Variable Duration Lifters

[Terry Stapley]

Has anyone had experience with variable duration lifters (aka Rhodes)?
I have been wondering if using this lifter in an engine with a big cam would tame it enough at idle to decrease emissions.
I have a 418W with a Comp Cams 268H and failed my emissions test miserably (HC idle). My 2500 speed HC and carbon monoxide numbers were really clean as was the idle carbon monoxide. I only failed the idle HC.
I appreciate any input or ideas as I would like to be "Clean" but do not want to replace the cam.

[nevermind65]

I've used the Crane variation and it didn't seem to make a whole lot of difference. Added a bit more vacuum, but I doubt it would cure your problem. What type of carb are you running? I've gotten some engines to pass in the past with pretty decent cams (low duration high lift) just by adjusting the carb and accidentally forgetting to hook up a few vacuum lines. The vehicle ran pretty bad, but it passed the sniff test.

Here's a few other things that might help also. Use these plugs, available at most Advanced Auto Parts stores. They aren't cheap though.

http://www.e3sparkplugs.com/

Run the tank low on gas and dump in a bunch of dry gas. If you have oxygenated fuel in your area, use that also. Make sure you have a 195 thermostat and the engine is warm and up to operating temperature.

I'm not sure if you can do all these because of compression ratio etc. You might be better off taking it to a local garage where they can mess with it for a bit to make it pass. I was lucky. My brother worked at a place they had a 4 gas analyzer, so we had lots of time to make the vehicle pass.

Good luck.

[Terry Stapley]

For a Carb I am using a Holley 750 DP with Mech Secondaries! I too have a friend with a garage and a sniffer and we worked on it for a couple of hours and could not get the idle HC even close to passing! I think I was in the 7000 ppm range!
What is the dry gas that you referred to?? I am clueless!!
I was wondering if a mixture of gasoline and alchohol would work for the sniffer but I think the alky would hurt the fuel lines and carb components.

[nevermind65]

Dry gas is like alcohol. It prevents fuel line freeze-up during the winter. You should be able to get it in any parts store.