wiseco??

[Fitzy]

just wondering what everyone thinks of wiseco 440 kits. are they reliable? has anyone had problems with theirs? thanks

[Hondaluva]

Getting the proper deck height might be a problem. I they may have corrected it, but the Wiseco piston I have is giving me some problems with deck height. I am planing with the gasket thicknesses trying to get the compression correct.

[SnellCRP]

What kind of deck height are you coming up with?

[Teufel]

I like the Wiseco Pistons , yes they did have some compression correction problems.

How are you determining your actual compression ratio???

[Hondaluva]

Well, I'm working on those numbers this weekend but I checked it without the base gasket and the jug not bolted to the case and the piston was sitting .028-.030 in the hole at top dead center. It's claimed to be a 11:1 piston, but I ran those numbers in a compression ratio calculator and only came up with 9.98:1 and that was with figuring a .010 base gasket and a .027 head gasket from cometic. It's a flat top piston.

[Hondaluva]

Using the CR calculator on www.rosspistons.com

Using these numbers:

Bore: 3.504
Stroke: 2.756
Head CC's: 37.2
Gasket thickness: .027 (head gasket)
Deck height: .038 (adding the .010 base gasket)
valve pockets: -1
cylinders: 1

It's a 440 EX.

I know that I still have to throw in the base gasket and torque the jug down to get the true deck height.

[SnellCRP]

In that calculator did you have to put in the cc's of the combustion chamber? I probably would not run the deck height any closer than .034-.036 because you will get some rod stretch and if you ever miss a gear and your quad dosen't have a stock rev limiter the piston could hit the cylinder head.

[Hondaluva]

Isn't the CC's of the cumbustion chamber the same as the CC's of the head?

It is my understanding that I need to be concerened with squish, which is the area from the top of the piston to the bottom ring around the head. Basically the deck height plus the head gasket thickness. I have been reading that the squish should be no less than .040. Guess I thought the goal was to have your piston siting .015 in the hole and then adding about .027 for head gasket thickness, getting you .042 of squish. That brings the CR ration up to about 10.7:1.

[Fitzy]

so wiseco isn't bad, you just have to mess around with it a bit to get it right?

[Hondaluva]

I have only heard good things about the quality and durability of Wiseco pistons. It's just this set up thing that seems to be giving me a problem. Also hear good things about JE pistons. And I don't think you would have the same problems I am having with a JE or Ross. Just my two cents.

[Fitzy]

ok, thanks a lot guys

[SnellCRP]

Originally posted by Hondaluva
Well, I'm working on those numbers this weekend but I checked it without the base gasket and the jug not bolted to the case and the piston was sitting .028-.030 in the hole at top dead center. It's claimed to be a 11:1 piston, but I ran those numbers in a compression ratio calculator and only came up with 9.98:1 and that was with figuring a .010 base gasket and a .027 head gasket from cometic. It's a flat top piston.

The reasons you are coming up with the lower compression ratio is because that is an XR/EX piston. In an XR the compression would be 11:1, but since its in a EX there is an extra .030" in deck height. I wouldn't say that its a Wiseco piston that has to have all this stuff checked. I have used Ross, JE, and Wiseco and if you are trying to squeeze optimum power out of the engine the deck height should be optimized in any piston combination. If you use a Ross 440 kit and a cometic flex steel gasket set that you can get from C & D have the machine shop press the sleeve out put the new sleeve in and then have them take .030 off of the base of the jug and your piston to valve clearance will be around .050-.070. This is assuming that the reliefs are cut in the piston right. Your deck height will be around .036 which is about all the closer I want to go. I have had a piston that had 4 exhaust size reliefs cut into it and if that were not have been caught the intake valves would have hit the piston. Instead of the machining off the base you could just use no base gasket and a thin head gasket. I just prefer to use a full head and base gasket.

[Hondaluva]

You are saying that my deck heght would be around .036 or are we talking about squish here? :confused:

[SnellCRP]

I am talking about deck height. Its the distance between the outside edge of the piston and the bottom of the cylinder head. I just take a piece of solder and some clay. I just use the clay to hold the solder in place. Make sure that the solder is at the edge of the piston where its flat and it has to be in line with the piston pin. If its not inline with the pin the measurement won't be accurate because the piston can rock back and forth in the sleeve on the pin. Put the motor together with some used gaskets because they are already heat cycled and are compressed to all the farther that they will go. You won't have to put the cam in unless you are checking the valves also. Then just turn the motor over by hand so the piston comes up to TDC and then take the head back off and check the solder where it has been flattened and that is the deck height.:)

[Hondaluva]

I'm not an expert, but from everything I have ever read you are talking about the squish right now. The deck height is how far the piston sits 'in the hole' (below the cylinder deck). You can measure that by just loading the piston into the jug with the rings and then bolting the jug to the case...then you use calipers to measure it. The measurments are most accurate over the wrist pins.

[SnellCRP]

You are right I had my terms mixed up the deck is how far the piston sits in the hole and the Squish band or quench is the distance between the head and the piston. Sorry:rolleyes:

[Hondaluva]

That's fine. It is my understanding that you want the squish to be about .040. I still think the quench is different than the squish. I think the quench is the area above the piston where the burn actually takes place.

So I am tying to get my piston siting at about .015 in the hole at TDC. Then I am using a .027 head gasket. Should give me about .042 of squish. Looks like I will be getting about .025 decked off my cylinder.

[SnellCRP]

You could do the thin gaskets instead of the machining then you could be running ASAP.

[SnellCRP]

The Squish Band or "Quench" is defined as that area between the flat of the piston and the flat of the cylinder head at top dead center (TDC). On the compression stroke, as the piston approaches TDC, the compressed mixture of fuel and air is "squished" to the remaining space of the combustion chamber where the spark plug and valves reside. The "squeezing" of the mixture creates turbulence and is expected to promote a better and more complete combustion.

Deck Height: The distance between the flat "quench" surface of the piston and the top of the bare cylinder (no head gasket). Typically an engine is set to zero deck height with the head gasket (compressed value) defining the "squish band" value. If the value is negative this indicates the piston's "quench" surface extends above the top of the bare cylinder


Just a little tech info
:cool:

[Hondaluva]

I was thinking about going with no base gasket and one layer of head gasket. But that doesn't make me feel warm and fuzzy inside. I would rather have the three piece head gasket in place. That is something that I am still tossing around. Thanks for the information...it's always good to bounce ideas/thoughts off other people.

[SnellCRP]

You are like me. I would rather take .030" off of the jug and run a full gasket set than run a thin head gasket with no base and take the chance of it not sealing properly. :macho

[pnut420]

I would rather buy a custom Wiseco piston from Micky D that is the right deck height and save alot of money on deck the head :cool:

[cals400ex]

does anyone know if these custom pistons by mickey are heavier than the normal xr/ex pistons you buy off the shelf?
also, would he be able to do the same work to a je or ross piston that he does to the wiseco pistons?

[K_Fulk]

Are you guys degreeing in your cams to adjust for the diffrent cam timing with the decked cylinders?

[Hondaluva]

I'm only talking about removing .025 of an inch. I think Mickey was saying that the degree would only change by a few and wouldn't make a difference. I'm not building a race engine here...So I wasn't going to worry about it. Hopefully it won't matter. I would have bought a custom piston but I jumped into this a little quick and now I am just trying to work with what I have.

[SnellCRP]

You could advance the cam timing a bit if you want it to hit hard or if you want to smooth out the powerband you could retard it a bit. I didn't change my cam advance for the little bit that the jug has been changed.