What is the engines weakest length?

[Timbo1969]

Pistons, Rings, Rods, and Bearings. The crank is a very good piece, if it's peened it can stand up to loads of over 600 hp in peek bursts.

[viper98885]

<blockquote>quote:</font><hr>Originally posted by CockyV6:


And valves. They are in the combustion chamber like the other two. The intense heat generated will fry just about anything not prepeared for it.

The valves are ground down to where they are really thin on the edges. That kind of heat will burn those suckers up pretty easily. Not to mention of the valve being made smaller to the point where the engine sucks a valve, :eek: :( which basicly sucks. <hr></blockquote>

I have NEVER heard of this happening on an engine that is actually on the street. Honestly, the stock valves on both the 3.4L V6 and the 3.8L V6 do not need to be touched if adding nitrous.

[CockyV6]

You've never heard of a burnt valve??

Or of an engine that has had sucked a valve?? Much less floated a valve?

I have seen this happen quite a few times. It happens from predetionation. Valves are VERY suseptible to being damaged by heat. They are one of the thinest pieces of metal ( right around the edge ) in the combustion chamber. As fast as they open and close combined with normal heat from combustion, much less what its like under a stressed condition ( WOT, low octane gas, and/or NO2 )

Ask anyone who has been around a track, or heck even a mechanic about what kind of damage can happen to valves and they will tell you about this. Its not a pretty thing when it does happen. [img]graemlins/omg.gif[/img]

[WickEdSix9838]

<blockquote>quote:</font><hr> And valves. They are in the combustion chamber like the other two. The intense heat generated will fry just about anything not prepeared for it.

The rings will deffanately go because they are trying to keep all that pressure in.

The valves are ground down to where they are really thin on the edges. That kind of heat will burn those suckers up pretty easily. Not to mention of the valve being made smaller to the point where the engine sucks a valve, which basicly sucks.

Then we all know what can happen to the piston its self. Holes comepletely burnt through and what not.

Not to mention a combination of all any two or all three.

I didnt mention fouled plugs because compared to the other three thats a relitivly easy fix.
<hr></blockquote>
valves dont burn up that easy, it takes serious heat to do it...the only burnt valve ive seen was out of one of my dads circle track customers motor, the fuel pump went bad, the motor got hot, then the guy never paid any attention to the water temp and it melted a piston and one of the exhaust valves had a hole in it a little smaller than the size of a marble, there was aluminum in the exhaust port where the piston melted and it ran out!! BUT thats at the complete extreme, there are more parts that will fail way before the valves...BTW, valves arent that thin in the edges when they are fairly new, when they get re-ground 2-3 times during rebuilds etc is when they get thin...

[CockyV6]

<blockquote>quote:</font><hr>Originally posted by WickEdSix9838:

valves dont burn up that easy, it takes serious heat to do it... the fuel pump went bad, the motor got hot, then the guy never paid any attention to the water temp and it melted a piston and one of the exhaust valves had a hole in it a little smaller than the size of a marble, there was aluminum in the exhaust port where the piston melted and it ran out!! BUT thats at the complete extreme, ..... BTW, valves arent that thin in the edges when they are fairly new, when they get re-ground 2-3 times during rebuilds etc is when they get thin...<hr></blockquote>

I thought that the edges of valves would be one of the thinest things in the combustion chamber. Outside of the piston rings I cant think of anything that would be any thinner than the outside edge of a valve. I mean there is the piston itself but I am relitivly sure that it is thicker than the edge of a valve. You can go with the head gasket blowing out as well, but in the combustion chamber its self the edge of a valve is one of the thinnest pieces of metal in there.

Youre right it takes serious heat to burn up a valve. Now what does Nitrous do in the combustion chamber? Why should we go with colder plugs? Why should we retard the timing by 2 degrees for every 50 hp of a shot? You also said his fuel pump went bad, isnt that one thing that we all worry about?

[WickEdSix9838]

the edge of a new valve is atleast .080-.100 thick, sometimes more, and true we worry about fuel problems but still the pistons will melt way before the valves will, if you keep on the gas/spray after it gets hot then the valves will probably burn but if you stop reasonably quick as it happens the valves probably wont burn...

[12secondv6]

Actually, I should add plugs

I've gone through MANY plugs w/ tuning

[Arctc Wolf]

pistons will go before anything else will. stock cast hypereutic pistons suck. When getting new pistons, have the skirts anti-friction coated and the top thermal coated. the anti-friction will lower the friction coefficient along the sides of the piston, allowing it to move more freely, taking up less hp and preventing scuffing. thermal coating is good because it keeps the heat inside the combustion chamber, rather than letting the piston, rings, pins, rods, crank, and oil soak it up. Forged of Billet pistons will be the strongest, as well as probably the lightest pistons you can get. Some many weigh the same as stock, and be 3 times as strong as stock.

next would probably be the rods, bearings, and low-end bolts involved. the rods are cast as well, and if u use upgraded pistons w/o new rods, and up the boost too much, u'll lose the rod through the oil pan. good bolts and bearings will keep the rods moving.

next would probably be the heads and valvetrain. valves are very thin, and can get over-heated and become damaged. upgrading the exhaust valve to inconel will prevent burnt exhaust valves, since most of the heat goes past the exhaust valve. intake valves can be of lighter material, such as stainless steel or titanium since it usually sees much cooler air past it. having the faces of the valves as well as the combustion chamber polished and thremal coated will help as well.