TO35 Engine Oiling System

Does anyone have a diagram for the oil flow circuit of the TO35?

Don't have a diagram.

What kind of problem are you having?

(quoted from post at 20:24:35 04/01/17) Don't have a diagram.

What kind of problem are you having?

Click to expand...

Hi Steve,

I'm working on a friend's TO35. The valve rocker assembly failed due to what I strongly suspect was lack of lubrication reaching Cyl 1 & 2. The top-end was repairable.

Naturally, I needed to, and in fact, I did drop the oil pan; because, I wanted to inspect and check the oil pump flow and volume to the cylinder head. As well as clean out the oil tank and all the usual mechanic stuff like that. I installed a cheater pipe to the oil intake at the pump and performed an unrestricted crank test.

I observe oil flow at unrestricted cranking speed. I see oil drip from the main journals at crank speed, so I know the oil pump is moving[b:658a921b68] at least some [/b:658a921b68]oil under pressure to the bottom end.

However, with the cylinder head removed, I am not seeing any oil flow up out of what I think is a cylinder head oil supply port. All I can say is that at unrestricted crank speed I see no place where any oil is flowing up to any place that would supply the cylinder head with critical oil.

I disassembled the oil pump, and it's OK... not the best. The gears appear to be in good shape. I could probably stand to replace the cover plate due to scuffing. That scuffing could result in partial oil cavitation and or oil re-circulation within the pump itself.

Fair warning: I am a retired USAF diesel mechanic, and spent many years working on diesel generator sets 20 years ago, so I'm fairly comfortable working around engines. I'm handicapped in a way... my ex-wife needed (and took) all my specialized tools so as to sell them for the lowest possible price. Also, I'm just doing non-mechanical friend a favor with this tractor repair... in a drafty old poorly-illuminated dirt-floor barn.

Anyway, in all my years, I've NEVER seen any engine not be able to pump oil up to the head at unrestricted crank speed.

I'm thinking that I either have a blocked oil supply port, or the oil pump is worn out much worse than I can tell with my formerly well calibrated eyes... Maybe both are true...

Does anyone have TO35 who can pull the spark-plugs and crank for 30 seconds, and give me an oil pressure reading on a cold engine? It would seem to be that the engine should develop about 10PSI under that condition with 15W40 oil.

Does the TO35 even push oil up to the cylinder hear? Where is the cylinder head oil supply port on the TO35? What is the TO35 cold-engine unrestricted crank speed PSI at 30 seconds?

Any advice would really help this old GI out...

And thanks in advance for any advice...

PS. I'm not under any kind of deadline to fix the tractor, I just want to make darn sure my repairs are well spend money...






















:lol: :lol: [/i]

Have I ever worked on a T0 35.....NO.

Have I seen a lack of oil to the top end...several times:

On engines with rifling from one of the mains, oil stopped flowing when MAIN Bearing shell turned:

Oil never was flowing to top end as someone installed a bearing shell with NO oil hole in Bearing shell:

Both halves of bearing shells were never drilled to allow oil to top end:

Bob...

(quoted from post at 08:05:51 04/02/17) Have I ever worked on a T0 35.....NO.

Have I seen a lack of oil to the top end...several times:

On engines with rifling from one of the mains, oil stopped flowing when MAIN Bearing shell turned:

Oil never was flowing to top end as someone installed a bearing shell with NO oil hole in Bearing shell:

Both halves of bearing shells were never drilled to allow oil to top end:

Bob...

Click to expand...

I was wondering if oil was some how provided to the top-end via a connection or tap from the crank shaft journal supply... and if perhaps one of the main bearings had turned to block the port... The location of what I (think) is the top-end oil supply port is directly above Cyl 4. Man... I wish there was a diagram for this old tractor... I'm considering taking a closer look at the crank... Other than time and safety wire, I can drop the crank down off the journals and see.

Oil to the rockers does come up the port from the rear main.

The most common reasons it fails to oil are, the rear main shells were reversed on installation. Only the top shell has an oil hole. Or someone put sealer on the head gasket, it squeezed out and blocked the passage.

But if it was running and stopped oiling, the most likely reason is the rear main has spun, blocking the oil port.

But, don't expect to get oil to come up by cranking, or supplying remote oil pressure with the engine stopped. The oil is very slowly metered through, only when the engine is running.

If you still have the pan off, drop the rear main cap, look to see if it has spun. Might roll the upper bearing out, make sure the hole in the bearing is clear. You can also blow air down the oil port at the back of the block to verify the port is not plugged. Air should free flow with the bearing shell out.

If you have been spinning the engine through with the head off, I hope you bolted the cylinder sleeves down! They just sit in the bottom of the block with oring seals. If any came up, or were disturbed in any way, they will have to come out and the bottom of the block cleaned and resealed with new orings.

Once you get it back together, and do your initial start up, head bolts retorqued, valve lash adjusted, loosen the rear rocker shaft boss, it will lift up enough to see oil come out around the base. If it is oiling there, it will eventually reach all the rockers. Also be sure the ends of the rocker shaft are plugged.

(quoted from post at 19:04:15 04/02/17) Oil to the rockers does come up the port from the rear main.

The most common reasons it fails to oil are, the rear main shells were reversed on installation. Only the top shell has an oil hole. Or someone put sealer on the head gasket, it squeezed out and blocked the passage.

But if it was running and stopped oiling, the most likely reason is the rear main has spun, blocking the oil port.

But, don't expect to get oil to come up by cranking, or supplying remote oil pressure with the engine stopped. The oil is very slowly metered through, only when the engine is running.

If you still have the pan off, drop the rear main cap, look to see if it has spun. Might roll the upper bearing out, make sure the hole in the bearing is clear. You can also blow air down the oil port at the back of the block to verify the port is not plugged. Air should free flow with the bearing shell out.

If you have been spinning the engine through with the head off, I hope you bolted the cylinder sleeves down! They just sit in the bottom of the block with oring seals. If any came up, or were disturbed in any way, they will have to come out and the bottom of the block cleaned and resealed with new orings.

Once you get it back together, and do your initial start up, head bolts retorqued, valve lash adjusted, loosen the rear rocker shaft boss, it will lift up enough to see oil come out around the base. If it is oiling there, it will eventually reach all the rockers. Also be sure the ends of the rocker shaft are plugged.

Click to expand...

Thank you Steve and Etal... I know the oil port is open at the top. The oil pan is still off, and so I'll check the rear main journal for a spun/reversed bearing, and make sure the oil hole is clear and blown out. The cylinder liners are secure in the block. We purchased a new rocker shaft unit, but I'll make darn sure the ends are sealed tight. I was definitely thinking about loosening the rear rocker shaft to see if oil was reaching that point after initial start up. I'll post my findings on the rear journal and oil port later in the week.

Thanks all for the insights. It's been a lot of years since I really did hard core wrenching on and internals of an engine!

Well, I found the problem with the top end oil supply. The former mechanic who rebuilt the engine about 4 years ago, never installed the plugs in the ends of the rocker shaft! UGG!

Oil would just pour right out the ends. Obviously, no pressure whatsoever would develop inside the rocker shaft with two doors wide open, resulting in little or no oil supply to the rockers, or valve guides!

The bottom-end is fine. I should have it back running in a couple more weeks.

So, listen up kids, in the photo below, is the end-view of the rocker shaft. This hole that my finger is pointing at should have a metal freeze plug pressed inside the end of the opening. Both ends should have seals. Because without seals, you get no oil pressure to the top end!