Plain Jane OEM nothing to see here rebuild

[RETed]

Originally Posted by JustJeff

I have gotten myself confused while checking my irons for warpage. I'm confused about the difference between checking for warpage and checking for step wear.

Warpage tolerance is 0.0016
Step wear tolerance is 0.003

Doesn't that mean there are areas on the combustion surface where step wear tolerance is higher/greater than warpage tolerance? I check my tolerance for warpage per the FSM at 4 points. Once I get into oil seal wear area there is an even greater tolerance(0.0008) and my 0.0015 feeler can slide under my straight edge. I'm also taking the straight edge across areas other than the 4 pts in FSM and finding some variations. Can someone help clarify.

Okay, "step wear" is defined by any gouge or valley *under* the measured surface.
I believe the FSM is specific to the areas - the most critical areas are at the 3 o'clock and 9 o'clock positions about 1" from the inner water jacket groove.

"Warpage" is defined by *any* deviation - whether is be "high" or "low" measured along a surface.
Technically, any "wear" (including the above "step wear") should not factor into this warpage inspection.
Warpage is to measure how much deflection out of parallel or perpendicular a surface is...usually across a broad area.


-Ted

[JustJeff]

Originally Posted by RETed

Okay, "step wear" is defined by any gouge or valley *under* the measured surface.
I believe the FSM is specific to the areas - the most critical areas are at the 3 o'clock and 9 o'clock positions about 1" from the inner water jacket groove.

"Warpage" is defined by *any* deviation - whether is be "high" or "low" measured along a surface.
Technically, any "wear" (including the above "step wear") should not factor into this warpage inspection.
Warpage is to measure how much deflection out of parallel or perpendicular a surface is...usually across a broad area.


-Ted

Gotcha, thanks for clarifying Ted.

[JustJeff]

I'm dissapointed that when I took my engine apart I did not find a smoking gun showing a blown out coolant seal and am concerned that I'll put this engine back together without identifying why/where/how the coolant seal failed.

Ted circled a pic in a previous post showing where he'd bet the seal failed. My concern is all my iron surfaces look very similar and seem to be tied to hylomar staining. Here's some pics with areas having similar staining.





Unrelated to staining, look how thin the wall is at this point. It looks cast that way and doesn't at all feel like corrosion. Should I be concerned?

[RETed]

You can ignore the outer water jacket groove.
I've never seen a failure on the outside one unless we're talking severe corrosion problem or extreme overheating.
The majority of the punishment is done to the inner water jacket since it has to seal combustion!
More specifically, the area from 12 o'clock to 9 o'clock (or vice versa, depending on how you're looking at the housing) which is the area where you start the ignition cycle through the combustion cycle to the end of the exhaust cycle is most important.

Sometimes it's very hard to tell from just pics on where the coolant leak came from.
It's almost necessary to be there - in person - to get a good idea of what is going on.
I tried to the best job just by the pics you posted...

Another question...
Assumed you did torque the engine down in the specified order...
How much torque did you tighten the tension bolts down to?
What kinda torque wrench?


-Ted

[JustJeff]

Originally Posted by RETed

You can ignore the outer water jacket groove.
I've never seen a failure on the outside one unless we're talking severe corrosion problem or extreme overheating.
The majority of the punishment is done to the inner water jacket since it has to seal combustion!
More specifically, the area from 12 o'clock to 9 o'clock (or vice versa, depending on how you're looking at the housing) which is the area where you start the ignition cycle through the combustion cycle to the end of the exhaust cycle is most important.

Sometimes it's very hard to tell from just pics on where the coolant leak came from.
It's almost necessary to be there - in person - to get a good idea of what is going on.
I tried to the best job just by the pics you posted...

Another question...
Assumed you did torque the engine down in the specified order...
How much torque did you tighten the tension bolts down to?
What kinda torque wrench?


-Ted

You have been very helpful Ted

I figured the same thing about that thin spot, but thought it was odd that it had a thin spot.

