D750 Cylinderhead Replacement - White Smoke While Cranking

[MIKLAV1315]

Dear Friends,

DISCREPANCY
After installing an entire brand new cylinder head; no start on B7100D, only white smoke coming out the exhaust pipe while cranking the engine. The engine is blowing more white smoke than a fog machine used in a headbanger M-TV music video from the 1980. So far I attempted six times to start the engine (five second bursts with the starter). Engine does coughs and wants to start. Some black smoke was noted on the next to last engine startup.

BACKGROUND
I recently replaced the cylinder head on my B7100D. During the cylinder head removal no damage to the pistons, piston rings, or engine block, nor could I visual see cracks in the old (replaced) cylinder head, my skill level is novice so I could have missed something. I replaced the following parts; a brand new complete cylinder head from Kumar Bros, new KUBOTA head gasket, new KUBOTA head bolts, new KUBOTA exhaust manifold studs, and KUBOTA cylinder head water pipe Oring.

SPECIAL NOTES
My first attempt with the cylinder head replacement I quickly discovered I inverted the head gasket. I caught this when I noted coolant leaking out of the number two exhaust port and from the unplugged exhaust manifold stud hole. I had attempted to fill the coolant system before I installed the new exhaust manifold studs into the new cylinder head. Fortunately I did not I attempted to start the engine.

Second attempt. I removed & replaced both the head gasket and Oring with a new (second) KUBOTA head gasket and oring and reinstalled cylinder head. Installed the new exhaust studs and added coolant. This time coolant was coming out of unplugged stud hole for the engine's hook, right next to cylinder number three exhaust stud. I inserted a new aftermarket stud and attached engine hook/firewall bracket and continued with filling the coolant system and reassembly of cylinder head.

CONCERNS
Did I flood the cylinder head's intake/exhaust ports again with coolant because I had not installed the new engine hook stud into the cylinder head prior to adding coolant?
Also, I did not install a shim on top of the head gasket because I was installing a brand new cylinder head which is not warped therefore not needed, my logic which could be wrong. Should I install a new shim? Part number of the KUBOTA head gasket installed is number 15975-03310. My engine serial number is 1130.

Respectfully,

Mike from CLE

 

[Mark_BX25D]

Check your glow plugs. Are they working?

 

[Roadworthy]

I wasn't there so I don't know what you may or may not have flooded. You seem to be trying to do the job right with all the new gaskets, etc. You don't mention torques, sequences, or valve adjustments. I hope you have done these things. As far as the shim you didn't use, I think it's to compensate for metal removed when milling the head not to compensate for warping. I think you're on the right track, just not quite there yet. Good Luck!!

 

[MIKLAV1315]

I wasn't there so I don't know what you may or may not have flooded. You seem to be trying to do the job right with all the new gaskets, etc. You don't mention torques, sequences, or valve adjustments. I hope you have done these things. As far as the shim you didn't use, I think it's to compensate for metal removed when milling the head not to compensate for warping. I think you're on the right track, just not quite there yet. Good Luck!!

Thank you for the reply. I did follow the cylinder head bolt torque sequence when removing and installing cylinder heads, also followed valve adjustments. I followed WSM and IT service manuals as references. Likewise, pre lubed moving parts while re installing them.

 

[MIKLAV1315]

Thank you for the reply. I did follow the cylinder head bolt torque sequence when removing and installing cylinder heads, also followed valve adjustments. I followed WSM and IT service manuals as references. Likewise, pre lubed moving parts while re installing them.

I will check glow plugs but I pretty sure they are working, I could smell the ozone and the dashboard board glow plug was glowing red. I did clean them before reinstalling them, alittle sand paper and brake cleaner and used brake cleaner on the fuel injectors.

 

[Win22wrf]

The next thing you need to do is a compression check. I had a D850 that was doing the same thing and found the compression was very low. I took the head off and the pistons looked fine in the cylinder but when I removed them and 2nd land was broken on all three. I assume that last owner used starting fluid on it and it caused that damage.

 

[kubotafreak]

Low compression like previously mentioned. Do you feel anything from the oil cap being off the valve cover? They can also get bent rods, effectively shortening the stroke.

