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I am working on the restoration of my '72 1800ES, and starting to turn my attention to the engine. One item on the list is to disassemble, clean up, inspect, and reassemble the oil pump. Pump was a bit full of gunk after sitting idle for a few decades. Once I get it cleaned up and inspected, what torque should I be using for the 4 bolts that hold it together? Have not found any information on this, and do not want to over tighten the bolts, which can cause damage to the aluminum castings. Nor, under tighten causing leaks and potentially have the pump come apart while driving.
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Gary D
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Finally got around to inspecting the oil pump.
There are some rub marks on the cover plate from the driven gear, but nothing that I could feel with my finger. Most likely a surface thing. I found the clearance between the driven gear is less than 0.004", but the other gear is greater than 0.004". Hard to get an idea of the lash between the gears since my feeler gauge is a bit wide to fit, but from what I could measure, it seems a bit loose or at least approaching the edge.
Guess I will buy a new oil pump and be done with it.
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Gary D
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If your oil pump bolts are 10 mm, than no more than 14 ft.lb = (168in.lb ).Clean the threads with acetone and use (blue) loctite.
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Nahtana -- bolt sizes are measured by the shank size. A 10mm bolt would likely have a bolthead size of 19mm and be used for holding a suspension together. The non-metric B20/B20E oil pump end plate bolts are probably 1/4" (not having seen one in a long time). I don't know, but, if metric - 6mm bolt, 10mm head. - Dave
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If your oil pump bolts are 10 mm, than no more than 14 ft.lb clean the threads with acetone and use (blue) loctite.
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Thanks all for the responses. While I still do not have a torque spec for the 4 bolts that hold the oil pump together, I think I have a path to figuring one out. The oil pump is still sitting in my parts washer, and hope to look at it in the next couple days. If the end play is near the upper limit, I was planning on replacing the pump anyway. 142guy, it is possible a piece of crud got into the check valve and fell out when you disassembled the pump. I have had similar experiences before. Did not realize the reinforcing collar from IPD was such a tight fit, and can see how that could accelerate wear. Guess I will not bother with putting a collar on. My engine has about 138,000 miles on the clock, so the pump should be okay. But, an inspection will tell. I can get a real Volvo pump for just over $100, which is not too much coin. Got the recent estimate from the body and paint shop, which is higher than planned thanks to inflation over the past year and difficulty in finding good body guys. So, I am looking for ways of limiting costs. But, if there is any question about the oil pump, it will be replaced.
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Gary D
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Sheet metal and paint work for a restoration always come in over budget - been there, done that, got the Tee shirt!
If you can find a genuine Volvo pump for a nudge over $100 that is a reasonable price. Last year the Melling pump from RockAuto was my lowest cost option after you included shipping and handling. Recent inflation seems to have adjusted that price quite quickly. On the basis of weight, the Volvo pump does feel like a toy compared to the Melling pump; but, weight is not an accurate indication of long term durability.
I don't know whether all the IPD reenforcement rings fit tight. I do know that on my original pump it was a bugger to get the ring on the pump shaft and the ring seemed to squeeze the pump shaft slot together enough to make the pump really hard to get it back on the drive gear shaft. In retrospect, I am thinking that the tight fit might have pushed the gear into the end plate causing my wear problem. My original Volvo pump had gone over 130,000 miles without issue. Its only after I 'improved it' that it suffered the low oil pressure after about 5000 miles of casual use. I did pry the ring off the old pump; but, decided against fitting it on the new pump, The old pump had gone 130,000 miles without breaking off the pump drive!
If the pump end plate shows no signs of marking, a plastigauge says the end float is good and the tooth flank clearance is good, then the original pump is probably just fine. If you can't find a spec for the end plate retaining bolts, on the web you can find tables of recommended tightening torques for different bolt sizes that you can use as a guide.
https://www.boltdepot.com/fastener-information/bolts/US-Recommended-Torque.aspx
Although not explicit, these torques are probably for steel threaded holes. The only references I have seen suggest a reduction of about 15% for the torque when the thread are in aluminum.
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Unless a customer specifies differently, we only use the cast iron Melling oil pump. We also always install an IPD re-enforcing ring although we only seen Volvo and aftermarket aluminum pumps experience shaft tip failures.
The problem you experienced with the IPD re-enforcing ring is due to the fact that the end of the distributor drive shaft is a little wider than the oil pump shaft. So for easier fitment, we always grind a little off the sides of the distributor drive gear right at the end of the shaft.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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I am now in the derek uk camp.
I rebuilt my B20E about 8 years ago. At the time, I inspected the pump and checked the end float on the gears (not easy to do) which is the primary spec for the pump. I also installed the IPD reenforcing ring and high pressure spring. Fast forward to last summer when everything was fine, then it wasn't. About 10 minutes into a fine evening drive the warning light flashed on my oil pressure gauge indicating low oil pressure when idling at a stop sign. Revved the engine and oil pressure recovered; but, it reoccurred at the next stop and at every stop on the way home. The next day I did a cranking oil pressure test to check my electronic gauge and got no material oil pressure at all so the pump or something related to the pump was dead.
I removed the existing pump from the engine and inspected it . The end float on the gears was at its upper limit; but everything else appeared normal (the oil pipe seals were all in place and in good condition) . There might have been something in the check valve holding it open and allowing oil to internally recirculate at low pressure causing the sudden loss of pressure. However, when I removed the spring and checked the ball it appeared to be seating correctly and passed a pressure test. I ended up replacing the pump with a new Melling cast iron pump that I got from Rock Auto (lower cost than the Volvo pumps which are made from aluminum). Put everything back together and everything was fine so the problem definitely was pump related.
The only thing I noted on the pump was scuffing on the end plate. That might have been caused by the IPD reenforcing ring which was a very tight fit and may have pushed the drive gear down slightly. I ditched the reenforcing ring when I installed the Melling pump. If you are thinking about re using the pump, make very sure that your end float measures out on the tight side. My experience suggests that if the float is approaching the upper limit you are going to have problems.
Final note, on my 140 I did not have to remove the engine to replace the pump. I built a fixture out of 2x4s ( a copy of the special Volvo tool described in the service manual) to raise the front of the engine a couple of inches which is all that is required to allow pan removal. I expect the same process would work on the other vintage Volvos as long as there is room available at the back of the head to allow the engine to be pivoted up on the transmission mount.
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If the gears are good the scuffed end plate can be refaced. This face is critical to match the gear faces. Has to be perfect or oil pressure will be lost. But, the ends of the gears also wear and they should also be smooth. Again, wear equals loss of pressure. The pump face can also be refaced a bit to bring them closer to the end plate. Not for the faint of heart. Clearance should be a bit less than a tenth of a mm. I guess you could measure that with plastigauge?
Bottom line? Get a new one.
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It's not very frugal, but I would consider fitting a new one. Sure, it maybe fine if it passes all of the tests but replacement isn't a job to be done with the engine in the car. It is the engines beating heart. A genuine Volvo one is about $140.
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Here are the B20 torque specs that Planetman (reliable source) had posted on Turbo Bricks:
https://www.turbobricks.com/forums/showthread.php?t=350747
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Hello,
The oil pump torque spec is for the pair of 5/16" bolts that hold the pump to the block, a figure I got out of a Volvo repair manual.
The oil pump bolts that hold the oil pump together are 1/4" and the torque is much lower for those 4 bolts.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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