Baffled by apparent reversion issues with Lightning headers and mild cam
 

I am running a set of Lightning's with the divorced collectors on a 489 Chevy with AFR 265's and a relatively mild hydraulic roller cam. Cam is 226*/230* with 114* LSA, .612/.596 lift. Stock Merc seawater pump, circ pump and T-stat housing.

I'm running it on a test stand. I even tried putting wood blocks under the front of the stand to get it at a downward angle similar to the boat would have. Every time I shut it down and pull a header, I get a teaspoon or so of water out of the primaries.

Headers were pressure checked with air a couple months ago. Held about 18 PSI of air for several days. Engine was dyno tested, and block was pressure checked with air during assembly, so don't think it is a head gasket or intake gasket. Oil is clean, no sludge showing up under breathers or anything. Plugs look slightly wet when I pull them, however. I ran these same headers on my previous engine, and did not see any signs of reversion with that engine.

Starting to wonder if I am going to have to plumb in some type of dump valve to limit the flow of water going through the headers. Has anyone encountered this issue with the Lightnings or some other type of header?

Any chance this could be something as simple as condensation on the inside of the primaries? It's extremely humid and about 86* today. Block temp is not getting above 120* on the hose.

Yes . Don't panic . + some water vapor is a byproduct of combustion . Any steaming under the valve cover ? Take off the oil fill lid and look at it and down inside , no moisture no problem . I have a friend with an all aluminum Donavon 540 and always has a little bit foamy just under the oil fill lid .

It appears to be bone dry under the oil fill in the valve cover. No sign of milkshake of foamy oil. Dipstick looks clean. However, I did pull a couple of plugs right after shutting it down, and could see just a little bit of moisture on them. That's my main concern.

Also seeing some water condensing on the inside of the clear vinyl tubing for the breathers, but that is pretty normal. You may very well be right. ;) Thanks for the reply!

Still wondering if it might be a good idea to set up a dump valve to limit the amount of water that is going through those pipes. Seems like a lot. I think I recall and OSO'er saying that he had done this with a set of lightnings - ezstriper maybe? I'll have to do some digging.

Budman, I run Lightnings on my motors, 238/248 duration no water issues. I have 4 very small exit holes in the collector at 12,3,6,9 o'clock for water to enter the exhaust and cool the rubber coupler, with a 1inch dump on each header to dump overboard, if you do the same you will be fine! They also worked well with 258/260 duration before I detuned the motors.

It's very possible that you may be at a 'bad' collector length for exhaust wave tuning. Remember, your rubber hoses and tailpipes will add more length, which greatly changes wave tuning.

You ever drag race an open header exhaust and a 12"-14"-18" collector extension makes your car run better and a bunch faster ?

I have Pipemax on my work computer and can run it for you, but may take a day or two since I have work up my azz.

It gives best and worst pipe/tube dimensions in regards to reversion and power.

Interesting. Doesn't sound like there would be any easy fix for that one, other than a completely different header design. I may give Lightning a call today to see if they have any ideas. I realize that sometimes cracks will only open up under expansion from heat, but this is happening on both tubes for every primary pipe, which I think effectively rules out leaks in the headers.

I can take some measurements on the primary lengths and collector lengths - do you need pipe diameters too?

Were your headers set up this way from Lightning, or did you install the dumps? Are they on top of the collectors?

Re-read my 1st paragraph.

Your headers collectors + everything to end of tails = your collector length. Thus that may be fine but just the open headers with no tails on your stand may cause issues.

I'll try to run it tonight.

Later.

I ran it both ways - just open headers and also with connector hose and muffled tips. Seemed to do the same thing.