International FBB298 Engine Magneto Timing

Schultz · Nov 2, 2011

This engine is out of a TA-40 Crawler or a W-40. It's currently on a run stand and I'm trying to set the ignition timing. It has a mag with an impulse coupling. I'm looking for a procedure to get me real close. Where should the engine be, TDC or 10 or so degrees before? Where should the magneto be before I try to line the plate up, with respect to the impulse coupling? I'm a distributor guy and the only other mags I've ever played with were automotive racing mags that didn't have impulse couplings.

Thanks,

Janicholson · Nov 2, 2011

With two full rotations of the engine, and the mag in place so that it is retarded the timing marks are aligned TDC compression, #1 cyl, then the mag turned until it trips. TDC atatic timing. The mag then goes to full advance. I assume this engine has no manual retard lever for starting. Jim

Tom Fleming · Nov 2, 2011

Jim is spot on as usual. Which magneto does this use? F4 or H4? Timing an engine with an H4 is a bit easier than an F4. If it is an F4, I will be happy to post the full timing instructions, OR will be happy to talk you through it on the phone.

Old-F20 · Nov 2, 2011

(quoted from post at 17:16:00 11/02/11) Jim is spot on as usual. Which magneto does this use? F4 or H4? Timing an engine with an H4 is a bit easier than an F4. If it is an F4, I will be happy to post the full timing instructions, OR will be happy to talk you through it on the phone.

F6 mag

T-40, TK-40, W-40, and WK-40 were 6 cyl engines

Tom Fleming · Nov 2, 2011

Old, ok, good point. Brain cramp on my end.

Old-F20 · Nov 2, 2011

(quoted from post at 17:57:20 11/02/11) Old, ok, good point. Brain cramp on my end.

no problem. since it was the only thing in the 30's that IH made that WASNT a 4 cyl people get confused sometimes. Plus, when they see they are a '40' series they think 4 cyl. People always ghad a strnage look when they would see my WK_40 and count the spark plugs, then the questions. lol

rustred · Nov 2, 2011

it is an F6 mag.

rustred · Nov 2, 2011

that6 cyl.FBB engine is out of the d-50 ihc series trucks and was adapted for the ihc tractors in a hurry. it was on of ihc big screw ups.the engine was just too light and did not stand up well being run to the pin day after day.

Old-F20 · Nov 2, 2011

(quoted from post at 18:29:20 11/02/11) that6 cyl.FBB engine is out of the d-50 ihc series trucks and was adapted for the ihc tractors in a hurry. it was on of ihc big screw ups.the engine was just too light and did not stand up well being run to the pin day after day.

wasnt another big problem was the fact the castings were just a touch too light and after being ridgid mounted to the chassis they would develope cracks in the blocks??

Tom Fleming · Nov 2, 2011

I have never timed an F6, but since it is similar to the F4, I would expect timing procedure to be the same. Get #1 on TDC on compression stroke. Disengage impulse on the mag. rotate rotor until leading edge of the contact is pointed at #1 on cap. line up coupling disk finding the 2 holes that will accept the bolts. install bolts. engage impulse. should be right on at that point.

No? Yes?

Schultz · Nov 3, 2011

If you could post the full timing instructions that would be great. If you have the time to give me a call that would be very appreciated.
You can reach me @ 734-536-1984

I don't see a way to disengage the impulse on this.

Thank you all for the help

Schultz · Nov 3, 2011

Got it running and the timing adjusted.

Thanks for all the help

rustred · Nov 3, 2011

that is quite possible. i have seen many with cracks between the sleeves on top of block . also lots with cracks behind carb, but thought it was from water freezing.

International FBB298 Engine Magneto Timing

Schultz

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Janicholson

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Tom Fleming

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Old-F20

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Tom Fleming

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Old-F20

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rustred

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rustred

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Old-F20

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Tom Fleming

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Schultz

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Schultz

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rustred

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