I don't remember the specific order I torqued the through bolts down in, but I did it in a chris cross pattern. I used a beam torque wrench and did them down to FSM specs..though I don't recall what those numbers are at the moment. I get where you are going with this though and talked to a friend about it just yesterday. If they weren't torqued down correctly wouldn't I have had leaks everywhere. I didn't have any signs of coolant in oil or any outer leaks through the irons and into engine bay. BUT I did transport the assembled keg to a friends shop to use his air tools for the flywheel nut. I doubt the engine "loosened" during transportation....but is it possible?

[RETed]

Originally Posted by JustJeff

I figured the same thing about that thin spot, but thought it was odd that it had a thin spot.

I think the molds were just getting bad toward the end of the production that some of the irons came out like that.
I've seen a lot of them on tear-downs, and they look awfully like massive corrosion...
It's so common that I've just chalked it up to "bad" molds.
Oddly enough, I've never seen a failure in those areas.

I don't remember the specific order I torqued the through bolts down in, but I did it in a chris cross pattern. I used a beam torque wrench and did them down to FSM specs..though I don't recall what those numbers are at the moment. I get where you are going with this though and talked to a friend about it just yesterday. If they weren't torqued down correctly wouldn't I have had leaks everywhere. I didn't have any signs of coolant in oil or any outer leaks through the irons and into engine bay. BUT I did transport the assembled keg to a friends shop to use his air tools for the flywheel nut. I doubt the engine "loosened" during transportation....but is it possible?

I believe the Mazda torque spec is around 27 lb-ft?
I only use Snap On torque wrenches - click-type.
I run my rebuilds at 30 lb-ft.
It's slightly higher than stock spec, but it's not tight enough to interfere with the rotating assembly.
I know guys run them higher, but you run the risk of increasing friction.
I've seen an engine torqued down to 40 lb-ft that almost could not be rotated by hand!
I know Snap On torque wrenches are not cheap, but the ~$200 investment is a good one in this case.


-Ted

[JustJeff]

Originally Posted by RETed

I believe the Mazda torque spec is around 27 lb-ft?
I only use Snap On torque wrenches - click-type.
I run my rebuilds at 30 lb-ft.
It's slightly higher than stock spec, but it's not tight enough to interfere with the rotating assembly.
I know guys run them higher, but you run the risk of increasing friction.
I've seen an engine torqued down to 40 lb-ft that almost could not be rotated by hand!
I know Snap On torque wrenches are not cheap, but the ~$200 investment is a good one in this case.


-Ted

I've got a Craftsman. I doubt that the torque was off unless the wrench was faulty. I like the beam type wrenches more cause I can see with my own eyse type thing. Trusting a click in a wrench makes me nervous. I got very anal and almost OCD when checking torque on nuts and bolts. I went around the through/tension bolts several times, but don't remember what the torque was on them. I took notes and pics through the teardown and tolerance speccing, but then at the end for assembly I got more focused on getting the job done and note taking fell by the wayside.

[JL1RX7]

The click type torque wrenches are very accurate as long as they are not dropped and used for the final torque. Beam are the least accurate. I have seen so many fail calibration brand new out the box.
The snap on ones are expensive but they are very good. Used them in the Navy torquing bolts and CADS on the ejection seats. Figure if they are used for that then it is more than good for a car.

[JustJeff]

I don't see myself springing for a Snap-On wrench. I've been reading up on checking beam type wrenches by hanging a weight and measuring distance from the socket end. Do some math and find out how accurate your wrench is.

I can get a Craftsman click wrench for $70...that I can justify spending if my beam type shows to be innacurate. Opinions on Craftsman torque wrenches?

[RETed]

If the $200 - $250 price tag for a brand new one bothers you, you can always get one used...
For a while, I was chasing a lot of them off of eBay.
I can usually get one for about $100 - $150 depending on condition.
If you're lucky, you can get one for under $100.
(A lot of pawn shops tend to dump them on eBay.)
You can always get them recalibrated locally through the Snap On dealer with a nominal fee.
Or, you can buy a calibration machine for like $1,000...

This is something that I would not skimp on.
That's just the way I view the work.
I first started out with a (brand new) Sears Craftsman torque wrench...
The nut in the handle backed out and fell apart in my hands...literally.
I went in and told them I wanted my money back.

