Sensei's B6 rebuild and swap

[Zanzer]

Oh yeah, I always look at new pistons when doing a rebuild just in case. Rock has some good prices on OEM replacements (although they show one "set" for $24.79 which I find a little hard to believe). Since this rebuild is for a daily driver car I didn't look into performance or flat top pistons. Plus the block had little to no ridge so when I checked ring end gaps they were close to the large end of the spec, but with tolerance. Had this been a performance rebuild I would have bored it to gain a little extra and to insure a straighter bore and tighter ring tolerances. I've looked into forged pistons for my B6ME project but I haven't found much offered. I was thinking of possibly trying to find some forged ones from a B6T. All the used B6T ones I've come across have been in the range of $400 and new ones were $500+ :angry7:


I didn't check deck height, but since I don't have the head installed yet I can get a measurement for you. :thumbright:

[blkfordsedan]

Just wondering if ATX motors have slightly higher comp than MTX motors did, or maybe B6ME pistons have less dish.........things like that. Even on stock replacement pistons, I've found that the dish volume, valve relief size and sometimes even the compression height of the wrist pin can vary between manufacturers. That's on SBF & FE block V8's.....and I was thinking the same thing may be true on the Mazda B series.

[Zanzer]

did you (or can you) measure the deck clearance? I'm curious how far the pistons are below the deck surface at TDC.

Just wondering if ATX motors have slightly higher comp than MTX motors did, or maybe B6ME pistons have less dish.........things like that. Even on stock replacement pistons, I've found that the dish volume, valve relief size and sometimes even the compression height of the wrist pin can vary between manufacturers. That's on SBF & FE block V8's.....and I was thinking the same thing may be true on the Mazda B series.

Ford was notorious for being all over the map with pistons and heads. Depending on what year, head, platform engine was used for, you could get many different designs.... especially after about '72 (I'm a hoarder of C8, C9, and D0VE cylinder heads for the 429/460 myself )

As far as the Mazda engines I've worked on, I haven't seen much difference between the B3's other than some have the centering hole in the center of the piston and some don't. I haven't been measuring things like pins, rod lengths, rod ends, etc, because they've all just been stock use rebuilds. I haven't seen any difference (that I've noticed anyway) in pistons used in autos and manuals. I would think this would be a bit of a production line nightmare if they did, but that's just an assumption. I just rebuilt the B3 in an auto L Plus and the pistons looked to be the same as the B3's in manuals I've done. I'll have the head off of an 89 auto in a couple of weeks so I can verify.

As for the 8 valve B6's, the pistons look like the same basic design as the B3's. They have 3 valve reliefs and a slight dish. The one big difference I did note between the B3 and B6 pistons was the B3's have more dish in that the bottom of the dish is fairly parallel with the plane of the piston top edge. The B6's however have a crown in the center so the "dish" center is even with the top edge of the piston, but drops down into the valve reliefs as it moves out from the center (you'll see in the pic I'm posting). As for as differences between the 8 valve B6 and the 16 valve B6ME, I haven't taken the head off of my B6ME yet so I can't comment on any differences between the 2 or if they are different between any of the other 1.6's such as the Miata.


Now, for your question concerning deck clearance: I found TDC with a dial indicator and then checked with a depth gauge. I'd believe it's a safe bet to say the 8 valve B6 is zero deck

[Zanzer]

In other related news

I didn't get a lot done to the engine today. Still waiting on freeze plugs to come in, did some badly needed cleaning in the shop to free up some room, and had quite a few friends stop in here and there.... and there's always time for chit chat

I got started on cleaning up the head. The machine shop hot tank job wasn't the best I've seen so I'm having to go back and focus on a few problem areas that didn't get cleaned. The biggest problem spot (as usual) is the exhaust runners. They still have tons of crud and carbon build up in them so it's taking multiple cycles of scraping, cleaning with SuperClean, repeat as needed.


Here's the head as delivered after hot tanking. You can see some of the buildup in the exhaust ports.




After scraping and cleaning for a while I decided it was best to go ahead and remove the valve guides. There's a lot of buildup around them that's hard to get to with the guide in the way and I need to clean the bores in preparation for the new guides anyway.

Here's some pics of a valve guide punch I made on the lathe a while back. Sometimes you can drive them out with a punch and hammer, but I've seen others that needed pressed out. I got lucky and these drove out quite easily.







Here's a shot with all the exhaust guides removed.



