Trojan Boat Forum

FWIW, GM (low end)specs are 10 psi per 1000 rpm...

John, John, John. Stop listening to the voices in your head (namely all of us) and do what you think is best for YOU. You mentioned taking some extended cruises and that you are basically not comfortable with the engine performance you have. So, consider (grasshopper) the following: Cost analysis of rebuilding what you currently have vs repowering. If you do repower I would not get too exotic or too horsepower crazy. You have other systems to consider, namely drivetrain, props, etc. If it were me, and it may be someday, I'd rebuild what I have on the boat before I got to the point where my engines are toast. The last thing you want it a constant feeling of "uh oh, I hope nothing conks out" when you're far from home or out is heavy weather. Again, do what's best and safest for you. I'm not a mechanic so I keep a boat bank account to handle the things I know I'll screw up - and engine and propulsion systems are right at the top of that list. Good luck.

I rebuilt a 305 one time and when i started it on the stand I got almost no oil pressure. Spent hours going over the big stuff then finaly took the oil pan back off, lowered the oil pick-up 3/16", put it back together and she's still running awesome 2.5 years later. Just sayin
Ron

FWIW, randyp is spot on. Once upon a time I WAS an "ASE" Master Tech., Chevrolet Master Tech., and a Cadillac Master Craftsman. Thankfully I'm no longer in that business. This much is for sure IF you keep running around with NO oil pressure at Idle and LOW pressure when running you WILL be REPOWERING. At that time rebuilding/repairing is no longer an option. Just food for thought. Good luck.

Is low at idle Or 0 ? previous posts I though it was low .

[quote="jddens"]OK, I have about 40 psi when dead cold when warm it drops to around 20 at 3000rpm and at warm idle I have ZERO. First thing I did was eliminate a bad gauge or sending unit, put in a known good mechanical gauge and it reads the same........when this first happened I had the oil analyzed and there were lots of bearing metal in it.

Prowler, First post was "Low" This quote is from OP's next post. 20 psi at 3000 rpm and zero at idle Not Good.

You could get a GM long block , still cheap and I would trust it a lot more then a jasper

I had a Chevy truck years ago with low oil pressure. I bought a high volume oil pump (wider gears) and it popped oil pressure back up to 38 psi hot at idle. Tough change on a boat but worth consideration. Oh yeah, eliminate all the 'gauge' posibilities first.

""when this first happened I had the oil analyzed and there were lots of bearing metal in it"

I missed this or I just forgot (getting Old ) so I have re thought this some It may be best to put a long block in ( or a short block) . Is it really hight bearing metal or just a little high then normal ? I had a truck that would drop to near 0 at idle , I switch to 15W-40 oil made a big difference 60k miles later it was running strong when I sold it

Again, thanks for all the input.....when this first happened I tried 20-50 oil with no noticeable improvement......if I go to the trouble and expense of rebuilding I want to dumb them down some.......I don't like the complexity of these engines. TBFI, closed loop cooling....to many hoses and wires....I have built hot rod engines in the past and these are so complicated I can't seem to figure them out.

After talking to a machinist friend I am toying with this plan....have the motors pulled at the marina with boat in the water. Tow boat back to my marina to my slip (I'm paying for it anyway. Take the motors home and build new ones maybe using existing rotating assembly if practical, if not long blocks from GM......Jegs has a full line of marine products. carbs, intakes, gaskets, etc......the goal is to build something I can service and repair going forward. I'm in fresh water so I want to go back to raw water cooling and get rid of the extra water pump and all the parts and hoses.

As you can see I'm still in the planning process and am having fun considering all options. I'd like to do this all for $10K or less, do you think that's possible or am I dreaming?????...............John

Sounds like you have the skills to do it, and I like your idea of simplifying things. I don't have the skill or experience to advise you on your budget.

I'd say since you're doing most of the work yourself that this budget should be more than enough. I would however, since you plan on keeping this boat for a while, consider going thru the transmissions as well since your there any way.

Crazy?

I would love to see photos of your engines I find TBFI as simple as it gets . And why do both engines If one is fine let it be . There seems to be the idea that you have to do both when doing one , as long as your not changing horspower there is no need .

Here is an option. 4 bolt main, base 350, 290hp.

http://www.marineenginesales.com/marine_engines.php

Good price.

aweimer wrote:Here is an option. 4 bolt main, base 350, 290hp.

http://www.summitracing.com/parts/NAL-12568758/

Good price.

From their site.

Notes This engine is designed as a stock replacement for 1987-1995 C/K-Series TBI trucks with 7,200 GVW (or lower) and VIN code K. This engine is not designed, nor intended to be used in any marine applications. Engines installed in vehicles registered and normally operated outside of the United States carry no warranty.