85_IDI_4x4
Full Access Member
*NEW EDITED POST*
Governor springs aside what part of these engines would be the limiting factor on how high of RPMs they can turn? My guess would have to be the the stock bolts holding the connecting rod caps on would be the first part to let go. In that case a set of stronger rods with studs could be used to eliminate that.
A member on this board has replaced his governor spring with the higher RPM spring from the GM idi and has iirc spun @ ~4500rpm for sustained periods of times. I would be interested to know how much his connecting rod bolts have stretched if he ever does a tear down of that engine. It has also been mentioned that his valves were floating but there has been discussion of using PSD springs which could be used to prevent that (you can also find places that will make you custom push-rods, valves and rockers if you give them specs, i have looked)
Just as a teaser if this engine was gas there is calculations you can do to determine what maximum rpm is possible using stroke length. it is based on what your mean piston speed would be and what is considered max safe speed for different levels of internal engine components.
Level: max rpm, mean piston speed
Stock: 5023 rpm, 3500 ft per min
Heavy duty: 5741 rpm, 4000 ft per min
Race: 7177 rpm, 5000 ft per min
http://thefirstgensite.com/code/maxrpm.htm
Governor springs aside what part of these engines would be the limiting factor on how high of RPMs they can turn? My guess would have to be the the stock bolts holding the connecting rod caps on would be the first part to let go. In that case a set of stronger rods with studs could be used to eliminate that.
A member on this board has replaced his governor spring with the higher RPM spring from the GM idi and has iirc spun @ ~4500rpm for sustained periods of times. I would be interested to know how much his connecting rod bolts have stretched if he ever does a tear down of that engine. It has also been mentioned that his valves were floating but there has been discussion of using PSD springs which could be used to prevent that (you can also find places that will make you custom push-rods, valves and rockers if you give them specs, i have looked)
Just as a teaser if this engine was gas there is calculations you can do to determine what maximum rpm is possible using stroke length. it is based on what your mean piston speed would be and what is considered max safe speed for different levels of internal engine components.
Level: max rpm, mean piston speed
Stock: 5023 rpm, 3500 ft per min
Heavy duty: 5741 rpm, 4000 ft per min
Race: 7177 rpm, 5000 ft per min
http://thefirstgensite.com/code/maxrpm.htm
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