Distributer Alignment

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gcbennet
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Distributer Alignment

Unread post by gcbennet » October 6th, 2018, 2:39 pm

So I took my distributer out of my ‘77 A2 to repaint/service and wanted to make sure everything was aligned as it should be upon re-installation. The truck ran fine more or less up to this point but will not start now. The book says looking down at where the dist shaft meets the oil pump gear the arrow on the oil pump should point forward directly in line with the cam, and once the dist is installed the rotor should point at #1 Cyl. To me logic would dictate that if the rotor is facing #1, the cyl should be at TDC. But, if I align the arrow on the pump to point forward like the book says, #1 cyl isn’t at TDC. FYI the short coupler shaft will only fit on the dist shaft one way, while it will fit either way (180 deg) where it meets the pump gear. Am I missing something here?
Gordon Bennett

1985 M998 HMMWV
1986 Bombardier Iltis
1977 M151A2

Fil Bonica
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Re: Distributer Alignment

Unread post by Fil Bonica » October 6th, 2018, 3:47 pm

The lntermediate shaft should only go one way in to the oil pump.
The oil pump should be parallel to the engine body or cam.
The distributor can go in either direction.
Is it possible you are out 180 degrees?
If number 1 is set to tdc and it is slightly off then the oil pump is installed incorrectly.
Just some thoughts.
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gcbennet
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Re: Distributer Alignment

Unread post by gcbennet » October 6th, 2018, 4:22 pm

Sorry, I got that wrong. The shaft will fit either way on the dist itself. The notch is offset of centre where it meets the oil pump so will only fit one way there. When #1 cyl is at TDC the arrow on the pump faces aft, not forward. Could this mean whoever had that apart in the past reassembled the oil pump 180 deg out?
Gordon Bennett

1985 M998 HMMWV
1986 Bombardier Iltis
1977 M151A2

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Re: Distributer Alignment

Unread post by Fil Bonica » October 6th, 2018, 5:36 pm

The oil pump may have been installed a 180 degrees out.
If that is the case then merely install the distributor in the opposite position so that the rotor points to number 1 at TDC. That should allow for proper operation.
If that isnt the case and the oil pump keyway is not parallel then the oil pump is not positioned correctly.

Hope that this helps.

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muttguru
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Re: Distributer Alignment

Unread post by muttguru » October 6th, 2018, 5:40 pm

GCB....what Fil has said. Plus..... make sure that the No.1 cylinder is indeed at the top of the COMPRESSION stroke and not the EXHAUST stroke.
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Re: Distributer Alignment

Unread post by kmam » October 6th, 2018, 6:56 pm

Bit late now, but for future reference - before removing the distributor take the top off, rotate the engine until the rotor or electronic unit points to cylinder number 1 position and then remove the distributor. Do not turn the engine again and when you have finished working on the distributor make sure the rotor or whatever is again pointing at number 1 position and reinstall the distributor. Everything will then fall into place.
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svramselaar
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Re: Distributer Alignment

Unread post by svramselaar » October 8th, 2018, 8:08 am

hi

if you rotorarm is 180 degrees out you can take the ground plate out
and set the cam 180 degrees take the wik out from the center and the litle ring

http://www.army-spareparts.com/shop/sit ... k=mFBcXrcE

george

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gcbennet
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Re: Distributer Alignment

Unread post by gcbennet » October 9th, 2018, 11:52 am

If the oil pump is out by 180 deg I don't think it would be of any consequence. However, from the looks of things it also may be off by a tooth. This is evident when I set the timing. With only the light, if the notches on the pulley align the truck runs like crap. If I use my ear and vacuum gauge to set the timing the notch is off by about a half of an inch or so. Seems to me whoever had this thing apart in the past and put back together didn't align the cam notches and aim the arrow on the pump gear forward directly in line with the cam as the TM clearly states.
Gordon Bennett

1985 M998 HMMWV
1986 Bombardier Iltis
1977 M151A2

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rickf
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Re: Distributer Alignment

Unread post by rickf » October 9th, 2018, 3:34 pm

It sounds more like the cam gear may be off by a tooth. The oil pump gear being off will not make any difference in how it runs once the timing mark is set right on the line. The only difference the oil pump position makes is it changes the position of the distributor in relation to the block. If it is running bad with low vacuum on the mark then the valve timing is probably off. May be time to pull the timing cover for a look see. But you say it ran fine before? Neither of these things are going to happen just by pulling the distributor out.
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1984 M1008
1967 M416
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gcbennet
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Re: Distributer Alignment

Unread post by gcbennet » October 11th, 2018, 4:11 pm

She ran fine (more or less) once I set the timing by ear and not by the mark. I suppose next step is to pull the gear cover and check out the notches...
Gordon Bennett

1985 M998 HMMWV
1986 Bombardier Iltis
1977 M151A2

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Re: Distributer Alignment

Unread post by rickf » October 11th, 2018, 4:42 pm

Keep in mind that you can get a really nice sounding idle and real high vacuum by setting the timing by ear, It will sound fantastic. But it will run like crap at high speed and probably ping like hell also. Setting the timing to the mark really drags down the idle amd sounds like there is something wrong but I can assure you that that is the ONLY place it will run good all across the power band. That is if the timing gears are set correctly.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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gcbennet
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Re: Distributer Alignment

Unread post by gcbennet » October 17th, 2018, 1:18 pm

Turns out my dist was out by 180 deg upon reassembly, so having been corrected the truck runs well now.

I decided to try Seafoam for the first time based on testimony from a few friends who swear by the stuff. I poured some into my gas and crankcase, as well as an ounce or so into each cylinder through the spark plug holes to see if it could make a dent in the 40 years of deposits. Quite the smoke show on initial start-up, but from what I'm able to see it's cleaned up the top of the pistons quite well. I figure the oil should be quite black when I eventually drop it.
Gordon Bennett

1985 M998 HMMWV
1986 Bombardier Iltis
1977 M151A2

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