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View Full Version : Finally figured it out!



Sweet Cheekz
09-18-2009, 08:46 PM
Tore my motor down this week and finally figured out what happened at Lake George and why I was not getting the speeds I assumed I was going to get.
I bought a 383 long block last winter and we kept it together, changed the cam polished and ported the heads , dynoed and put it in the boat. Turns out the rings were not well and by the time I got to Lake George they were letting fuel into the oil causing my oil pressure problem. At some point early this summer I took a couple of lobes off the cam and was only getting 4300 rpms by this fall Never more than 5000 for the year. Crank is out of balance causing a wicked vibration I had all year Amazing I got 74 mph and 61 hours on it
We are now tearing it down and starting over with more compression, different cam, pistons and going with a hydraulic roller setup Should smooth out and get a lot bigger Looks like I never had over 390 horses.
Might be testing in 3 weeks
Parnell

BlownCrewCab
09-19-2009, 08:32 AM
Where did you get the 383 from? sounds like someone just slapped it together and totally mislead you.

Just Say N20
09-19-2009, 10:55 AM
Glad you figured it out.

Think of the potential you have. 75 mph with a "sick" engine. Think of what a healthy one is going to do for you!

You might have to chose between two awesome boats for the gatherings next year. Decisions, decisions. . . . .

BUIZILLA
09-19-2009, 11:02 AM
Parnell, seems hard to believe that much fuel would get by the rings to thin out oil... no matter who's ring set it is... seems that you'd have a puddle on top of the piston on every startup??... is the fuel pump diaphragm leaking? something else happened here IMO

Newby
09-19-2009, 11:36 AM
As long as you have a mechanical fuel pump on the block I agree that it would be worth replacing. It could dump a lot of fuel into the block and possibly thin the viscosity of your oil.

Sweet Cheekz
09-19-2009, 10:13 PM
This is the mechanics info, I'm no expert but the fuel pump was new. I will ask. I was getting consistent oily spray coming out of the breathers. When I had my oil pressure problem twice the oil pressure would drop to nothing and I would shut it down then immediately restart it and have 40-50 pounds It would start dropping after 30 seconds at the same rate whether I reved it up or not. Both times its how I got back just doing that and ideling along. First time we pulled the pump after LG and could not find anything wrong with it but replaced it anyway Ran 25 hours seeing oil spray everytime but good pressure then it happened again the other day so I shut it down and pulled the motor. Any other thoughts or ideas will be appreciated
Parnell

BCC I bought the long block from a guy on the cheap with pretty good aluminum heads My mistake originally was not tearing it down completely Lesson learned there for sure

BigGrizzly
09-21-2009, 10:14 AM
I saw this once before with an old type second ring in upside down- on all the pistons, there was another problem too but I do not remember what it was,

Sweet Cheekz
09-21-2009, 10:43 AM
Grizz I will ask about the type of rings that were in there Thanks

A2VeeDub
09-21-2009, 12:44 PM
Did the same thing recently. Lot of boost for a lot of miles. Started filling a catch can off of the breather way too frequently. Oil smelled burnt and really strong of fuel. Ran it for a while anyway and oil pressure was eventually averaging only 25 lbs or less. Eventually wiped main and rod bearings.

So I do think it is possible for fuel dilution to cause this.