115 ci engine

Keith-OR

Well-known Member
I am rebuilding 115ci engine out of a 1010, here is my problem, I have crankshaft installed and was installing camshaft, was lining up center punch marks on crank gear and cam gear, noticed there are 2 center punch marks on cam gear, they are 6 teeth apart. 1 is just below the hash mark between the cast cam gear numbers, and the other is 6 teeth from it.. So which one is the correct cam timing mark for the 115 gass engine???

Thanks
 
Put it on a mark & turn it slowly so the crank is TDC on #1 then look at the cam lobes. If not right use the other mark.
 
I check on another forum, I was told the punch mark lined up with the key way on camshaft. So i pulled snap ring that holds gear on camshaft and the mark I had it set at, is one that lines up with camshaft key way. I can't understand why someone would put another punch mark on the cam gear. Oh well, with all the other fly by night that someone has done this crawler, this don't really surprise me.

Thanks for the response
 
Would be very difficult to call it without the same engine torn apart to same stage as yours and I don't have that for you.

If alignment is made with crank throw for #1 at TDC position one might be able to infer which of the marks is the valid one by inserting valve lifters for #1 cylinder and pressing down on them with two fingers of same hand while rolling back and forth thru alignment. If alignment point seems to coincide with even stephen up/down of lifters then that should be the valid mark. You may have to roll it 180 to achieve the valve overlap area we are looking for here as one TDC will be compression/power strokes with no valve movement anywhere close to it and the other TDC will be exhaust/intake strokes. You would then have to work with only crank mark rolling into alignment with cam as the cam out 180 would have the 'real' mark 180 away - hope this part makes sense to you. TDC on exhaust/intake strokes should have one valve opening as the other closing and it would be pretty much balanced movement over TDC. Six teeth away will be noticeably biased and not centered at all. That's the goofball mark that somehow got on there by mistake. And it does happen. Very certain here that one mark is correct and you can find/verify it by above method.
 
I'm not sure what you are asking, but when both dots are lined up as per manual, looks like the crank is off from TDC about 20 to 30 degrees. When ya keep turning crank to get both valves lifters down, then the crankshaft would put piston at TDC. At this time I do not have piston in block, will be putting pistons in today.

Here is what I plan on doing, put engine back together completely, minus putting front end back on. Then crank engine over to determine TDC. this way I can change cam gear accordingly if need be.

thanks for the response.
 
I don't know specifically about your engine, but there's numerous engines out there where #1 piston is NOT at tdc when the timing gear marks line up.

Remember, you are setting the relationship between the camshaft and crankshaft, and NOT (at that point) determining #1 TDC.

As the others have said, time to one of the marks, then check to see if the #1 valves at at "rollover" one CRANKSHAFT revolution after #1 compression TDC at the end of the EXHAUST stroke.

If not, try the other mark.
 
Thanks Bob. I still have no idea why someone would put another punch mark on cam gear. This probably the reason it would not start when I first bought it. I never check the timing marks when I tore it down, just figured it needed rebuilding. I was correct, who ever worked on it last must have got a case of form-a-gasket for Christmas..
 
Whenever I've questioned the camshaft indexing on an engine I've always looked at the position of the lobes with respect to the piston at TDC for a particular cylinder.

With the piston at TDC(end of compression stroke/start of power stroke) both intake and exhaust lobes for that cylinder must be on their base circle.

Roll the engine over 360 deg. to TDC(end of exhaust stroke/start of intake stroke) and the intake & exhaust lobes for that cylinder should be on their overlap(brief moment where both intake & exhaust valves are open at the same time).
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top