My build is finally progressing. Been way too long, but you play the hand you're dealt.

I am converting my stock four port to a six port. I want to reinforce the block as much as possible, but have gotten conflicting advice from a lot of people. I would appreciate any input that can be provided. My goals for this project were never to make huge power, but if upgrades need to be made, this is the time.

Option 1: add two additional Mazda dowel pins

Option 2: add five 12mm studs (some machining)

Option 3: replace all tension bolts with 10mm studs (no machining)

Option 4: replace all tension boots with 12mm studs (lots of machining)

Thanks for your help

 

What does your builder say? Talk to him about the use of solid one piece dowel pins. Although I doubt you will make enough HP to need studding or dowel pinning.

 

I agree I probably will not ever make enough power to need it. I asked my engine builder, and he is the kind of guy who when you ask what time it is, he tells you how to make a watch. I got the history of the tension bolt, the history of his RX7 NHRA car, the story on half a dozen RX8 rebuilds....but no firm answer.

As such, I'm seeking the wisdom of the crowd. Also, I am the type of person who thinks an ounce of prevention is worth a pound of cure. Will spending a few hundred dollars now prevent an engine failure later? (Yes, the tune is key. Yes, Steve is still going to tune it if I ever get a motor in the damn thing.) Will studding it delay needing a rebuild, or is just money down the drain?

 

Can only comment on what I have done which was to dowel the engine in 4 places adjacent to the combustion chamber :

https://www.rx8club.com/attachments/...1-img_1866.jpg

I know this works . Two dowels sounds like too few to be effective . Any of the other solutions sound like an improvement over stock to varying degrees.

 

Thanks, Brett. I have yet to hear from the vendor (Rotary Performance) where the 5 12mm studs would go. I assume they in the high pressure / high stress area.

 

I added two extra dowels and going with aftermarket 10mm studs, these are stronger that stock so can tighten more to reduce flex

 

Thanks for the advice, SKC. I went with something a little bigger than 10mm

 

Problem with 12mm is that you have to drill which weakens the housings