Agreed, that would make it a ton easier. And that bolt for the chain guide is also a good point to make. I have seen people forget to take that out and pull up on the head. oops broken chain guide lol

The timing cover really isn't that bad to do. On the gen2's it's even easier. No Power steering pump! We had the Head off Doug's car in a couple hours. Started at 9 and had it off at 11:30.

Tomas, you'd still have to take the timing cover to take the head off, iirc the cover is bolted to the head itself.

If you're gonna do the internals swap, it's a good time to swap chain and tensioner too...to be on teh safe side. That's my intent.

Now, @Tomas What aftermarket pistons hit the oil squirters?

And do we have any idea how strong the stock pistons are, genjuan or genpoo? I saw the ginormous ring land and my thought is it'd be pretty hard to put a crack in that sucker.....think they'd be strong enough for 500-550whp?

If people figure they're strong enough for 550whp, I might as well keep my stock pistons and just get some k1's or eagles!

I know for a fact Wiseco pistons hit the squirters but I can't recall any others that do.

I'd like to stick with my stock gen2 pistons. That's $500 in my pocket. Haha. And I think they are plenty strong enough for 500hp. The only issue I think we have seen was bluestreak cracked a ring land, but there haven't been any other known cases

bluestreak cracked a ring land?
hmm.

I'd like to stick with my genjuan pistons. I'd think they're just as strong as the poo but obviously different flame pattern design.

Ya IIRC it was cylinder #3. He was having an intermittent misfire, then it was slightly low on compression, which is why he went forged.

EDIT: It was #3. Here is the link. http://www.mazdaspeedforums.org/foru...ml#post1043619

hmmm. That may dash some of my hopes.

Yep. Cyl 3 took a crap on me during time attack.

I was out on the track for 30 mins at a time in 35*C (95*F) weather. That day did my motor in.

I imagine the pistons could put up with DD and 1/4mile abuse longer than tracking but that's just an educated guess based off me leaning back in my chair and staring at ceiling tiles.

EDIT: This was on my GT3071 at 20PSI and 12* timing up top. Kept things "safe" so I wouldn't pooch the motor.... Ha.

Need money and timing tools! AAHHHHH!!!

I just want to do rods. We have not seen a lot of piston failures just rods.

I agree but my thought process is this. If you're swapping the rods so that you can hand your car an epic beating whenever you'd like, why would you want your pistons to be your new potential weak point?

I'm not saying that it would ever even become an issue but for the peace of mind an extra $500 is well worth it.

The bolts on the side of the head protrude through the timing chain cover so if you take them of the only thing holding the head down is that bolt on the chain guide. Well, and obviously the head bolts.

You are are right about replacing the chain and may be the VVT too. It's just that if you could do rods in one week end and chain and VVT in another it would be much less stressful than trying to do all this shit in a week end working solo. That's what I usually have to do. I can only have the car down for the week ends as I need to ride to work.

Correct. I can also confirm Wiseco's hit the oil jets. You can assume from this the CPe pistons do the same. Not sure about JP or Arias.

Make sure you label all the bolts, etc. I had taken off some stuff before I even had it towed to save time, and had all my shit labelled in separate bags. Wouldn't you know it but the only missing shit (later found, but time wasted) was not in labelled bags, lol.

Crap. Don't want to have to modify the jets/squirters.

and yeah I know what you mean, I'd be working solo too.

SIG:
358WHP & 381WTQ (93 OCTANE PUMP GAS K04 W/N2O!!)


LMFAO!! So much for that 5 months ago:burnout:

Modifying the squirters would be a breeze. If the skirt is hitting them or whatever is, just bend or dremel it a quarter of an inch shorter.

I bent mine a little further to the center and rotated the entire assembly to make sure there wasn't any contact. I haven't taken the oil pan off to inspect but I'm assuming everything is still fine. I'm sure I would've had wristpin (grinding noises) issues by now if the squirters got damaged or weren't effective in their new position.
http://farm8.staticflickr.com/7021/6...da4bfbdd_b.jpg

You got to watch out with that assumption. Your wrist pins are still being lubricated by the oil being thrown through the crank journals and rods. Oil jets are not really needed in most engines. They are a nice performance upgrade Mazda made on these engines. I think that's also one of the reasons the OEM pistons hold up so well. Not because of good material but because they are being cooled by the oil from the jets. If one of the jets is bent, you would most likely not notice anything while driving around. Road racing on the other hand might all off a sudden cause one of the pistons to crap on itself. Melt, crack a ring land, etc.

There are some pics of my build on this thread. http://www.mazdaspeedforums.org/foru...eekend-110042/


Block stayed in the car and I used a Flex-Hone tool to hone it myself. Just nuts and bolts, not hard at all. I worked alone and probably could have finished in 2 days if I needed to finish that fast.

My Wiseco pistons cleared the squirters, but apparently that's not the case for others. You should be able to bend them from up top though.

Good luck

FFFFUUUUUUUU

I'm going back on the rollers soon to smash 400whp in the mouth

I've heard from various sources that honing isn't really necessary on modern, close-tolerance motors.

As for the install....your cams look like they were at an odd angle with the timing tool in there. I think before I pop out the cams to remove the head I'll probably rotate to Cyl1 TDC and take a pic of the cam position with cam plate on just for reference when putting the chain back on, heh.

