Just wondering what some opinions are on this?

First off, for some reason my tuner thought I had series 4 irons, but after some research and help I confirmed that they ARE series 5 irons so rear iron dowel breakage is less likely under higher boost...

But he also recommended getting my engine dowel pinned for 400 rwhp, I know the whole dowel pin thing is overrated in most cases and just causes more problems than good. But he had an excellent point, since the engine mounts are further appart when the engine is swapped into a FB (front engine mount is all the way up on the front cover) more twisting force is applied through the engine.

Just wondering what others have found, or have had issues with. If I don't have to dowel pin my engine and risk leaks, and other problems associated with the modification I would like to avoid it. But if it is absolutely needed in order to have any sort of longevity it will have to be done.

 

Don't dowel unless you plan on detonating.

Tune rich for safety!

EDIT: Found this, you might have too.
https://www.rx7club.com/showthread.p...ht=dowel+turbo

 

get a video of her

 

The big thing in that thread is they are refering to the weak dowel pin area on the S4 irons. Since I have the stronger reinforced irons (S5) that should not be as much of an issue with a good tune. Moreso concerned about it being more of a problem due to using the stock crossmember and having the front engine mount much further forwards than in an FC.

 

What about adding a rear torque brace, that should limit the amount of twisting from front to rear. We have a shop local out here building 600+ rwhp cars and all his engines get dowelled and do not have leaking issues.

 

Yeah, that is where my car was tuned, and who suggested it. Just at the time of the build I decided against it, because of all the negative things I have heard. But I can always pull my engine appart and take the block to RX-7 specialties in Calgary to get it done. The more I think about it, I think I should just try and run the 15 psi and only tear it down if it breaks...

 

Don't worry about it until something breaks. You've been building this car for how long now? Get plates, insurance, and drive it. Enjoy it.

 

if you're worried about twisting, make a thicker oil pan baffle plate....

if you're worried about detonation, buy colder spark plug, 9's are highway plugs...

 

For the cost and problems you could potentially have with dowling an engine, I wouldn't do it. You can stud the engine for a fraction of the cost and that is almost as strong. If you have a problem with breaking a seal and causing damage to one of the housings or irons, you will have to send the whole engine to be redrilled and redowled. Whereas a studded engine, you can just replace one housing or iron at a time. Just something to think about and consider.