JAM* Spec Venolia forged pistons.........simply the best.
Several observations that I have made after running the JAM shortblock for about 10k miles:
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
Several observations that I have made after running the JAM shortblock for about 10k miles:
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
I will address your points and try to avoid a pissing contest here. Let's try and keep this purely technical. If you have anything to add please feel free to PM or call me 410-859-3269
The top land is positioned farther away from the crown of the piston to isolate the top ring from the excessive heat in the chamber from high boost and unleaded fuels. The .180" will not hold up in a high boost application for any extended period of time.
The skirt isn't as long as it appears to be. The photo is deceiving. The length is comparable to the OEM piece. It can't be any longer because then there would be clearance issues with the crank, oilers AND rods.
Incorrect. The grooves are designed for oil retention and is not detrimental as you imply. The thin film of oil serves to supress noise (piston slap) during cold start and DECREASES the wear on the cylinder walls due to the added lubrication. They do NOT collect carbon! Blatant misinformation. How do you end up with carbon past the rings if they're sealing properly? Sound like a result of poor piston design to me.
Everything about the pins is designed for strength. The material has been moved to the highest load bearing area which is the center. Please go back and read the thread. This is called "taper boring" or "taper walled".
Please go back and read the original post again. The buttons are NOT for pin retention. They are used in place of an oil support rail on stroker pistons where the pin intersects the oil ring groove. We use a spiral lock for pin retention. This is FAR superior to a wire lock. More misinformation.
Yes, but not all. It is a feature of the piston that is worth mentioning and describing the benefits of.
You are correct, however it's not true forced oiling. Most of the pistons that we've seen come through the shop have the oil hole in the bottom of the pin bore which creates a weak spot in the most critical area and also inhibits proper lubrication and engine life. The Venolia forces pressurized oil between the pin and bore.
But for how long? I can make 1000hp with just about any parts on the market but what we're after here is high HP AND longevity. You can't win a race if you can't finish a race.
You couldn't be farther from right. Venolia is a HUGE manufacturer that supplies pistons to all forms of racing around the world. Just because you don't know what they do, how they do it and why it's done is no reason for you to make derogatory, slanderous comments towards their products. They aren't as widely known as some of the other companies because they don't offer a shelf piston and don't sell to the general public. Don't use this as ammunition against them.
The top land is positioned farther away from the crown of the piston to isolate the top ring from the excessive heat in the chamber from high boost and unleaded fuels. The .180" will not hold up in a high boost application for any extended period of time.
The skirt isn't as long as it appears to be. The photo is deceiving. The length is comparable to the OEM piece. It can't be any longer because then there would be clearance issues with the crank, oilers AND rods.
Incorrect. The grooves are designed for oil retention and is not detrimental as you imply. The thin film of oil serves to supress noise (piston slap) during cold start and DECREASES the wear on the cylinder walls due to the added lubrication. They do NOT collect carbon! Blatant misinformation. How do you end up with carbon past the rings if they're sealing properly? Sound like a result of poor piston design to me.
Everything about the pins is designed for strength. The material has been moved to the highest load bearing area which is the center. Please go back and read the thread. This is called "taper boring" or "taper walled".
Please go back and read the original post again. The buttons are NOT for pin retention. They are used in place of an oil support rail on stroker pistons where the pin intersects the oil ring groove. We use a spiral lock for pin retention. This is FAR superior to a wire lock. More misinformation.
Yes, but not all. It is a feature of the piston that is worth mentioning and describing the benefits of.
You are correct, however it's not true forced oiling. Most of the pistons that we've seen come through the shop have the oil hole in the bottom of the pin bore which creates a weak spot in the most critical area and also inhibits proper lubrication and engine life. The Venolia forces pressurized oil between the pin and bore.
But for how long? I can make 1000hp with just about any parts on the market but what we're after here is high HP AND longevity. You can't win a race if you can't finish a race.
You couldn't be farther from right. Venolia is a HUGE manufacturer that supplies pistons to all forms of racing around the world. Just because you don't know what they do, how they do it and why it's done is no reason for you to make derogatory, slanderous comments towards their products. They aren't as widely known as some of the other companies because they don't offer a shelf piston and don't sell to the general public. Don't use this as ammunition against them.
I'm providing factual information here. I could go on about the skirt grooves, skirt tail, buttons, and wrist pin selection (if endurance was the purpose of the design, why a tapered, thin wall pin?).
I'm not saying this piston won't work, I'm saying there are much better options out there.
Venolia is not a huge piston manufacturer...I've been there.
