Resolved Wrong Ross 9.0:1 pistons

[lee98talon]

My engine block is ready for assembly, but my Ross pistons don't fit. Seem like I bought the wrong one. I got the 9.0:1 compression ratio and 85.5mm bore which comes with the "compression height" of 1.130 . So, the ross pistons are sitting ~ 0.250 too low form the engine deck. What can i do ? and why the differences between the "compression height" and "compression ratio" ?

I got these pistons. 9.0 cr and 85.5mm bore from MAP.

http://www.maperformance.com/ross-racing-pistons-2g-dsm-4g63.html

 

[lee98talon]

I am building just a regular 2.3l block nothing too special. Got the standard Manley rods and standard crank.

I am assuming this ross pistons is for a stroker build ?

 

[arrowhead]

I am building just a regular 2.3l block nothing too special. Got the standard Manley rods and standard crank.

I am assuming this ross pistons is for a stroker build ?

You are building a stroker, there is no "regular 2.3l block", what crank do you believe you have?

 

[boost97gst]

http://www.extremepsi.com/store/product.php?productid=16691
Just googled "ross 2.3 stroker pistons" and hit on the first link. Pretty sure if they're not "stroker" pistons, they arent going to work. Could be wrong, been wrong plenty before haha, check out the specs though and i think you'll see what i mean

Looks like you needed part number 99871 from MAP
Look at the stroke difference

Btw: Really cool that ross has .030 over. Most of the time i just see .020, .040, and maybe .060(though when your .060 over its time for a new block IMO)

You DO have a stroker crank right? Not a standard 4g63 crank. That would explain a lot if that were the case as well, but i dont think you would have missed something that big.

 

[Fullthrottle7]

Sounds like he meant to say that he's building a "Regular 2.0" block to me perhaps but we'll have to wait to see for sure. If he has a 2.4 block that would explain why they are .025 ~ 6mm below deck height, however it wouldn't explain the bore difference so maybe he did actually get stroker pistons for his 2.0/std crank setup and just linked us to the wrong item on MAP's website? Can the OP make sure that the link you sent to the model number 99815 is the correct set you got, thats going to make a big difference in the advice people give.

Oh and if it turns out you actually are trying to get standard 2.0 pistons, got stroker pistons instead, and can't return them for whatever reason, I am in the market FYI! GL with the project!

 

[arrowhead]

He more than likely has the 88mm, regular 2.0 crank, the bore on the 2.4 would be different.
He can not miss on that many counts.

 

[Fullthrottle7]

There are a ton of engine combos out there at this point, he very easily could have ordered pistons that are wrong in more than one way by mistake. You were the one who said that he's building a stroker not him, I said right away the bore difference should have also stuck out if he had a 2.4l block. If he's surprised they are too short however, there is a definite possibility the piston to wall is not immediately caught too... Regardless, we are both in agreement that he most likely has a stock 2.0L block and crank and ordered stroker pistons with the 6mm higher pin and different dish meant for a 2.3l build.

OP, if that is the case, you still have several options. 1) Get a 100mm crank for your version block (6/7 bolt) and just do a real stroker, the 150mm rods you should already have stay the same. 2) Buy custom rods and do a long rod 2.0l. These can rev to the moon and since they are more popular these days than years back the 156mm rods are not as expensive anymore. 3) Sell me your stroker Ross pistons and then buy the right ones!

 

[bpk1337]

OP post the part number of your piston. My Ross pistons were stamped with the part number on top.

 

[arrowhead]

Sounds like he meant to say that he's building a "Regular 2.0" block to me perhaps but we'll have to wait to see for sure. If he has a 2.4 block that would explain why they are .025 ~ 6mm below deck height, however it wouldn't explain the bore difference so maybe he did actually get stroker pistons for his 2.0/std crank setup and just linked us to the wrong item on MAP's website? Can the OP make sure that the link you sent to the model number 99815 is the correct set you got, thats going to make a big difference in the advice people give.

Oh and if it turns out you actually are trying to get standard 2.0 pistons, got stroker pistons instead, and can't return them for whatever reason, I am in the market FYI! GL with the project!

Did you read his second post?, that is what I quoted, I really think he was just swayed by the compression numbers and did not look at anything else, but whichever way he needs to double check all the parts he has and order accordingly.

 

[lee98talon]

Sorry, for the confusion. I'm trying to build a forged 2.3l 6bolt. Stock crank and Manley rods with the 22mm pins and a bore of 85.5mm. Got the pistons wrong when I ordered them. I got the Ross piston part number 99871* on the link I provided above. Look at the different "compression height (c.h.)" .

And for a stroker you need shorter pistons(higher pin set) to match the stroker crank, stroke... according to my search?
I'm I correct?

Also, I'll will be selling these pistons shortly when I get them back from the machine shop and sort things out. Pistons are still at the machine shop.

 

[boost97gst]

100mm crank right(or STOCK 4g64)? Idk what you mean by stock, assuming stock '64 crank

 

[Fullthrottle7]

You're right in what you think is needed to create a stroker, but it still seems that the parts you actually have aren't what you think. To begin with lets clarify that a stock DSM comes with a 2.0l motor with an 88mm crank and 150mm rods. A 2.3l stroker starts with the same block but borrows a 100mm crank from a 4g64 (or 4gcs, G54B, etc) to get an extra 6mm throw at the top and bottom of the stroke. The same 150mm rods are used, and the pistons need to have the pin height adjusted up 6mm to take up the extra stroke gained.

All that said, you told us you still have a stock block and crank, and that you ordered stroker pistons. If your intentions are to actually build a 2.3l stroker, then what you actually need is a 100mm crank, not different pistons. If you are OK with sticking with the block and crank you have, then what you need is just a normal set of 4g63 2.0l pistons, which is exactly what the first link you posted is for! So the part number for the Ross .020 over set at 8.3:1 is 99815!

 

[lee98talon]

Yes, you are correct, Fullthrottle 7. You basically got my idea\plan for the build. I'm just building a stock 6bolt 2.0l. No stroker, but I didn't know and I bought the stroker pistons by accident

Thanks for the reply.

 

[Fullthrottle7]

Sent a PM to you as well, but also make 100% sure your rods are for a 6 bolt crank and have the 22mm small end pin holes. The only 6 bolt ones I know of that you can order with the bigger 22mm pin size (without being custom) are the Eagles and the MAP house rods. If you have Manley rods for a 6 bolt right now, there is a good chance you need to get actual 6 bolt pistons as well which would actually be part number 99811 for the same 85.5mm (.020 overbore) as before! The Ross pistons are a great product and power some of the fastest guys out there. I also like the Manley pistons for our car, the are quite a bit lighter by design and have a good skirt coating thats extra of the Ross. Can't go wrong either way!

 

[lee98talon]

Follow up:
I'm building a basic 2.0l 6 bolt 4g63 turbo motor with the 22mm wrists pins pistons. I firstly order the wrong set, part number from link above, 99871*. Which are "stroker" pistons.

But, I wanted the just the standard 22mm pin pistons from Ross with a .020 over bore. So, at the end of day, I got the pistons I wanted with a little help from Fullthrottle7 and a little more research. Also, I will using the 22mm small end Rods for my 6bolt to machine the 22mm pins on the pistons.

Thanks.