Overhead valve Cylinder Head Gurus feel free to apply within

I had gathered up some gear to do my own heads over the past couple of years and have an old black and decker valve grinder and Sioux valve seat grinder with dressing attachment and a variety of other goodies.

Recently I noticed some oil seeping from the #1 and #8 sparkplugs in a set of double humps I had rebuilt years ago by a local old timer that built race motors, he had machined it out for double springs, I installed screw in studs and did a half ass port and polish job. So I decided great time to break out the new machines and see what's what.

What I noticed first off is that he didn't use any valve seals, is there a reason of this? seems obvious looking at them that the valves at each end of the heads where oil tends to gather most is seeping down the valves. Not sure if there is a valid reason but I plan to add them to eliminate that issue.

Next I plan to do a 31, 46, 60 valve seat angle, reason for the 31 and 46 over the 30/45 is I came across a nice carbide seat grinder in those angles, any problem with that?

For the valves I figured I would do a 30 degree cut back, but am open to suggestions.

Lastly, with the double springs using the C clamp style compressor didn't work well at all, I tired an older unit and bought a new craftsman unit and both didn't work well at all, I switched to a 2 jaw puller type that worked well for removable but I imagine will suck fo reassembly, so open to suggestion for a clever idea there also.

not looking to build a 1000 horse motor, just looking to do it myself, I've been assembling my lower ends for years but always had my heads done when I would get the block machine work done. thanks in advance

 

IIRC, many older SBC's do not have a typical umbrella seal. There is and O-ring at the top of the valve and a metal hat which sits under the retainer. The hat and o-ring prevent excess oil from running down the stem and into the guide.

Way back in the olden days, they wanted a little oil to reach the guide to lube the valve stem.

 

There could be a couple of reasons for the lack of valve seals. As you probably know, original SBC seals were simply "o-rings" and tend to deteriorate over the years. They often break and simply come off, making their way elsewhere. That being said, even on high-mileage heads there are usually a few still in place.

One school of thought was that after setting the guide clearance very tight, you could leave the exhaust seals off to provide a little more lubrication (or use the o-rings on the exhausts) since they tend to expand a bit more. There have been guys who didn't run seals on either valve. I have known a few old-timers who still follow this philosophy. My own take on this is that with any engine intended for racing, you really, really don't want any more oil in the chamber than you can help. Detonation is not our friend.

The slight change in the valve angles probably won't make much of a noticeable difference. It takes some fairly sophisticated port work to make it to the point where it would, if ever.

There are a variety of good compressors available, at various prices. This style seems to work well for the SBC and can be used with the heads on or off the engine: http://www.summitracing.com/parts/SUM-906784/ Note that I don't know how good the Summit piece is...but others make a similar item. An enterprising person could probably make something like it....

...and then there is this: http://www.summitracing.com/parts/WMR-W84002/ which could be made as well, out of a simple flat prybar available from a local hardware store, and would be sturdier. Mine originally was a good USA-made Vaughan prybar, and I still use it occasionally. The paint has to be stripped off too, no big deal.

 

the valves did have O rings in the slot below the retaining clip, maybe that was the idea, for a motor driven often would I be better off using an umbrella type seal or letting it oil the valve guide a bit?

I have the second type of comressor also which works well if the head is bolted down but seemed like it would be a pain when installing valves because you'd have to clamp it down, hold up the valve, hold the compressor and slide the clips in, does the first compressor lock into position, seems years ago I had an air operated unit but I had never used it so not sure how well they work

 

As you can imagine the intake ports see vacuum. The two end and two center exhaust ports see pressure. Highly unlikely that they will suck oil into the exhaust ports. So some people leave the seals off exhaust valves as they feel them unnecessary and maybe if a little oil did get in there it would be a good thing. I have seen good (read expensive-Snap-On) C clamp valve spring compressors and less expensive ones with a steel back bone cut out and welded on to them to eliminate flex.

 

Late traditional SBC's like the circa 87-91 Corvette ones got real seals, rubber with clamp on intake, teflon on exhaust, entirely adaptable to earlier with a simple cut on top of guide.

 

check the guides for wear and valve stems if the guides are worn you can install a bronze liner the cut the tops of the guides for Teflon seals and have built many race motors without exhaust seals but not street motors as they might smoke on start-up if oil gets in the cylinders