So what exactly are your credentials to be spouting off so much technical misinformation? What piston company do you work for in California? You can't argue with the success we've had with our pistons, our designs and our builds. They last AND make power. Go back and read my first reply to you where I have already addressed all of the points you're trying to make....again.
Because they're not backwards! They work. Call it "old school" or whatever you wish.
Where did I ever say that it was a thin wall pin? Nowhere. Where did you get that from? And they do hold up in endurance applications so once again your theories are out the window.
According to who, yourself?
Originally Posted by SeanC
I'm just surprised that more people don't realize that this piston has some backwards design features.
Originally Posted by SeanC
(if endurance was the purpose of the design, why a tapered, thin wall pin?).
Originally Posted by SeanC
I'm providing factual information here
Several observations that I have made after running the JAM shortblock for about 10k miles:
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
The top land IS way too thick, you can't argue that fact. .240" -.280" is plenty almost any turbocharged application. A large top land increases the crevice volume around the outside of the piston (since the top land is tapered) and lowers efficiency by providing an area for raw fuel to "hide" from combustion. Yes, the top ring temperature will be lower, but at the cost of power. All Wiseco, JE, CP, Mahle, Cosworth and other aftermarket pistons all have a top land thickness of .180" to .280". There IS a reason and it has proven to be reliable. Look at the top land thickness of the stock cast EVO piston and how many people are making 500whp in a daily driver...enough said.
I can see what you say about the tall top ring land creating what would be something akin to a quench area between the land and bore. As to what (if any) real world difference this would make one way or another, who can say? The Venolia piston looks to me something like an NHRA piston - a piston that one could beat on with a hammer and not worry about it.
As for the ring lands in the factory pistons, be advised that the most common death for a factory EVO piston is a broken top land. Being that my long-rod 2.0 calls for a stroker piston, I'm guessing that my top land may be 6mm (0.236") shorter than the regular Venolia 2.0 piston.
Obviously, the button is serving a different purpose than what we commonly think when we see a piston button. Interesting . . .
As far as the skirt length, it reminds me of the piston that BMW used for its high rpm DTM engines. IIRC, the purpose was to transfer more heat away from the piston, which improved longevity during endurance racing. It sounds plausible enough, but I'm only repeating what I've been told.
Anyway, I guess the only ones who could better explain the rationale are those who designed it.
(4) I forgot to mention that I expected to see the top coating deteriorated after 10k fairly hard miles, but I was pleasantly surprised. It's all there.
Several observations that I have made after running the JAM shortblock for about 10k miles:
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
(1) If there is any cold start piston slap, it isn't enough for me to notice it.
(2) The bores show no sign of the sidewall scuffing typical of the stock pistons.
(3) Oil consumption is zero.
So far, so good.
Evolving Member
Joined: Dec 2005
Posts: 248
Likes: 1
From: Malaysia
We bought 2 sets of customs Venolia's from JAM last year for a custom 93 mm stroke crank to run 2.2 litres in a very hard to find Mitsubishi tall deck block.
One of it have been in an Evo 8 running for almost 8 months now and haven't seen him coming back to complain bout nothing. Engine build, out of the shop, one month later to retune after running in for about 1000km's and never seen him since! I guess when that happens you can only make it out that the pistons are absolutely perfect.
I was quite surprised when I got the pistons just could not believe the finishing on it and how tough we felt that it would compared to the other piston makers that we usually run.
This piston was absolutely custom to our specification, nothing that was available in any setup in the US markets due to the odd 93 mm stroke crank. The other set that we have sitting here is not going anywhere except into my Evo 9 that I will have come in soon and one of the requirements of the piston that JAM had to make me was one that could run in a car running GT42R that will hit close to 900WHP on race gas!
I couldn't recommend more than anyone else to them if they are serious about putting a set of hardcore no bull pistons into their motor!
Dixon
One of it have been in an Evo 8 running for almost 8 months now and haven't seen him coming back to complain bout nothing. Engine build, out of the shop, one month later to retune after running in for about 1000km's and never seen him since! I guess when that happens you can only make it out that the pistons are absolutely perfect.
I was quite surprised when I got the pistons just could not believe the finishing on it and how tough we felt that it would compared to the other piston makers that we usually run.
This piston was absolutely custom to our specification, nothing that was available in any setup in the US markets due to the odd 93 mm stroke crank. The other set that we have sitting here is not going anywhere except into my Evo 9 that I will have come in soon and one of the requirements of the piston that JAM had to make me was one that could run in a car running GT42R that will hit close to 900WHP on race gas!
I couldn't recommend more than anyone else to them if they are serious about putting a set of hardcore no bull pistons into their motor!
Dixon
