Well, Here's the Damage!

gwstang

Well-known Member
If you care to search awhile back there will be detailed posts of my recently (last January) rebuilt 8N sidemount engine. I put new gears in the oil pump body/new sleeves/pistons/had the crank turned/new valves etc. Just a standard rebuild job to last a long time. Only problem was low/no oil pressure at startup. It doesn't take long to tank the bearings/crank shaft either. Here are some pics. Just *#@&*&^











I did send the oil pump to TOH after I figured out there was not enough oil pressure to amount to a hill of beans. He put new gears in it and sent it back. I installed it and still had low/no oil pressure. By then the bearings/crank was already messed up. I guess I will pull the engine and see about getting a used crank. This one is .060 rods/.040 mains so it is now a boat anchor. Maybe this could be polished out, I can barely catch a finger nail on the one crank main? I don't know at this point. Glad I got a new Kubota back in the spring....lol I would have been up to my ears in grass/weeds by now. :shock:
 
Wow. That's in a couple hours run time?
I'm sure TOH did a good job with the pump, but no pump can
build good pressure without back pressure from the bearings.
Those look to be toasted. :(
 
It appears from the pictures the wear is worse on one end. If you have to tear it down that far it might be wise to consider a line bore of the main bearing caps. Just a thought.
 

I did the pump with new gears that I put in, the first time. When the pressure would not get above 0-5 lbs, I pulled the pump and sent it to TOH (with some more new gears) to work his magic. I got it back and installed and it was just too late for the bearings by then to do much good. I should have plastigauged the crank...but trusted the machinist to do the crank right. If I can catch a finger nail on the crank, does that mean it has to be re-ground? Or can that be polished out? I'll dig around to see if I can find another crank that isn't at it's limit. Might get lucky, who knows...lol. :roll:
 

They were supposed to be. I used what the machine shop said it was ground too. I got a new pickup the first time to see if that would help and it didn't. Then I sent the pump to TOH. Sorry for the confusion.
 
It was line bored at the machine shop. If I get a different crank, it will have to be line bored too...and probably turned to new sizes for bearings. Ugh, the fun never ends with these old machines...lol. I can't complain, she served me well for many years.



She's just mad because I got a new mistress last spring...lol
 
When I had my oil pump problems (new gears 0.007" shorter than originals) and pulled things apart I had a small bit of scoring on #4 rod journal (could feel with fingernail) but didn"t look bad and bearing
looked reasonably ok so I got some wet 1500 grit paper (3M) at Home Depot, cut some the size of the bearing inserts and put them on the bearing insert which was placed in the rod and snugged down the
rod cap and nuts (hand tight) and rotated the crank about 10 times for an even polish. That removed less than 0.0005" and cleaned it up. No adverse results after reassembly. You might give that a try and
check it with a micrometer.
 
That engine was put together dirty. All those little specks you see on the inserts is dirt imbedded in the Babbitt.
 
If you had no oil pressure on startup then the pump was not primed and you could have damaged the crank and bearings then on that first run. Assembly lube if in place on bearing surfaces should have
given a little run time, but not long-just until oil pressure kicks in. If apart you may want to re check the gear end face clearance in the pump-should be around 0.003-0.005". Can do with plasti-gage.

Also make sure relief valve plunger is seating and spring pressure is good and you may want to pull the end plugs from the main galley and clean it out and make sure all passages are extremely clean, same
with rod galleys in the crankshaft-use a brush and good cleaning solvent several times until really clean.
 

I cleaned everything really well before assembly. Washed the crank with my pressure washer and the block. I've put V8's together and never had this problem. Don't see how it happened this time. I think it's just dust that got on there when I wiped it with a rag to take the pics. Maybe not?
 
(quoted from post at 19:12:12 09/20/15) If you had no oil pressure on startup then the pump was not primed and you could have damaged the crank and bearings then on that first run. Assembly lube if in place on bearing surfaces should have
given a little run time, but not long-just until oil pressure kicks in. If apart you may want to re check the gear end face clearance in the pump-should be around 0.003-0.005". Can do with plasti-gage.

