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Thread: Anyone know the difference between rotor head designs?

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Posts: 1-10 of 14
2014-09-25 22:07:55
#1
Anyone know the difference between rotor head designs?
The other day I was looking up replacement rotor heads for my dizzy and noticed there are at least 2 part numbers for the same application. I ordered up 2 of them that came in today and it looks like the contact strip on each is different. I am not sure what purpose the differences serve. Does anyone have any input on if one is better than the other or why one is coated in a black material and the other is not?



2014-09-25 22:36:46
#2
the black material will scrape off, possibly to protect it from arcing better?
2014-09-25 22:44:04
#3
Originally Posted by NSMO240
the black material will scrape off, possibly to protect it from arcing better?


IDK it is weird
One is 22157-0M512 and the other is 22157-0M513

I just noticed that Nissan also shows 22157-54C01 as another possibility for a rotor head on the SR20 dizzy
2014-09-25 22:48:49
#4
Lowport and highport use a different style rotor to connect to the rotor shaft. The highport has a small bolt with an hex head on it and needs to be tightened into place. That is where the infamous "wayne cox hp trick" came from. The lowports just kinda press onto the rotor shaft and do not use a bolt to hold the rotor to the shaft.

I have no idea what the differences are in those since they are afterMEHket and not OEM.

OEM rocks.
Last edited by Kyle on 2014-09-25 at 22-50-48.
2014-09-26 06:19:06
#5
I ordered a rotor for a 99-01 G20 to modify my VE distributor from the dealer and received the rotor in the Ist pic. Don't know if Nissan is cheaping out on OEM but it's working fine per Vadim's mod.
2014-09-26 06:29:31
#6
Re: Anyone know the difference between rotor head designs?
I bought a 99-01 G20 rotor to replace the VE rotor per Vadim's mod for the VE distributor. Rotor looked just like the 1st pic, this was from the dealer. Don't know if Nissan is cheaping out on OEM on most of their replacement parts but the rotor is working just fine.
2014-09-26 14:29:41
#7
Originally Posted by Kyle
Lowport and highport use a different style rotor to connect to the rotor shaft. The highport has a small bolt with an hex head on it and needs to be tightened into place. That is where the infamous "wayne cox hp trick" came from. The lowports just kinda press onto the rotor shaft and do not use a bolt to hold the rotor to the shaft.

I have no idea what the differences are in those since they are afterMEHket and not OEM.

OEM rocks.


what is this mod you speak of?
2014-09-26 15:05:51
#8
Originally Posted by Kyle
Lowport and highport use a different style rotor to connect to the rotor shaft. The highport has a small bolt with an hex head on it and needs to be tightened into place. That is where the infamous "wayne cox hp trick" came from. The lowports just kinda press onto the rotor shaft and do not use a bolt to hold the rotor to the shaft.

I have no idea what the differences are in those since they are afterMEHket and not OEM.

OEM rocks.


The pictures are just ones I found on the internet but I have oem parts here that I am comparing.
I must have overlooked it but didn't see a threaded hole on either rotor head.
2014-09-26 15:31:58
#9
Originally Posted by HP10T
Originally Posted by Kyle
Lowport and highport use a different style rotor to connect to the rotor shaft. The highport has a small bolt with an hex head on it and needs to be tightened into place. That is where the infamous "wayne cox hp trick" came from. The lowports just kinda press onto the rotor shaft and do not use a bolt to hold the rotor to the shaft.

I have no idea what the differences are in those since they are afterMEHket and not OEM.

OEM rocks.


The pictures are just ones I found on the internet but I have oem parts here that I am comparing.
I must have overlooked it but didn't see a threaded hole on either rotor head.



It has been a long time since I last changed the cap and rotor but I am pretty sure the shaft of the distributor is threaded to accept the bolt and there is some sort of provision for the hole or some slot on the rotor whereas the lowport design is 360 degrees around the distributor shaft and simply "clicks" on.
2014-09-26 15:46:36
#10
Originally Posted by NSMO240
Originally Posted by Kyle
Lowport and highport use a different style rotor to connect to the rotor shaft. The highport has a small bolt with an hex head on it and needs to be tightened into place. That is where the infamous "wayne cox hp trick" came from. The lowports just kinda press onto the rotor shaft and do not use a bolt to hold the rotor to the shaft.

I have no idea what the differences are in those since they are afterMEHket and not OEM.

OEM rocks.


what is this mod you speak of?


"The distributor shaft has several pieces screwed together that the rotor mounts on. There is some slop in them. If the slop all stacks up in the same direction, your rotor may not be optimally aligned with the electrode inside the cap when the ignition fires. Having your timing advanced through mechanical adjustment and/or an ECU will aggravate the problem.

"Here's what'cha do: Remove dist. cap. Remove rotor; be careful, if your rotor is stuck on the shaft *do not* twist too hard on it. You can break it like I did There's a screw in the end of the shaft - loosen, twist counter-clockwise against the bolt slop and retighten. Put the rotor back on and twist it counter clock wise while tightening. I slotted out the hole in my rotor for some extra adjustment. I verified this using a cap with a hole cut in it and a timing light to see the position it fired."

Further comments by Pat Griffith:

Wayne went on to say to double-check your timing after doing this to make sure you didn't twist the rotor or anything. That's about it.

He also had a disclaimer that said this works on the '91-'93 SR20s but wasn't sure about the different distributors on '94+ SR20s but that it should still apply.

Sounds more complicated than it actually is -- takes maybe 15 minutes.
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