Hitchcocks Forum

Hi, I'm in the process of rebuilding an Indian classic 500 bullet engine from the ground up. Got it all reassembled up to the point where the engine is in the frame and the primary and timing side are attached.



At this point, I thought it prudent to bleed oil through to make sure the oilways are primed and everything is getting oil like I do if I've had the timing cover off my 350. Usually by either kicking it over repeatedly or "walking" it around in gear with the plug out. So far I've bled oil through as far as the quill bolt opening. Not having much sucess getting any further and I'm pretty knackered walking the thing round now!



Anyway, every time I crack the quill bolt, it seems to be slightly pressurised but I'm pretty sure oil isn't passing through the crank. There never seems to be oil IN the stem of the quill bolt. I've removed the crankcase drain plug for the time being on the basis that the first sign of oil feed to the crank/big end will be oil coming out of here. Not a drop so-far.



I've also tried forcing oil along the end of the crank (through the pump worm seal) with a syringe. Getting a fair bit of pressure up to no avail. I'm not really sure how much resistance there ought to be here but I suspect very little? I ought to be able to force oil through with a syringe? The straw off a WD40 can goes in to the end of the timing shaft.



I'll admit to being a bit fuzzy about exactly what happens to the oil after it gets to the end of the timing shaft. I presume it makes its way up an oilway in the flywheel to the crankpin, through the middle of that then out into the big end? From whence it oozes out and drops to the bottom of the crankcase?



This leaves the worrying question of why the oil won't go through there. The crank had minimal sideways play and no vertical play when fitted and looked altogether pretty ship-shape.











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I can only think of three things:



1) I have an unreasonable expectation of the pressure it takes to force oil through the crank/big end, you can't actually do it with a syringe (I'd estimate I was putting about 10kg of force onto a 1/2" diameter plunger, by "feel" about as much force as it takes to put 90psi of air into a bicycle tyre with a hand pump) and I should persist trying to prime it using the oil pump.



2) There is a blockage somewhere between the end of the timing shaft and the big end. I have some high flashpoint solvent and I'll bring my compressor back from work tomorrow and try to give it a blow through if no other ideas come up.



3) Someone has fitted the crank pin the wrong way round. This is not inconceivable, the previous owner(s) of this engine had some very neat engineering work done alongside some diabolically bad fitting. It's a 350 out to 500 which takes a degree of machining skill but there were also broken bits of piston ring in the bottom of the crankcase which shows a lacklusture degree of attention to detail. It didn't LOOK like they'd been at the crank but they might have.



I'm getting that sinking feeling that instead of having this engine running tomorrow as planned, I'm going to have to take the whole thing apart again and have the crank re-worked.



Very much open to other suggestions.

A closer look at my photos suggests the crank pin isn't in the wrong way. There's a "hollow" side and a side which is blanked off with an insert and looking at photos of standard cranks on our hosts website, the "blanked" side is on the timing side like it's supposed to be.

Not having checked the oil way through the crank is a bit of a oversight?


Obviously this is a pre 2002 crankshaft sans OPR in the timing shaft; your cold eng oil will be hard to push through the oil way/floating bush with just a syringe.


Your average thumb trigger squirty oilcan is able to generate in excess of 75psi, more with 'heavier' oils. Turning over the engine while applying oil pressure via a squirty can into the crank end will soon prove if the oil way is clear...


OR, you could try positioning the crank at BDC and feeding kero/diesel (lighter flushing oil) into the crank, it will soon run though and 'prove' one way or the other...


OR, simply hook up a compressor and Blow Down the system, you will soon hear when the air has cleared the oil from the crank/big-end passages...

Not only does the pin need to be inserted the 'right way' around, but it also needs to be orientated so that the drillings are aligned...

Thanks for the reply. I'm not sure what year the crank is. It's a 1991 350 engine but converted to a 500 so I don't know anything about the crank itself.



I think I'll give the compressor a try tomorrow. If I read you correctly, oil feed to the crank is also dependant on position and that position ought to be BDC all things being equal?

Ahh.

Panic over.

It was pretty much situation 1) ie. me expecting more than I could deliver. I managed to push some ATF through there, although in fairness, there was a lot of resistance then a sudden "give" so I wouldn't totally rule out there having been a blockage of some sort.

Lesson learned, check this stuff out before assembly! Still need to get it pumping oil round so it feeds the top-end, more walking on the cards for tomorrow I suspect.

Hi Stinky,
Oil should reach the big end regardless of the position of the crankshaft. There is a drilling through the timing side shaft which meets up with a radial drilling to the crank pin. There is a drilling in the crank pin which needs to line up with the radial drilling in the flywheel when the crankpin is pressed into the flywheel (which I think is what Tim meant) If you use an oil can to pump oil in the timing side crankshaft it should find its way through to the big end. If you want to try avoid removing and stripping the engine to check you could try just removing the barrel and piston and checking with a torch while you pump with the oil can. Some later engines have a pressure relief valve on the inside of the timing shaft and oil may find its way out of there instead of feeding the big end if there is a blockage, poor fitting or faulty relief valve. I've just been through the same thing myself with a s/h engine I've rebuilt and I was also concerned about oil flow to the big end, especially as mine has a pressure relief valve which seems to lift very easily.

If you take the rocker covers off you will see the oil coming out along the rocker shafts and you will know that the oil is getting to the top of your motor. If it is up there then you know that you have full oil circulation as the only way that it can get there is from the oil delivery pump into the crank and then from the sump via the oil scavenge pump to the top of the motor to drain down the push rod holes and round and round. I always check to see if the oil is coming out of the rockers when I do an oil change just to be sure that I have proper oil circulation in the engine. RE paranoid behaviour I suppose but I just like seeing that oil at the top of the motor.

Looks like you posted while I was replying Stinky, glad you have it sorted without having to remove the motor.
Binary. That doesn't prove proper oil flow if your crank is fitted with a pressure relief valve, but it's the best we can do without stripping the engine.

Hi mustaphapint, Exactly right. I have had my motor apart and know that it does not have a pressure relief valve in the timing shaft and I can see that if a pressure relief valve stuck open the oil would still continue to pump into the crank to be picked up by the scavenge pump and pumped up to the top of the motor. Mean while the conrod floating or roller bearing on the crank pin would be getting little if no oil at all and would seize up. Very interesting.