The Stovebolt Site Forums The Shop Area Engine Shop Alright, what the heck is on my exhaust valves?

So, this is the first overhead valve engine I've taken the head off of. Dang, it's so heavy! I've worked on flatheads before only, and mostly tiny ones, like the Model T engine.

I'm working on the 235 in my bus here, and I was both amazed to see that the intake valves were so darn big, and to see this weird junk stuck on the exhaust valves. I've only ever seen carbon before. This stuff is a funny colour, and it seems even harder than carbon. There were also deposits like this in the combustion chambers, and on top of the pistons. In fact, in some places, it was 1/16" think, and even more tan-ish-ly-white than on this valve.

This engine sat for many years before I woke it up. I have put about 2000 miles on it in the last few months.

Thanks for any info.

http://i221.photobucket.com/albums/dd45/HomeCrafter/IMGP2166.jpg

http://i221.photobucket.com/albums/dd45/HomeCrafter/IMGP2165.jpg

http://i221.photobucket.com/albums/dd45/HomeCrafter/IMGP0001-13.jpg

What brand of gas are you running?
Did this engine burn much oil?

Well, I fill up at the old Co-op here, but this engine sat for about 40 years before I fired it up. I never took the head off 'till now. I think these deposits are much older than the past 2000 miles, as my plugs look fine, I put them in new when I started it up.

The valves are soaking right now. Hopefully it will scrape off easier tomorrow!

When I started it, the rings were frozen, and it was smoke city. I let it idle for some time before returning it to the road. It no longer smokes, and the bores are nice looking.

Its most likely modifier/additive deposits from the previous owners driving habits or cheap gas they bought.
Id say do as youre doing,,,clean it up and keep driving it.
Good Luck,

It's lead oxide or led bromide deposits from TEL and lead scavenging compounds
in the older gas. Not unusual and that's not really a large build up you have there. I've
buffed up a lot valves in my seven decades and I've seen some exhaust valves with it as
thick as 3/16". One good thing, it doesn't look like she's been pushing oil which may
indicate that the short block is in good shape.

Install a wire brush on your bench grinder, don a dust mask and a pair of leather gloves
and have at it, they will look like new in a half hour.
Denny Graham
Sandwich, IL

I had similar deposits on the valves of my 216 that had been sitting for years before bringing her back from the brink. My thoughts are similar to Denny's in that it's probably lead deposits. I did what Denny suggests and used the wire brush on my bench grinder to clean them off.

I also had the thought that these were lead deposits. Especially if you have kids, be very aware about keeping this stuff contained.

Kurt

We all appreciate keeping things safe, but the "lead is dangerous" thing has been intentionally exaggerated by the government and the media.
Lead was used in paint for a hundred years - nothing happened.
Why did this suddenly become high priority?
Because certain children ATE THE PAINT off the wall, and somehow the parents never noticed.
Do your children do that?
Inhaling dust is much, much less important - firing ranges begin to show statistics after years of continuous exposure to fresh air-born lead particles.

The official answer: "It can't be the parent's fault. We can't be racist and say that this only happens when the parents leave child rearing to the state, so we have to pretend that it happens to everyone".

The lead danger is real, but it has been exaggerated. Range officers at shooting ranges, and some competitive shooters do show dangerously increased lead levels in their blood, but unless you spend all day every day at a bench grinder cleaning up old valves, you're not likely to show any ill effects. The guys who spent every day radius-grinding asbestos brake shoes back in the 1950's thought they were safe, too, as I recall.

I cast thousands of lead-alloy bullets every year, but I use a "Darth Vader" looking respirator and do as much of the wheel weight smelting and alloying as possible outside with a Coleman gas-burning stove. The indoor bullet casting gets done with an exhaust fan operating, and I'm wearing the respirator. Just use a few common-sense precautions like at least a dust mask, and wash any exposed skin after you'e finished cleaning the valves. No problem.
Jerry

I'm used to being around lead, and wearing protection. Working in a boat shop, you get to sand allot of Red Lead Primer, and use Red Lead seam putty.


I was wondering if it was lead bromide on the valves. The only time I've seen this, is when looking at pictures of aircraft spark plugs when I bought my plug cleaner. I guess lead-fouling is troublesome when burning av-gas.


Thanks for the info!

Av Gas typically has much higher concentrations of TEL in it than is used in automotive
fuel. Most light air craft use 100LL and high performance recip engines often require 130
octane which can run as high as five times the amount in auto fuel. Because of this it also
has much higher levels of lead scavenging compounds. These don't do their job at lower
temperatures such as idle so it’s recommended that engines be warmed up and shut
down at higher engine speeds such as 1200-1500 rpm to prevent plug fouling. At higher
temperatures the lead bromide will vaporize and gets pumped out of the cylinder, it re-
condenses when it's expelled into the cooler air. the auto engines are operated a lot of the
time at lower speeds which do not produce a high enough temperature to vaporize the
compounds so they deposit on the valves, pistons and plugs.
Denny Graham
Sandwich, IL