Volvo Md7a

[weephee]

I'm in the process of rebuilding my Md7a and the question I have is which cylinder in #1. I have the emanual but it doesn't tell me. Thanks

[weephee]

I'll try again. Does anyone know which cylinder is #1 on a Volvo md7a. Thanks

[model 10]

I'll bet they are on the engine or head casting somewhere. Then I'd bet #1 is in the front too.

[weephee]

Thanks for your reply. I assumed #1 Cylinder would be at the flywheel but wasn't sure.

[hpeer]

I've had the head off and didn't see any marker.

Why is it important to know?

[model 10]

Originally Posted by weephee

Thanks for your reply. I assumed #1 Cylinder would be at the flywheel but wasn't sure.

Funny, one of us is probably right.

[weephee]

It is important to know because the manual calls for piston #1 to be TDC when adjusting the injection pump.

[model 10]

Originally Posted by weephee

It is important to know because the manual calls for piston #1 to be TDC when adjusting the injection pump.

You can figure it out logically. Note the direction of rotation. Turn the engine until the front piston is tdc. Check to see if the both valves would be closed. Look for the timing mark on the fuel pump drive gear. If that did not work check the rear one . If you are still puzzled, figure out the firing order from rotating the engine and watching the cam. #1 will not be one of the middle cylinders.

[Shawn67]

"It is important to know because the manual calls for piston #1 to be TDC when adjusting the injection pump."

#1 is the flywheel side of the engine. Are you removing the injector pump? If so make sure you remove the access cover (where the water pump is) and spin the engine until the timing mark on the injector pump gear AND on the drive gear line up. If you have lousy access to the rear of the engine (my Sabre's is tough) get a $99 bore scope from Home Depot. It makes this dramatically easier to see. There is a 2:1 ratio between the pulleys so you might need to spin it over twice to get the marks to line up.

Removing the exhaust riser (and manifold) really helped give more access to this area. On my MD7A I had a couple of corroded bolts due to a leaking water pump. I had to drill them and that was not fun.

I initially tried to duplicate the injector timing based on where the old pump was. However, I found adjusting the timing based on the actual running of the engine seemed to work better. I would adjust it slightly, start engine and see how easily it started and how much smoke it had. I adjusted timing for the least amount of smoke and the engine has run great after that. Small movements make pretty big difference in the amount of gray smoke you get and also in how easily the engine starts. If the timing is off too much the engine won't start at all.

Shawn

[weephee]

Thanks guys, I really appreciate your responses. The engine is out of the boat so I will try your suggestion Shawn and see how that goes. I intend to start it before installation so I should be able to adjust accordingly. I also have a yanmar 2qm15 so I'm not sure yet which engine I'm going to install in my 8.7 columbia. The MD7A will be in good shape so I will sell it if I install the Yanmar. Thanks again