 

[Win22wrf]

Also, the compression should be between 375 - 425 for each cylinder for it to have a chance to fire.

 

[Jim L.]

If you don't mind us asking, why was the cylinder head removed/replaced to begin with?

Is the starter turning the engine with normal quickness?

Have you pulled glow plugs to check for coolant getting into chambers? If it is, and coolant being incompressible, something will get damaged.

 

[MIKLAV1315]

Unfortunately I don't have a diesel engine compression gauge. Why I replaced the cylinder head the previous owner used 100% anti freeze as coolant and I later discovered the whistle was missing. So after a few hot run ups with the engine I began to smell and see anti freeze droplets around cylinder head bolt number 10. Later I discovered #10 cylinder head bolt was stretched and snapped on removal.

Attached is a audio recording of the engine after warm up. RPM speed idle around 1300 rpms, driver's side is exhaust side and passenger side is intake side. The recording started with cylinder one, six inches from the engine, same for exhaust side. Also I measured the temperatures of the fuel injectors and exhaust manifold ports, I discovered a difference of 12 degrees fahrenheit between cylinder number one and cylinder number three, both the exhaust port and fuel injectors. Cylinder two/fuel injector two temperatures was the same as cylinder/injector number three.

 

[Mark_BX25D]

Have you checked your glow plugs yet?

Start with the basics before you go playing Sherlock Holmes.

 

[Jim L.]

After installing an entire brand new cylinder head; no start on B7100D, only white smoke coming out the exhaust pipe while cranking the engine. The engine is blowing more white smoke than a fog machine used in a headbanger M-TV music video from the 1980.

Mike,

I'll readily say that I am not there looking at the machine.

My first concern would be coolant leaking into the cylinder(s). Take out the glow plugs, and then crank using the starter briefly. (Fuel off or disconnected). I'd be looking for any coolant thrown out the glow plug holes at first crank. If there is a leak, you want to know before getting a critical amount of coolant into the cylinder before cranking.

Having done that, and making sure that there is no visible coolant leak, the next step would be to perform a compression reading on each cylinder. There are three Harbor Freights in the Cleveland area to buy a compression gauge and adapter for the glow plug hole threads. It is also possible to borrow one from auto parts stores. You need to know the compression readings: you've replaced the gasket and it won't start, while blowing white exhaust. Is it coolant or unburnt fuel? With the fuel disconnected, are you still getting white exhaust? If so that indicates coolant. Please post the compression readings, more help will follow from the forum.

 

[MIKLAV1315]

Update, thank you everyone for replying and providing very insightful information, this is my first diesel engine project. Thank you for your patience.
I did purchase a Harbor Freight diesel compression tester, model number 62594. The engine has 3,288 hours on the meter. I removed all of the fuel pipes, fuel injectors, exhaust manifold, and air filter. All of the reading are in Pounds per Square Inch (PSI). I warmed up the engine before the compression test, Cylinder #1 (closest to radaitor) 260, cylinder #2 260, cylinder #3 260. Stunned by the low compression so I squirted oil (SAE30) into each cylinder and saw an increase in PSI, cylinder #1 320, cylinder #2 360 cylinder #3 330 (PSI).

By the way during all of the compression checks and engine starts, I did not attach the Compression Release cable thinking the Compression Release defaults to the "off position" when the Compression Release cable is not attached????

Also while removing the fuel injectors, I did not notice any coolant on the glow plugs, tops of the cylinder heads, or inside the combustion chamber, only carbon build up.

Observation. The only time I saw white puffs of smoke coming out of the exhaust ports was when I installed the compression tester to that specific cylinder meaning each cylinder would only puffs white smoke when hooked up to the tester. No installed fuel injector-tester, no puffs of white smoke.

Unfortunately I did not check cylinder compression prior to any repairs.

 

[Mark_BX25D]

Cylinder #1 (closest to radaitor) 260, cylinder #2 260, cylinder #3 260. Stunned by the low compression so I squirted oil (SAE30) into each cylinder and saw an increase in PSI, cylinder #1 320, cylinder #2 360 cylinder #3 330 (PSI).

