Technical Rocker Arm Removal

[MotoLojo]

Rocker Arm Removal: Anyone have thoughts on how to remove a rocker arm on a 1970 FIAT 500F so I can replace a pushrod? For some reason, it's missing a bushing on top of the rod, so I have to replace the entire rod. Need help...ugh. Thanks in advance!

 

[the hobbler]

Rocker Arm Removal: Anyone have thoughts on how to remove a rocker arm on a 1970 FIAT 500F so I can replace a pushrod? For some reason, it's missing a bushing on top of the rod, so I have to replace the entire rod. Need help...ugh. Thanks in advance!

You cannot remove 'A' rocker-arm on its own. The complete rocker-shaft has to be removed. This is a very simple operation---remove the rocker cover (2 x 13mm nuts) and then, also 2 x 13mm nuts, the complete rocker shaft. Replace the faulty push-rod and then replace the rocker shaft. A word of warning---as well as making sure that the rockers are sitting correctly on the top of the push-rods as you tighten down the 2 x 13mm nuts that hold the rocker-shaft in place, you have to ensure that the long tube that carries lubricant up to the rocker-shaft is correctly in place. Sometimes this tube lifts off with the rocker-shaft, if that happens you have to make sure that it is sitting correctly in the crankcase at the bottom of the tube before you fit it back into the rocker-shaft and tighten the rocker-shaft down. If it DOESN'T lift with the rocker-shaft, just check that it is in place and fully down before tightening the rocker-shaft down. Lack of this tube in the correct place will starve the rocker-shaft of lubricant. If the tube DOES lift off with the rocker-shaft, it is easier to remove it from the rocker-shaft and fit it into the crankcase before you refit the rocker-shaft. When you have tightened down the rocker-shaft, you MUST go through all the tappet settings (6thou--0.15mm Inlet and exhaust, COLD) and adjust them as required

 

[MotoLojo]

You cannot remove 'A' rocker-arm on its own. The complete rocker-shaft has to be removed. This is a very simple operation---remove the rocker cover (2 x 13mm nuts) and then, also 2 x 13mm nuts, the complete rocker shaft. Replace the faulty push-rod and then replace the rocker shaft. A word of warning---as well as making sure that the rockers are sitting correctly on the top of the push-rods as you tighten down the 2 x 13mm nuts that hold the rocker-shaft in place, you have to ensure that the long tube that carries lubricant up to the rocker-shaft is correctly in place. Sometimes this tube lifts off with the rocker-shaft, if that happens you have to make sure that it is sitting correctly in the crankcase at the bottom of the tube before you fit it back into the rocker-shaft and tighten the rocker-shaft down. If it DOESN'T lift with the rocker-shaft, just check that it is in place and fully down before tightening the rocker-shaft down. Lack of this tube in the correct place will starve the rocker-shaft of lubricant. If the tube DOES lift off with the rocker-shaft, it is easier to remove it from the rocker-shaft and fit it into the crankcase before you refit the rocker-shaft. When you have tightened down the rocker-shaft, you MUST go through all the tappet settings (6thou--0.15mm Inlet and exhaust, COLD) and adjust them as required

Thank you Hobbler! Much appreciated advice, and I'll pay particular attention to the lubricant tube fitting.

 

[Toshi 975]

Rocker Arm Removal: Anyone have thoughts on how to remove a rocker arm on a 1970 FIAT 500F so I can replace a pushrod? For some reason, it's missing a bushing on top of the rod, so I have to replace the entire rod. Need help...ugh. Thanks in advance!

One concern I might have is what happened to the push rod end which must have come adrift and possibly dropped down into the engine. It could have dropped down the push rod tube and be lodged on top of the cam follower. With the offending push rod removed I would be inclined to insert a magnetic probe in there just in case.

 

[fiat500]

Stripdown and correct reassembly of the rocker shaft is a job that looks easy, but which can have some challenges. The easier it is, the more likely it is that something is worn or that past bodging has taken place.
Take care to make sure that all parts go back in the same order and are matched with the same location and orientation on the shaft.
If you have the means, when disassembled, it is a good idea to carefully measure that everything is within wear limits and running tolerances. The rockers and shaft work very hard and under high levels of stress. A good rocker assembly goes a long way towards having a good engine and that is particulrly true on this car.

 

[MotoLojo]

One concern I might have is what happened to the push rod end which must have come adrift and possibly dropped down into the engine. It could have dropped down the push rod tube and be lodged on top of the cam follower. With the offending push rod removed I would be inclined to insert a magnetic probe in there just in case.

Indeed. Absolutely will be searching for the wayward bushing! Cheers!

 

[MotoLojo]

Stripdown and correct reassembly of the rocker shaft is a job that looks easy, but which can have some challenges. The easier it is, the more likely it is that something is worn or that past bodging has taken place.
Take care to make sure that all parts go back in the same order and are matched with the same location and orientation on the shaft.
If you have the means, when disassembled, it is a good idea to carefully measure that everything is within wear limits and running tolerances. The rockers and shaft work very hard and under high levels of stress. A good rocker assembly goes a long way towards having a good engine and that is particulrly true on this car.

Agreed! Any idea what the torque tolerances would be on the two 13mm nuts that secure the rocker shaft? I can't seem to find that in my factory manual. Thanks!

 

[Toshi 975]

Agreed! Any idea what the torque tolerances would be on the two 13mm nuts that secure the rocker shaft? I can't seem to find that in my factory manual. Thanks!

 

[MotoLojo]

View attachment 436417

Thank you @Toshi_975