Engine and Transmission Tech

Do they just use an electric pump then? I suppose I could just add a momentary switch on the dash to hit just before startup.

Nic, think of it as a "Bank" for extra oil savings. The oil pump in the engine supplies the pressurized oil to the resovoir,(accumulator). Loss of oil pressure, with or with-out solenoid control valve allows pressurized oil,"saved" in accumulator to re-enter oil feed galleys to maintain pressure. Quite basic compared to dry-sump, but effective. roverman.

OH I get it. SO the reservoir stays pressurized. That sort of re-pressurizes the system just before startup, right? That makes sense. So you're saying just use some type of servo valve with that opens with the "run" switch for the motor. Cool!

We always just put a ball valve on the bottle and opened it up just before hitting the start switch, shut it just before shutting down the engine. But solenoids are cool too..

Jim

For a street car I'd recommend a solenoid vavle that would be open when the ingition switch was on. You turn on the key and get a shot of oil into the engine just as you start to crank it. While it's running it refills the acumulator and that's there in case you get the pick up uncovered during a high g maneuver then just give it a bit of a rev when shutting down to get the pressure up to max and turn off the key holding the oil in the tank until the next start cycle. Nothing to worry about or valves to remember. The only downside is when you change the oil, then you'll have to drain the accumulator and do a "dry" start when you first crank the engine and then top off the oil level once the accumulator is filled.

Ok, let's say your the meticulos type, your 1.5 qt. bottle has a quick latch system and valve is mounted on the bottle. Oil change time you drain bottle,refill,close valve and pressurize,(air valve is included on top). Now your ready to pre-lube, cold start.roverman.

Hey all, after reading this and the Lotus Headed Rover thread, I gots to thinking a little.

In the schematic that ex-tyke posted you can see how (from the front of the engine) that only the left side lifter gallery feeds the main bearings, and the plugs in the front of the block are (I think) where the oil feeds are drilled from (and have to be plugged) and its done that way to allow oil flow around the cam to the right side lifter gallery and up into the rocker shafts. Its a pity they dont show the start of the left hand head feed, but you can always guess.

As you can see, the lifter galleries just stop at the back of the block and I too think that a joiner here would only be a good thing. I would also be interested to hear if anyone thinks it would be possible to drill and tap some fittings to join these inside the valley, then take a gauge feed off of there?
Or, could you plumb a feed INTO both of these for a drysump setup, avoiding the front of the engine totaly?

Hack

Hack and clan, notice the two, very handy, pipe plugs that just happen to cover "both" galleys in the back? I think there's room to clear the flywheel. How could it get any simpler? roverman.

Hey Art,

Nics original post =
I measured the gap between the block and the flywheel. There is 1 1/2" to work with. Should be more than enough. SWEET!

So Ive been looking at a few photos after reading and it looks very, very tight... So, thats sorta why I was wondering about internal fittings.

Hack

I initially thought it was tight too, until I measured it. I think there is enough room to put a couple 90º bends in the pipe threads.

I've seen , brass pipe, "loose 90 deg." fittings, with a 45 deg. at appex of both pipe threads. Every 90 deg. can reduce pressure up-to 10 psi. A pipe plug with a tube flare fitting on opposite end, coming straight out of galley and theaded into an "oil log", between both galleys, might work. roverman.

But it wouldn't be the ONLY way across. You know what I'm sayin'? I'd have the crossover in the front and the back of the galleries.

I suppose it would mess with the accumulator though.

I think it's over the top and I don't see any sense in it. On the BOPR all the mains are fed from the left side so all you're doing is adding a redundant passage to the other side which only feeds that side's valve train. The passages in the front should be plenty, and unless someone can point to an oiling related failure of the far side valve train I just don't think it makes any sense at all. Maybe if you want to tie in for an accumulator or a pressure gage the near side fitting would work, but otherwise, I can't see it and I'm a little sorry I even brought the subject up.

Jim

OK OK. Just relax man. It never hurts to flesh out a concept. Is they front bypass the same on the early blocks?

Jim, Nic and clan, true it may be a little over the top but as you pointed-out Jim it will be a handy place to plumb a gage/accumulator. This over-the-top will be "much" easier than that other,(ott) the Ford into Rover, cranky issue.Happy Holidays to all. roverman.

the old way of equalizing pressure and flow to the lifters on the iron blocks was to groove the cam bearing journal in the front of the block

Thanks to Wotland for the link in the 4.02 Inch Bore thread...

