The Stovebolt Site Forums The Shop Area Engine Shop Auxiliary oil line to head

I'm finishing building my 1962 261 and yesterday I looked at a friends 235 that had an oil line from the middle of the distributor side of the head to the oil outlet on the manifold side of the block.

There is a port on my head that is plugged that I could set up for this.

Does anyone think this auxiliary oil line is important enough to set it up if it didn't come that way?

I've heard from several people that the oil line was an add-on for use when the motor got old and the internal oil gallery got clogged up with sludge, reducing the oil flow to the head. Nevertheless, I put one on my freshly rebuilt 235 just to be safe. Can't have too much oil, so long as you have good valve seals.

Steve

Steve-

Thanks for the tip. I read a few more unrelated threads after posting this and got the same idea you just posted, that the auxiliary oil line is for when the regular oil passages are clogged. I guess they would get clogged easier and quicker without oil filtration or with only a bypass filter.

Like you I'm going to put it on my fresh rebuild just to be safe 'cause I can't see it hurtin' anything if the valve seals are good, as you say.

Thanks again!

I wouldn't bother, my 261 gets plenty of oil to the top end without it. You will know when you start it up, as long as oil drips off the lifters you are fine. You don't want too much oil as it will get sucked past the valve guides. The stem seals on this engine are not very good.

It is almost imposible for a 1959-62 engine to plug the oil supply to the head. Up through 58 the oil passed through a 1/16" restrictor which can plug up, but in 59 they increased the hole to 11/32"(the size of your valve stems),tuff to plug.

I agree with 4onthefloor. Not too little, not to much oil for the rockers.

The auxiliary oil line to the head was installed when engines with early blocks got a 58-62 head and rocker assembly replacement.

The later rocker arm oil passages and pipes were altered to match the difference in oil pressure to the head from the later blocks. The supply pipe to the rockers were kinked on purpose.

Early or late heads are identical with oil passages, but watch for the later rocker arms with cast#s 85,86,87,88 and kinked pipe.

If you got earlier rockers with different cast# you don't need the auxiliary line, as they allow more oil flow.

Later blocks should always run matched later rocker assemblies or you probably get too much oil up there.

It's just a valve cover without torque-ing down, mostly to keep debris and dust out. Rockers shouldn't splash and spill or worse flood valve guides.

If you got a vented valve cover or PCV valve that leaks oil - check your rocker cast#s - could make a difference.

I had the rocker assembly rebuilt at a shop in California and didn't think to look at the numbers cast into the individual rockers after I got them back. It's probably too late for that though!

As far as getting the block oil passages blocked, not only will filtration make a difference, so will detergent oil, which I don't believe they had in 1962.