By the way during all of the compression checks and engine starts, I did not attach the Compression Release cable thinking the Compression Release defaults to the "off position" when the Compression Release cable is not attached????

I don't know your tractor, so I could easily be wrong, but in my experience, a compression release is pretty thorough. I don't think you'd get that much compression if the release valve were open.

Which points to a (theoretically possible) valve problem (possibly timing? adjustment?) or collapsed rings.

If it's the rings, it might be possible to replace them in situ. If there is sufficient access to the bottom end, you may be able to pull the pan and remove the rod caps. This lets you pull the pistons out the top to replace the rings.

If you do go that route, there are a couple of things to keep in mind:

1. Check your bearings while you are in there. No sense in putting it back together if the bearings are shot. Plastigage is your friend.
2. You'll probably have a ridge at the top of the cylinders where the rings did not reach. This results in an area of the bore that is NOT worn down, so you can't get past it to remove the pistons until you remove the ridge with a special tool called a "ridge reamer".

Since it was running before you did the head, I'd say you need to take a close look at the valves. Maybe you didn't adjust them correctly?

But on the principle of "simple things first", verify that compression relief situation. The valves next. Rings last.

 

[GeoHorn]

By the time a cylinder “ridge” is formed...the piston rings usually have sufficient wear to remove the pistons... But the ridge definitely needs to be removed before installing new rings and/or pistons or run the risk of breaking a top ring.

 

[Henro]

Observation. The only time I saw white puffs of smoke coming out of the exhaust ports was when I installed the compression tester to that specific cylinder meaning each cylinder would only puffs white smoke when hooked up to the tester. No installed fuel injector-tester, no puffs of white smoke.

Unfortunately I did not check cylinder compression prior to any repairs.

Seems logical that since the only cylinder developing pressure would be the one the compression tester is hooked up to, that only that cylinder would cause white puffs of smoke to be produced...

 

[Mark_BX25D]

By the time a cylinder “ridge” is formed...the piston rings usually have sufficient wear to remove the pistons... But the ridge definitely needs to be removed before installing new rings and/or pistons or run the risk of breaking a top ring.

I first learned about cylinder reaming watching my dad and oldest brother sitting in the engine bay of our 48 Chevy, reaming the cylinders (inline 6) so they could remove the pistons.

The rings expand against the cylinder wall, so they hit the ridge, even if they are too worn to seal effectively. They'd have to be pretty far gone to clear the ridge without it being removed first.

 

[Jim L.]

Well, it does look that there is a ring/cylinder problem. The good news is that the pressures track within 10 percent of each other.

I would measure the valve clearances and record before tearing down. Reset after rebuild but info that you will have should you want it later.

Check piston protrusion before teardown. Doublecheck that gasket is right thickness in agreement with protrusion.

Measure cylinder diameter before removal of pistons.

Mark pistons and assume no interchangeability with parts. Follow WSM to ring orientation and prelube before re-installation.

I'm assuming that injector fuel pump has never been serviced and it has over 3000 hours. So decision: leave fuel pump alone until after fixing compression, or get it serviced while engine is down. Also have injectors tested or replace with quality injectors - another decision, maybe depending on (un)successful start after compression fix.

Look forward to following your progress as we all learn from these experiences.

 

[GeoHorn]

I first learned about cylinder reaming watching my dad and oldest brother sitting in the engine bay of our 48 Chevy, reaming the cylinders (inline 6) so they could remove the pistons.

The rings expand against the cylinder wall, so they hit the ridge, even if they are too worn to seal effectively. They'd have to be pretty far gone to clear the ridge without it being removed first.

I paid my way thru college and flight school working at an engine overhaul outfit in south Houston (Precision Motors) where we rebuilt engines for commercial operators and over the two year period I typically disassembled a half-dozen engines each week and never reamed the ridge for disassembly.... only for inspection-prep. If the block and cyls passed that inspection they were acid-bath and went to assembly.

 

[Mark_BX25D]

I'm kinda thinking there's a reason that ridge reamers exist....