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phorvati 04-12-2022 08:08 AM

Lehman SP90 Injection pump timing
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I am getting ready to take of my injection pump to send for a rebuild. Prior to doing this, I looked over the service manual to learn how top place the engine in proper timing, looks like 20deg before TDC on #1 cylinder. Service manual talks about timing tool 10965. Do i need this or can i just take the timing cover off and look through the hole to line the engine.

page 33 in service manual

Piaro 04-19-2022 11:49 AM

You "can", but that pin also keeps the crank from moving while you are monkeying with the pump. If you can find washers to fit in the hole you can use a piece of threaded rod with a couple nuts with several washers in between, may need to grind the diameter of the rod down. You can also find a bolt that threads into the hole and do the "pencil sharpener" with a grinder and grind a tapered point then screw that in hand tight. Just make sure you're on the compression stroke LOL.

phorvati 04-20-2022 12:11 PM

Few things to note. My engine is actually NE90 not SP90 so Atlantic Diesel did not marinize mine.
There was no marking on my pump gear. I ended up getting to TDC, then a mark on the engine crankshaft gear was facing the pump gear. Unfortunately, there was no marking on pump gear. No marking on pump gear anywhere whatsoever along the entire perimeter. I placed a mark using a centerpunch. Injection Pump gear is keyed so there is only one way to come in on the pump. I took off the gear and drive hub and shipped the pump for service. Injection pump service guy walked through the marks with me and I think I should be good.
As far as that tool, I think its fine if it takes me few tries to line up my mark with engine's crankshaft gear mark. We wont know until i put everything back together.
One interesting note is that drive hub (item 2 in pic attached) mounts to IP shaft using the center nut. Ring Gear(item 1) mounts onto drive hub via 4 Retaining screws(hex item 3 in pic). Gear actually has slots where screws go through which allows for fine-tuning. Then retaining plate (item 4) keeps gear from moving along slots. I guess fine tuning cannot be done while engine is idling. This is different from rotary type Injection pump like Lucas CAV DPA that sits on perkins and westerbeake 4-108. That pump you can rotate while engine is idling to fine tune the timing.

syjos 04-20-2022 10:10 PM

You can line up the timing marks by eye but make sure you can get your head low enough to not have parallax error. I use a mirror or camera to see the mark through the hole.

You might need to clean rust off to reveal the markings.

I use a bar on the front pulley to turn and hold the crank.

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