Wossner pistons in boosted talon.

[Killer223]

Has anyone here done Wossner pistons? i've used them for years on other builds without issue.
Any thoughts how they'll hold up to a boosted talon? The skirt design looks similar to the factory style, where when looking at the CP they are a different design skirt, I'm wondering if the Wossner design will hold up or crack like the stock ones do.
It's a JR turbo, no other engine mods.
looking at the 10:1 CR.
Also looking for a service manual, i can find the paper version i'd like to have the PDF version. links to where i can purchase that would be great.

 

[Admin]

 

[Remington]

looking for a service manual, i can find the paper version i'd like to have the PDF version. links to where i can purchase that would be great.

Become a life/supporting member and you will have access to one on here

 

[HondaTech]

We went CP (after getting thr correct ones, don't ask)

I'd be sure to ask if they have a boosted piston, that was the problem with our orignal CPs, they weren't designed for boost and swelled too much.

 

[Killer223]

We went CP (after getting thr correct ones, don't ask)

I'd be sure to ask if they have a boosted piston, that was the problem with our orignal CPs, they weren't designed for boost and swelled too much.

even in none racing applications? how do the stock ones hold up for so long?

 

[HondaTech]

We were told the stock pistons wouldn't last even in non competition vehicles. Our stock pistons cracked/broke both skirts, but that was during a 10 hour endurance race.

Our machine has been raced since the J.R turbo install. Even on a car I didn't plan on racing I would install pistons and make sure they were set-up to handle boost.

 

[SLOWPOKE693]

Cast doesn't expand as much as a forging and that's why the CPs seize in the bores at .0003 cylinder wall clearance.

I have a pair of Talon Wossner pistons and I also have a pair of Talon CP pistons. If the compression ratio on the Wossners was closer to what I needed for my N/A engine, hands down I'd run them over the CPs. Their forgings and machining are far superior to the CP pistons.

 

[ToolTime]

As others have mentioned, pay attention to the cylinder wall clearance.

 

[SLOWPOKE693]

As others have mentioned, pay attention to the cylinder wall clearance.

This.

.003 is not enough clearance for the CP pistons to live a long life in the Talon cylinders. The Wossners are spec'd at .005 and fit much better in the stock bores.

 

[ToolTime]

In my experience they did ok at Jackson Turbo levels of boost, I think the additional heat generated by running more boost caused the additional piston swell you’re speaking of on ours. Always trade offs in the pursuit of power. The life expectancy running the looser pistons is something to consider if you aren’t planning on doing 12+ Lbs. of boost.

 

[Killer223]

In my experience they did ok at Jackson Turbo levels of boost, I think the additional heat generated by running more boost caused the additional piston swell you’re speaking of on ours. Always trade offs in the pursuit of power. The life expectancy running the looser pistons is something to consider if you aren’t planning on doing 12+ Lbs. of boost.

well i didn't see this post till today, and i've already ordered the pistons, Wossner 10:1.

 

[SLOWPOKE693]

well i didn't see this post till today, and i've already ordered the pistons, Wossner 10:1.

Good decision IMO.

I posted pictures of the pair I have in a thread somewhere around here but can't exactly remember what one it was.

 

[Killer223]

A friend of mine ordered cp in 9.5:1. I guess we’ll see how things go. He said he’ll up the boost on his, I’m not going to change anything but pistons. I’m all about reliability.
being I have rides where I’ll but 200-500 miles a day on. I need it reliable.

 

[SLOWPOKE693]

A friend of mine ordered cp in 9.5:1. I guess we’ll see how things go. He said he’ll up the boost on his, I’m not going to change anything but pistons. I’m all about reliability.
being I have rides where I’ll but 200-500 miles a day on. I need it reliable.

The Wossners may be closer to 9.5:1 than you think if they are like my set. The reason I didn't use the pair of 12:1 Wossners I had was because their compression claims didn't add up after looking at the dome on the pistons I recieved and comparing them to stock to see if maybe the pin height was different. Nope, same-same. We figure the actual CR of their 12:1 pistons is alot closer to 11:1 and not the 12:1 they advertised. I'm not saying yours will not be what they claim, I'm just stating my experience.

Post pictures when you get them if you don't mind.

 

[SLOWPOKE693]

Pictures for reference comparing dome sizes


This is a Brian Crower (CP)12.5:1 piston...

