Mazdaspeed Forums - Drop-in forged internals

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- - Drop-in forged internals (http://www.mazdaspeedforums.org/forum/f10/drop-forged-internals-102383/)

Keep in mind if you want a fresh surface for the rings (which frankly was the thing everybody was told to do with new pistons/rings, but isn't so much necessary anymore based on the new tight tolerances), Sears sells a cylinder bore hone kit that you throw on an electric drill. I knew a guy who built SR20's, and any block with clean cylinder walls, he'd use that on with great success.

I agree that bearings can be measured in the car, rod bearings, and if anything, have the piston/rod combo assembled prior to installation and balanced to match weight as best as possible.

Anyhow see if this works... I got a video for checking cylinder bore too. They are all from that 100 series blueprinting youtube series. good stuff for a DIY to see if the block is good.

Blueprint 106 - Cylinder Bore Inspection - YouTube

That guys entire series of vids are great. I ran across them about a month ago I have them all bookmarked.

Quote:

Originally Posted by Dano (Post 1213251)

Yup. The eagles for the sti build, 3 were identical with one being one gram heavier

There is also balancing each end of the rod and we will be doing that and getting them to within .5 of a gram iirc. Getting the whole rotating ass balanced as well. Pully-crank-FW

This is also going to be a high compression setup, somewhere around 9.5 iirc

Should be fun.

For me, I like to put in some gen2 pistons if you can get them cheap, w k1 rods and call it a day.

For you and nitros I would replace the pistons fo sho.

Tappin

9.5:1 is pretty much a stock compression ratio lol. High comp is 10.5/11:1 but generally reserved for E85 builds as it resists detonation much better than regular fuels.

I'll probably have a few friends whom are very experienced in engine assembly help me with this if/when I decide to do it. Even though they're not familiar with the MZR themselves engines are universal in theory and application.

Also, I'd like to avoid moving the oil squirters so it seems CP pistons are in order opposed to the Wiseco pistons I originally intended. I'm not a fan of the K1 rods strictly because they're not of the stronger H-Beam design, and if I'm loading the car up with nitrous at low RPM's I need the peace of mind lol.

Lol. I may be off on the comp ratio. How about a higher Than OE comp ratio?

He's already on E w 1200cc top feed injectors.

Quote:

Originally Posted by Dano (Post 1213434)

Lol. I may be off on the comp ratio. How about a higher Than OE comp ratio?

He's already on E w 1200cc top feed injectors.

My bet is definitely on the 10.5/11:1 area lol

Gen2's, per Mazda's literature, come with Forged Rods and Forged Crank from the factory. Pistons are hyper I believe.

Quote:

Originally Posted by mrmonk7663 (Post 1213457)

Gen2's, per Mazda's literature, come with Forged Rods and Forged Crank from the factory. Pistons are hyper I believe.

Gen1's come with forged internals too. It doesn't change the fact that although forged the design is still weak. If you compare an OEM rod to an Afdtermarket rod you'll see a significant size difference between the two.

Forged does not = strength

Just stating the literature...not debating over the effictiveness of aftermarket selection. I know the aftermarket is superior in metallurgy, design, and strength :)

In for future fail.. I kid, if you need any help lemme know

Quote:

Originally Posted by Don06speed6 (Post 1213477)

In for future fail.. I kid, if you need any help lemme know

You know I do not fail....unless it's transmission related lol

Well, since I spun a rod bearing about a month and a half ago and required a new crank and rods and etc. I could be interested in giving this idea a shot possibly.

waiting on the new rods to show up so I can take everything to get balanced and then it's game on again :)

Quote:

Originally Posted by essejkcamraw (Post 1213500)

I tried to tag you earlier on in the thread Jesse but I forgot how to speel your username lol.

Quote:

Originally Posted by MS3-a(sore)ASS-rex (Post 1213503)

I tried to tag you earlier on in the thread Jesse but I forgot how to speel your username lol.

and the word "spell" too apparently :biggrin:

I saw that, I read the thread earlier on my phone and saw the tag. anyways, depending how I feel at the time when it comes to start rippin' apart my car I'll decide if the motors coming out, or if I would want to give it a shot with it in if you haven't already. depends how lazy I want to be about it :)

I'm giving the Eagle rods a shot this time too. although the K1's were damn nice, I cant buy just a single K1 so, I went with Eagle H-beams this time. it's been two months almost since my cars ran, shit's making me depressed now.

Quote:

Originally Posted by MS3-a(sore)ASS-rex (Post 1213438)

My bet is definitely on the 10.5/11:1 area lol

His pistons are 9:8 but with the head calc comp will end up at 9:2

OE is 8:2 I believe ( according to him) so although not a "high" comp motor it's higher than OE.

