Smallie cam question

[OldmanRick]

Every cylinder looks different on the piston tops? I have to believe some plug reading over those miles would have uncovered a problem.

Maybe i'm just out of the loop, but where I came from, pre ignition/detonation would show up as speckled spots on the plugs.....Not to mention some pounding on the rod bearings that would confirm it.

There's enough oil stains to look like it rattled the pistons at some point, but I just wonder if the tune changed at some point to cause that?

 

[Captainkirk]

One thing I do KNOW. Old TRW Power forged pistons,take a lot more than that one did. I like this build. The compression,makes it work. We ran a actual 11:7 to 1 340 in a 72 Dart,on Cali 91 pump gas. Small roller cam,Manning Brady heads. 4:88's ,huge stall. The gear multiplication and stall ,reduces the "load" on the engine lugging. When he raced,we dumped in some Av gas,low lead.(like 102-104 octane). Hope this helps.

Avgas is currently offered at most airports in 80/87 (red) and 100LL (blue). You were most likely blending with 100LL which is what I intend to use.
They used to offer 115/130 (green) and 145 (purple) which were produced for WWII-era supercharged, turbosupercharged, and compound radial engines, but those fuels haven't been seen since the late sixties except maybe at Reno.
As I mentioned, 100LL has FOUR TIMES the lead that was added to leaded premium back in the day. To achieve a 93 octane antiknock rating without adding tetraethyl lead, current unleaded premium has to be re-refined (cracked) many more times than the old 97 octane, which was basically cracked a couple times and then had TE Lead dumped in it to retard knocking. What this means, in a nutshell, is that the 93 octane unleaded you buy today is a much more highly refined fuel than 'back in the day'...and when you blend it with a ultra high lead fuel such as 100LL, you really boost the anti-knock rating. FYI, the reason it's called 100 'Low Lead' is because it was labeled in comparison to the green and purple fuels, which had even more lead added for supercharged aircraft engines.
If I could only get my hands on some of THAT........:burnout:

I run 100LL in my bikes on occasion..and they LIKE it!

 

[Abodybomber]

Nice post,dead on! Everyone hates "leaded fuel". Not me,in the slightest. "Cracked", a new term. People were trained to forget the cooling effect, and lubrication benefits of leaded gas. Nice post!

 

[Captainkirk]

Nice post,dead on! Everyone hates "leaded fuel". Not me,in the slightest.

Me neither!

"Cracked", a new term.

Not really.Been used in the refining industry for decades.

People were trained to forget the cooling effect, and lubrication benefits of leaded gas.

Not I...I work in the aviation industry where the majority of GA aircraft are still powered by 4 and 6 cylinder air-cooled engines where the cooling and lubrication effect on valves and piston/cylinder assemblies is still a very necessary requirement.

Nice post!

And again.....Thanks!

 

[Captainkirk]

Here are a few pix of the old cam after I unwrapped it.......

Useable, or no?

 

[RustyRatRod]

If all of the lobes look as good as those pictured, sling new lifters on it, break it in like a new one and go.

 

[txstang84]

I think I'd break out the verniers or C mics and check for proper journal diameters, and consistent lobe measurements-then run it

EDIT: you beat me to it, Rob

 

[Abodybomber]

X3....^^^

 

[txstang84]

And then post up videos if you can surely we'd all love to hear it

 

[Captainkirk]

I think I'd break out the verniers or C mics and check for proper journal diameters, and consistent lobe measurements-then run it

Probably has less than 3,000 miles on it. Here's a pic of the whole shebang:

So, what about my engine guy's comment that old cams + new lifters = metal in the oil? Is he full of it, or smarter than me/us?

 

[RustyRatRod]

He needs to go read The Crane, Comp, Lunati, Schneider, Oregon and any other cam site. They all agree running new lifters on a used cam is fine as long as you break the combo in just like you would a new set. You have metal in the oil on ANY new engine after break in. This is why you CHANGE the oil after break in. New lifters on a used cam has been an accepted practice for a long, long time. Run that cam. It looks like a goodun.

Probably has less than 3,000 miles on it. Here's a pic of the whole shebang:

So, what about my engine guy's comment that old cams + new lifters = metal in the oil? Is he full of it, or smarter than me/us?