F-2 Speedy

iTrader: (6)

Stand up guy, pretty rare if you get your money back, good luck

Budman II

iTrader: (1)

KR, any chance it is reversion? What cam are you running? I had a lot of issues with reversion while idling on a stand with my 489. I would see about a teaspoonful of water sitting in each primary when I pulled the headers. Oil never got milky, but I was definitely getting reversion when it idled - you could shine a flashlight up the collector and see that it was wet as hell all the way back to where the primaries connected. Interestingly, when I installed a set of mufflers on the collectors that had salisbury flappers it almost eliminated the reversion. I did extend the inner pipes in the collectors just in case, but I was surprised how much of a difference a set of tips made. The flappers acted like a backflow preventer. This engine was running some pretty mild cam specs too, so I was quite surprised to see any reversion at all, but sometimes you get a "perfect storm" of factors coming together to bring it on.

It would be nice if you had a set of known good headers or manifolds to run on it real quick. It is good that you have the avenue of returning the pipes if they fail the pressure test.

Good luck with it.

KR252Boss

Cam pretty mild. 228/236 @50. 590's lift on 114. I do have a set of Gills with tails I can put on to test as well

KR252Boss

I also had about 1/4-1/3 of a cup in each primary too lol

Budman II

iTrader: (1)

My cam had milder specs than that (on paper), but slightly higher lift. However, you have to keep in mind that the specs at .050 lift can be deceiving when it comes to reversion, especially with roller profiles. Rollers usually get the valve off the seat much quicker, so the actual overlap can be longer than with a flat tappet that has similar specs. Also, in my case I had a set of AFR heads that have a much more efficient exhaust port, which allows exhaust to flow into the cylinder as easily as it flows out. Add to that the fact that it has a stroker crank that pulls the piston down the hole with greater velocity, and you can see that "perfect storm" developing that I was referring to.

Another thing to consider is the angle that the engine is sitting when it is on the stand. You might need to block the front of the stand to give it similar "pitch" to what it would have in the boat. Things like that can make a huge difference.

KR252Boss

Thanks for info. Pressure testing this afternoon and will go from there

KR252Boss

Headers are fine. Problem is the guy had custom 15 degree flanges welded on the ends where the tails would attach. Also in these angled extension has a 90 degree elbow with a corkscrew looking water sprayer. This is all so the headers can be run without tails and you can just use 4 inch rubber hose between header and tips. Anyway they never tested them by actually flowing water from rail all the way through to the sprayers inside the collector. Anyway with the headers off the boat I hose clamped a water hose to feed on rail and put the connector in line to run water all the way through the sprayer. Well the sprayers were installed too close to end of collector and diverts some water straight back into the exhaust tube almost immediately filling the rear primary with water I know everyone reading this will be like water sprayers in the collector?? What the hell are you talking about haha. I've never seen it either. It was all done by a shop called Stainless Works in Arlington Washington custom stuff but wasn't planned out well or tested for that matter. Anyway I've got some experimenting to do with them to fix the problem but it's doable Take the sprayers out of the equation and pressure test headers 100% fine

Budman II

iTrader: (1)

Sorry, you made me do it!

My Lightnings had a weird design for the way the water was introduced into the exhaust stream - they just had about four 3/8" holes in the top of the collector spraying a curtain of water straight down. Damned thing looked like Niagara Falls. And on the bottom they had another 3/8 hole to drain the water out of the collector when not running - this also sprayed straight up. The result was two large streams of water converging and splashing everywhere. I had an exhaust shop add a stainless steel inner pipe to direct the whole mess towards the transom.

Here is a link to my epic thread with some pictures of what I had to do. Maybe it will help. (scroll to page 11 to see what I'm talking about)

http://www.offshoreonly.com/forums/g...-mild-cam.html