Rod bolts, main caps, and what not.
11-29-2014, 05:21 PM
#41
The most murderous action placed on rod bolts is when the rod stops and then starts and continues to accelerate back down from TDC on the exhaust /intake stroke. IE
verlap.
No compressive forces helping to keep the piston + such pushed towards the rod cap.
So, its not really horsepower, it's rpm's vs piston/ring/pin/ good part of the connecting rod itself weights that's trying to seperate from the connecting rod's cap.
All my IMHO of course.
verlap.No compressive forces helping to keep the piston + such pushed towards the rod cap.
So, its not really horsepower, it's rpm's vs piston/ring/pin/ good part of the connecting rod itself weights that's trying to seperate from the connecting rod's cap.
All my IMHO of course.
Also, every circle track engine I have seen come apart is when lifting off the throttle coming into a corner.
11-29-2014, 06:26 PM
#43
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And was your point to derail this? Thanks for the recap and your Marine engine wisdom genius! FYI, we're talking lower ends, NOT cams.
*FYI, an outlaw car that is locked in gear, entering and exiting corner, lifting (dragging the lower end) and hammering the throttle, at much higher RPM is very abusive to the lower end. Tolerances are critical since the bearing sees loads on all sides. Marine engines, sees this only when the prop is moving air. BOTH are abusive environments and alot can be learned by both. Let's keep an open mind.
*FYI, an outlaw car that is locked in gear, entering and exiting corner, lifting (dragging the lower end) and hammering the throttle, at much higher RPM is very abusive to the lower end. Tolerances are critical since the bearing sees loads on all sides. Marine engines, sees this only when the prop is moving air. BOTH are abusive environments and alot can be learned by both. Let's keep an open mind.
So now that we got lawn mower racing out of the way let's talk lower ends. Only offshore boats need stout lower ends.
11-29-2014, 06:43 PM
#46
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No problem. Since we are talking long lasting engines that run sustained speeds and get crazy shock loads.
Here's the link to the specs on my lawn mower engine. Mine is model 4029.
http://www.briggsandstratton.com/us/...0BuiltVert.pdf
It does all that without pressurized lube, inconel exhaust valves, or water cooling.
Here's the link to the specs on my lawn mower engine. Mine is model 4029.
http://www.briggsandstratton.com/us/...0BuiltVert.pdf
It does all that without pressurized lube, inconel exhaust valves, or water cooling.
Last edited by ham_r_down01; 11-29-2014 at 06:49 PM.
11-29-2014, 06:52 PM
#47
I know an old time drag racer that used to insist that at the end of the quarter mile kill fuel and ignition but leave the throttle wide open to minimize the stress put on the cap and bottom of the piston when forces switch direction.
Also, every circle track engine I have seen come apart is when lifting off the throttle coming into a corner.
Also, every circle track engine I have seen come apart is when lifting off the throttle coming into a corner.
