Brantel
Well Known Member
So during my investigation into why may engine suddenly starting occasionally popping thru the exhaust, I discovered that the engine builder that put my engine together had improperly installed the rocker arms in the wrong places as determined by Lycoming SI 1454A. (Fairly certain that this had nothing to do with my original problem, just kinda lucky to find this error now)
He had some with the rockers switched and one with two of the same rocker arm on both valves.
With that situation I now must start over with setting the dry tappet clearance since I will be moving the rockers to the proper location.
Only 3 of the 8 pushrods in my engine have part numbers. 2 are 73435 and 1 is 73434. A couple of the rods look to have been ran in some kind of engine that can rub on them about 3-4 inches from the end as these rods have some material rubbed off of them in that area (nothing in my engine could possibly do this best I can tell). A couple more have some evidence of old corrosion from the past. The bottom line is that I plan to replace all of them for safety.
That being said, I plan to order new custom rods from Smith Bros. Pushrods. I understand that their quality is superior to OEM.
So first I plan to order an adjustable one in order to use it as a gauge to determine what length rod to order for each valve. In order to do that, I need to know what length adjustable rod to order. I have looked at the Lycoming SI 1060M and see that the range of rods for my engine is from 12.483 to 12.564. The 1060M does not state how this length is determined. I plan to purchase one with a middle length of 12.5235" which is dead center of the range of rods called out by the SI 1060M. This would be the overall length minus whatever is lost by the oil holes in the ball ends.
For the engine guru's out there....Any issues with this plan above?
Next question....
Do I set the clearance up to be on the tight (.028), wide (.080) or middle (.054) of the range allowed by Lycoming SSP-1776-3?
I am getting an education with this thing that is for sure!
He had some with the rockers switched and one with two of the same rocker arm on both valves.
With that situation I now must start over with setting the dry tappet clearance since I will be moving the rockers to the proper location.
Only 3 of the 8 pushrods in my engine have part numbers. 2 are 73435 and 1 is 73434. A couple of the rods look to have been ran in some kind of engine that can rub on them about 3-4 inches from the end as these rods have some material rubbed off of them in that area (nothing in my engine could possibly do this best I can tell). A couple more have some evidence of old corrosion from the past. The bottom line is that I plan to replace all of them for safety.
That being said, I plan to order new custom rods from Smith Bros. Pushrods. I understand that their quality is superior to OEM.
So first I plan to order an adjustable one in order to use it as a gauge to determine what length rod to order for each valve. In order to do that, I need to know what length adjustable rod to order. I have looked at the Lycoming SI 1060M and see that the range of rods for my engine is from 12.483 to 12.564. The 1060M does not state how this length is determined. I plan to purchase one with a middle length of 12.5235" which is dead center of the range of rods called out by the SI 1060M. This would be the overall length minus whatever is lost by the oil holes in the ball ends.
For the engine guru's out there....Any issues with this plan above?
Next question....
Do I set the clearance up to be on the tight (.028), wide (.080) or middle (.054) of the range allowed by Lycoming SSP-1776-3?
I am getting an education with this thing that is for sure!