Restoring the Governor
Don't get sold anything less
than a full restoration
Many pumps we see that have been previously 'restored' show a distinct lack of evidence of full disassembly. They may say it's not necessary, but anything that isn't taken apart contains just as much, if not more, grime, dirt and decades of buildup as the outside of your pump or the rest of your vehicle in general.
At Black Forest we meticulously disassemble every piece of the governor, despite the intricate process required. Each part gets disassembled, cleaned, replated where necessary, tested and reassembled to exact specifications. If parts are worn out, we replace them with new or restored options. No stone is left unturned and no nook or cranny unexplored.
Take a look through the gallery to see how we completely restore your governor and test to ensure optimum performance.
Here you can see how we remove the camshaft bearing seal, requiring a specific tool many shops do not have. The pictures below show the grime that accumulates between the governor body and seal, which increases potential for leaks.
After cleaning the seal and housing, it is carfeully reinserted using a hand-operated press as seen in the step-by-step above.
Next we disassemble the camshaft seal bolt assembly followed by removing the seal itself. Without removing the governor, none of these parts are accessible to be restored or cleaned. With the amount of steps and special tools needed you can see why would rather avoid these areas, but each part is just as important as any other. Not restoring these parts isn't any more acceptable than not restoring the injectors, lines, or replacing paper seals.
We now move onto the lever assembly. While technically accessible through the body of the pump, disassembly of the lever would be extremely difficult via that route. With the multitude of miniscule parts, this task is best addressed with the governor removed and requires a meticulous attention to detail, as need in the photos below.
Now imagine trying to do that without the governor or solenoids removed. You'd have minimal access through the body of the pump leaving almost no room to operate. If they're not removing the governor, they're taking the VERY hard route, or more than likely, they aren't restoring these parts at all. Remember, this lever combined with a space cam directly controls the air/fuel mixture provided to the engine. If you're not making sure this is in working order, what is a pump restoration really doing for you?
Our next step is reattaching the governor to the pump body with a fresh paper seal. If your seal isn't visible or is a dark, grimy brown, they didn't remove the governor. We use brand-new seals made to spec for our restorations.
We then reassemble the camshaft, bearings and seal and move onto testing the resistance on the camshaft. Without taking the seal apart, calibration of camshaft resistance is impossible. Too much or too little resistance on your camshaft can cause various running issues and will eventually override any improvements made by an incomplete restoration.
This tool is the resistance meter we use to measure the resistance on the camshaft. Too much will wear out the bearings, too little and the camshaft will have the opportunity to come out of alignment. Neither are good for the operation of your pump and engine and you can only correct this by adding or removing shims as seen in the images below. It may seem minute, but even .15mm makes a drastic difference in resistance.
In addition to the seal the governor is attached with five specific bolts. Note one longer bolt without a lock washer in additon to the four others. We actually aren't sure why they made one bolt longer, but in between models Bosch engineers made the switch and we aim to keep your pump exactly as intended. These bolts go through the same cleaning and plating process as all your fuel injection pump parts and are replaced if needed.
The pin rests on the camshaft plate and measures the movement allowed when pulling on the camshaft. In these images you see that the movement of the camshaft is too great meaning additional shims are needed. Based on experience we knew it was about .15mm off and we keep specific shims of various thickness for this exact reason.
After adding the shim, you can see the difference in the meter reading. Before we had almost 20 nanometers of play. After inserting the shim we have less than 3. Yes, it required disassembling and reassembling the camshaft endplate via press, a 10-20 minute process, but there's no reason to skip this step if quality is your goal.
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After the camshaft shims are calibrated, we actually remove the camshaft and move on to reassembly of the rest of the pump. Plungers and barrels need the lower area of the pump free so the camshaft cannot be left installed after testing. However, testing has to be done at this point as the plungers and barrels, when installed, contact the camshaft and produce increased tension that will throw off the meter readings and lead to potential issues.
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