Grey Motor teardown

[Orange Betty]

Hi all, i've just taken Betty's grey motor apart and below is what I found. While all the major bits will go to a machine shop to get checked over I'm happy to get anyone's advice, opinion or diagnosis as I've not done this before and not sure what I'm looking at. I don't know when the engine last ran, but it turned over easily by hand with a couple of sticky spots.

This is what the pistons and chambers looked like:

pistons in situ.JPG (78.9 KiB) Viewed 899 times

Head just removed.JPG (63.07 KiB) Viewed 899 times

Pistons 1, 2, and 6 had the top ring broken. Rings were stuck on #5 but all pistons came out easily. There is a slight ridge at the top of each cylinder but they otherwise look fine.
Interestingly Piston #3 is stamped as 4 and the stamp on #4 is not clear. Also the connecting rods were installed with the rod oil hole facing the wrong way (apparently). The manual indicates this should be facing the camshaft. Not sure what the consequence of this is

Also the rods have various stampings on them, 60 NF Holden 0593 or 3 Nat Holden 0593, or AO8B AFB Holden 0593. Why would that be?

The two sticky spots in the rotation might be the rod bearing on #2 and #6. These have really worn out flanges and appear to be much thinner than the other bearings. They also have no locating tables and smaller oil holes and look quite different to the other rod bearings

#6 & 2 Rod Journal Bearings.JPG (123.25 KiB) Viewed 899 times

The top of piston # 2 and 6 shows a definite pattern matching the combustion chamber but the others don’t?

Piston issues (2).JPG (91.8 KiB) Viewed 899 times

After a clean up the combustion chambers all show some damage to their edges (picture) and to most water jacket holes but #3 has definite pitting where the others don’t. Is that all wear and tear that will be overcome by machining the surface?

#6 Chamber.jpg (36.75 KiB) Viewed 899 times

#3 Chamber.jpg (35.39 KiB) Viewed 899 times

All valves came out easily with the exception of #4 inlet but it only needed a little manipulation. The seals were all brittle and broken which I guess is expected and the springs were quite easily compressed to remove the keepers. After a little clean up with a wire wheel the valve faces look like this. Don’t know what is good or not. The seating faces (bevelled edges) look ok, no pitting. The inlet valves are all marked with Holden 115 and have the dish in them and the exhaust valves are marked with Holden 1 and are flat.

Valve organised.JPG (149.36 KiB) Viewed 899 times

The lifters and push rods all came out easily and look fine (to me…). Same with the cam and crankshaft. No visible damage and looks nice and shiny where it supposed to be.

So overall I'm hoping it can all be salvaged and re-used as much as possible.

Thanks for reading

Dave

[Errol62]

Very clinical and thorough. I know zip about greys.


FB ute fixer upper, EK van on rotisserie

[Blacky]

You certainly got your moneys worth out of those bearings !!!
Interesting that #3 had no piston damage but the head looks the way it does, appears something has let go at some stage and bounced around in there - obviously its been apart at least once before, maybe #3 piston and possibly others were replaced and the rods reinstalled incorrectly ?

[FireKraka]

Hey Dave if I saw those bigend bearings in #2 & #6 in one of my large diesels I would say they have spun, the way the sides look it is saying lack of oil, they get hot and spread the sides into the oil wedge area and you say they are a lot thinner is a good indication, what does the crankshaft look like on those two cylinders it would be interesting to put a micrometer over the journals Dave.
Regards
Neil

[FireKraka]

Hey Dave I also meant to say that the combustion chamber marks on top of the pistons tells me the pistons have touched the head due to the extra clearance made by the bad bearings maybe lucky it didn't do more damage.
Neil

[Blacky]

Hey Dave I also meant to say that the combustion chamber marks on top of the pistons tells me the pistons have touched the head due to the extra clearance made by the bad bearings maybe lucky it didn't do more damage.
Neil

That would also explain the broken top rings , the rings would impact on the lip in the bore and break them .

[FireKraka]

Agree Blacky.

[Orange Betty]

Ahhh, thanks Neil and Blacky. That kinda makes sense now you say it. I don't have a micrometer but will be interesting to see the machine shop diagnosis. Hopefully the pistons touching the head hasn't caused any damage not immediately obvious.
Cheers
Dave

[Blacky]

If the bore has a lip and they have been hitting the head I would imagine it would not be recommended they be reused and if the block needs boring which is likely you would need oversized ones anyway. Wouldnt imagine it would cause any damage to the head, was the motor still running ?

[Blacky]

never mind, I just reread the first post ...... if it was tight in places the crank will need a grind at best or replacing at worst

[ardiesse]

What Blacky said. The crankshaft will probably be good for the bin - measurement with a micrometer will tell. Standard size for the journals is 2.000" and 1.750" for the crankpins. Because No.2 and 6 big-end bearings have spun in their conrod, the conrods will need to be closed and honed (at best), and put in the bin (at worst).

Both the block and the head will need to be surfaced - from the looks of the head gasket you have a leak between 2 and 3; but the head says that there was a compression leak between 1 and 2; 2 and 3; 3 and 4; and 5 and 6. Be warned that unlike your old head gasket, the newer type of head gasket will not forgive the mating surfaces being out of flat. You'll have to put up with a little pitting around the water jacket holes even after machining.

Is there any pitting on the underside of the cam followers? If no, they're good to re-use.

The valves may come up OK with refacing as long as the stems aren't worn (the guides can be replaced if they're worn - no. 1 exhaust always flogs out).

Your rocker arms will need to be refaced, and probably re-bushed if there's been a lubrication failure. If the rocker shafts are badly worn it's best to chase down good second-hand rocker gear. The ball-end of the valve adjuster wears, leaving a little "nub". File the nub off on all the rockers.

Rob

[Craig Allardyce]

Unless I've missed something, those big end bearings are not correct. No grey motor ever had side flanges on those bearings. You just cant fit them in unless the crank or rods have been modified. Only one main bearing set was configured this way because of end thrust loads on the crank.

[Orange Betty]

Thanks Rob. Is the leaking between all adjacent bores typical in a grey? What would cause it - block and/or head surface not flat, faulty head gasket or head not torqued up enough?

The underside of the lifters look fine (to me) as do the valve stems and faces. Not sure about the valve guides.

I haven't had a close look at the rocker assembly yet as it needs lots of degreasing. Job for today!

Dave

[Orange Betty]

Unless I've missed something, those big end bearings are not correct. No grey motor ever had side flanges on those bearings. You just cant fit them in unless the crank or rods have been modified. Only one main bearing set was configured this way because of end thrust loads on the crank.

Hi Craig, yes it is curious. They certainly look like thrust bearings and other than being completely flogged out fit the rod big end neatly

[ardiesse]

Dave,

I have a grey motor that had a serious case of the death-rattles, with no. 1 big-end being the worst. When I stripped the motor down, the bearing shells had "oozed out" just like yours. This is what happens when a big-end bearing suffers lubrication failure.

Rob