Tappin

Quote:

Originally Posted by essejkcamraw (Post 1213652)

That sucks man. What's the time frame for you getting it back together? What about bearings, gaskets etc..?

Also, what pistons are you running?

Subs for....

Poor Compression

Quote:

Originally Posted by Brian MP5T (Post 1213901)

Subs for....

Poor Compression

Lol. Our stock compression is 8.5:1 I intend to bump it to either 9:1 or 9.5:1 and it'll probably be the latter.

Quote:

Originally Posted by MS3-a(sore)ASS-rex (Post 1213913)

Lol. Our stock compression is 8.5:1 I intend to bump it to either 9:1 or 9.5:1 and it'll probably be the latter.

Stock compression is actually 9.5:1. So if you plan to bump it you'll be one of the first to go for 10:1 or 10.5:1 which the DI will probably love if you can get the tune right.

Quote:

Originally Posted by MS6_Auburn_Fan (Post 1213931)

Stock compression is actually 9.5:1. So if you plan to bump it you'll be one of the first to go for 10:1 or 10.5:1 which the DI will probably love if you can get the tune right.

Are you sure about that? According to CP Pistons our stock compression ratio is 8.5:1. I doubt Mazda would have given us a 9:1 compression ratio on a factory turbo'd car. They like to keep it low.

CP Pistons link: CP Pistons Mazdaspeed 3 MS3 Mazdaspeed 6 MS6

Quote:

Originally Posted by MS3-a(sore)ASS-rex (Post 1213124)

Oh shit hey alex lol. Yea man I'm playing no games this time around

Sup man! Lol. Finally got my Evo :P Wish you wouldve gotten the 5.0 but this platform has exploded since then so I'm glad to see you back at it ready to show a lot of these nooberts how it's done. Hope all is going well for you man

Quote:

Originally Posted by 4G63 (Post 1213944)

They just over complicate things lol. The dsm-er in me won't allow for that lmao

No Poor Compression as in...

Installing new Pistons into an engine that has not been machined... and thus not holding compression because the rings are not seated properly...

Quote:

Originally Posted by MS3-a(sore)ASS-rex (Post 1213943)

I dont know man, the ms6 training manual says our cars are 9.5:1
https://lh6.googleusercontent.com/-E...ompression.jpg

Stock is 9.5:1

Do allows u to run higher comp ratio on boosted cars

Quote:

Originally Posted by Brian MP5T (Post 1213977)

No Poor Compression as in...

Installing new Pistons into an engine that has not been machined... and thus not holding compression because the rings are not seated properly...

If the cylinder wall isn't damaged and I hone the cylinder (like I always do) for a good cross hatch and gap the rings properly, there should be no reason for the car to have poor compression.

Quote:

Originally Posted by crazyp (Post 1213987)

I dont know man, the ms6 training manual says our cars are 9.5:1
https://lh6.googleusercontent.com/-E...ompression.jpg

I wasn't arguing just saying what I'd seen. Thanks for the info!

I agree that machining is not always necessary.

Someone mentioned using gen2 pistons. Is there a difference between gen1 and gen2 pistons?

Second, forged, yes there's a difference. Our stock rods are forged powdered metal, if I remember correct. Aftermarkets are either forged or billet.

Again, I'm thinking if all the surfaces are good with no scoring (they should be), then you should be good to go. However, you may need a week or so downtime because you'll need to measure for bearings, order bearings, and perhaps have the bearings coated to make sure clearance is within spec.

But, if you get the pistons/rods assembled with rings, make sure they're balances as best possible, I don't see how you'll have any issues throwing them on the crank. As people mentioned, stock crank and harmonic balancer are pretty well balanced from factory.

If I were building a motor and had the money to spend, I'd have it all balanced, but I'd also have the crank knife-edged and cryo'd. Knife edge to minimize friction with the oil and splashing as well as reduce weight, and cryo'd for additional strength. Then of course have the crank, pistons/rods/pulley/flywheel/clutch all balanced together.

Gen2 pistons are dished which promotes better atomization and flame front travel.

I will have to look up 06speed6's compression numbers but I think you guys are getting static compression confused with dynamic compression. What the piston manufacturer states their pistons are is not what compression you will have in the cylinder.

in the scoobie example his weisco's are 9:8:1 and in the car he will be running 9:2:1

our cars compression calculates out to 8. something with OE cams.

BRB

8 seems rather low. We'd be pretty damn sluggish off the boost with 8:1 compression..........that doesn't seem right. Remember, the OEM compression rating isn't referring to the pistons.

