ok wanna upgrade piston and cam. Have no problems now but want more compression. Should i bored cylinder or keep std bore? Also should i get 10.5 -1 comp or 12 - 1 ???? i dont wanna run race fuel all time. Just wasnt sure if i should bore bigger or not. Also whats a good cam to use with application. I want more ponies ;D
Pistons?????
- Thread starter tony1177
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98warrior
Well-Known Member
You could have searched this as its been covered many times. Anyways, as far as boring I'm not sure, when I put in my web cam and hi comp piston I didnt bore it. Well actually my uncle done all the work haha. As far as compression I've heard people running 11.1 on 93 octane. I run 10.25 compression on 93 octane but I've used 87 before and it ran ok, although I would suggest running 93 unless you run out and need gas asap. As far as cams go it depends on where you want your power. As far as brands STAY AWAY from hotcams, a lot of people see all the hot cams adds in magazines and think that they must be the best, but not true at all. Go with web cam, megacycle, or powroll. Stage 1 cams usually add a low rpm to mid rpm gain and the stage 2's add to mid to top end power. Personally I went with a wiseco 10.25 piston and a stage 2 web cam with kibblewhite valve springs.
jasonp
Well-Known Member
good post 98 warrior. 
I'd say then you'd want to run a 10.5:1 piston would be the most I want to go. I would do a light clean up for and have the cylinder bored out so the rings seat. It's up to you how far you want to take your over bore. They can bore it up to 2mm over or .080" over. Which will end up to be a 366cc. But then you'll have to replace the jug if the cylinder is wore.
Cam it all depends on what type of riding your doing where you want the power.. You can either go for a torque cam or big high rpm rev'r. You'll also need new heavy duty valve springs.
I'd say then you'd want to run a 10.5:1 piston would be the most I want to go. I would do a light clean up for and have the cylinder bored out so the rings seat. It's up to you how far you want to take your over bore. They can bore it up to 2mm over or .080" over. Which will end up to be a 366cc. But then you'll have to replace the jug if the cylinder is wore.
Cam it all depends on what type of riding your doing where you want the power.. You can either go for a torque cam or big high rpm rev'r. You'll also need new heavy duty valve springs.
dave76
Well-Known Member
Dose anyone know the cc of the JE 12.1 piston dome, if so I can do a static compression calculation. Because if your deck is high and you have'nt milled your head , plus Cometics 0.053 compressed head gasket, chances are the compression will be somewhat lower.
98warrior
Well-Known Member
dave76
Well-Known Member
I just did some calculations, a 85mm bore, 64.5mm stroke, 85mm bore cometic head gasket with 1.34mm compressed thickness, a JE 12.1 piston with I think a 15cc dome and using jasonps deck height of 1.34mm, the static compression will be 11.39:1, so with a good cam with some good overlap pump gas shouldn't be a problem if your running a good oil cooler like the big autozone one. Like I said the deck height could be different and the piston dome could be more cc.
jasonp
Well-Known Member
Alba does use stock gaskets from what I understand and they come with a .043 crushed head gasket and .020" base stock. At least that was mine stock.. Obviously you can't use a stock head gasket for the 85mm bore as it doesn't have enough clearance, there only made for 84mm. So total would be about .063" of gasket space.. The then we don't know is how far does the piston come up in the bore. Or compression height is I believe what they call it, from piston pin to the top of the dome of the piston. Also we don't know actual CC of the dome of the piston.
There where two reasons I didn't buy a 12:1 piston. The dome height. More then .100" of dome greatly effects combustion dynamics or the flame front travel in which the flame has to travel over the hump and around vallies for complete burn. It's been said that on a V8 engine that more then 100 hp can be lost from this.
Everybody that I had talked to about the alba kit or that used a 12:1 piston said that they had to mix racing gas to stop the pinging at low allitude.
98warrior
Well-Known Member
Thats just dave and jason getting really technical
It happens a lot. I really wouldnt get a 12.1 compression piston because jason said people that ran the 12.1 needed to mix in race gas for it to run right. If I would have done it over I might have got the higher quality cp or je piston but with the same cam and with the addition of a good port and flow job. If your gona do something do it right or you will regret it later Now you cant expect to do all this for a little bit of money, if you want more power you cant be afraid to dish out the dough.jasonp
Well-Known Member
When building a engine there always small things that you can do to your engine to make it perform better. This is one of those things.
When you do a piston upgrade or get a high compression piston many places will say there static compression is rated at 0 deck clearance. Which means the piston is level with the top of the deck or cylinder or comes to the top of the bottom of the head with no clearance. This can be a big issue as in reality there is no way the engine to run like this as the piston would hit the head from expansion from rpm and heat. Some manufactures take the stock gasket thickness into account. Either way it's good to know just so you know so it will help you determine how much static compression you will have.
When building performance engine you have to remember all the details as well. Deck clearance is a huge thing as .040" is about perfect what you want to have for deck. This allows more air fuel mixture when the piston is coming up in the bore and allows the squish happen more violently within the combustion chamber mixing and turning the air fuel mixture. This also cools the charge and helps the engine run cooler and be less prone to detonation and also ups the static compression. So it's something to be considered when installing a piston and for the price of a custom made gasket is pretty cheap in performance you'll get out of this.
usdsk8er540
Well-Known Member
98warrior, why do you say to stay away from hotcams? i have a hotcams stage 2 stroker cam on my warrior and i have had no problems with it. if you have some reasons why they are not good i would like to hear them. you didnt give any reasons and im just curious. not trying to say you are wrong or start an argument or anything, i just dont see your reasoning and why you think the others are so much better. thanks
usdsk8er540
Well-Known Member
blonka, i think the .20 over takes it from 349cc to 353cc. i believe thats the first piston swap i did. it gives it a little more power, but you may want to do a new cam with it as well to compliment it. just my two cents on that. hope that helps.
98warrior
Well-Known Member
If you look at the specifications on the hot cams they are a very mild cam compared to other brands such as webs, megacycles and powroll. They are not as aggressive which also does'nt require stiffer valve springs such as web cams etc. Most people will tell you that if you want a maximum power gain from a cam not to get hot cams. I realize a lot of people run them but probably because there are ads for hot cams everywhere you look. I think jason would agree with this also. I'm not saying hot cams are a total waste but for the most hp gains I would opt for a web or megacycle.
98warrior
Well-Known Member
Little side note...
Now owning a z400 I'm on z400central all the time now and about everyone running hot cams are running the "older style" hot cams which they claim to be more aggressive than the new style resulting in more hp.
Now owning a z400 I'm on z400central all the time now and about everyone running hot cams are running the "older style" hot cams which they claim to be more aggressive than the new style resulting in more hp.
usdsk8er540
Well-Known Member
hmm. right on. well thanks for the explanation. i may look into a new cam, but for now the hotcams stroker cam is working great. thanks again.
jasonp
Well-Known Member
98 said it well. The hotcams are just a very mild cam in compared to the others out there as they have to be because the use the stock weak springs.
If you want the most out of that stroker setup I would use a Web .430 or Megacycle .450
