Valve clearance adjustment on a Volvo Penta MD2B
This season I realised my valve clearance for my Volvo Penta MD2B were due for adjusting. I was experiencing some more than usual white smoke coming from my exhaust.
Even though I realized, the white smoke issue would not be competely resolved by adjusting valve clearance, they were due for inspection anyway.
I was always under the impression that these projects had to be done by a diesel mechanic. On the other hand, I heard that the task would be doable, even with little experience, especially on these older diesel engines. So being a novice to this process, I faced a learning curve, but with patience, the owner’s manual, internet research and careful attention, I was able to successfully complete the task.
Why adjust valve clearance?
Valve clearance adjustment, also known as tappet adjustment, is essential for the proper functioning of your engine. Over time, valves can wear down or become misaligned, leading to decreased engine performance, reduced fuel economy, and even engine damage. Regular valve clearance checks and adjustments are crucial to maintain your engine’s health.
First of all, let me give you a disclaimer; this is a personal experience with this task. I am not a diesel mechanic. It’s crucial to consult the owner’s manual and seek expert advice, especially if you’re new to engine maintenance. Incorrect valve clearance can lead to engine damage.
Tools required for the job
- Owner’s manual (I was working with a digital copy)
- Torque wrench to ensure proper tightening of nuts and bolts
- Valve clearance feeler gauge
- Socket wrench set
- Screwdrivers
- Rags
- MD2B valve cover gasket
Preparation
First of all, for this specific model, the Volvo Penta MD2B, the manual states that the valve clearance has to be checked with a warm engine. Before I warmed up the engine, I removed the valve cover, and located all of the required adjustment screws. Also, I practised locating the TDC (Top Dead Center) of the engine, and marked this on the flywheel. The way to do this, first of all remove the valve covers. With these removed, you can look directly at the valves . Turn the engine by hand (either using the hand starter, or by simply turning the flywheel), untill the inlet valve starts to open, and the exhaust valve starts to close. At that point, turn the flywheel one more full turn. That is your Top Dead Center, at which you will adjust the valve clearance. Repeat this exact process for the second cylinder. You will find that the second TDC is at 180 degrees of the first one. Please note: the MD2B is a 2-cylinder diesel engine. The process is different on more cylinder diesel engines.
Measuring valve clearance and adjusting it
When I marked my TDC, and felt comfortable that I was up for the job, I reinstalled the valve covers, and warmed up the engine. After finding the first TDC, I checked clearance of the first cylinder, by using the feeler gauge. To my surprise, I found that the clearance was actually lower than what is recommended by the owner’s manual. Therefore I increased the clearance. For the MD2B, the manual states 0.30mm for the inlet valve, and 0.35mm for the outlet valve.
Make sure that no dirt gets into the engine, it could also be a good opportunity to clean the valve covers and air filters at this point. Also, it’s wise to double check the measurements, by doing a few rotations, going back to the TDC and checking once more with the feeler gauge.
After both cylinders have been adjusted, it’s time to reinstall the valve covers. In case the gaskets that were installed are worn or torn, it’s best to use new gaskets. Tightening the bolts of the valve covers should theoretically be done according to the specs of the owner’s manual. This may also be a good time to clean your air filters. I used a basic brake cleaner spray to clean mine; you can also use diesel oil.
Conclusion
Adjusting valve clearance on a Volvo Penta MD2B diesel engine can be a rewarding DIY project. By following the steps outlined in this guide and consulting your owner’s manual, you can help maintain the optimal performance and longevity of your engine. As mentioned before, in case of any uncertainties, always consult a professional, and keep in mind, safety first.