Here is one post but not the one I was looking for. I guess it doesn't really matter which compression ratio you quote but everyone does need to be on the same page and I for one think you need to be referring to Dynamic ratio but who knows...lol

so we are somewhere between 8:1:1 with no VVT and 8:58:1 at full advance OE cams

Quote:

Originally Posted by 06Speed6 (Post 318977)

I just took apart the VVT mechanism I have laying here, it advances towards the exhaust stroke which would be a lower LSA number.

Ironicly it also doesnt advance 30*, the max is 18* on my degree wheel.

Lets run the numbers again with this in mind...

Assume stock LSA is 108*, then:

Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 108*
Inlet Valve Closes After Bottom Dead Center (ABDC): 54* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.19:1
Dynamic Cranking Pressure: 141.89 PSI
Dynamic Boost Compression Ratio: 18.22:1

And with 18* max advance:

Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 90*
Inlet Valve Closes After Bottom Dead Center (ABDC): 45* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.58:1
Dynamic Cranking Pressure: 150.30 PSI
Dynamic Boost Compression Ratio: 19.09:1

Discuss in relation to the VVT chart.

Edit:

ok here is the post I was looking for which just has more "what if's" for LSA.

Quote:

Originally Posted by 06Speed6 (Post 318778)

Ive been doing some pretty intensive research into cam specs, stroke, rod length, and bore diameters and their effects on engine performance and how they all tie into each other.... so I can build an engine that will make enough hp to bitch smack all you naggahs back to 1983.

An explanation of Dynamic Compression Ratio (DCR) vs Static Compression Ratio (SCR): SCR is calculated from total amount of compression available from the measurement beginning of Bottom Dead Center (BDC) which is the maximum amount of compression mechanicly available. DCR is calculated on the compression stroke after the intake valve closes since you cant really have compression with the valves open. The DCR will always be less than the SCR and the DCR is closer to a real world compression ratio.

The only difference between DCR and SCR is that on the DCR the intake valve closing is calculated into the equation.

My engine specs with aftermarket cam:
Bore = 87.5mm/3.445"
Stroke = 94mm/3.701"
Rod c/c = 154.75mm/6.092"
Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 115*
Inlet Valve Closes After Bottom Dead Center (ABDC): 57.5* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.00:1
Dynamic Cranking Pressure: 137.81 PSI
Dynamic Boost Compression Ratio: 17.80:1

The dynamic compression ratio for this setup with my aftermarket cams is 8.0:1 which is the middle of the acceptable range of 7.5:1 and 8.5:1 for pump gas engines. Anything less than 7.5:1 is bad for power and torque and anything above 8.5:1 will generally knock on pump gas.

If we change only the LSA to the factory cam spec of 108*, we get:
Bore = 87.5mm/3.445"
Stroke = 94mm/3.701"
Rod c/c = 154.75mm/6.092"
Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 108*
Inlet Valve Closes After Bottom Dead Center (ABDC): 54* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.19:1
Dynamic Cranking Pressure: 141.89 PSI
Dynamic Boost Compression Ratio: 18.22:1

Now to Lex's theory, which I generally laughed at: He stated that low rpm torque lead to grenaded engines and the boost and timing ranges needed to be altered to move the peak torque higher in the powerband.

I knew Lex was onto something but I also though he was wrong because we have a very long stroke and if our rods were that weak the piston velocities would be grenading engines left and right at high rpm and high boost long before the low rpm torque would do anything.

Here is something that struck me today when I was running the numbers and expectially after reviewing Subparpunk03's VVT chart. The variable valve timing advances the intake cam a max of 18* in relation to the exhaust cam, in the higher load ranges of RPMs less than 5000. This cam advance does two things, it moves the powerband of the cam lower so we can have both a low rpm high torque cam and a high rpm high hp cam, but here is the catch: it raises the dynamic compression ratio of the engine in low RPMs to potentially dangerous levels that could induce knock.

If we advance the LSA of the 108* cam 18* we get:
Bore = 87.5mm/3.445"
Stroke = 94mm/3.701"
Rod c/c = 154.75mm/6.092"
Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 90*
Inlet Valve Closes After Bottom Dead Center (ABDC): 45* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.58:1
Dynamic Cranking Pressure: 150.3 PSI
Dynamic Boost Compression Ratio: 19.09:1

If we advance the LSA of my 115* cam by 18* we get:
Bore = 87.5mm/3.445"
Stroke = 94mm/3.701"
Rod c/c = 154.75mm/6.092"
Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 97*
Inlet Valve Closes After Bottom Dead Center (ABDC): 48.5* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.44:1
Dynamic Cranking Pressure: 147.28 PSI
Dynamic Boost Compression Ratio: 18.77:1

This dynamic loading could explain why our engines like to knock and grenade at low rpms and almost no one blows at high rpm or high boost. The bottom line is that the closer you get to 8.5:1 dynamic compression the more likely you are to knock and engine reliability goes down the drain. At around 8.58:1 near idle coupled with very advance timing and close to stotch a/f I think we could be walking a razors edge for low rpm knock even with the benefits of direct injection.

