It has come to our attention that the Arias pistons from the group buy may have too long of a skirt which upon reaching full operating temperature may come into contact with the driver's side oil squirters.

Unfortunately the pistons do not make contact with the oil squirters until they reach operating temps so it is not readily aparent on installation. It is my understaning that Arias has agreed to modify the skirts to fit, but this was only after all three driver's side oil squirters were broken off a in a motor after it was installed and warmed up.

Here are some pictures for reference purposes only:

 

I just a call from Arias this morning. I spoke to Berry at length on this topic. I just sent everyone this email, but I wanted to post it here just in case I didnt have your correct email addy.

Hi Everyone,

I just got a call from Berry at Arias Pistons, and it seems that there is an issue with their pistons design for hte VQ motor. THis is NOT specific for the GB product...so if you have Arias pistons from another source, or you are a vendor that sells Arias pistons...you might want to take note as well.

To make a long story short, there is the potential for the skirt of the piston to hit the oil squirters on the driver's side of the engine block. I confirmed this also with Charles from CJ motorsports, as he also used the Arias pistons. The clearance is VERY tight, and what could happen is when the engine heats up and expands, the piston could actually contact and break off the oil squirter.

At this point, there are two simple options...both of which will quickly solve the problem.

1) Notify your machine shop/engine builder of this clearance issue, and have him put an 1/8 inch notch on the piston skirt so it will clear the oil squirter on the downstroke. This is what I plan on doing. Any machine shop will know how to do this, since its relatively common for minor machining to be done on rods and pistons during the final assembly of the motor.

2) Berry from Arias has agreed to allow anyone to ship their pistons back to them, and Arias will machine the notch, and ship them back to you. Freight will be paid both ways. Just leave an email for Jason or Nancy at sales@ariaspistons.com They are all in the loop on this issue. They will send you a freight tag, and you simply package up the PISTONS ONLY. Do not send the rings, wristpins, or locks. Just the pistons alone. Obviously, include you name and return shipping detail.

So I will leave the choice to you. Again, I am planning on having my machine shop do this work for me, but feel free to send them back to Arias if you prefer.

Lastly, Arias is notching all of their inventory of 350Z pistons, and they are updating the schematics so all future pistons will have the notches.

 

And uhh, if anyone from the group buy wants to sell their pistons, you can PM me. k thx bye

Chris

 

That really sucks for the guys who already have their engines built

 

yeah i just got my engine built and i'm in the final stages of dynoing.....WTF am i going to do. take the car apart and have them fix the pistons? i've been waiting very long to have my car finished. and not i have to wait even longer? who is going to pay for this? i'm sure the FU*K not. this sucks so f'ing bad. i was going to get my car back on friday. now who the hell knows. God Da*m this turning out to be a bad day.

Dustin (pissed the f off)

 

Dustin, if they are dynoing the car, and they dont hear anything unusual...then forget about it. Your engine will be fine.

The clearance is tight, but I am sure there are plenty of engines that were successfully built with these pistons...without the notches. It's probably hit or miss. If they arent hitting after heat expansion, then they never will.

Also, most good machine shops/engine builders will check the clearances of the oil squirters, and machine adjustments accordingly.

Hope that helps.

 

double post..sorry.

 

they are checking now....update later

Dustin(still nervous)

 

OMG am i lucky. My machine shop has been on hold for the main bearings from Nissan so the bottom end still hasnt been assembled and balanced. Nothing lost. Weeeeh, close call.

Please, no more suprises!

 

yeah i had to wait on those main and rod bearings for like 3 weeks. stupid nissan. still no word yet on the oil squirters and clearences

Dustin(without anymore nails to chew off)

 

lucky for me my heads were not ready for use so its no big loss for me either. my machinist is extremely depressed that he did not notice this, he has picked up on the smallest things before, thats why i never questioned it. its just so hard to notice because of how close it is... when cold you can spin the motor by hand and you will not notice. and on this engine its hard to get a clear look at the squirters so i can see how so many motors got assembled like this.

this is the result of how manufacturers do not test their parts in engines before selling them.

 

Same exact thing happened to me..waiting for bearings...no assembly yet. thank god!!

 

For all the good things said about Arias in the past, I have to say that this is extremely objectionable. I understand that the almighty dollar reigns supreme, but there is no excuse for not testing your product. I'm fairly disappointed. I'd say that I'd go purchase some other company's pistons, but I have no faith that any other company tests theirs either. It's sad, especially when failure would cost the customer thousands of dollars.

I suppose it's easy enough just to slap the "only for off-road use only, not liable for any damage caused by this product" sticker on there.

 

Azrael, the problem is that very few if any piston manufacturers test fit the pistons in an actual engine. They base the design on the stock piston, and stock rod. Think about the hundred different engines that these companies make pistons for...it would be cost prohibitive to buy and engine to test fit them. I am not making excuses for Arias, but they have sold thousands of piston sets for different cars and have never had this issue.

I still think that even in this case, the person that assembles the motor should take some responsibility for insuring the clearances are correct. But at the end of the day, Arias made an error in the design of the piston, and they will correct it.

 

I would drop the lower oil pan and make sure the oil squirters are not already broken off because the noise may not continue if they broke off cleanly and are not still coming in contact with the skirts.

 

Caveat Emptor, let the buyer beware, huh? I'm sure Arias devotes space on their website to express their close tolerance production techniques for a precision fit of their products, right out of the box. If the product is defective/sub-standard/mis-labeled right out of the box, I can't see how Arias, in this case, could duck their responsibility to make things right. Sure, it's costly for them, but that's the price you pay sometimes when you rush an otherwise perfectly good product to market. (It's always the small details that get you...!)

Does Arias provide installation instructions with their pistons? Do they mention clearances should be checked and rechecked prior to final assembly? Do they advise possible trouble-spots to look out for, like notching piston skirts to clear oil squirters?

Lastly, it could be that contact is made only after warm-up and during high rpm driving. Certainly Arias could have contemplated engines equipped with their pistons would see high-revs once in a while... I guess I don't expect a manufacturer to be perfect, but I do expect them to test products, and if a design/production fault manifests itself after product release, it is their responsibility to make things right, even if the pistons have been installed.

Good luck, all.

 

Arias been pretty "stand-up" about the issue. If they were a dicky company, they could have told us all to f-off and be done with it. But they are paying freight both ways for anyone that wants their piston skirts notched, and they have already changed their design diagrams to include the modified skirt...so future pistons will be correct.

 

Well I guess I can say Im lucky also . Only the upper oil pan has been put back on the block . I need to contact SGP and see if they checked that clearance for the squirters .Im lucky the heads are not done or the block would have been back in the car today.
Im sure this is going to cost a days labor to take the pistons out of the block , notch them and reassemble . I hope Arias takes care of the cost of every one to fix this problem

 

Won't grinding a clearance notch on the pistons throw the balance of all the reciprocating parts off?

 

When they cut the notches, they rebalance the entire piston to less than .5 grams of one another. So the balance will be correct.