Yeah, I had to correct the timing. I ended up shaving down a 21mm wrench to fit between the timing cover and VVT cam bolt, broke them lose then tq'd in the correct spot.

The cam plate will not fit inside the slits on the cams unless they are positioned correctly. The slits on the cam ends do NOT run through the middle of the camshaft. They are off center.

Are the wiseco pistons machined to go into the OEM bore size? I thought the bores had to be honed to a larger bore diameter for more piston to bore clearance. Does not look from your thread that you did any meassuring. And since it seems you haven't check your thread lately I am posting that question here.

How about piston slap during start up? Is there much noise?
Does the engine smoke more / have lower compression than stock?

I have genpoo pistons ready to go for my week end "insitu" build but I'd concider doing forged pistons with updated Gen2 piston crowns if I don't have to precision hone the cylinder liners. Just de-glaze them.

Sock bore, stock compression, I get absolutely no piston slap at start up. The engine runs just as it did stock. I expected it to be a little noisy, but you honestly would never be able to tell that it was built unless you dropped the oil pan.

^^^ and 5 over

I think you're thinking deglaze anyways tomas. Hone is typically done so that the rings can seat against a "fresh" surface (deglaze?). Any more aggressive than that and I'd call it a cylinder bore hone.

So what I'm looking at doing is ball hone, I guess. Flex-Hone®, Cross Hole Deburring, Ball Hones

@MS3-a(sore)ASS-rex going to be dropping mine in over the next few days. No major rush for me. Could be back together in a day......who knows maybe I will just finish it up once I start. But I like taking my time!

That's exactly what I got.
3 1/2" (89mm) 240 grit.

What grid did you use on the hone?
How many runs did you do on each cylinder?

I don't fully remember. I went on Flex-Hone's website and followed the demonstration. Something like 10 sec with a few slow passes, then 5 sec with a few fast passes. Just be carefull need the squirters because it could catch. The rings do not reach the very bottom of the sleeve anyway.

With a ball hone I do three passes up and down in quick succession to get myself a nice crosshatch (which is the goal of honing). Odds are that when you pull the pistons you'll still have a nice crosshatch from your factory hone unless your car has epic high mileage.

Your goal is a 45* crosshatch. Make sure when you use the hone to also use a lubricant like liquid wrench to ensure no scoring of the cylinder

We ended up using motor oil to lube the hone and walls. We also didn't go all the way down, so we wouldn't risk hitting the crank.

I think flex hones instructions said to do some 20* passes then a few 45* passes, so this sounds right to me. The first passes are probably to help deglaze I assume. I used P'BLaster as honing lube. It seemed to work well.

Same difference, the oil will prevent scoring and carry away particles as well. Going to the bottom of the cylinder isn't a big deal either since the piston doesn't travel all the way to the bottom of the cylinder.

You're correct. I prefer a ball hone to a flex hone as a personal preference

IIRC, Flex hone says to use a water based oil and not to use motor oil on one of their 'how to' videos (or it may have been something I read). I don't see how motor oil could hurt though.

IDK, I'm just a noob at this kind of stuff though.

Huh? I thought they're the same thing?
You mean flex hone as opposed to regular 3 leg stone hone?
The flex hone uses lil balls. Like the ones sitting below my penis.

And if there is still a nice cross hatch on the cylinder walls, why not just deglaze by using an abrasive nylon filament wire brush? Why hone at all?

Edit:

I just got of the phone with Wiseco. I asked whether the pistons they sell for the MZR DISI would require additional honing of the cylinder walls from a brand new stock block to accomodate the required cylinder to wall clearance and they said yes. I.e. the pistons are not made with a tolerance for a new block. Wiseco assumes if one were to install their pistons that it would be on an engine that will have the cylinders honed out a little larger.

They said stock clearance is 0.003" and their pistons require 0.003 1/2 to 4. Not much actually but it might matter.

The forgings are 2618 and expand quite a bit unlike the 4032 alloys. Not trying to crap on theschrum's party but I'd be worried when shit gets really hot that a piston might seize.

So for me I am sticking to my gen2 pistons.

I was referring to a flex hone as the 3 leg stone hone. I've only ever referred to a ball hone as a ball hone, never a flex hone. Fault is mine.

I still hone the cylinder regardless of the condition of the factory crosshatch simply as part of a process I do.

Edit to your edit: awesome info that you found for the Wiseco pistons. Honestly I dontthink clearances would become an issue on an engine with some mileage on it as opposed to a brand new block that hasn't had any piston rings seated to the cylinder walls.

A bit of wear would probably be all the cylinders need to be "safe" to run the Wisecos. Perhaps that was their theory when they made them? Idk.

Fuck. Now I am really torn between using some aftermarket pistons and the gen2s.
My engine has perfect compression. I was just going to change the pistons as part of changing rods to K1. Now I have to lay sleepless at night again trying to decide what pistons to use. lol

I actually did ask how much he thought one would have to hone to get the higher clearance and he said "quite a bit". Does not look like it going by the tolerance he gave of 1 thousand of an inch more, but I have no idea how much one would have to hone to get there.

What about the arias pistons?

And yeah. When I do mine, I'll have 80k+ miles on the block....should be plenty of wear to just to a ball hone and throw the pistons in.

.0005" is not much material, and I bet hitting with the hone alone would shave about that off, which would get it right within wiseco's spec of .0035"-.004"