One final thought after sleeping on everything last night, if we look at that chart and take it as a percentage of the whole 18* of maximum advance, then 30 on the chart would be 30% of 18* which is exactly the nice round number 8.30:1 dynamic compression as evidenced by the following:

Bore = 87.5mm/3.445"
Stroke = 94mm/3.701"
Rod c/c = 154.75mm/6.092"
Static Compression Ratio (SCR): 9.5:1
Lobe Seperation Angle (LSA): 102.6*
Inlet Valve Closes After Bottom Dead Center (ABDC): 51.3* (Lash not factored in)
Test Boost Pressure: 18psi
Altitude: Sealevel
Dynamic Compression Ratio: 8.30:1
Dynamic Cranking Pressure: 144.26 PSI
Dynamic Boost Compression Ratio: 18.46:1

The bonus to all of this is that with the proper aftermarket cam, we can have our cake and eat it too because we can run an agressive, lopey cam and still enjoy a smooth idle.

Special thanks to Subparpunk03 and Superskaterxes for helping me with this.

What are your thoughts?

entire discussion here

http://www.mazdaspeedforums.org/foru...tml#post318778

Bearing clearance seems to be the biggest issue so far. That's why I'm waiting on Jesse to assume his engine with the eagle rods.

Well, that and the head. I hate fucking timing chains. I suppose itd be smart to swap the vvt shit while it was all apart

lol where does it end...get a DCR VVT if your going there.

yes it does seem that the oil clerenes are a big unknown for us thus far...some are way lose [Dustin] some are way tight [jesse]. There are alot of rod bearing combos so the only way to know is measure.

I'm gonna try and get my hands on a spare long block so that I can experiment with some shit. Don't know when I'll get one but this way I can spec everything out then just do the swap in the car (and by that I still mean the drop-in internals) fuck pulling the engine.

Quote:

Originally Posted by chimmike (Post 1214055)

8 seems rather low. We'd be pretty damn sluggish off the boost with 8:1 compression..........that doesn't seem right. Remember, the OEM compression rating isn't referring to the pistons.

Excerpt from the quoted post regarding the acceptable range of DCR on pump gas.

The dynamic compression ratio for this setup with my aftermarket cams is 8.0:1 which is the middle of the acceptable range of 7.5:1 and 8.5:1 for pump gas engines. Anything less than 7.5:1 is bad for power and torque and anything above 8.5:1 will generally knock on pump gas.

back in the day I had a 302 with 10:5:1 pistons and had to run either C12, C14 or I could get by on a mix of 93 and C12 if I retarded my advance...and to do that you turned the distributor....lolololol

Quote:

Originally Posted by Dano (Post 1214099)

doesn't sound like the MZR, hence referring to aftermarket cams.........and I think the direct injection changes things a little regarding knock on pump gas.

Where's Pablo?

you do know we haz turbos that increase the compression ratio way beyond 8:5:1 right?

my quotes are from 06speed6 and the work he did on his MZR.

In looking at that thread, I find the following very interesting too:

Quote:

Originally Posted by 06Speed6 (Post 860506)

Completely off topic, but the rods are plenty strong. There is a drag car that runs a stock MZR-DISI short block to north of 1000hp with no modifications.

So a stock short block motor making 1000hp on stock rods? OP might wanna look at this

http://www.mazdaspeedforums.org/foru...23/index3.html

Quote:

Originally Posted by chimmike (Post 1214118)

In looking at that thread, I find the following very interesting too:

So a stock short block motor making 1000hp on stock rods? OP might wanna look at this

http://www.mazdaspeedforums.org/foru...23/index3.html

I've seem that elsewhere too. I'm still concerned about a high load at low rpm

lol...I'm not sure of the definition of "stock block" in the 1K HP story. If its the motor I am thinking about its a MZR block with PI head and only the "block" is stock....not the internals.

Meaning no girdling or gussets added to strengthen the block itself.

I could be totally wrong but god 1K HP would be insane on our rods and long stroke.

still interested to see the end of this "drop-in" story...be it Tom or Jesse.

Im running ~2.2 load at 2000rpm, stock block and turbo, zero knock.

I am also running ~30* max cam advance from idle to about 1500rpm because there isnt enough oil pressure to keep the vvt from hitting its internal stops.