This is an 11.5:1 CP piston...

And this is a 13.5:1 custom piston......

 

[SLOWPOKE693]

This is my Wossner "12:1" piston...

Notice the valve reliefs are not nearly as deep as the CP 11.5:1 I posted above? Pin heights are identical, centerline of pin to top ring land is identical and the Wossner has less material sticking up "out of the hole" than the CP. Either I recieved the wrong set in the correct box (I verified # on piston with the Wossner catalog and that didn't happen) or they stretched the truth a little bit..... ?

The machining on the Wossner pistons is incredible though and as a bonus are nearly identical in weight to stock pistons so you won't be throwing it out of balance. Like I said earlier, if those pistons were true 12:1's I'd run those over the CPs in a second.

 

[Smitty335]

This is my Wossner "12:1" piston...
View attachment 361417
View attachment 361418
View attachment 361419View attachment 361420

Notice the valve reliefs are not nearly as deep as the CP 11.5:1 I posted above? Pin heights are identical, centerline of pin to top ring land is identical and the Wossner has less material sticking up "out of the hole" than the CP. Either I recieved the wrong set in the correct box (I verified # on piston with the Wossner catalog and that didn't happen) or they stretched the truth a little bit..... ?

The machining on the Wossner pistons is incredible though and as a bonus are nearly identical in weight to stock pistons so you won't be throwing it out of balance. Like I said earlier, if those pistons were true 12:1's I'd run those over the CPs in a second.

I think your nuts, how does that help jumping logs? Come ride with us. Ride with you, I've been there done that, got some very expensive tee shirts and pieces of wood to show for it.

 

[SLOWPOKE693]

I think your nuts, how does that help jumping logs? Come ride with us. Ride with you, I've been there done that, got some very expensive tee shirts and pieces of wood to show for it.

Huh?

 

[Killer223]

This is my Wossner "12:1" piston...
View attachment 361417
View attachment 361418
View attachment 361419View attachment 361420

Notice the valve reliefs are not nearly as deep as the CP 11.5:1 I posted above? Pin heights are identical, centerline of pin to top ring land is identical and the Wossner has less material sticking up "out of the hole" than the CP. Either I recieved the wrong set in the correct box (I verified # on piston with the Wossner catalog and that didn't happen) or they stretched the truth a little bit..... ?

The machining on the Wossner pistons is incredible though and as a bonus are nearly identical in weight to stock pistons so you won't be throwing it out of balance. Like I said earlier, if those pistons were true 12:1's I'd run those over the CPs in a second.

looks as though the reliefs for the valves are not as deep on my pistons.

 

[Killer223]

No cracked piston skirts, everyone told me they would be cracked. i have over 4K miles boosted. 7800 miles total on machine. kinda frustrating spending the money on pistons and teardown when it wasnt really needed. oh well.
the scratches in the cylinders i'm sure is from when the stock JR air filter let some dust by,
it looks like some minor dust is still getting by but the whole intake track is clean no dust to be found. so i'm not sure what to make of that. i'll get a ball hone and hone the cylinder best i can, and put things together with new pistons.

^^^ this is the only one with a groove enough to feel with a finger nail. dispite some others looking much worse.

 

[SLOWPOKE693]

No cracked piston skirts, everyone told me they would be cracked. i have over 4K miles boosted. 7800 miles total on machine. kinda frustrating spending the money on pistons and teardown when it wasnt really needed. oh well.
the scratches in the cylinders i'm sure is from when the stock JR air filter let some dust by,
it looks like some minor dust is still getting by but the whole intake track is clean no dust to be found. so i'm not sure what to make of that. i'll get a ball hone and hone the cylinder best i can, and put things together with new pistons.
View attachment 362598

View attachment 362597View attachment 362599View attachment 362600View attachment 362601^^^ this is the only one with a groove enough to feel with a finger nail. dispite some others looking much worse. View attachment 362602View attachment 362603View attachment 362604

Every Talon engine I've seen (boosted or N/A) looks like that. Always scuffed on the thrust surface of the cylinders.

Do yourself a favor and don't use a ball hone. They don't do a very good job of keeping the cylinder walls straight and leave lots of trash in the engine. Grab a 3 stone cylinder hone from your local parts store and use thst instead.