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rambler 195.6 ohv block, oil pan, side covers

updated 11 apr 2021

overview

block variations

there are a few variations in the casting itself, mainly to deal with lubrication shortcomings. all of the pre-1964 engines have the small external oil pump with optional partial-flow filtration, fed by a 3/16" steel line off the main gallery into the filter located up top/front of the engine, and draining back into the pan on the drivers side. 64-up engines in the new 01 (american) chassis have an oil pump with integral full-flow oil filter. the full-flow pump and filter will not fit into the tight confines of the earlier 01 chassis, but see the oiling section for other solutions. however, the 1964/1965 block accepts the 1963-old pump without modification. the oil pum pmounting boss on the block is much larger, but amc designed the block to accept the older pump. see photos below.




crankcase ventilation

it is routinely accepted that this engine consumes a lot of oil. in my experience most of this is oil mist drawn through the pcv system (or out the road draft tube). oil consumption increases with operating RPM; about half a quart per day driving over 500 miles at 65 mph and above (2800 - 3000 rpm). A good pcv system hugely improves oil mess and consumption.


oil pan

My 2010 build was assembled with no oil pan gasket, instead sealed with Permatix Right Stuff. Two years later it had zero seepage; pulled out of the car for the 2017 it had not developed even one oil leak. the 2017 build, in the hands of a professional engine builder, it was assembled more normally with a Best (brand) gasket set. Two years later (2019) there were signs of minor oil seepage in the usual places. Modern engines are assembled with goops, not gaskets.

The oil pan is ordinary enough, with a small baffle at the front to lessen air in the pickup under hard braking. In sports car type use, California desert and mountain twisty roads, the pickup does go dry. My next fast engine will have some form of crank scraper and overall better oil control. for ordinary driving the stock system is adequate. (2019: Accusump system installed in the roadster.)

the Best (brand) oil pan gasket set came with the wrong rear pan seal. i ended up re-using the old rear pan seal, which was supple enough, but i used enough right stuff to ensure it would not leak.

That nice looking drain plug is no accident. i spent a lot of time getting that right. i bought a magnetic drain plug (thanks Nate for the suggestion), and filed the mating surface perfectly smooth.

The oil pan seals to the timing chain cover at the front, which is 90 degrees from the bottom of the block. This requires a back-and-forth tightening sequence to pull it into place.




oil pan studs, not bolts

The single biggest change to the oil pan system was replacing all the bolts with studs. pan bolts seem to loosen with time, i'm sure it's related to shrinking and shifting gaskets, so i did this pan with studs and serrated face locknuts without washers.

Timing cover installation must be completed before the oil pan can be torqued down.

i was very generous with Right Stuff around the rear main and seal, if you look closely, you can see that i got it to extrude between the casting and cap, eliminating yet another leak source. the rear pan seal has right stuff under and over it.

Here's two of the nuts visible, one on one off. The stud system was cheap, it's just grade 5 hardware from MSCDirect. The pan cannot be tightened yet, the timing cover base plate must be installed and sealed first. This was done within a few minutes of these photos.




timing cover

The timing cover of this engine is slightly fussy, but nothing serious. This is one area AMC improved in the new six; most of these annoyances were eliminated.

The timing cover is in two halfs; a base plate that bolts flat to the block and a more ordinary cover. The base plate seals to the oil pan. pressurized oil passes through the base plate, and there is a gasket behind it.

Note that there is a 1/4" npt pipe plug in the end of the main oil gallery under the timing cover, and one on the back of the block. It is easy to forget these plugs!

Install the timing area base plate, camshaft retainer, timing chain oil scraper, and the oil slinger onto the crankshaft nose. Timing chain and sprockets then installs as per the factory service manual.

do not tighten timing cover bolts until you have read all of this section. The final position of the timing cover is determined by the crankshaft seal for the front pulley/harmonic balancer. Tightening the cover bolts too early may cause the seal to leak.

Press the seal into the timing cover with a socket or something that presses carefully on it's steel shoulder, not the rubber. The rubber seal must remain perfectly round or it will leak.

Install gasket, sealer, timing cover and most of it's bolts, loosely, so that the cover can slide around a bit. lubricate the seal in the cover and the harmonic balancer journal with oil, and slide the balancer onto the crank nose (it's a slip fit). the seal and timing cover are now centered on the shaft. timing cover bolts can now be tightened, but be warned that on this engine that the oil pan attaches to the back side of the timing cover as well as the bottom of the block; a test fit now is a good idea.

I added a bracket to attach the ford EDIS crankshaft position sensor (reluctor). the "36-1" wheel bolts to the harmonic balancer later.

The timing cover has a machine screw that serves as the ignition timing mark pointer. They're often bent or loose and leak oil. Nothing special about this screw, hardware store 10-32. I didn't record the length.




side covers

The very existence of these covers is comical. They're a vestige from when this was a flathead -- then, the adjustable cam followers were under there. There is no reason to ever take these covers off. Their only purpose today is to leak oil. I sealed them with right stuff and loctited the covers on.




rear cam plug

What i thought was a leaking rear seal in the old engine turned out to be this rear cam plug, seeping down the back of the block under the bellhousing plate. It's at the end of the pressurized oiling system, at full gallery pressure. There's an ugly smear of sealer there that looks worse than it is. when i installed the engine, at the last second, i put a bead of Right Stuff in a circle around this plug so that the plate would be an additional oil seal, should the plug leak. I put a piece of tape across it to remind me when i'm flat on my back under the car. I don't expect it to leak in the first place, but this double-fix is trivial to do.




general block pictures

Just some semi-random photos of the block. note that the old drivers-side l-head distributor hole is still there. it met the same camshaft gear, from 90 degrees away.






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