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Post Info TOPIC: 235/261 inline six timing gear set question.


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235/261 inline six timing gear set question.


I have installed a new solid lifter camshaft, solid lifters and a new gear set on my 1957 261 inline six. I have the pointer on the flywheel dead on the ball timing mark and i have the crank key way at 12:00 straight up. Number one piston is at top dead center but the closest i could get the two timing gear marks together is where they sit now in the photos. If the timing dots on the cam gear and crank gear are dead lined up. then the timing ball on the flywheel is not lined up with the timing pointer in the bell housing. My question is first of all, am i going about this the  right way or am i missing something. Is having the two dot timing marks on the  two gears dead lined up, what really matters and not lining up the bell housing timing pointer and ball marking. I do not want to finish putting my 261 motor back together until i know for sure, for obvious reasons. The 57 Shop manual does not explain one way or another. Are there any old time mechanics out there or some one that replaced their gear set on a 235 or 261 motor that knows for sure. I would appreciate any help in this regard and thanks. The photos are not that clear but they show where i presently have the timing gear dots. Cheers. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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HI GEORGE, LOOKS LIKE THE OLD CRANK GEAR, DOES THE ORIGINAL CAM GEAR MARK (DOT) AND KEY WAY LINE RIGHT UP WITH THE NEW GEAR

IF SO IT SHOULD BE OK,  THE ONLY OTHER IS THE KEY PLACEMENT IN THE NEW  CAM , BUT WHAT ARE THE CHANCES THAT WOULD BE OUT.

 



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Poncho Master!

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Right, the dots are what's important and yours are lined up. The ball on the flywheel is for ignition timing and is normally a few degrees before TDC.

Thanks
Randy



-- Edited by GLHS60 on Wednesday 28th of January 2015 03:44:20 AM

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GLHS60 wrote:

Right, the dots are what's important and yours are lined up. The ball on the flywheel is for ignition timing and is normally a few degrees before TDC.

Thanks
Randy



-- Edited by GLHS60 on Wednesday 28th of January 2015 03:44:20 AM


 Randy, i would actually have to turn the crank clockwise just a bit to really line up the two dots. In doing that the timing ball on the flywheel will pass the bell housing pointer a bit. It would then be past TDC and not before TDC. Would this make a huge difference then. I find working on V-8's a lot easier than working on these old inline sixes. Where the two dots are now is not dead on lined up and i am afraid that by lining them up, it would put me too far past TDC. Any thoughts on the matter and thanks to everyone. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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OURWAGON wrote:

HI GEORGE, LOOKS LIKE THE OLD CRANK GEAR, DOES THE ORIGINAL CAM GEAR MARK (DOT) AND KEY WAY LINE RIGHT UP WITH THE NEW GEAR

IF SO IT SHOULD BE OK,  THE ONLY OTHER IS THE KEY PLACEMENT IN THE NEW  CAM , BUT WHAT ARE THE CHANCES THAT WOULD BE OUT.

 


 Hello Keith, the crank gear is new. I bought a new matched set. The dots on both gears are not 100% matched up, maybe 90% to 95% matched up. With the two dots exact and right on, it ends up sending the timing mark on the flywheel way past TDC. 



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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George, you don't want to let the ignition timing ball confuse you, as all you need is to have the crank and cam in sync.
There seem to be variances in timing ball locations as some Stovebolts actually listed ignition timing at after TDC, and some before TDC as is the norm, so the ball is not necessarily TDC.

It's possible to verify the timing dots are correct on their gears, if there is any doubt, by eyeballing lifter movement if the side cover is still off, or even the valve cover. We can discuss this in detail if needed.

Just like Chevy V8's, when the crank/cam timing dots are aligned together, like shown in your pictures, it is not firing on # 1, but on # 6. Your way isn't wrong as long as you are aware your rotor should be facing # 6, not # 1.

Factory timing dot alignment is done with the cam dot facing away from the crank dot, not meshed together as in your pictures. If you rotate your crank one full turn the cam dot will be where # 1 plug is firing. The factory recommended using a straight edge from the crank center through the cam center and the dots would fall within the straight edge if in alignment. The cam turns at 1/2 crank speed so the cam dot is opposite the crank dot every 2nd revolution of the crank, this is why its impossible for the cam timing to be out 180 deg. This is also why many folks who assemble their engine dot to dot and cant get it to run as the rotor should be facing # 6, not # 1 as is often assumed, resulting in backfiring etc. The distributor turns with the cam, not the crank.

#1 and #6 piston should both be at TDC when the crank/cam timing dots are correct, some folks use a straw etc. to stick in the sparkplug hole find when the piston is at TDC, to verify TDC manually. This will require rocking the engine a few degrees each way at TDC to verify TDC as there is a moment where the piston stands still while the crank throw changes direction.

Thanks
Randy




-- Edited by GLHS60 on Wednesday 28th of January 2015 04:25:11 PM

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GLHS60 wrote:

George, you don't want to let the ignition timing ball confuse you, as all you need is to have the crank and cam in sync.
There seem to be variances in timing ball locations as some Stovebolts actually listed ignition timing at after TDC, and some before TDC as is the norm, so the ball is not necessarily TDC.