Another thing I noticed while cleaning the head was the nasty casting of the combustion chambers. One looks pretty clean, 2 look like the one in the pic, and the last is somewhere in between. I'll be cleaning these up some so carbon deposits have a harder time finding a home and to eliminate some possible causes of pre-ignition and detonation.
NOTE: You can also see just how nasty the exhaust runners are in this pic, you can't even see the valve guide.

[FestYboy]

do yourself a favor and hog out that shelf in the exhaust runner while you're in there.

[iceracerdude]

+1 Also pick up some "Dawn power dissolver" next time you're in the dish washing soap department in the grocery store. You'll like what it does to baked on carbon.
And at $2.40 a bottle, it will be a regular in the garage, right next to the brake cleaner.

[Zanzer]

do yourself a favor and hog out that shelf in the exhaust runner while you're in there.

Already on the "to-do" list Along with some pocket/bowl blending on the back side of the valves where the head was cut for seats You can see it has a pretty big ridge in the pic of the intake side.

+1 Also pick up some "Dawn power dissolver" next time you're in the dish washing soap department in the grocery store. You'll like what it does to baked on carbon.
And at $2.40 a bottle, it will be a regular in the garage, right next to the brake cleaner.

Awesome Thanks for the tip! I'll pick some up today and give it a try :thumbright:

[lanemeyer14]

Might come up there tomorrow if you'll be around.....gonna see about picking up that ugly festiva bringing down your property value!

[Zanzer]

^^ Yup, I'll be here :thumbright:

Yours looks better than the other 9 I have sitting here and is the least of my problems when it comes to my low property value LOL :mrgreen:

[Zanzer]

+1 Also pick up some "Dawn power dissolver" next time you're in the dish washing soap department in the grocery store. You'll like what it does to baked on carbon.
And at $2.40 a bottle, it will be a regular in the garage, right next to the brake cleaner.

I want to give a big thanks to Iceracerdude! I got a bottle of the Dawn Power Dissolver and tried it today and I gotta say THIS STUFF ROCKS! I had to learn to be patient with it because I found that it has to soak longer than the recommended 15-30 minutes, but after that it starts peeling carbon like paint stripper! Also, it doesn't blacken aluminum like some other cleaners I've seen. Just the opposite, it makes it look brand new. I think the next one I clean I'll use Superclean to take off the loose oil and grime and then apply the Power Dissolver and maybe let it sit for a few hours or overnight and see how it performs.

I think between the Power Dissolver and Superclean I could take the stripes off of a zebra now! LOL :mrgreen:

My only complaint....I wish it came in a bigger bottle I hope Walmart has a truck coming soon because with all the cleaning of engine parts I do, I'm going back to buy up their remaining stock! LOL :toothy3:

Thanks again man! You were right, I now have a new favorite to add to the consumables shelf

[Zanzer]

I worked on cleaning the head some more today but it's gotten to the point where even the Dawn is like "that's it dude, I'm out" so I scraped out the small amount of remaining carbon and I'm going to give it one more good scrubbing tomorrow. Then the real fun begins :evil1:

Brad (Sensei) came over today and snatched the motor and transmission out in no time. Next up is giving the engine bay a good cleaning. This car has set for a long time so the mud daubers have built quite a few condos, it looks as if a family of squirrels and mice called the bay home for a while, and there are the remnants of some kind of vine that was growing up through the radiator support at some point.


Here she is swinging in front of the car. Out with the old!




Some shots of the dirty engine bay.





Notice all the mud on the frame rail and under where the air box mounts. You can see some of the vine around the AC dryer. Sorry it's kind of blurry, I hate my camera. The screen is so small I can't always tell if the pics came out sharp or not.

[FestYboy]

that's dirty!?! man i'd love to see what clean is.

[Zanzer]

I'll be taking pics after we clean it up

[Safety Guy]

What Arty said! You may have some mud and vegetation in there, but not much grease and grime like I'm used to! Brake lines look great as well. Up here in the Land of Road Salting, I felt the need to replace all of my hard lines on AquaMutt.

I hope to be redoing a B3 soon. It'll be my first (almost total) engine "rebuild." Your head cross section thread was great to look at what needs to be done.

Karl

[Zanzer]

We're pretty lucky down here when it comes to rust. Unless a car comes from the mountains of NC where they get snow, we don't really see a lot of bad rust issues. This car is a total gem though. It hasn't been on the road since 06 and I don't think it was driven much before then. Other than years of oxidation on the paint the car is in pristine condition both inside and out. I'll have to get you a few pics of the interior and floor pans. I was amazed at how clean this car is.