Fletch1971

The greatest feature of this forum is the amount of knowledge that exists from all those experienced rotary engine gurus out there. It is wonderful that I usually get prompt replies to my questions and concerns. On the negative end, I have been receiving replies that haven't fully addressed my situation, which implies that other members haven't fully read or comprehended what I have posted. Case in point: The dilemma I am experiencing in using an FD eccentric shaft in my FC S5 build.Through bits of advice, I am settled on the reality that I will need to be using RX-8 front and rear stationary gears with my build, since the oil holes in these units will perfectly match with the oil holes in the front and rear main bearing journals of the FD eccentric shaft. However, I have not received any feedback regarding the situation of how to remedy the mismatch of the oil holes in the RX-8 stationary gears to the oil holes in the FC front and rear side housings.Is this mismatch really a concern? Why or why not, and is there someone or some modification technique that can correct this situation?

The comments that I have received have sort of "blown off" my concerns in this area. I might come off as paranoid about this situation, but after spending around $5,000 in new parts so far, I don't want to risk an improperly matched part damaging an engine that so far has been 14 years in the making. For other members like me, it would be great to have a section with a rundown with what parts can and cannot be used with any particular build, considering that certain critical engine parts for the 13B, and especially the 12A, have become extremely expensive and downright unavailable over the years.

rxtasy3

iTrader: (2)

looks like this post answered ur question. https://www.rx7club.com/new-member-r.../#post12609312

then there's this one on the difference in the oil hole. https://www.rx7club.com/general-rota.../#post12612286

even thought u really want to use the hardened rx8 gears, the diabolical1 mentions in the first link that u can not. so my question is, what answer were u hoping for? maybe ask in the 2nd and 3rd gen sections if none of the comments so far don't suit u.

https://www.rx7club.com/2nd-generati...-1986-1992-17/

https://www.rx7club.com/3rd-generati...-1993-2002-16/

dguy

iTrader: (8)

Your question was answered very clearly.

Fletch1971

You are correct...My apologies...peejay on 9/03/24 replied: "Wait a minute. If the difference is only 2.13mm...that isn't going to make any significant difference. The oil passages will still line up just fine, and everything will work okay."

There are two different discussions elsewhere on the forum where members were discussing the need to have the oil hole in the FD/RX-8 rear stationary gear "elongated" to work with the FC rear side housing, presumably to match the oil feed hole in the housing. Adding to my insecurity is a you-tube video made by Dan Atkins around February of this year that compares the different eccentric shafts. In this video, Dan discusses the difference in the position of the oil holes between the FC and FD shafts. He commented that he used an FD shaft in an otherwise full FC motor, and after 10 years of driving with no problems, he tore down the engine to find abnormal wear in the front bearing. Dan therefore highly recommended using FD gears on an FD e-shaft. It was interesting, though, that he never mentioned any problems in the rear bearing of the FC S5 gear he was using. Furthermore, he never brought up an issue regarding the alignment of the oil holes with the FC front and rear side housings.

So, it is really those few comments on elongating the oil holes in the stationary gears that has me thrown off and questioning whether or not a further modification is needed. There was a post on 9/10/2020 at 7:45 pm by WondrousBread where he confirms that the oil hole in the rear stationary gear needs to be elongated to work properly with the oil passage in the FC rear side housing.