Saturday, August 21, 2010

Tuning valve clearance on rocket arm engine types

check and adjust the clearances of the valve opening on engines with rocker/arm timing.

this is an example based on the Universal Diesel 5416 engine but if you take any other engine that uses this design, the instructions are pretty much the same. For example, Moto Guzzi motorcycle engines can be tuned much the same way.

In a 5416 engine, the first step is to remove the valve cover. This is remarkably easy on this engine since only two bolts keep the cover in place. Remove the bolts and carefully lift the cover. Note: some engine have the optional breather. The breather is hold in place by two more small bolts, simply remove those and lift the breather out of the way before removing the cover.

Then pick one rocker at the time and follow the instructions from the engine manual to rotate the engine to TDC for that rocker. Basically what you need is the camshaft to be at the lowest point for that arm thus giving the rocker the most clearance. You *could* just rotate the engine by hand looking for the TDC. I do not condone this method but I do admit that it works for old engine where finding documentation can be nearly impossible. Once the rocker is at it loose state, use a wrench to loosen the nut while using a flat screw driver to keep the arm from rotating. Once the nut is loose, place a feeler in between the rocker and the top of the valve and screw in/out the arm until the feeler can fit snugly in the gap. Now carefully tighten the nut making sure you hold the screwdriver firmly in place so the arm does not rotate. Repeat for each rocker arm and you are done. Trust me, it sound more complicated than it actually is.

Marine Diesel - replacing the sending unit

old, and I mean old, marine diesel engine inexplicably looses oil pressure at idle when the engine is warm.

check your oil pressure, do not trust your sending unit. Chances are you have no problem at all, the sending unit is simply failing. If the pressure you measure is within range, you just need a new sending unit (oil pressure sensor).

Universal Diesel 5416
If you have one of these very popular marine engines, the sending unit can be purchased at Napa Automotive for nearly 1/3 of the price of the OEM. Here are a few photos of the part you want.

Costant Velocity Joint replacement, Audi A4

clicking noise coming from one of the front wheel (front wheel drive car) upon turning and accelerating from standing still. For example, turning right/left at a stop sign. The car in this post is an Audi A4 (B5 model).

There are tons of sites that already post the instructions on removing the CV boot and the CV joint itself. Please see this one or even better, this one for a full description. Note that replacing the CV boot and replacing the CV joint basically require the same amount of work. Simply replace the old CV joint with the new one when replacing the boot and voila, you saved a ton of money. In my case it was $100 (parts + DIY) Vs. $850 estimate from the local dealer. What I wanted to share here is some tips and tricks:
  1. make an extractor tool out of the bolt you remove from the old CV by simply grinding off the first 1/4 inch of the thread (tip end, of course). I used a Dremel power tool and it works like a charm. Once you prep the bolt this way, you can screw it back in all the way and the CVJ pops right off the axle effortlessly.
  2. turn the wheels all the way to the opposite side you are working on. Say you are working on the right wheel, turn the wheels all the way to the left. This will push the steering arm all the way out. Once you pop the support arms (see photo) this will give you all the room you need to work on the CVJ and CV boot without removing the axle.
  3. do ease all the wheel bolts including the axle bolt before lifting the car. I am talking about 1/2 turn, no more. This will just make life easier once the tire is off the ground and you cannot and should not put torque against the axle/transmission
  4. if you are replacing the CVJ, note that a new one hardly swivel by hand whereas a worn one will easily swivel just by touching it (once removed, of course). The point here is the tolerances are very tight on the new part and they will loosen over time up to the point where you will start hearing the aforementioned ticking noise when turning. The ticking is generated in fact by the excessive clearances in the joint.

A sample of the tools I used for the job. Basically you want to have a basic tool kit of metric sockets and wrenches. For this project you will also need these three tools that are definitely not off the shelf so if you do not have them, please make sure you procure them first:
  1. depending on the specific year of your A4 you may need either a 27mm socket or a 17mm hex. If your car is prior 2001, chances are you need the socket.
  2. a CV boot clamping tool. This is a pain to find but Napa Auto parts actually carries it. Starts there.
  3. long arm torque wrench capable of 120 lb torque. I bough mine at the local Osh.