MILD THUNDER

iTrader: (3)

Will you be redynoing?

Budman II

iTrader: (1)

Oh that's just great, MT - now you have given me something else to worry about with my motor! I'm running the screens, a 10778 pump, and I was already a little concerned about the small drainback holes in the AFR heads. I guess I'll just have to run this thing at a max of 3500 RPM's all day.

mike tkach

iTrader: (3)

i am not a fan of screenes in the vally,if a lifter breaks it is almost always the axel that lets go and the needle beabings go to the btm of the pan so the screene would do nothing.i just cant see anything restricting the oil from getting back into the pan as a good idea.

Budman II

iTrader: (1)

Mike I agree, but I have to wonder what kind of difference it would make if the oil he was using in the video was heated up to around 175*. I would think it would be considerably thinner. If I had seen this before I installed the intake I would consider taking a pair of dykes to the screens. Kind of late now.

Doubt if I would see this issue appear on the dyno, as they usually just do a quick 10-second run. It would probably only manifest itself on a longer full-throttle run. Has anyone actually documented an incident where the screens were restricting oil flow back to the pan to cause an oil starvation issue?

Don't want to derail the thread too much. Might start a new one just dealing with this subject - more in an interest of helping others who are considering the screens. I probably wouldn't have installed them if I had seen this - seemed like a good idea at the time.

headshothills

as much as I would love to spend a day unrigging and yanking the motor, transporting it to the shop and wiring it up to the dyno, which was a pita by the way... Getting the Superchiller connected, and the water to the motor, and headers swapped out, I just don't think its feasible... We pretty much know what the motor is capable of, yes it would help to truly know the numbers, pyros, what the carbs are doing, etc, but Brasswell is pretty good at getting stuff almost spot on when they know exactly what your build is and giving them all the dyno runs with what the old carbs did, rather than just an off the shelf deal, so the only reason I could see would be bragging rights... We know with the right flow, a safe tune, distributor adv and jetting, we should be in the 900's on pump gas... That's good enough for me... Yah, Im sure we could push the limits and get 1000, but what am I really gonna do with that... The motor will spin to 7k, we were still building HP while the dyno still had ahild of it up to 6600 rpm.. We never saw the HP dip or fall off even with the crappiest tune.. In theory, even at 7k, 15% slip, 32p prop, that works out to 120mph... Yah, that more than enough for a Mach 26... I don't know if I'd want a fast blast at 120 for too long.. The old worn out motor with a stock 30p at 5900 with 6ppl and full tanks pulled 92mph... Again, without ICC's, it gets old quick... LOL

Im hoping that the AFR meter will do the trick for the final tune so we don't have to play, make a pass with a stopwatch and time your RPM's...

Here's a pic of where my bung port is... Everything I have read says water will destroy an 02 sensor, is there any trick to this or any special housing or 02 sensor to get that wont be affected by the wet headers?

By the way, this is a pic of the old motor setup... the boat and motor have been completely re-rigged with Black braided hoses and Black anodized Push-Lok fittings with matte black laser engraved valve covers... The carbs look sexy, but that's about it... LOL



Heres a couple extra pics of the carbs and 3 lobe helix in the 420 Mega....

Budman II

iTrader: (1)

There was a lengthy thread by another OSO member who was trying to get his O2 sensors to live with his Lightnings. IIRC, he had switchable exhaust built into his, so that was probably part of the issue.

http://www.offshoreonly.com/forums/g...g-headers.html

headshothills

Good read.... So with the jacket, and the bung at the collector, assuming I can do my best to keep "reversion" from happening and water coming back to the sensor after it mixes with the exhaust, I might be ok, for at least trying to get a tune...Honestly, even if we got a couple hours out of it... Did the Orielly deal, just to get us a tune or even close in my eyes would be worth it...

ICDEDPPL

iTrader: (1)

That bung is really close to the collector , heat and water kills 02 sensors. but I think you need to be at least 6" away from the collector for an accurate reading

Bawana

I agree 100%. its looks like hes has CMI sport tubes, the bung needs to go back as you said. What I do is put a plug in the bung then start motor warmed up while out on the pond & then stop, put your sensor in and make a run... See where your at and take sensor out and make changes... Then repeat the drill. what people don't realize is the exhaust will sweat on the inside during long Idle periods and actually paules bach toward the motor. This will get O2 wet & sometimes ever gets back into the motor. I did several videos at work showing how I could make the headers look like they were leaking and shooting water out the back of the tail ever with dry tail (dumpr on the outside of tail). I would tell people all the time that if they were running in cold water and had long Idle periods to put drive in neutral and clear the motor(s) every so often; and always do that before final shutdown.

ICDEDPPL

iTrader: (1)

^^^^ agreed .. I`ve also had some success at making them live longer by only turning on the gauge after a 5 minute ride at 3500rpm+ .. figuring they had time to dry off.