Need help finding compression TDC to adjust valves on kubota D1105.

[MrFix-it]

I have a Kubota zd28 tractor with a D1105E engine. It recently started to run hot and eventually blew the head gasket. When I removed head it was cracked so I bought a new complete head and everything I needed to replace it. I know where the timing marks are but am not sure whether I have number one piston on the compression top dead center. I need to know the best way to find the compression stroke with all the valves closed and the valve adjusters backed completely off. I had to remove the rocker arms and assembly so I'm starting over basically. I have service manual which says find compression TDC and adjust number one cylinders intake and exhaust valve both along with number twos exhaust valve and number threes intake valve. Then turn engine 360 degrees to overlap position and do number two intake and number 3 exhaust valve. I just need a definite way to make sure im starting on the compression stroke with the number one piston at top dead center. I can use timing marks on flywheel but that won't tell me which stroke it's on. Anyone know a good way to do this?

 

[jaydee325]

Rotate crankshaft until #1 rocker arms "rock". That is the exhaust valve closing and intake opening. That is TDC of #1 Exhaust stroke. Now, rotate crankshaft a full revolution and you will be at TDC #1 Compression stroke.

Both of these states should line up with the TDC timing mark either on the flywheel or balancer on front of engine.

 

[Roadworthy]

I don't know if my method is acceptable but after torquing the head I rotate the engine until pressure is removed from both valves of a given cylinder. I figure this point must be TDC on the compression stroke. I adjust the valves on this basis. I continue the process for the other cylinders. It may involve more rotation of the engine to get a feel for what I'm doing but it seems to work for me.

 

[Rebeldad1]

line up tdc timing marks.
tdc... is one rocker tight? if so you are just coming off power stroke. spin 180 degrees.

tdc...both rockers loose? you are at tdc compression stroke.

 

[oldnslo]

Mrfixit
You will have to figure out a way to watch movement on one of the pushrods. You can then use that information to determine TDC of compression.

 

[Leejohn]

Take glow plug out and put a finger over hole. Bump over engine and when it blows your finger off, then turn my hand until timing marks line up. Adjust #1 cyl and go on from there.

 

[denchen]

Like jaydee above said but a slight variation, put in the last two push rods, number 4 cyl. , turn the engine and the rear rod will lift, turn slowly, it will go down but as soon as it gets to the bottom, the .next rod will start to lift. Stop. As soon as that rod starts to lift, you have just passed TDC on number one.

 

[RalphVa]

Just watch the valve action. Don't have to be exactly at TDC. Have done on Benz diesels many times.

 

[the old grind]

When a valve is fully open (give or take a few degrees) the other valve on that cylinder will be on it's base circle and lash can be checked/adjusted. Loosening glow plugs can make turning the crankshaft with a wrench a bit easier. No fancy dance to find TDC is ever needed but one may have to hold their mouth right.

 

[MrFix-it]

line up tdc timing marks.
tdc... is one rocker tight? if so you are just coming off power stroke. spin 180 degrees.

tdc...both rockers loose? you are at tdc compression stroke.

Thanks for taking time to reply. This is is where I'm kinda stumped. All of the adjuster nuts on the rocker arms are completely backed off so I'm not sure which valves are open or closed if that makes any sense. Maybe I can tighten both adjusters on #1 cylinder a little and be able to tell if both are the same or not. If exhaust is trying to open I will know it's wrong.

 

[jaydee325]

Put a finger on each push rod to feel motion or hold the rockers down on the push rod to the same effect.

 

[denchen]

Forget `all the valves`, just hold down the two back [No' 4 cylinder]. Turn the engine over the right way. You'll feel the last one go down, then come up, when it gets to the top, the next valve along will start to drop. STOP. you've just past `top dead centre` on number one cylinder.

 

[ROUSTABOUT]

Thanks for taking time to reply. This is is where I'm kinda stumped. All of the adjuster nuts on the rocker arms are completely backed off so I'm not sure which valves are open or closed if that makes any sense. Maybe I can tighten both adjusters on #1 cylinder a little and be able to tell if both are the same or not. If exhaust is trying to open I will know it's wrong.

You can't just watch the push rods? Ive rebuilt several Kubota diesels and never had a problem.

 

[jaydee325]

There have been several references on here that the D1105 engine is 4 cylinder. It is not. It's a 3 cylinder (Kubota Link).

 

[denchen]

Ahhh. it seems its a 3 cylinder. So, hold down the rocker arms on number one cylinder. Turn the engine so one arm [the exhaust] goes down. It will go down then come up. When it gets to the top, the inlet will immediately start to go down. STOP. mark where the crank is, turn it exactly one full turn 360 degrees. That cylinder is at TDC

 

[Gregster613]

Dumb question here but....How does one know/find out the firing order on a 3 cylinder? IE...how do I know which cylinder is the #1 to even start this process? Eventually I will want to adjust valves on my TYM and this thread reignited my curiosity. Thanks and I do not mean to highjack thread. My question goes along with the theme.

 

[denchen]

When the exhaust goes down, then come up, as soon as it up all the way the inlet immediately starts to open. I've always been taught `the valves are on the rock`. So if you turn an engine over slowly, you will see number one valves go on the `rock`. Number one is the front of the engine, opposite end to the clutch end. Now with number one cylinder on the rock, slowly turn the engine and watch which is the next valve group to go on the 'rock', keep going until all the valves until all have 'rocked' and number one comes up again after two full revolutions, that's your firing order.

 

[Gregster613]

Thanks denchen, that explains my dumb question easily and is simple to do. Now I will be able to figure out my firing order and adjust my valves whenever I need to. Greg

 

[MrFix-it]

Dumb question here but....How does one know/find out the firing order on a 3 cylinder? IE...how do I know which cylinder is the #1 to even start this process? Eventually I will want to adjust valves on my TYM and this thread reignited my curiosity. Thanks and I do not mean to highjack thread. My question goes along with the theme.

The 3 cylinder D1105 has a firing order of 1, 2, 3 with number 1 cylinder being at front of engine. (Where the water pump, alternator, cooling fan is). The number. 3 cylinder is at the back with the flywheel, starter.