Degree an Engine

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1.) You will need a way to mount the dial indicator to the top of the head. The normal mounting accessory for a dial indicator is an articulated arm. The type that attach to any convenient, nearby bolt or stud are probably the easiest to use. Others use a magnetic base; however it isn't going to stick to an aluminum head. If that's what you have, you will need another way to attach it.

For the Lotus/Ford Twin Cam engine, for example, make a small "U"-shaped tray/table out of plywood or lumber-core. Cut it large enough to bridge the spark plug valley and overlap the inner cam cover studs. The legs of the "U" only need to be about an inch wide to be strong enough. The bottom of the "U" should be wide enough to provide a mounting surface for the magnetic base... probably covering the two rear sparkplugs. This configuration will provide both a solid mounting surface and easy access to the #1 sparkplug hole.

Set it in place on top of the cam cover studs and use a mallet to strike it smartly above each stud, making impressions on the bottom side. Flip it over and drill clearance holes for the studs, using the impressions as position guides.

Remove the cam cover, set the board down over the studs such that it rests on the bearing caps and secure it with four washers and nuts. Clamp, bolt or screw the magnetic base to the table. Both the table and the indicator should be solid, as any movement will translate into bogus readings from the dial indicator.

With a little creativity, a similar set up can be used for most engines.

2.) The stem of the dial indicator is not long enough to reach through the head and touch the piston at TDC. Extensions are typically available, but I don't have one yet. I'm looking for an off-the-shelf item now, or I may have something beautifully machined or totally cluged. If you decide to buy your own indicator, inquire about extensions.

3.) The biggest problem degreeing the Twin Cam engine as installed in the Europa is going to be reading the degree wheel attached to the engine's front pulley. It's a two person job with someone lying under the car taking degree readings and someone else topside reading the dial indicator. I don't have a good alternative for you right now. If you have one, I'd like to hear it.

4.) To find TDC... a simpler, slightly less accurate alternative to the dial indicator is a bolt/jam-nut screwed in through the sparkplug hole. Put the piston at TDC. Run the bolt in until it touches the piston. Back the piston down out of the way. Screw the bolt in about another .200" or so and tighten the jam-nut. Now you have a positive stop for the piston at a fixed distance down from TDC.

With a positive stop, you obviously can't keep rotating the engine in it's normal direction. It wil be necessary to bring the #1 piston up to the stop-bolt and take a degree reading. Then reverse direction one revolution and take the piston back up to the stop from the other direction and take a second reading. The effect is "similar" to taking dial indicator readings at the same height on the way up and on the way down.

The problem with it is that:
A) Any clearances or slack in the engine components will effect the accuracy of the readings when you reverse the direction of rotation. With a tight, fresh engine the error should be minimal. With a worn engine it may be questionable. Even so, this method is probably more accurate than using the cast-in pointer.
B) This method only simplifies determining "TDC". You will still have to use the dial indicator on the cam lobes to measure MOP (after removing the stop-bolt -- two crank revolutions per cam rev). If the engine is still in the Europa, you're back to a two-person job again. Since you have to enlisted a helper anyway, you may as well do the whole thing the optimal way.

The beauty of it is that:
C) This method is dead simple (turn it until it stops), requiring no special skills in the use of a dial indicator. You can achieve a slightly reduced level of accuracy easily with minimal chance of introducing any operator error. If you don't know what you're doing, but you insist upon doing it anyway, this may be the way to go.
D) One person could "TDC" the Europa from under the car. Just use a wrench on the front pulley bolt to turn the engine back and forth while taking readings. Be sure to re-torque the pulley bolt when you're done.

NOTE: ...of course, you still have to deal with the dial indicator and a helper to measure the cam's MOP.


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