All your mil-spec and civilian contractor torque wrenches will most likely be Snap On, although I've seen a few Proto's here and there.
You'll see them pop up on eBay - with set torque levels that cannot be adjusted.

This is something I see as an investment.
Your torque settings can make or break what you're building or servicing.
In the end, is the ~$200 that expensive?
Most of us drop at least $1,000 for a rebuild just on parts...
Specifically for the tension bolts, since we're looking at the 30 lb-ft range, you're most likely looking at a wrench that does 0 - 50 lb-ft.
(Rule of thumb is to shoot for the middle of the adjustment range.)
That covers the majority of fasteners in your FC short of the flywheel nut, front eccentric shaft bolt, wheel hubs, and maybe some of the larger suspension fasteners, so that torque wrench is not likely going to just sit on the shelf collecting dust once you're done with the rebuild (tension bolts).


-Ted

[RETed]

Originally Posted by JustJeff

I can get a Craftsman click wrench for $70...that I can justify spending if my beam type shows to be innacurate.

One problem with the beam-type is that parallax can be a problem.
Depending on gradiation, you could be off by as much as 5 lb-ft in some cases...

This is why I asked what #'s were you shooting for.
If you're trying to shoot for 25 lb-ft, if we account for possible parallax error, it could be as low as 20 lb-ft...
20 lb-ft is a bit too low for most rebuilders.


-Ted

[JustJeff]

Originally Posted by RETed

One problem with the beam-type is that parallax can be a problem.
Depending on gradiation, you could be off by as much as 5 lb-ft in some cases...

This is why I asked what #'s were you shooting for.
If you're trying to shoot for 25 lb-ft, if we account for possible parallax error, it could be as low as 20 lb-ft...
20 lb-ft is a bit too low for most rebuilders.


-Ted

IRRC I did the tension bolts to 30lbs. I was very thorough in checking them repeatedly. As you tighten them it lessens the torque on the ones tightened before the most recent. I went back through and checked them a few times.

I may do a little experiment. I may buy both a cheap Harbor Freight clicker as well as a Craftsman. I've got some spare trashed n/a irons. I may find a spot to tighten a bolt down with all 3 wrenches and see how much variance there is. Maybe just do a nut on an exhaust stud?

[JustJeff]

Oh the one thing I did was stop at the machine shop I use. I showed him my front iron and he has the equipment to lap my irons if I want it done. He's confident he can lap as little as 0.001 if that's what I want.

Now I need to research prepping them for lapping and re-read the pros and cons of lapping

[RETed]

Originally Posted by JustJeff

IRRC I did the tension bolts to 30lbs. I was very thorough in checking them repeatedly. As you tighten them it lessens the torque on the ones tightened before the most recent. I went back through and checked them a few times.

Very good point...
I'll normally do a minimum of 4 rounds of tightening the tension bolts.
1st @ 10 lb-ft
2nd @ 20 lb-ft
3rd @ 30 lb-ft
The above is done with the Mazda recommended torque pattern in the FSM.
I'll do one last torque down set at the same 30 lb-ft final but just go around in a clockwise pattern - that's #4.

I may do a little experiment. I may buy both a cheap Harbor Freight clicker as well as a Craftsman. I've got some spare trashed n/a irons. I may find a spot to tighten a bolt down with all 3 wrenches and see how much variance there is. Maybe just do a nut on an exhaust stud?

Good idea but stay away from the exhaust fasteners.
Most dedicated exhaust fasteners have special (thread) profiles to keep them snug - usually the female or nut side of things.
Torquing and retorquing might not be consistent.
I'll try and pick something else?


-Ted

[RETed]

Originally Posted by JustJeff

Oh the one thing I did was stop at the machine shop I use. I showed him my front iron and he has the equipment to lap my irons if I want it done. He's confident he can lap as little as 0.001 if that's what I want.

Now I need to research prepping them for lapping and re-read the pros and cons of lapping

Only thing you gotta worry about is the eccentric shaft play and possibly adjusting the spacer in the front assembly.
Mazda has the specs for this in the FSM.


-Ted