Ray70
Well-known member
- 2,372
- 5,073
- 113
- Location
- West greenwich/RI
Hello everyone, I've rebuilt a few more Mep-002a / 003a injection pumps over the last few weeks and pulled out a bit of hair trying to figure out a problem on one!
So I thought I would share a couple new things I have learned.
#1 when reviving a machine that has been sitting and has a stuck pump, if you can not get it freed up using the methods listed on this forum and end up having to remove the pump to free it up, DO NOT attempt to put the motor at the PC mark first because chances are you will break the plunger guide ( Ambac M50 ) or destroy the pump completely ( Bosch PSU model ) as soon as you attempt to turn the motor. Once the pump is repaired and ready to install ,some guys get mixed up and wind up 180* off on the pump.
A simple way to get to #1 compression stroke is to simply look in the IP opening in the block. The cam lobe near the right side of the opening is the intake of cyl.#1. Rotating the crank clockwise will result in the cam turning counterclockwise. Rotate until the cam lobe pushes up on the intake valve lifter. Continue to rotate until the cam lobe points towards the opening for the IP. continue to rotate the crank clockwise a bit more. the cam lobe will begin to angle downward. Now look in the bellhousing timing hole and you should soon see the PC mark coming around.
Once PC is in the window you are now ready to align and install the pump.
No need to remove valve covers etc. to find #1 Compression stroke.
#2 If installing a used pump or attempting to time a rebuilt pump and you follow the steps to "Flow test" the timing, if you CAN NOT get the fuel flow to stop within the specs listed ( 1 drip every 5-10 seconds ) most likely you have an excessively worn plunger / pump body or a pitted or otherwise damaged plunger. NOTE: fuel flow that fails to stop abruptly during the test is an indication that the pump will be unable to produce enough fuel pressure to open the injectors. Unfortunately Ambac lists the plunger as "non-serviceable" as it is a mated part with the body and metering block.
Hopefully this will someday help someone get their air-cooled up and running a little easier!
So I thought I would share a couple new things I have learned.
#1 when reviving a machine that has been sitting and has a stuck pump, if you can not get it freed up using the methods listed on this forum and end up having to remove the pump to free it up, DO NOT attempt to put the motor at the PC mark first because chances are you will break the plunger guide ( Ambac M50 ) or destroy the pump completely ( Bosch PSU model ) as soon as you attempt to turn the motor. Once the pump is repaired and ready to install ,some guys get mixed up and wind up 180* off on the pump.
A simple way to get to #1 compression stroke is to simply look in the IP opening in the block. The cam lobe near the right side of the opening is the intake of cyl.#1. Rotating the crank clockwise will result in the cam turning counterclockwise. Rotate until the cam lobe pushes up on the intake valve lifter. Continue to rotate until the cam lobe points towards the opening for the IP. continue to rotate the crank clockwise a bit more. the cam lobe will begin to angle downward. Now look in the bellhousing timing hole and you should soon see the PC mark coming around.
Once PC is in the window you are now ready to align and install the pump.
No need to remove valve covers etc. to find #1 Compression stroke.
#2 If installing a used pump or attempting to time a rebuilt pump and you follow the steps to "Flow test" the timing, if you CAN NOT get the fuel flow to stop within the specs listed ( 1 drip every 5-10 seconds ) most likely you have an excessively worn plunger / pump body or a pitted or otherwise damaged plunger. NOTE: fuel flow that fails to stop abruptly during the test is an indication that the pump will be unable to produce enough fuel pressure to open the injectors. Unfortunately Ambac lists the plunger as "non-serviceable" as it is a mated part with the body and metering block.
Hopefully this will someday help someone get their air-cooled up and running a little easier!