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dtoeppe85

H60 Timing Question

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dtoeppe85

I'm trying to set the timing on an H60, but have a question. First off let me say that I have very little experience with small engines. The engine is a new Tecumseh short block, but I am using most of the components from the original engine. I've installed the cam breaker and bolted the magneto to the engine. I've set the piston to 0.080 BTDC using a digital depth gauge and I am not close to being at the high point of the lobe on the breaker, see the picture. It's really at the base of the lobe, the red arrow shows about the high point of the lobe In the picture, the piston is at exactly 0.080 BTDC. Am I missing something?

 

 

post-13303-0-31286800-1408819991_thumb.j

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sorekiwi

Its a long time since I decided to stop playing with Tecumsehs, but I will try to remember.

 

Firstly is the piston set at .080" BTDC, or .080" below the top of the bore?  At TDC the piston is probably not flush with the deck face.

 

Are you sure you are turning the engine the right way?  That is are you sure you are at .080" BTDC and not ATDC?

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dtoeppe85

Yes, the piston is set at 0.080" BTDC when the output shaft is turning counter clockwise when viewed from the output side of the engine. I don't know if it matters, but I am setting the timing on the up stroke with both valves closed. The gauge is set to zero at piston TDC, not flush with the deck face.

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gwest_ca

I don't think you are that far off. This manual wants .090"-.100" BTDC for the 6hp when the points start to open. That's when the coil fires.

 

 

Garry

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dtoeppe85

If I set the points to 0.020" at 0.090 - 0.100" BTDC, I am moving further away from the high point of the lobe. This is my first time doing this, but I thought 0.080" BTDC would set the follower right at the high point of the lobe of the cam breaker. Is that not the case?

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gwest_ca

You set the points first to .020" on the high point of the cam. Then rotate the assembly to get the points to start opening at the specified piston location. A self-powered test light or ohmmeter will show you when they start to open.

 

Garry

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dtoeppe85

Just so I'm sure, the assembly is bolted to the engine, close to the final position, set the points gap to 0.020" on the high point of the cam, set the piston to 0.080" BTDC, then move the entire assembly so the points start to open at the piston location, using the bolts that hold it to the engine?

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gwest_ca

That sounds correct to me.

 

Garry

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dtoeppe85

I think I got it last night, but I will only know once the engine is completed and I try to start it.

 

Thanks for all the help.

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