98 replies to this topic

[Ron Alan]

Alberto...you might convince a local engine builder to swap you a ready to go crank for yours and a few dollars 

 

By the way...your picture with the red circle you were asking about...it is an oil galley plug. If there is not a plug there it should be...speak to the guys who did your block!

 

"There is a very good reason to take your engine rebuild to a reputable SM engine builder"

[Alberto]

Alberto...you might convince a local engine builder to swap you a ready to go crank for yours and a few dollars 

 

By the way...your picture with the red circle you were asking about...it is an oil galley plug. If there is not a plug there it should be...speak to the guys who did your block!

 

"There is a very good reason to take your engine rebuild to a reputable SM engine builder"

 

Hmmm...  Interesting idea. Didn't think of that.  Thanks.  Although work is too busy for me to take an afternoon off to go out that way.  I'll check into that option.  Maybe he has Saturday hours.

 

On the red circle, yeah i noticed that earlier.  The other block has a brass plug.  So much easier to figure out when you have another block on hand to compare to.

[Ron Alan]

He is in Fremont most Tuesday evenings!

[fotostars]

So Austin, Brandon, JohnnyD and my recently transplanted NY'er family friend Steve dropped in on Sat and we yanked the 91, big nose crank motor out of the car.  Flipped it upside down on the garage floor and removed the crank out.  Crank looks to be in great shape.  Cleaned it up with carb cleaner today.  Contemplating whether to take it to the machine shop to clean or if carb cleaner is gonna be good.

 

Hoping to re-assemble next week.

 

Hey Alberto, How much can you "clean" a crank that's coming from a good running engine? You're probably over thinking it. I cleaned mine myself. Just my 2 cents...

[Alberto]

Hey Alberto, How much can you "clean" a crank that's coming from a good running engine? You're probably over thinking it. I cleaned mine myself. Just my 2 cents...

 

You are probably right.  I tend to do that on things that are unfamiliar to me.  

 

Thanks.

[Alberto]

Update

 

the machine shop offered to prep the new crank gratis so I dropped it off on the way to work and picked it up the next day.

 

I have thoroughly cleaned all the coolant and oil passages a few times at this point.  They weren't very dirty.  The oil passages in the crank were the dirtiest.  I also chased all the threads on the block.  Time consuming stuff.

 

I ordered a boss for an oil temp sender that I'm going to add to the oil pan.  I like data.   I also ordered a wideband O2 bung that I'm going to have welded into the exhaust - probably downpipe. 

 

Mazda Motorsports is allowing me to return the SNC parts (yippee) and I ordered the big nose oil pump and keyway.  I'm ready to start assembly.  Probably going to do that next week since I don't have a running car for the first race weekend. 

[Alberto]

Cleaned throttle body and intake manifold inside and out.  It was nasty on the inside...

Installed my cleaned and tested fuel injectors.

 

Before:

 

 

 

[Alberto]

After:

 

 

 

Added 1/8" NPT bung for an oil temp sender.  It was a pita trying to weld the aluminum bung to the cast aluminum oil pan.  Finished it off with some JB Weld just in case...

 

 

I tried removing these panels covering the underside of the cavities under the valve cover but bent them up a fair amount trying to pry them out.  The previous owner's mechanic had sealed them up with RTV...     Decided to use the valve cover off the '91's motor instead.  I might try to fix the old valve cover at a future date.  For now, I got better things to spend time on.

 

 

Speaking of better things to spend time on....  Started assembling the block today.  First time ever doing this and first time using Plastigage too.  Interesting experience. 

 

The ACL bearings look a lot different from stock bearings.  The stock bearings are rather shiny.  The ACLs are... well... not shiny.

 

 

 

Plastigaging the main bearings.  Very consistent.  A wee bit bigger than .002 and a bit smaller than .0015.

 

The crank is now installed and the mains torqued down. 

 

Going to assemble the piston rings tomorrow and install.  Real slow going since it's the first time I've ever done this but it's going together nicely.  The FSM is not always helpful by itself.  Neither is the enthusiast manual.  Using those two plus this forum and Googling for answers sometimes yields results - except with regards to piston ring end gaps.

 

 

Question:

Do those ACL bearings look normal to you more experienced peeps?

Where can I find specs on the piston ring end gaps?  It's not in the FSM for the 1990. 

 

Thanks.

[Bench Racer]

Thanks for sharing your rebuild.

Ring end gap = top of page B-59 1990 Mazda FSM. I hate that crap when kids tear out pages.

Top: 0.15-0.30mm (0.006-0.012 inch)

Second: 0.15-0.30mm (0.006-0.012 inch)

Oil Rail: 0.20-0.70 (0.008-0.028 inch)

Maximum: 1.0mm (0.039 inch)

 

Options with the oil temp bung in pan. I used a bulkhead fitting with Permatex then a thin brass washer each side and tightened the nuts. Three years later, no leak to date.

[Alberto]

Options with the oil temp bung in pan. I used a bulkhead fitting with Permatex then a thin brass washer each side and tightened the nuts. Three years later, no leak to date.

 

 

Thanks Bench. 

 

I had read somewhere that a bung was preferable and my friend with the welder was happy to agree to weld it in.  Once we started, we realized that we should have just tapped the pan or used bulkhead fitting. Welding on cast was a challenge to get a clean weld.

[Bench Racer]

My welder friend at the get-go suggested because of cleaning, don't dream of welding cats aluminum. Bulkhead decision made using his experiences.

[Alberto]

Another question...

 

I'm installing piston rings onto the pistons.  The FSM and enthusiast manual state that the top of the top ring is marked with an R.  I see no such marking on any of the top or middle / 2nd ring.  On the top / 1st ring, I do see a white paint mark on the side of the ring.  Can someone please shed some light on which side is up?

 

thanks.

[Bench Racer]

From the Mazda FSM page B-62 lower corner, the second ring is shown with a "corner undercut" to be downward. Who manufactured your rings, look on line/youtube maybe they show/talk about up/down ring direction.

[Alberto]

They are OEM Mazda rings in the Mazda box from Mazda Motorsports.

 

I understood the second ring.  Trying to figure out the top / 1st ring.  That one seems the same on each side and does not have a marking.  Been googling but striking out...

 

Thanks.

[Bench Racer]

Found a youtube from Mike the Miata King. He showed some good things about measuring ring gap and a couple other things but he only installed the oil rings and second ring.

[Alberto]

Found a youtube from Mike the Miata King. He showed some good things about measuring ring gap and a couple other things but he only installed the oil rings and second ring.

 

 

Yep.  Been watching his and other videos often.  We were even playing this one in the garage while examining the pistons and rings:

 

Makes reference to a top and bottom at 3:27 but doesn't describe how to distinguish.  At 5:48 or so, he is installing the top ring and mentions that it does not have a direction...  Hmmm...  Didn't notice that yesterday...  If that is true, then what is the purpose of the white paint?

 

Pics of one of the rings:

 

 

[fotostars]

[Bench Racer]

Very interesting, the Miata King says no up or down for the top ring for the 90/93.

fotostars FSM page shows the top ring with a inside diameter chamfer faces to the top for the top ring, for I presume his car is a 1997 per his profile.

Come on guys, wheres all the mentor support.

[fotostars]

This is a picture of the Haynes Repair Manual for All Models from 1990-1997.

They don't seem to indicate that 1.6 is different than 1.8 on this matter.

I rebuilt my 1.8 and I remember the rings from Mazda I received were identical to the picture. P/N BPY1-11-SC0

That's all I know. Never done a 1.6...

[Ron Alan]

Alberto...Mike Haag will not bite you...he will answer your questions if you call him!