It's possible to verify the timing dots are correct on their gears, if there is any doubt, by eyeballing lifter movement if the side cover is still off, or even the valve cover. We can discuss this in detail if needed.

Just like Chevy V8's, when the crank/cam timing dots are aligned together, like shown in your pictures, it is not firing on # 1, but on # 6. Your way isn't wrong as long as you are aware your rotor should be facing # 6, not # 1.

Factory timing dot alignment is done with the cam dot facing away from the crank dot, not meshed together as in your pictures. If you rotate your crank one full turn the cam dot will be where # 1 plug is firing. The factory recommended using a straight edge from the crank center through the cam center and the dots would fall within the straight edge if in alignment. The cam turns at 1/2 crank speed so the cam dot is opposite the crank dot every 2nd revolution of the crank, this is why its impossible for the cam timing to be out 180 deg. This is also why many folks who assemble their engine dot to dot and cant get it to run as the rotor should be facing # 6, not # 1 as is often assumed, resulting in backfiring etc. The distributor turns with the cam, not the crank.

#1 and #6 piston should both be at TDC when the crank/cam timing dots are correct, some folks use a straw etc. to stick in the sparkplug hole find when the piston is at TDC, to verify TDC manually. This will require rocking the engine a few degrees each way at TDC to verify TDC as there is a moment where the piston stands still while the crank throw changes direction.

Thanks
Randy




-- Edited by GLHS60 on Wednesday 28th of January 2015 04:25:11 PM


 Randy, all fully understood and thank you. So if i am hearing you right, what really matters is aligning those two dots on the gears and do not worry too much about what is happening on the other end, where the bellhouseing is with the indicators for timing. I will do the straight edge thing on the gear centers, that is a great idea. All else is fully understood. Thank you sir. Cheers. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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I double checked a 1957 Pontiac ( canadian ) manual .. and yup. that is all it says.. line up the dots .. double check with a straight edge..

 

and your good to go !



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I'm a collector...not a builder!!Located in sunny central Saskatchewan at the lakehead!


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rabbit64cs wrote:

I double checked a 1957 Pontiac ( canadian ) manual .. and yup. that is all it says.. line up the dots .. double check with a straight edge..

 

and your good to go !


 Cheers to everyone. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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Keep us posted on your progress!!

Thanks
Randy

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GLHS60 wrote:

Keep us posted on your progress!!

Thanks
Randy


 Randy, both no. 1 and no. 6 are at TDC and both timing gear dots are dead on with a metal straight edge. I have my new solid lifters and new push rods in. Will be putting on the timing gear cover on soon with the harmonic balancer that i put a speedy sleeve on. The balancer had the usual groves that chew up the seal, so the speedy sleeve was an easy fix. Once that is done i will continue restoring my rocker arms. Some of the arms had half moon impressions on the valve stem contact area's. With those impressions you can never get an accurate reading on your feeler gauge. Thanks again for the great advise. Cheers. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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George, when I was a youngster working in machine shops we had a fixture to reface those rockers.

Thanks
Randy

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GLHS60 wrote:

George, when I was a youngster working in machine shops we had a fixture to reface those rockers.

Thanks
Randy


 Randy, obviously i do not have that same fixture. I am carefully grinding the surface and then brass wire wheeling to buff out. Seems to be working ok. Randy do you have any thoughts on the way i am going about repairing my rocker arms. I am open ears and always willing to learn new tricks. I put the oil pan back on today and that was fun on these 261 motors. Keep in mind i am working on this motor in the car and not on a stand. Timing cover and fuel pump back on today as well. It is always appreciated, getting good advise. Cheers. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8



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George, the fixture guided the rocker arm tip curvature against the grinding wheel, it sounds like you are on the right track.
The only reason I mentioned the fixture is it reminded me labor was so much cheaper than parts in the "old days", just about everything was repaired/rebuilt, opposite of today. Hard to believe but it was cheaper to recondition a piston than replace it. Pistons had spacers installed in worn ring grooves, skirts were knurled to make them tighter in worn cylinders and oversize wrist pins were installed when needed.

Thanks
Randy

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GLHS60 wrote:

George, the fixture guided the rocker arm tip curvature against the grinding wheel, it sounds like you are on the right track.
The only reason I mentioned the fixture is it reminded me labor was so much cheaper than parts in the "old days", just about everything was repaired/rebuilt, opposite of today. Hard to believe but it was cheaper to recondition a piston than replace it. Pistons had spacers installed in worn ring grooves, skirts were knurled to make them tighter in worn cylinders and oversize wrist pins were installed when needed.

Thanks
Randy


 Randy, i hear you but generally i prefer to install new parts over rebuilt parts any day. I will rebuild if i have no options or the options are way to expensive. Granted it is fun rebuilding stuff but it has to make sense. I do refuse to put crappy off shore parts on my car. I will pay extra for a quality part or just rebuild it myself. You mentioned "knurling", i always thought that that whole process was half ass and not worthy. Sort of a temporary quick fix. Well sir, i will keep plugging away on my 261. Cheers. George.



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low milage original 400 V-8

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