Arias Pistons

[BOOSTD]

Just an update, I talked to my old builder **** ***** Engines today and he agreed to rebuild my motor free of cost excluding parts....hmmn would u trust them again?-I think not.

Peter @ ADVAN is going to gap my rings and check bottom end clearance's for me before I put it back together. At least I'll know it is perfect. ADVAN also stamp the block which should help at Re-sale time. My head needs new valve guilds aswell....I'm running out of dollars fast...grrr

[Blitz]

Matt,

Glad to see its coming together, be it at a cost - I feel your pain!

Here are some picks of my new CP's which from memory are the same pistons you opted for now?

[Bl4cK32]

Just an update, I talked to my old builder **** ***** Engines today and he agreed to rebuild my motor free of cost excluding parts....hmmn would u trust them again?-I think not.

<{POST_SNAPBACK}>

that states he knew he ***d up. I'd still be ringing C.A. and tell em you want a refund for parts and labour.

I wouldve laughed if he offered to build it for free minus parts...labour is sfa compared to the thousands youve probably already spent.

Good luck with the new motor anywaqy

[wrxhoon]

Matt,

Glad to see its coming together, be it at a cost - I feel your pain!

Here are some picks of my new CP's which from memory are the same pistons you opted for now?

Are you using 86.5 mm pistons or 87 ? What clearence , piston to bore ?

Replacing rods as well ?

Edited August 29, 2005 by wrxhoon

[Blitz]

Are you using 86.5 mm pistons or 87 ? What clearence , piston to bore ?

Replacing rods as well ?

Hi Jerry,

87mm, not sure on clearances, was leaving that to the engine builder.

Retaining standard rods, but having them prepped, shot peened and strengthened.

[wrxhoon]

Hi Jerry,

87mm, not sure on clearances, was leaving that to the engine builder.

Retaining standard rods, but having them prepped, shot peened and strengthened.

<{POST_SNAPBACK}>

I had 87 mm bore in my old 33 and 8.7 to 1 comp , she was a quick stock car , 11.7 @121 mph with just N1 turbos and power f/c .

So you should have a very quick car if you keep the compression up .

Good luck with it Nick .

[Beer Baron]

wrxhoon,

you might be able to answer this for me: is the slight increase in volume (comparing 86.5 to 87) worthwhile? I would have thought going the smallest over bore over stock (86mm to 86.5mm) would be the way to go in order to retain nice thick walls, and the scope for another rebuild should the need arise (a bit pessimistic i know). also wouldn't the smaller bore help with the CR or is it easily rectified with different piston design or head work?

cheers

[Roy]

....shot peened and strengthened.

<{POST_SNAPBACK}>

Sorry for being a sticker for details...but it doesnt actually strengthen the rod...does it???

My understanding is that all it does is remove imperfections and surface defects meaning you are minisming the instance of failure due to their weakest points...not strengthening them over and above the norm.

[wrxhoon]

wrxhoon,

you might be able to answer this for me: is the slight increase in volume (comparing 86.5 to 87) worthwhile? I would have thought going the smallest over bore over stock (86mm to 86.5mm) would be the way to go in order to retain nice thick walls, and the scope for another rebuild should the need arise (a bit pessimistic i know). also wouldn't the smaller bore help with the CR or is it easily rectified with different piston design or head work?

cheers

<{POST_SNAPBACK}>

I would only go to 86.5 given the option ( if i could clean the bore with .5 mm ) but when i rebuild mine a couple of years ago i didnt think i could get away with 20 to thou so to be sure i went 40 thou.

walls are thick enough with 87 mm bore even for highly moded engines .

Bigger bore will give you higher comp if everything else stays the same , piston pin height , h/gasket block and head .

You can increase comp by using a thinner h/gasket and or decking the cil head just as easy .

.5 mm extra bore will give you 30cc extra so you have a little more capacity as well but its only very little gain like 1.2%.

[wrxhoon]

Sorry for being a sticker for details...but it doesnt actually strengthen the rod...does it???

My understanding is that all it does is remove imperfections and surface defects meaning you are minisming the instance of failure due to their weakest points...not strengthening them over and above the norm.

<{POST_SNAPBACK}>

Agree with that , if i wanted stronger rods i would change them,

but each to their own .

[Blitz]

Sorry for being a sticker for details...but it doesnt actually strengthen the rod...does it???

My understanding is that all it does is remove imperfections and surface defects meaning you are minisming the instance of failure due to their weakest points...not strengthening them over and above the norm.

Shot peened AND strengthed (i.e crygenically treated etc) - Geez read the post will you tapas boy

I am well aware that shot peening itself isnt a strengthening process.

[wrxhoon]

Shot peened AND strengthed (i.e crygenically treated etc) - Geez read the post will you tapas boy

I am well aware that shot peening itself isnt a strengthening process.

<{POST_SNAPBACK}>

Sure the freezing will make them stronger and the shot peening helps as well Nick , it all depends on what you are looking for though , stock rods are very good and they dont fail with moderate mods but rod bolts do .

[BOOSTD]

Matt,

Glad to see its coming together, be it at a cost - I feel your pain!

Here are some picks of my new CP's which from memory are the same pistons you opted for now?

<{POST_SNAPBACK}>

yep, same ones. I took a few pics of the vennolia's beside the CPs but they didn't come out to clear... The piston skirt on the CP's are at least 1mm thicker. The Vennolia's looked the same thinkness as the stock pistons- 2.12mm. The Vennolia's had thicker ring lans a thinner rings... I'll try the pic ...I would definately get the spirolock grooves machined deeper and use wire or circlips! if using vennolia's

[Beer Baron]

wow! the piston on the right has much thicker ring lands. i wonder which is preferable, thicker rings, or thicker lands?

wrxhoon, thanks for the explanation on that. it's something i have often wondered about as i have seen people go to 86.5 where as some jumps straight to 87mm.

[Roy]

Shot peened AND strengthed (i.e crygenically treated etc) - Geez read the post will you tapas boy

I am well aware that shot peening itself isnt a strengthening process.

<{POST_SNAPBACK}>

Ok, again from my reading and understanding of metallurgy, you are not increasing the strength of the basic metal used in the casting of the std rods. You are improvong the grain structure to remove imnperfections....so just liek shot peening you are removing the weaknesses, not makign them stronger then the basic metallurgy and casting allows....

its a matter of as strong as its weakest link and you are improving the weakest areas

[BOOSTD]

Update,

Engine is completed and running well. I have done 150k's so far without any issues. The motor is very quiet. The noisiest part is the valve train. Stay tunned for the first compression test.

[Blitz]

Good to hear Matt!

Mines going into the workshop shortly - cant wait

[blk180]

yer my valve train is also noisest after rebuild but have done about 3000kms now so will do leak down test soon and start moddn

Edited September 8, 2005 by blk180

[BOOSTD]

Done 350kms....first oil change was very clean, still all good.

[ferni]

How did this go BOOSTD?