Picture and text from

www.espritv8.net

Quote:

Holes in block for back end oiling, Oil was also fed into the rear end of the oil galleries behind the flywheel to avoid oil starvation of the aft crank pins. These two holes had to be made for the pipes to pass through.

Hack

Just to explore this idea a little further, let's say the holes in the block feeding the mains are 1/4" diameter. That should be correct but feel free to verify it. We have 5 such holes feeding the 5 main bearings. The flow rate of a round pipe, or passage in this case, quadruples each time we double the diameter so it stands to reason that for full flow through all five main bearing feeds the oil galley from the pump should be just a bit over 1/2" diameter. It is not. In fact it could be a bit under 1/2" and this is where the external feed idea is born. But the matter doesn't end there as we have restrictions at various points. Most importantly, the hole in the bearing shell is probably closer to 3/16" to start with, and the area that is available for the oil to flow out into the bearing is much smaller than that. In fact it is at this point that we first encounter the principles of good oil management in the BOPR/SBB block. It is common to allow about .002" of bearing clearance for the mains of production V8 engines of almost all types but experience has shown that doing so in any of the Buick engines is courting disaster. These engines were designed for bearing clearances of around .001" and even less (check the Buick factory specifications for confirmation) and there was nothing done in the Rover variant to give us reason to think these clearances should be opened up. Also there is no justification for larger clearances in the aluminum motors over those of the iron block motors. Our brothers in the drag racing fraternity uniformly stress the necessity of keeping these clearances to the low side, a practice that is in direct opposition to common wisdom in engine building. As far as it applies to these engines, common wisdom is completely and unequivocally wrong.

Using the proper bearing clearances then, the bearing itself is the restriction in the oil feed system and the rest of the system is sized to allow more than adequate flow behind that restriction as long as those clearances are kept in check. What we have found in every case where adequate oil flow was a problem is that either bearing clearances were excessive, or oil has been allowed to escape at some other point in the system such as by poor fit in the lifter bores (a common problem) excessive clearances in the cam bearings, (bad installation, damaged bearings, etc.) or excessive leakage at the rocker shafts. These engines were designed and engineered to run with tight oil clearances. Pay proper attention to those clearances. Enlarge the feed to the oil pump to 5/8", set up the pump with minimum end play, eliminate leakage and your oil feed and oil pressure will not give you trouble. Done properly, band-aids are not needed even with a high rpm engine. Overlook any one area and your band-aid won't help either.

An externally adjustable pressure relief is often recommended and is a good idea to limit oil pressure during cold start-up and possible rupture of oil filters. (We've seen this happen) The pressure relief does not boost low RPM oil pressure in any way. Porting of the oil pump passages and chamfering of oil passage transitions and corners are worthy and recommended performance modifications. End clearance of oil pump gears is recommended to be about .001-.0015". In practice, shimming the cover until the gears just stop dragging seems to work well. A worn cover should be replaced of course, and a so called "booster plate" provides a new wear surface for the gears and stabilizes the pump cavity. It also can be smoothed or ported to enhance flow. Cam bearings can be a problem as the bore size in the block can vary significantly, often resulting in undersized bores, difficult cam installation, and poor practices such as bearing scraping which lead to loss of oil control. Make sure the bores are correct during the machining phase. Pressurize the oil system before installing the intake and valve covers and any serious leakage points in the upper end will be revealed. Do this before the pan is installed for a complete check. It may be messy but that is a much more temporary problem than spun bearings.

As far as adding external lines, that was tried and discarded decades ago in the drag racing sport. It adds multiple extra failure points and provides no benefit if the engine has been properly built in the first place.

Jim

one thing that has not been mentioned as far as I have seen, is the added benefit of the pressurised accumulator is it acts as a dry sump if the suction pipe in the wet sump is ever uncovered when using the car in anger

A large/qualified, engined rebuilder states, "1lb. of oil pressure per 1 square inch of (sleeve bearing), surface per. 1,000 rpm., is adequate." When you, "do the math", will better explain. Oil pressure loss/throw-off, from sleeve bearings increases to the square of bearing clearance increase, ie., .001"=40 psi, then .002"=10 psi. Another way of excess loss,is with too much con-rod side clearance,which also puts too much oil on the cylinder walls,(flooding the rings), and increases windage. Some engines, like 390+, AMC V8's, need a lifter galley cross-over line to prevent "main" problems for serious use. We think nothing of adding external lines for remote mount filters/coolers. I feel the quality of the installation determines suitability. Given a choice, I would use the crank driven pump on the Rover.



Edited 2 time(s). Last edit at 01/09/2010 11:59AM by roverman.