I have just finished putting the new barrels and pistons into my 1220 motor, reassembled it and when I tried to build up oil pressure before actually starting it, got no response. Before I pulled it down, the oil pressure was fine. During the rebuild I did not disturb anything in the crankcase or the oil pump. I had the motor on a Rotary stand, and turned it on to each side to install the barrels vertically , thus presumably removing any residual oil from the oil pump. The motor was dry for about three days. It seems that the oil pump is not drawing oil from the sump. I removed the oil filter and tried to prime it with oil through the gallery from the filter to the pump, then turned it over again and still have no oil pressure. Is there a technique to prime these oil pumps or have I got a bigger problem? Thanks. Ian.
GS oil pressure problem
- Thread starter wheelnut
- Start date
Mmmmm......
Maybe feed oil in as you did at the filter mount, and turn the engine backwards...
Maybe that will pull oil back down into the pump?
Otherwise, double check the head feed pipes. Connected ok? Not cracked, rusted, leaking. Oil cooler mounted with new rubbers?
Ummmm..... thinking.
Maybe feed oil in as you did at the filter mount, and turn the engine backwards...
Maybe that will pull oil back down into the pump?
Otherwise, double check the head feed pipes. Connected ok? Not cracked, rusted, leaking. Oil cooler mounted with new rubbers?
Ummmm..... thinking.
like Bob says check the alignment of the oil feed pipes bolts to the heads, mark the alignment of the hole on the screw/bolt head with a texta and see where the inlet hole is on the head. Then tighten till lined up. I think I had the same problem when putting back together mine, worth turning with pipes dangling to see if oil is flowing through briefly for starters. Get your crank handle out and crank it with some gusto too!
I initially ran mine with the rockers covers off to make sure oil was getting into the rocker rods, thats another point where you have to have them aligned correctly. Messy but fun!
I initially ran mine with the rockers covers off to make sure oil was getting into the rocker rods, thats another point where you have to have them aligned correctly. Messy but fun!
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The banjo fittings on the oil pipes should not require alignment of the hole. Banjos are designed to allow flow with any alignment.
I always first start an engine after major work with the rocker covers off. It's good to see fresh oil dribbling down the rockers.
I always first start an engine after major work with the rocker covers off. It's good to see fresh oil dribbling down the rockers.
Thanks all for your input. The problem is that the oil pump is just not picking up oil from the sump ie. an air lock. . I am guessing that there is air on both sides, and so at cranking speed,there is not enough lift to get the oil started. Tomorrow I will try to fill the galleries from the oil filter end while turning the motor directly on the crankshaft at a higher speed than cranking with a starter.
On doing a bit of research on Dr Google, I have learned that this is not uncommon (although I have never had it happen on the several rebuilds I have done in the past on various brands), and the remedy from days gone by was to fill the oil pump veins with petroleum jelly to prevent air from the output side being drawn back into the input side and thus obtain the required lift to start the flow. I'll go that route if I have to , but it will involve disconnecting the all ready primed hydraulic pump etc. which I hope I will avoid.
I will report back once I've tried those options, hopefully with a thumbs up. Ian
On doing a bit of research on Dr Google, I have learned that this is not uncommon (although I have never had it happen on the several rebuilds I have done in the past on various brands), and the remedy from days gone by was to fill the oil pump veins with petroleum jelly to prevent air from the output side being drawn back into the input side and thus obtain the required lift to start the flow. I'll go that route if I have to , but it will involve disconnecting the all ready primed hydraulic pump etc. which I hope I will avoid.
I will report back once I've tried those options, hopefully with a thumbs up. Ian
I was suss on the bolt ( banjo) as it didn't have a recess (from memory) and I thought this thing needs lining up. Anyway. Bon chance.
Haven't worked on these engines but with older engine rebuilds, we packed oil pumps with Vaseline or petroleum jelly.
These oil pumps are externally mounted so this shouldn't be too difficult?
These oil pumps are externally mounted so this shouldn't be too difficult?
Did you try cranking with the oil filter removed? Sometimes that is enough resistance to keep the pump from priming.
Yes John No result. I'm just making up a tool to spin the oil pump pulley with an electric drill, in the hope that turning at a greater speed while backfilling oil via the filter /pump gallery will do the trick. Watch this space. Oh, and I like your collection. Ian
Hi folks. The world is bright and beautiful again. I made up tool to fit snugly into the holes in the Oil pump pulley, drove it with the electric drill and had oil pressure within about 30 seconds. I had loosened the right side head feeder banjo to be able to see the oil feed . It seems that it just needed some extra speed to cause enough suction to lift the oil into the dry pump. I'm happy to report that the engine is running sweetly and Gaston will be back on the road tomorrow morning to do a number of shopping errands to meet with our Covid restrictions and get a few K's up. Cheers. Ian
