same as the early 4afe and there obviously gears for the 4age. Here is some background info:
Early 4af/4ac: ⅜” pitch, 18/36(crank/cam # teeth) teeth, .75” width, square teeth
Late afe: 5/16” pitch, 24/48 teeth, .84” width, rounded <- Has the trigger wheel we want
4age: ⅜” pitch, 18/36 teeth, .75” width, rounded
As you can see, the early 4afe and 4age are so close to compatible, but the early 4afe has square cut teeth on the belt and pulleys. This is relevant because a company offers a modified 4age crank gear that works with the 96+ oil pump and has a 36-1 trigger wheel on it. Since I have heard so much about people swapping 4age cranks into 4afe’s, I think it is safe to say the thickness and bore inner diameter of those two gears are the same but it is worth double checking. I also have a hunch that a 4age cam gear would mount up to any of the afe cams based on pictures but couldn’t find anyone online asking or confirming. We would obviously just use the exhaust one in that situation. So the two option are:
1: Use the modified 4age 36-1 crank timing gear with a single 4age adjustable cam gear.
2: Weld a trigger wheel onto the back of an early 4afe crank timing gear with the 4ac adjustable cam gear.
Both of these solutions would be around $200 but option #2 involves a little more time on the lathe and welder. However there is a little more room in option 1 for it to not fit. Sooo who knows. I think I will wait till I get everything running on the stock 96+ timing components for ease of setup. I also think that it would involve a lot more precision practices to time those 2 homemade setups without the original timing marks. So I will save that headache for later and stick to the stock stuff for now.
I will be finishing up my internship this week and heading back home for a tad so not sure how much progress I will be able to make until life settles down for a bit.
Excited as always, see ya
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