Block cut in half?

[seth gordon]

It seems that oil drainback from the heads builds up in the lifter valley. at some point oil returns to the pan by exiting through holes into the timing chain cover or it goes through holes above the cam tunnel. If the front holes are slotted, less oil goes into the crankcase and windage is reduced, but what effect does this have on cam lobe oiling. I know that the con-rod squirt holes are supposed to supply oil to pistons & cam lobes but is that sufficient.

Thanks, Seth

68 AMX 390

[jeepsr4ever]

Seth finding rod bearings with oiling holes is hard to do unless someone has some older NOS bearings or if you have patience and can grind out oiling holes. Almost every rod mfg quit installing the side oiling holes. One can assume that the foam from the crank bleed of oil did a good enough job of lubricating so they quit that part of the machining process. Another thing to consider is the holes were there for cylinder oiling as well. High rpm and excessive oil flow do not mix well if the crank is bleeding off oil and the rods are bleeding off oil a large amount of foam and windage can cause smoking and powerloss. AMC cam lobes get oil from the lifters and as they spin oil flows up and over and down and around. If camshafts had to rely on rod holes and the few large flowback holes I doubt the cams would last very long at all.

[AMX69PHATTY]

I've seen pictures where they drilled a number of small holes, maybe 3/16 or so, in the valley area in a row down each side in a low spot somewhere near the lifters to prevent oil collecting in the valley and to improve drainback, but the drilled holes definitely must not intersect any other oil passages like the lifter gallies. Anyone else ever done that ?
I don't remeber where I saw that picture.

[jeepsr4ever]

Yep been drilling blocks like that for a while now but I try not to build engines anymore...too busy making parts.

[seth gordon]

So it seems that the oil squirt holes were used as insurance. It seems that a lot of the lifter valley oil drains through the cam tunnel holes, especially in the rear of the engine; Your description indicates that diverting that oil away from the crankcase will not cause lobe/lifter wear whether a flat tappet or roller tappet.

What is your opinion about crank-saracpers & windage trays?

Thanks, Seth

[jeepsr4ever]

Both scrapers and windage trays work well. The scraper helps keep the foam down and keep the crankshaft balanced at higher rpms. The windage trays help keep the oil from running up into the crank and this also allows the oil pump to do its job by not trying to suck the oil out of the pump. When you start to get above 7000rpm the force of the crank weights and rods make for some strange windage in the crank case. Alot of strange things start to happen! Some of these items do a couple of things for instance if you offset grind a 360 crank and use a chevy rod you will have a rod journal that is much wider than a chevy rod and will have massive oil bleedoff (If you can call it massive). This will cause a smoking stroker To eliminate the smoking a crank scraper can be utilized to scrape the excessive oil off the crank. A dual scraper works better yet. Alot of these items are for special applications and for high rpm use and are not needed in a low rpm offroad or street engine. I still cant believe people still buy trap door oil pans. Swinging pickup pans are superior to the trap door pans in my experience and opinion. (Everybody has one )

[seth gordon]

My concern is controlling the oil too much and causing starvation. since racing engines typically have a larger bearing clearance, perhaps the squirt holes may be unnecessary under those conditions. The application I have in mind is a 390 with a moderate roller cam ~6500 rpm. Many around here are using the Canton road race oil pan. I can not recall seeing a windage tray for an AMC engine being offered. Some people suggest that a crank scraper results in not enough cylinder wall / cam lobe lubrication, especially at idle.

Thanks, seth

[tomcat]

I bring up the old Q. Please post the pics again, im curious to see it.
Unfortunately my hacksaw is to small to do it by myself

[Jtomas801]

AMX69PHATTY, I believe i found what you are talking about. hot rod magazine did an article on how to build a 500 horse 401.
Here is some links to the article pages:
http://www.javelinamx.com/JavHome/articles/hr0698-1.jpg
http://www.javelinamx.com/JavHome/articles/hr0698-2.jpg
http://www.javelinamx.com/JavHome/articles/hr0698-3.jpg
http://www.javelinamx.com/JavHome/articles/hr0698-4.jpg
http://www.javelinamx.com/JavHome/articles/hr0698-5.jpg

Thanks,
Jon

[seth gordon]

It seems that the opinion is somewhat mixed. Some people open up the front drain holes, which perhaps also improves oil to the distributor/cam gear. others drill holes next to the lifter boss and bypass the cam tunnel holes. Extreme applications route the oil from the valve cover directly to the pan.

If new bearings are without squirt holes perhaps it is wise to not prevent oil in the lifter valley from going into the crankcase. Or the alternative: With squirt hole bearings one can take measures to route lifter valley oil away fron the crankcase.