how do i know where timing marks are on a AQ125-145

[denisecapps]

it was running and then quit. replaced plugs coil with condencer in it getting spark as far as i know. we are thinking it jumped time. how do i check and fix the problem if it did jump time. thanks for any help that comes back

 

[dennis461]

rotate engine to 0 degrees on flywheel,
Look for mark on timing gear. should be dead center between two front valve cover bolts.
Remove dist cap, rotor should point to mark on top edge of aluminum dist, the edge/rim the cover sits on.

May need to rotate crank a couple of times, go slowly to let compression bleed off

 

[bruceb58]

The timing gear pretty much doesn't matter. It can pretty much be anywhere. People think it needs to be lined up perfectly but it doesn't. What you need to worry about is the crankshaft to cam timing. There is a mark on the cam pulley that aligns with a mark on the sheetmetal behind the pulley when you are at TDC on compression stroke with #1 cylinder.

If that is correct, just time with a timing light to spec.

 

[dennis461]

The timing gear pretty much doesn't matter. It can pretty much be anywhere. People think it needs to be lined up perfectly but it doesn't. What you need to worry about is the crankshaft to cam timing. There is a mark on the cam pulley that aligns with a mark on the sheetmetal behind the pulley when you are at TDC on compression stroke with #1 cylinder.

If that is correct, just time with a timing light to spec.

The "timing gear" as you call it is the auxiliary shaft drive gear.
The aux. shaft spins the oil pump, and spins the distributer.
If you don't line it up, or it skips a tooth or two, you cannot get the distributer to fire the correct cylinder.
The adjustment slot in the dist base of the Volvo 4-banger has limited movement, unlike some car engines, which allow lots of flexibility.

So, when the engine is at TDC, the dist must be lined up to cyl. #1, confirmed with the small mark on dist lining up toward front and rotor toward front.

 

[bruceb58]

The "timing gear" as you call it is the auxiliary shaft drive gear.

LOL...You called it the timing gear. It's true name is the intermediate shaft. If its off one tooth, you should still be able to adjust the distributor and still stay within the distributors range.

Look for mark on timing gear. should be dead center between two front valve cover bolts.

BTW, the intermediate shaft is no where near the valve cover

The serious jump would be the camshaft timing. I would be extremely surprised if a tooth jumped on the auxiliary shaft. Of course, seeing if the aux shaft moved can easily be confirmed with a timing light and no need to pull off the front cover to determine that.

 

[dennis461]

No Title

denisecapps send me a PM, there is some bum info on here.

If you sucked in some seaweed and your strainer is not working good,
the intermediate shaft could have skipped a tooth making running difficult ( the shaft turns the raw water pump as well as the dist.).
When that happens, the crank and valves are still in synch, but the points/ sparkle rotor lose synch.
I can send you pic's of how I set up the timing on my engine, a B230 which is basis for both the AQ125 and 131.

Here is a pic looking at timing gear from the rear/top of engine the red/yellow thing at top is the heat exchanger lip which covers the gear making it hard to see.
Crank is at TDC (actual) the timing mark on the harmonic dampener is not always accurate.

 

[bruceb58]

Here is a pic looking at timing gear from the rear/top of engine the red/yellow thing at top is the heat exchanger lip which covers the gear making it hard to see.
Crank is at TDC (actual) the timing mark on the harmonic dampener is not always accurate.

That is the camshaft gear!

OP...just check your timing with a timing light. If it's not off, you didn't slip.

I have replaced timing belts in these engines at least 5 times back in the day. I have never seen a timing belt slip once.

 

[bruceb58]

but the points/ sparkle rotor lose synch.

Absolutely impossible. The shaft that the rotor sits on is driving the points.