Jeff20B

Ok, with any luck, the irons should be done today. The rotor housings are almost done. I just need to touch up the bevel to make them perfect.

andynogo

Taking the exhaust ports down 1mm will be fine. Won't really effect torque.



Yes, the discolouration would be carbon and other combustion gunk but I just thought there was a little more than usual- not having the proper bevel might cause this?



Re-using seals? Check that they are 100% flat.



How old were they- it's just that the Real World Solution aviation seals are so cheap... I guess if the seals were fairly new you should be fine. I hope you kept all the end pieces with their respective apex's...

Jeff20B

I think they have around 500 miles on them. I looked at one today and it looked pretty good. I'll make sure they stay in their broken-in slots.



It's a shame the engine overheated, but on the bright side, at least I can fix the ports.

Jeff20B

I fixed the intake ports. The next thing to do is to wash all the internal parts like the oil pump etc while it's still light outside. I typically use gas because it's cheaper than solvent. I'm not recommending this to others because gas is flamable, it's also full of benzine and other wonderful stuff.



Anyway, when the parts are washed, I'll start assembling the 13B.

Jeff20B

I got the shortblock together. I'm going to recheck the torque on the tension bolts in a few minutes. I used hylomar on the bottom corners and I know it has a tendency to flow very slowly while being torqued down.

Jeff20B

It seems I forgot to add some hylomar to one one side of the rear rotor housing. Will this allow oil to seep up from the pan and make the engine dirty?

Judge Ito

It's a very tight fit. The sealant around the legs of the housings are for precaution. Just in case. I have forgotten many a times on my brothers drag racing engine when i'm in a rush and had no leaks anywhere by the bottom of the engine.

pk797

Jeff

Where did you get this side over "D" design?

Your work looks good, especialy for someone that hasen't been doing for very long. I just wonder about those exhaust ports, shaped the way they are. Usually you want the arch of the D to be at the bottom for proper flow characteristics and to avoid excess blow-by, which is what it appears the old ones were showing in your photo's. Let us know how she run's when your done.

PK797

Jeff20B

Ito, I pushed some hylomar up into the seam as best as I could. There is now a bead of hylomar acting as a physical barrier between the oil pan and the leg of the rotor housing. It should stay-put even with oil sloshing all around down there. Even if it eventually erodes away, it's good to know that it should not be a serious problem.



Another thing I'm wondering about is the oil pump chain. It feels a little sloppy. Do you find yourself replacing oil pump chains fairly often? I've already installed the front cover, but I can pull it back off to swap chains in a few minutes. I may need to reapply some hylomar to the O ring, but that's it. Should I swap chains?



pk797, I got the D port idea from peejay. Here are some pictures of what happens when you run a 12A past 8500RPM with stock apex seals. http://my7.rx-7.org/PJ/ Scroll down to the bottom for some pics of his exhaust ports.



I decided to keep my port openings at the stock location and move the port closing later by a few degrees. I'll let you know how it runs.



I should have gotten a pic or two of the intake ports before I assembled the engine.

Jeff20B

Speaking of PJ, he's said that a V8 carb can be used on a rotary if it's given a 'plenum' between it and a seperate runner manifold (either stock or a Racing Beat Holley manifold). I'm curious as to how large this plenum needs to be. What I mean by plenum is a channel between both primaries so the vacuum pulse signal (or whatever it's called) won't cause the carb to go super-rich at high RPM. Er, also both secondaries will be joined together too.



An idea I'm having is to use a stock '74-'78 13B intake manifold on my 13B with a Holley adapter on it to fit an Edelbrock square bore carb (same bolt pattern and four barrel spacing I believe). My question for anyone who'd like to tackle it, is how large the channel needs to be which joins the primary runners together. How tall and wide do you think it should be?



I'll work on a picture to show an idea I have.