Hi All,
Anybody ever heard of boring a cylinder off center (biased toward the intake valve) to improve the breathing by unshrouding the intake valve?
dennis
if you mean boring it laterally: it would result in an oval bore.
if you mean boring it diagonally, it would result in engine death.
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Rich Grayo Jr. wrote:if you mean boring it laterally: it would result in an oval bore.
if you mean boring it diagonally, it would result in engine death.
i figured my hurry up post wouldn't be detailed enough...sorry.
What I mean is that, it could be bored perpendicular to the crank more on the intake side than the exhaust side.
That is, say assuming a .060 overbore, .050 of it would be toward the intake side of the block, and .010 would be toward the exhaust side.
I should also include that I'm particularly thinking of the LN2 because 2 valve engine are more likely to have intake valve shrouding. One other effect would be that it would bias the centerline of the bore to create a slightly increased rod angularity and improve low end torque.
dennis
MasterFlight wrote:Rich Grayo Jr. wrote:if you mean boring it laterally: it would result in an oval bore.
if you mean boring it diagonally, it would result in engine death.
i figured my hurry up post wouldn't be detailed enough...sorry.
What I mean is that, it could be bored perpendicular to the crank more on the intake side than the exhaust side.
That is, say assuming a .060 overbore, .050 of it would be toward the intake side of the block, and .010 would be toward the exhaust side.
you would have to be damn sure the piston was centered on the rod. which it is stock. which means moving it over .050, it wouldn't be. that would impart severe stress at off idle.
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Rich Grayo Jr. wrote:
you would have to be damn sure the piston was centered on the rod. which it is stock. which means moving it over .050, it wouldn't be. that would impart severe stress at off idle.
Not true at all. As a matter of fact, most vehicles have a slight offset from center wrist pin setup from factory nowadays. Its mainly designed for forward loading of the piston and/or to keep cold start-up noises to an acceptable level. But it can also allow for better rod/stroke ratio combinations as well. Both Wiseco and Diamond pistons for the EcoTec are designed with a wrist pin offset. These are more common with full floating designs but semi floating designs can have a wrist pin offset as well.
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There's truth enough in unshrouding the intake valve by offsetting the bores to that side, however, when you're doing that to an engine that wasn't build that way in the first place, everything else needs to be redone to match. And frankly, you're talking about spending thousands of dollars for a marginal gain at best.
I'm sure this has probably been done before by professional racing organizations, but these are people who have the money to burn to get every last ounce of power out of an engine. For a hobbyist level build it's pretty much cashing out your bank account, building a nice pyramid of $100 bills, and setting them on fire. For a street car and a person of normal means, you look to maximize the bang for your buck.
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JerseyJayL61T wrote:There's truth enough in unshrouding the intake valve by offsetting the bores to that side, however, when you're doing that to an engine that wasn't build that way in the first place, everything else needs to be redone to match. And frankly, you're talking about spending thousands of dollars for a marginal gain at best.
I'm sure this has probably been done before by professional racing organizations, but these are people who have the money to burn to get every last ounce of power out of an engine. For a hobbyist level build it's pretty much cashing out your bank account, building a nice pyramid of $100 bills, and setting them on fire. For a street car and a person of normal means, you look to maximize the bang for your buck.
Appreciate your comments, but I'm not a bolt-on or pay somebody to do it hobbyist. (and am not offended by anything you said)
In most circumstances your comments would be correct. Even so, I'm no different than most who weigh the pros and cons vs. budget. I have access to a boring bar, lathe, milling machine, valve grinder, etc. Also, I've been a mechanic for 40 years and am a certified aircraft mechanic. The difference for me is that I can do most of the labor myself and have experience with engines and modding them back to the 70's.
dennis
