Typical Oiling Modifications

[sanborn]

Early in November, I posted that we were building a SB for a friend to use in limited late model at the local track. To review, this is a 362" engine, W2 headed, non ported head, flat top piston, flat tappet camshaft. We think the engine will have to turn 8000 frequently(because of competition) so we have pretty much done everything we think necessary to live in that kind of environment. The oiling system is wet sump(because of cost). In this class, dry sump oiling systems are legal.

The modifications are fairly straight forward and can be accomplished with some extra long drill bits, rotary files and a lot of patience and care. I must admit, being an old geezer, and owning a Bridgeport, I did a lot of my work in the mill using the power feed to bore the holes. But, you can do the same thing using a hand drill.

Oiling Philosophy- My belief is all an oiling system must do is oil the rod bearings properly at max RPM. The trick is to get an adequate supply of oil to all the rod bearings. In order to do this you must start at the very beginning-the oil pickup.

For this engine we chose a Canton oil pan and pickup. The pan looked real good and at first look the pickup did too but closer inspection of the pickup reveiled some problems. The pickup tube is 3/4" OD and 5/8" ID. That's good but where they welded the pickup tube to the base, the weld flowed through the tube and closed the ID down to 1/2" in places. That's too small. We ground the excess weld away inside the tube to make the opening 5/8"

[sanborn]

To backtrack a little, when we got all our parts together and started measuring we found most of the oiling passages in the pump and block were .400" to .420" in diameter. This is OK for a lower RPM engine but for our application we felt the passages must be enlarged to insure oiling. After looking closely at everything we decided .500" minimum passages were possible. How much is that extra diameter worth, about 40% more flow. That's a bunch!.

We wanted the pickup tube to be larger, 5/8" because that's the suction side and that large a intake is necessary to feed a 1/2" line under pressure.

Next we looked at the pump, it is a Mellings High volume. The oiling passage is .420" out of the box. We enlarged this to .500". Be very careful when drilling by hand it's easy to get off and hang the drill bit(hard on the wrist). Try to do this in a drill press if possible. After the hole is enlarged, carefully blend the opening in the pump to the hole. Oil doesn't like to flow around sharp corners and a little blending eliminates any oil flow turbulence inside the pump.

When we bolted the pump to the rear main cap, we got a surprise-the two oil passages didn't meet at all! Look at the photo of the rear main cap to see how much we had to slot the cap to make the passages meet!

[sanborn]

I neglected to add, we also drilled the passage in the rear cap to 1/2" as well. The larger hole in the rear cap matched to the vertical oiling hole in the block very nicely. That vertical hole intersects with a hortizontal hole that carries the oil out to the oil filter area. We drilled this hole out as well to 1/2". We then tapped the hole 3/8" NPT for a fitting to be attached to carry the oil to a remote filter(I will explain why later). Where the vertical hole and hortizontal hole intersect, look very closely to see they meet properly, most don't. And, oil doesn't like to flow smoothly around sharp corners so we got a rotary file with a 1/2" round head and carefully rounded the intersection of the vertical and horizontal hole. That makes the oil flow more smoothly.

OK, we have enlarged the lower hortizontal hole in the block, tapped it 3/8" for a hose fitting. Now, we need to do the same for the upper hortizontal hole. Here we got a surprise! On this block, the hole wasn't drilled all the way through. It was less than 3/8" in diameter at the very end. We repeated the procedure, drill the passage to 1/2" and tap to 3/8" NPT. We couldn't round this intersection because it is so far inside the block. So we had to leave it alone.

[sanborn]

Excuse me, had to get a coffee refill!

Remember we said earlier that we fed the oil(#12 line) to a remote filter? At the filter we split the return to the block. One # 12 line goes back to the rear of the block AND a #8 feed line goes to the front of the block. "X" and "R" blocks have provisions to feed oil from both ends. And for high RPM applications we believe it is necessary.

Too many times we have seen front rod bearing failure at high RPMs. We believe it is due to oil starvation. The problem is partially solved with 48 degree "R" blocks but it is still a good idea. Here we drilled and tapped a 1/4" NPT hole for a #8 feed line. We could have made it larger but don't think it is necessary and the smaller line made it easier to get around the fuel pump.

