Finding Top Dead Center

[LynnsABCs]

My son bought an almost new Mexican 1600 dual port engine for his 65 camper we are trying to get running. No distributor was installed. There is only one VERY small notch on the front pulley that could be a timing notch for TDC or it could just be scratched.

John Muir's idiot book says to watch #1 intake valve as you rotate the engine. As it dips in (begins to open the valve) and then starts to close--that's top dead center.

I think I have the 009 distributor 180 degrees out of sync with TDC--getting some nice strong back-fires when the engine tries to start and run.

Is there another way to verify than looking at #1 intake valve to make sure? How far past the valve closing is TDC? in case the pulley TDC notch is not valid? The pulley is painted solid black with no other noticeable markings. Sort of makes life difficult.

Thanks!!
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LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[john walker's workshop]

the proper way to find TDC is to pull #1 plug and stick a dial gauge down thru the hole to contact the piston. in your case, a stiff wire will do in a pinch. rotate the engine clockwise until the wire just stops moving outward. and make a mark on the pulley that lines up with the split in the case. rotate a bit further clockwise and the wire will start to go in again. now start to rotate the engine counter-clockwise until the wire just stops moving outward and make another mark on the pulley. TDC will be the center point between the two marks. a dial gauge would be a hair more accurate, but this will get you started.
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John Walker's Workshop 206 789 6800
7613 Greenwood Ave. N. Seattle, Wa, 98103
www.johnwalkersworkshop.com

[LynnsABCs]

John:

Your method sounds a lot more scientific than anything I have found. I have a 911 dial gauge and clamp, so I will try using it. Thanks for your quick reponse!
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LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[john walker's workshop]

for those who didn't follow, there is a point in all engines where the crank is turning and the piston is not moving. that would be at the bottom and top of each stroke. the piston reaches TDC before the crank does. that's why you do the procedure by turning the engine in both directions and splitting the difference.
_________________
John Walker's Workshop 206 789 6800
7613 Greenwood Ave. N. Seattle, Wa, 98103
www.johnwalkersworkshop.com

[edgy]

This will find approximately TDC. Unless you pull off the head and do it, it is only close. Suggest you do it just like MUIR told you to and then when the mark comes up, stop and static time the engine. Then start the engine and put a vaccum gauge on it to set the timing.

[john walker's workshop]

how is it approximate? you're working off the piston crown, same as if the head was off. and i would take anything muir said with a grain of salt. he was a hammer and chisel guy, remember.
_________________
John Walker's Workshop 206 789 6800
7613 Greenwood Ave. N. Seattle, Wa, 98103
www.johnwalkersworkshop.com

[edgy]

Unless you are using a micrometer I don't think you can see exactly when the wire quits moving. In any case, it is hard to set the timing so close that that much precision is required. I doubt if hte distributor shaft is that tight anyway. I suspect the point gap is farther off than either method can measure.

My point was that close is good enough.

[LynnsABCs]

John Walker's suggestion worked like a charm. I used Muir's method watching for the valves to first start opening, then stuck a clean long-blade screwdriver to touch the top of the piston. As it pushed the screwdriver out I watched both it and for the timing mark. TDC was right on the money for the small timing mark on the Mexican pulley. That eliminated being out 180 degrees of time.

Next stop was to re-take off the Kadrons and used what I learned on the Mr. Kadron site. I put a small nut on each accelerator linkage so there was not slop. I pulled and unstuck each accelerator nozzle (that sticks down into the throat of the carb). One check ball was missing from one carb.

Also realized I had #3 and #4 plug wires reversed. Hooked it all together and it sounds like a VW engine is supposed to--will be ordering carb rebuild kits from Mr. Kadron, a check valve and another accelerator nozzle if not both. Want to also see about getting a set of springs to hook up to each carb accelerator arm like a Zenith carb on a 356 Porsche. Don't want carbs to stick wide open and blow the new engine.

Next stop is to finish the front brake lines and buy a set of new tires.
_________________
LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[LynnsABCs]

John Walker's suggestion worked like a charm. I used Muir's method watching for the valves to first start opening, then stuck a clean long-blade screwdriver to touch the top of the piston. As it pushed the screwdriver out I watched both it and for the timing mark. TDC was right on the money for the small timing mark on the Mexican pulley. That eliminated being out 180 degrees of time.

Next stop was to re-take off the Kadrons and used what I learned on the Mr. Kadron site. I put a small nut on each accelerator linkage so there was not slop. I pulled and unstuck each accelerator nozzle (that sticks down into the throat of the carb). One check ball was missing from one carb.

Also realized I had #3 and #4 plug wires reversed. Hooked it all together and it sounds like a VW engine is supposed to--will be ordering carb rebuild kits from Mr. Kadron, a check valve and another accelerator nozzle if not both. Want to also see about getting a set of springs to hook up to each carb accelerator arm like a Zenith carb on a 356 Porsche. Don't want carbs to stick wide open and blow the new engine.

Next stop is to finish the front brake lines and buy a set of new tires.
_________________
LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[john walker's workshop]

edgy, i did say to use a dial gauge for a precision measurement, but a wire or the like will get you pretty close.
_________________
John Walker's Workshop 206 789 6800
7613 Greenwood Ave. N. Seattle, Wa, 98103
www.johnwalkersworkshop.com