Looking for some view's and advice on what piston's and con rod's to go for with my up coming APS build.

I was dead set on a full cosworth bottom end (piston,rod,stud kit,bearings,HG and piston ring set) but a a few weeks ago a mate who's been running the cosworth gear developed a bad sound coming from his motor. After having the motor stripped down two of the low comp cosworth pistons had failed (Cracked piston skirts).

After a phone convo with Mark@abbey motorsport here in the UK he advised me not to use the cosworth pistons due to them needing quite a high piston-to-wall clearance. He said he would go with the wossner turbo pistons and rods of my choice.

This now has me in a bit of a dilema as im not sure what components to use??

Does any one have any advise for a good Rod/piston combo?

Also the wossener pistons use 4032 Alloy (T6) and the cosworth run 4130 i think. Im looking for a piston with low expansion so the P-T-W clearance can be as small as possible to reduce piston slap and get the motor running nice and smooth.

Any help is great guys.

Thanks Tim.

 

i say 90% of all built motors in the US use an eagle rod/arias or weisco piston combo

 

Weisco pistons (8.5:1), pauter rods here, ACL bearings, HKS HG, L19's

tom

 

CP Pistons or Arias ED and Pauter rods IMO.

 

+1

Eagle rods are proving themselves to be very good. They held up to over 800 whp on XKR's last build, and over 600 whp on mine. (I way over-reved my motor and destroyed 2 bearings, and hence have a new build underway).

Pauter rods will be stronger, but also a bit heavier. That means there is more recipricating mass, and thus more stress on the bearings. Carillo rods are also supposed to be very good, and may even be lighter than the Eagle rods, if I remember correctly. Also, GTM has their own brand of rods, and these also seem to be very good.

Wiseco, Arias and CP pistons are all well proven. I have not heard of any issues with Wiseco or CP pistons. Previously, there was an issue with Arias pistons breaking off oil squirters, but I am fairly confident that Arias has addressed this issue. Also, I have been told by one person that Arias pistons expand more than Wiseco or CP pistons. I do NOT know whether this is true, however. (EDIT: This was confirmed by rcdash below).

On my current build, GTM had Arias pistons in stock, but I opted to wait for Wisecos. The price was the same either way for this build because they are custom pistons with a 97mm bore. The Wisecos are my preference based on some research and speaking with long time engine builders. When I originally researched the piston issue, I came accross this thread in another forum:

http://hondaswap.com/forced-inductio...vs-ross-40393/

The thread speaks about a report for testing that was performed comparing Wiseco, CP, JE and Arias pistons, but the report no longer appears to be avialable. Nonetheless, you can get the gist of the report contents from reading the thread. It is from 2004, so things may have changed in the last 5 years, so you may take it with a grain of salt.

In summary, I don't think you will go wrong with any of these pistons. Wisecos are my preference, but others prefer CP pistons, and still others prefer Arias... For off-the-shelf pistons, Wisecos tend to be the least expensive.

 

Arias ED + eagle rods, as has been stated, is a tried and true combination. Give Sharif a call 770-792-0202. I believe he had a hand working with Arias to provide some feedback on the design of their ED piston for the VQ platform.

 

Hi Raj, so is the Wiseco/Eagle combination, and various combinations of Wiseco, CP, Arias pistons with Eagle, Pauter, Carillo and GTM rods. I don't beleive the OP will go wrong with any of these combinations. There is no "right" answer. If the OP is going to get into serious hp (i.e. >900 whp), he should talk to the respective rod manufacturers before making a decision.

 

I only reiterated that combo because it's the only one I have personal experience with. The OP also asked about piston to cylinder wall clearances. As I recall some of the pistons are zero silicone forged, while others are low silicone. This has an impact in the amount of piston slap that the OP is looking to avoid. Only a builder that has built with all of them is going to be able to provide a useful comparo. So I'd still recommend just calling them up for recommendations.

 

The piston-to-cylindar wall clearances should be based on the piston manufacturer's specifications. For example, Wiseco recommends 0.003" for a N/A motor or a moderate hp turbo motor, and 0.0035" for a high hp turbo motor. (This is FACT - I personally spoke with Wiseco Engineers regarding the proper clearances for my new motor).

It is my understanding (UNCONFIRMED) that Arias pistons require 0.005" piston-to-cylindar wall clearence. This would correspond to the other bit of information that I heard pertaining to Arias pistons expanding more than others. Nonetheless, based on my research and discussions, I am not interested in Arias pistons - so I never investigated this issue further, and thus my understanding could be incorrect.

UPDATE: I was missing one zero in each of my clearances.

 

This is all you need.

 

Pricing from Import Parts Pro:

Wiseco 8.8:1 CR, 96mm pistons: $699

Arias 9.0:1 CR, 96mm pistons: $1,045

Now, I greatly respect Sharif and whole heartedly recommend Forged Performance. Nonetheless, there is a $346 price difference. Even though alot of people have good luck with Arias, alot of people have good luck with Wiseco.

So, does anyone have a logical explanation for spending the extra $346 on Arias pistons. If someone has a clearly logical explanation, I want to hear it. And pleeeaaaasssseee don't just come back and say "more people use them," because I'm just going to come back and say yeah, well more people also have had their oil squirters broken off by Arias pistons too. In other words, just because more people use them does not make them better, just as the oil squirter argument may no longer be valid if Arias has already addressed the issue.

 

In my build i went with Wiseco 8.8 96mm ($599 shipped), and Eale H bear rods. So far so good, I do get piston slap when cold but thats common for Wiseco's since they need to expand. I have been told that Arias dont expand as much so you can run a tighter clearance (i have not verified this info since I didnt go with Arias).

 

What are your piston-to-cylindar wall clearances?

 

As I recall Arias developed their ED piston line after some failures with their first design for the VQ. So while there were some reported failures with Arias, I haven't heard of an Arias Extreme Duty failing to date. I'm sure all manufacturers have a failure rate due to QC, defects, etc. Again, only someone that deals with multiple brands is going to be able to provide some useful comparison. All we can do is speculate about our own choices.

By the way, I confirmed that Arias ED pistons are zero silicone forged and require slightly greater cylinder wall clearances due to thermal expansion characteristics (in exchange for additional tensile strength and reduced fatigue characteristics).

 

If I remember correctly, .035, I have it in writing somewhere, so I could be wrong.

 

Great. Thank you, Raj!

0.005" I'll bet.

 

+1 for Wiseco pistons

Intense prefers them for their high power Supra and VQ builds. They order them made to their spec.

Crower is another quality rod worth consideration that is proven in high power builds.

 

This is exactly the kind of information we need more of on here, thanks for your input guys!!!

 

Wiseco ED + Eagle rods.

 

just call sharif....he wont make u pay retail
arias extreme duty and pauter rods is what i have but like already stated eagle rods are a great alternative and have proved themselves