[sanborn]

OK so you don't have an "X" or "R" block. What do you do? This next photo shows how you can accomplish the same thing with a standard block.

Drill a 7/16" hole and tap it for 1/4" NPT, run a steel line from that fitting to the back of the block. Drill a 3/4" hole in the back of the block right beside the oil pressure passage and directly below the intake surface. Install a #8 bulkhead fitting in the hole at the back of the block and connect it to the line coming from the front. Then connect to a remote filter and presto you feed the oil galley from both ends. Your bearings will thank you!

[sanborn]

Next let's go to the main bearings. The passage from the main oiling galley(that's now fed from both ends) goes to the main bearings via a 1/4" drilled hole(some blocks are drilled 17/64"). We want to enlarge these holes to 9/32". Use a 12" long electricians drill and carefully drill from the main bearing area up to the main galley. This will do two things; enlarge the passage and ensure the holes are fully drilled. We have found holes not fully drilled many times. Some builders drill the front hole to 9/32" and the center three main bearing are drilled to 5/16". This is OK too. The passage in the rear main is large enough from the factory(5/16").

The next photo is very important! It shows how we modify the main bearings. We machine a slot in the mains approximately 1/2" in length and 1/4" in width. Why? The slot in the bearing now fits the slot in the block. And an oiling slot(versus a hole) in the bearing gives the rod bearing feed hole in the crankshaft more time to fully fill up with each revolution. For very high RPM engines(such as this) we enlarge the slot in the block to 5/8" in length and make the slot in the bearing the same length.

[sanborn]

This engine is being built with Jesel rockers that feed oil to the rockers through the pushrods. So good , consistent oiling of rockers is essential. But we don't want to feed the left side oil passage from the front main bearing as a standard block does. So we block the passage that goes from the front main bearing up to the left side oil galley. We do this with a deep freeze plug in the left side oil galley to cover the hole.

[sanborn]

We then feed the left side oil galley by drilling and tapping a 1/8" NPT hole in the front of the right side galley and drill and tap a 1/8" NPT hole in the center of the left side galley. We connect the two with a 3/16" steel line. This insures constant feed of oil to the left side without possible starvation of the front main.

You will note the aluminum block off plate over the cam opening. This is done to keep oil from being thrown up into the valley by the crank/camshaft.

[sanborn]

That pretty well covers the subject. I'm sure I probably forgot something.

A lot of what we did is maybe overkill. But I would rather have too much oil at the rod bearings any time than not enough.

If you see something there you don't understand or don't agree with, let's talk about it.

Right now though, I think I have already turned into a pumpkin. I will be back in the morning, er, later in the morning.

[sanborn]

It's wonderful how a cup of coffee helps to charge ones batteries in the morning!

I know a lot of you get tired of some of us talking about "X" and "R" blocks at times. Most of you work with stock blocks only. I understand, did the same thing for many years. So for those of you that haven't even seen a "R" block, here is a photo of one of the first "R" blocks. There are several later versions but at least you can see what the 48 degree lifter bores look like.

[sanborn]

The oiling system modifications described earlier are for typical limited engine oval track racing. If you get into really high RPM oval track racing,IE, Nascar Supertrucks, Super Late Model, etc. there are additional modifications to be done to the block, bearings and other components. Or if you use high vacuum dry sump systems there are other things to do.

We have also found several things to do to the cooling system to produce more consistent cooling throughout the RPM range.

Now that I have discovered a new toy(publishing photos on the net), I will probably bore you with all this stuff.

Got to get to work!

[jimm II]

Thought all the mods were GREAT....we used some of these for our late model,few years back. Just a couple of thoughts , we made a stamped tin valley baffle to keep the oil from being flung by the camshaft.Was a lot of fun going around the oil lines that deverted the lifter oil . Now on your valley photo ,the valley drain back holes did you inlarge them or cover them to return the oil to the rear of the engine,by cam gear.. Also very good idea of painting the inside of block ,helps seal poris block (cast) and aids in drain back to oil pan where oil is needed....Thanks for the pics they are a great help to all of use here. JimmII