Hi I am rebuilding my 13b out of my 93 rx7 and since im going to be running around 22psi what should I do regarding to studding the engine or dowel pining. Also I talked to a rotary engine re-builder and he said that as long as you let the engine warm up properly I will not need dowel pins or studs but I think he may be wrong so that's why I'm asking you guys.
Thanks

 

bump

 

I would be doweling it if you aim anything over 300hp especially if you have the money at rebuild stage. Just get it done for peace of mind I would say

 

Dowelling isn't necessary for 300whp, you must be mistaking generations...

If anything just replace your stock tension bolts with a set of (same size) upgraded studs that Turblown sells. Those will give plenty of even clamping force, and you can further reinforce the engine with either an oil pan brace, or the excessive oil pan (sold by pineapple).


Dowelling an FD doesn't make sense to me (because removing material is supposed to add strength???)

 

In addition to Oil Pan brace (or new oil pan) check or change Motor mounts and as usual change all vacuum hoses with silicone ones....

 

I did not say anywhere it was necessary and I am not mistaking gen

I am simply stating if it was My own rebuild I would. Any work you can afford to get done to your engine to reinforce it is going to help you later, even if you never push your power to that point.

 

Except that you're TAKING AWAY friction surface (the friction is what provides the grip and prevents torquing of the engine) by adding doweling in an area where it's not necessary. Not to mention that removing the material necessary to add extra dowels could actually weaken the engine there (where you need strength).

I don't feel that adding dowels is really necessary on a third gen, ESPECIALLY not at your magic line in the sand of 300whp (which is rather easily achieved with minor modification).

I'm basing my opinion on conversations I've had with experienced engine builders and Mechanical Engineers who work for rather well respected organizations.


Doweling is the "cheaper" version for less power. Studding is for more serious power, and also much more expensive due to the large(r) amount of machining required to make the 12.7mm studs fit. REC Services | Machining & Modifications | Studding & Dowell Pinning

A cost effective alternative to both is the 10mm stud kit I suggested earlier (13B Engine Stud Kit - Turblown Engineering) that would be very effective if coupled with the uprated oil pan, or oil pan brace.

 

Hi on dowel pinning I looked into it and the material around the extra dowel pins gets very thin,scary thin so I think I will probably just go with the turblown studs.

 

No reason to pin the motor for those power levels. I recommend the Turblown stud kit, RX Parts apex seals, and adding a couple thousanths to all the seal clearances.

 

First off, you'll have better results with your questions if you "properly" label your threads. I don't know why you insist on not doing it. I've helped you out again, but changing the thread name. Next, check this thread:

https://www.rx7club.com/rotary-drag-...ou-run-964978/

 

No, you don't need studs or dowel pinning.

 

Bingo. This also made me laugh.

 

Yea, agreed not needed at current power goal, but if your gonna plan to push it further one day Ihor hit it on the nose. Clearance, Studs, and good seals
but reality is you don't need anything but the clearance &seals to get to 700 with a good tune (ran733 whp for a entire season with factory fd dowles and studs just clearanceing)

Dowels seem to be builders opinion, ive seen some with 4 extra, some with every hole from 2oclock to 6 oclock done, reality is its all in the tune, these measures are there for if you see detonation& big boost flexes everything, but even if you cure motor flex in these big boost cars you still have e shaft flex, to deal with, but with current goals and lets just say 50% more none will ever be a concern to you

 

Hi thanks for all the help but would you guys recommend that I get the rotors race clearance.
Thanks

 

Having your rotating assembly balanced, and rotors clearanced, is never a bad idea

 

Ok I will talk to atkins rotary and see if he does it.
Thanks

 

An oil pan brace will help seal the oil pan perhaps, but adds very little to the rigidity of the engine.

A cast aluminum oil pan may not be for everyone (the pros and cons of that have already been discussed ad nauseam in other threads), but it does add to motor rigidity.

 

Ok thanks I will look more into the pros and cons.
Thanks