Ok, So I am a dick for one reason. I was following the torn up haynes manual that was soggy in the back of my trunk when I bought the car, and only torqued to 40lb/ft. I came home, and laid the green and red plastigauge down and torqued to 60 lb/ft and actually used the arp lube (I was saving it for the final assembly). The green read pretty much .002 On the red it was always a bit smaller than .002 I am no where north of .003 as I had suspected due to improper torque, I would imagine. I assume this is at or near the larger end of factory spec, but not much to worry about at this juncture. I didn't think that much torque would make a difference, but then again, this is a thousandth of an inch we are talking about here.

 

I looked at the FSM, enthusiast manual, and the haynes manual is the only one that shows how to stagger the piston rings is the haynes. It says to stagger the top ring 30 degrees to the left of the wrist pin, and the bottom one 30 degrees to the right, leaving 60 degrees of stagger between the two, and on the opposite side, the same with the oil control rings, with the ring spreader thingy centered between them, Is that correct?

 

Supertech has instructions on how to set the piston rings up on their little sheet that comes with the pistons.

 

Yeah, it said it was an example of a subaru or something on the front. I wasn't sure if that was legit. I guess I will use that then.

 

Its standard issue on most all pistons. The piston doesn't know what car its in

 

How tight are the wrist pins supposed to be in the rods. Mine are kind of tough to move, and not as easy as the ones I pulled out. They take some encouragement to move from side to side, and the wrist pin moves easier inside the piston than the rod. Is this ok? Or do I need to have the insides of the rods machined out?

 

They are, in my experience, tight on initial install but did you grease them with assembly lube (or at least lots of oil) first? I've had to tap them in even if they were greased first on occasion.

The ones you took out had worn a bit, assuming you're using pins that came with the pistons they should be the correct size for the pistons.

 

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Yeah, I had to tap it in. Not too much effort though.

 

For the record, they are belfab rods, and supertech pistons, wrist pins.

 

Wrist pins are supposed to be tight in the pistons. You want the movement in/on the rod.

 

Where do you guys get your engine clearance specs? I bought the Mazda workshop manual a while back but noticed it doesn't have this information. Is there a Mazda engine specific workshop manual?

 

I'm pretty sure there are stock engine bearing clearance specs in my 94 FSM. I can look them up if you need. On the various specs that are necessarily non-factory (piston-to-wall with forged slugs, ARP fastener specs, etc) that's where the accumulated experience of people on this forum comes in handy.

 

I'm trying to gather up as much info as possible. I'm planning to put 99-00 pistons in a 2002 motor with forged rods, nothing fancy. I believe I'd be looking for factory specs for the mains, rods, and piston rings. Very n00bish with this stuff, so I'll probably be asking for specs for other things as I go.

 

94 FSM lists clearances in metric and also lists the inch conversions, but if you do the math you'll find the inch spec they list is sometimes off by a ten-thousandth or so. These are the inch specs taken verbatim:

Piston ring end gap:
Top: .006-.011"
Second: .006-.011"
Oil rail: .008-.027"

Wrist pin fit in the piston has a negative clearance spec of 2 to 5 ten-thousandths, IOW "tight."
Wrist pin clearance in rod small end: .0004-.0010"

Main bearing oil clearance: .0008-.0014"
Rod bearing oil clearance: .0008-.0017"

 

What ended up causing all my problems were the stupid belfab rods. They were infact too tight up top, and out of round on the bottom, causing lots of problems. After hearing someones experiences, including mine, I would avoid belfabs at all costs.

 

Thanks for listing the values. I'll mark that down.

I am going to be using a set of $170 ebay rods.

 

I can stop by the machine shop sometime and get them. I just threw in the towel and had them spec everything. I certainly don't know them off the top of my head. All I know is when I plastigauged the rods is that the green plastigauge was smooshed on one side til it was too big for the paper to read. Like .0005

 

Are you referring to the big end of the Belfab rods? I'm hoping these china rods are ok. The defunct Leatherface used them and said his didn't have any clearance issues out of the box.

Are the wrist pins press fit or do they have a spring retainer? My searches result in conflicting information.

 

Do you guys hone the cylinders yourselves or is this something I want to pay a shop to do? $25 vs $200 question up here.