Also make sure relief valve plunger is seating and spring pressure is good and you may want to pull the end plugs from the main galley and clean it out and make sure all passages are extremely clean, same
with rod galleys in the crankshaft-use a brush and good cleaning solvent several times until really clean.

I did prime the pump on several occasions to try to get the pressure up. It was very low and then went to none at some point. I replaced the oil pressure gauge just to be sure. Good idea on the pump clearance with the plastigage. I did the cleaning on the gallery with the long brushes (harbor freight) and used much brake cleaner on every passage after using the pressure washer. I don't see how any junk could remain in there? One thing for sure, the engine runs like a brand new one....just no oil pressure. :shock: This is going to take awhile to get straight. I'm not in a big hurry and it has gotten very hot down here...again!
 
It appears something was under the main bearing in the first photo. And yes, if you can catch your fingernail on it, it can't be put back in service that way.
 

The engine is needs to come completely apart :cry: and be cleaned up so none of the contamination from the crank and bearings will kill the job again...

The only limit on how far you can go with the crank is the ability to find replacement bearings... You would have to search for 70 are 80's...
 
The first picture shows that the upper bearing was installed in the bottom main cap??????

The upper bearing has the cut out groove for the oil to be applied to the crank.

Zane
 
I'm leaning towards Zane's thinking.
Are the bearings installed so relief is in block and are holes lined up with oil passages?
It doesn't explain low/no oil pressure but with take bearings and crank out in short order.
 
(quoted from post at 04:28:52 09/21/15) You don't have to re-align bore the block. That procedure is only done for main saddle issues, not crank issues.

OK, thanks. I do remember now that I did get a new oil pump body because the old one I sent to TOH was worn beyond repair. He said that was one of the floppiest ones he had ever seen...lol
I then got a new body and put the gears in and had everything line bored. Pressure was low after putting everything together. I then took the oil pump out and sent it to TOH. He said one of the gears was a little cocked and put new gears in it and fitted them. Got that back and put a new oil pickup on to eliminate that... still had low pressure. Dropped the pan and that's where I am today. Took me awhile to remember all that. What a mess. Should have just let the machine shop put the whole dang thing together. I am careful about keeping things clean and covering with a bag, in between working sessions on it.
 
(quoted from post at 05:58:06 09/21/15) The first picture shows that the upper bearing was installed in the bottom main cap??????

The upper bearing has the cut out groove for the oil to be applied to the crank.

Zane

I thought for sure that I line them up correctly. Ugh. :oops:
 
Sounds like you did everything right. Did TOH check the pump for output, he has a jig to do that so he probably did, good to check with him on that. How is the pick up tube, if it has any leaks around the plate facing the pump that can cause a loss of pressure as the pump is not pulling the oil in. Also check that the front and rear plugs to the oil galley are in place. If the rear was out that would show up as a puddle of oil on the floor, but the front plug is behind the cam drive gear and if open would result in no oil pressure and the oil would just dump down into the pan.

Real mystery, but there has to be a logical reason.
 
Before I start a newly rebuilt engine for the first time, I always leave the plugs out, ground the coil wire and turn the motor over until it has oil pressure. Then replace the plugs and coil wire and start it. Always watching the oil pressure for the first few minutes.
 
(quoted from post at 14:18:26 09/21/15) Sounds like you did everything right. Did TOH check the pump for output, he has a jig to do that so he probably did, good to check with him on that. How is the pick up tube, if it has any leaks around the plate facing the pump that can cause a loss of pressure as the pump is not pulling the oil in. Also check that the front and rear plugs to the oil galley are in place. If the rear was out that would show up as a puddle of oil on the floor, but the front plug is behind the cam drive gear and if open would result in no oil pressure and the oil would just dump down into the pan.

Real mystery, but there has to be a logical reason.

The front and rear oil gallery plugs are in, I did the block/sleeves/pistons etc myself. When I do re-do this engine, I will submerge the oil pump pickup into a container of oil and make sure it picks up correctly. I did swap the old oil pickup for a new one when the pressure was low. That didn't help any. I used the permatex brush on sealer that was recommended with the gasket to seal the faceplate on the pump.
I like the chevy/ford oil pumps that can be primed with a drill...lol
 

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