Plain Jane OEM nothing to see here rebuild

[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.

[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]

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?

[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

[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

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

[JustJeff]

Originally Posted by RETed

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

On my first assembly I actually just shaved down that spacer. I had to replace the front rotor and housing on my first rebuild. I now have a second spacer from an N/A engine I tore down. If I do have the iron lapped or replace it; hopefully one of those spacers has the correct end play.

For the record shaving down that spacer was a PITA and took forever, but I didn't want to wait a week for shipping to get my engine together. What I did after I saw end play was out of spec was take apart the front stack. Sand down the spacer and constantly was checking with my micrometer to make sure I had it evenly shaved. I believe I checked on either 6 or 8 pts around the spacer. So I'd take some material off, assemble the front stack, check endplay with my dial indicator and repeat the whole process till end play was within spec.

[JustJeff]

This is a noob question, but what are the circled rings on the irons called?

Those of course need to be removed for lapping and then I assume simply pressed back in after lapping. I talked to the machine shop about doing the lapping, but I don't think they really want to do the work. Owner said (what I already knew) that those would need to come out so the iron can lay flat for the lapping....but didn't offer or say "we can pull those for you" Do they come as easily as getting some Vice Grips and working them loose?

I didn't even ask the machine shop costs on having the iron lapped cause instinct tells me that if I can find a replacement that is in spec that is going to be the best moneys spent. I left the shop thinking, "It's an option, but not the best options...I'll find a used iron." Problem is that irons and housings are getting very hard to find. I suspect that with 20 yr old parts that rotary shops are buying up the parts and holding them. The flooding in Japan certainly doesn't help matters.

If I do have 0.001 lapped, should I also be re-nitrating? I wouldn't think I'd have to. That surface is 0.004 thick which still leaves me 0.003 of material.

[RETed]

Originally Posted by JustJeff

This is a noob question, but what are the circled rings on the irons called?

Those are dowels.
Yes, those are press-fit into the (front) iron.
They can be removed, if need be.
They are used to locate the front oil cover into the proper position for installation.
They don't take very much stress.


-Ted

[JustJeff]

I've decided to use my front iron. I simply need to make a list of the small parts I need that I hadn't already ordered and get them on their way.

I decided to replace my flywheel with one VRRacing was selling and also replaced my exhaust manifold. Waiting for both those parts to arrive.

[JustJeff]

While making what I hope is my final order of parts....Should I worry about replacing the bearing plate? My instinct is no, that the thrust bearing is riding on a film of oil between the bearing plate and the bearing.

[RETed]

Originally Posted by JustJeff

While making what I hope is my final order of parts....Should I worry about replacing the bearing plate? My instinct is no, that the thrust bearing is riding on a film of oil between the bearing plate and the bearing.

Wow, that looks like "galling" to me!
Unless the pic looks worse that it is, I would replace it.
Does any of it drag on your fingernail?
If it does, you need to replace it!

On the other side...
I would inspect the Torrington bearing that was in contact with this plate!
I would bet some of the needle bearings are scored?
I would recommend to replace that Torrington bearing too.
At the same time, inspect the other Torrington bearing too...
It's not supposed to look like that unless we're talking really high mileage, high power, and / or lack of oil lubrication?


-Ted

[JustJeff]

Originally Posted by RETed

Wow, that looks like "galling" to me!
Unless the pic looks worse that it is, I would replace it.
Does any of it drag on your fingernail?
If it does, you need to replace it!

On the other side...
I would inspect the Torrington bearing that was in contact with this plate!
I would bet some of the needle bearings are scored?
I would recommend to replace that Torrington bearing too.
At the same time, inspect the other Torrington bearing too...
It's not supposed to look like that unless we're talking really high mileage, high power, and / or lack of oil lubrication?


-Ted

It does look worse in the pic than it is. There is one spot where I can catch my nail. Unless it went to scrap, I do have another plate from an N/A engine I toredown, or I have a friend who has one. Replacing it won't be an issue.

For what it's worth and IIRC that is how the plate look on the original teardown and rebuild. The engine is a JDM but did not appear to be high power. It had factory turbo, factory fuel injectors. That wear is on the underside/engine side of the plate and I'll certainly look over the bearing. I need to replace the top/cover-side bearing as I damaged it during dissasembly. Atkins sells them as a pair. I was going to call Dan and ask him to sell me only one because all the parts have about 2k miles on them.

One thing I'm thinking of while ordering parts is doing some porting. I would like to do at least some exhaust porting and maybe get templates. I have some ruined housings and N/A irons I can practice on.

[diabolical1]

i agree with Ted. replace the plate.