New engines or rebuilts?

majoma

Member
Oct 10, 2008
284
San Francisco
Boat Info
2000 340, V drive
Engines
Twin 7.4
On my 2000 Sea Ray 340 I have two original 7.4s with about 1000 hours each. I really like the boat but I am considering either new engines or have them rebuilt. I would appreciate any comments from member who already went through this dilemma and, if possible, what type of cost I should expect. Thank you.
 
Well if there FWC motors you have at least another thousand hours left
 
IMG_2098.JPG
Why did you ask the question? Using lots of oil? Poor power and high fuel consumption? 454s are very robust engines.
 
I have a 1995 330 with 1400 hours on my 454s. I plan on them lasting much longer
 
One of my 454 Horizons made it to 3500 Hours before it needed to be rebuilt. The other is still going strong at 3700 hours. 1000 hours is nothing if they were taken care of....
 
Those puppies are just broken in. What's the issue?
 
Why replace? I'd like to know also. Maybe he has weekends off..lol
 
Thanks for your comments. The reason is that when I reach around 2,000 rpm they start making strange loud noises which the mechanic thinks is either the valves or the pistons and he recommends a rebuilt. I have the new raisers and elbows so it should not be water ingestion issue.
Maybe I should change mechanic.
 
At least get a compression and leak down test. This will tell you if you have a bottom end issue or a top end issue.
 
I agree with West32 and Douglee. In fact, I wouldn’t even think of pulling a motor out with out doing a compression and leak down first.

When was the last time you changed plugs, wires, cap and the rotor? Can you reach your WOT RPM? Are the operating temps normal and how about oil pressure?
 
I agree with West32 and Douglee. In fact, I wouldn’t even think of pulling a motor out with out doing a compression and leak down first.

When was the last time you changed plugs, wires, cap and the rotor? Can you reach your WOT RPM? Are the operating temps normal and how about oil pressure?

Water temperature is normal and stable at 170 deg. but the oil pressure starts at 40 psi and goes down to 20 psi after about 20 minutes. I am afraid to go to WOT. The compression was checked last year and was fine at all cylinders at around 180. Now I don't like that tapping sound. Something is not right.
 
IMG_2098.JPG
My 7.4s used to show the variations in oil pressure you describe. I always assumed it was the guage on the dash or the sending unit that was a little off. Boat did it when it was new and never changed during my ten years of ownership. I even heard a little tappet noise at times. The tech adjusted the lifters on one engine and the double nutted one which seemed t make the issue disappear. Those engines never failed to start, use oil or show other signs of wear. I used to run them at WOT each spring for a minute or so and prior to laying the boat up in the fall. 454s are very robust.
 

Forum statistics

Threads
112,950
Messages
1,422,878
Members
60,932
Latest member
juliediane
Back
Top