Finally!!!, but it bust loose on me

[jbj]

first you should consider a bbc. if you stay with the 455 then u need a high volume oil pump w/at least an 8 qt pan. olds is hard on the bottom end so u need more oil there,as for cam crane & comp have good selections for marine use. it has been my exp with used motors i was buying someones problems &junk.

[572Daytona]

5200rpm sounds high for an Olds engine unless it was specially built for it. At high rpms the Olds have a bad habit of leaving all of the oil in the the top end of the engine with usually a bad effect on the bottom end. You didn't say what impeller you have but if you are getting 5200 with an A your pump may need rebuilding as well. I have a '76 Tahiti with a 12JC with an A impeller with a slightly modified Olds (edelbrock intake and carb, electronic ignition) and get 64mph GPS at about 4700rpm.
There a things that can be done to the Olds to improve oiling (Bigger oil pan, restrictors in pan) but even so I would still try to avoid extended high rpm runs. Putting in a BBC is also a solution but can be pricey since you need to replace the exhaust, motor mounts, bellhousing, etc. Depending on how much you are in love with the boat and what shape it is in, it may not make sense financially. I debated for years about doing this for the Tahiti and finally decided just to leave it alone and saved until I could afford my Daytona 21 with a BBC.

[Hallett of a Dream]

Actually, the boat is in beautiful shape, just a handfull (honestly) of scratches on the hull from being beached or the occasional "missing the trailer with too much speed and not enough steerability" scratch. I may be guilty to one or 2 of those, but other than that and a new clear coat, she is perfect.
I now know of the Olds oiling probs which is why I am getting the $500 Mondello 10qt and restrictor system, but I think the biggest problem I had was letting my wife and her girlfriend take it for a run when it was only 2 days old (to me) and hearing it come around the corner. I figured it sounded a little high on the revs side which might have starved the oil pan and burnt the bearings.

[572Daytona]

Sounds nice...from what I understand the Hallet were very well built hulls it is probably worth spending the $$$ to fix her up. I still think it may be worth your while to have a pro look at your pump. With a good rebuild you can make the same or better speed with less RPM which would help you with both engine life and fuel economy

[bajaruner]

Stop now while your ahead. Although it my seem like a little more time and money today, In the big sceme of things if your going to keep your boat, and want to enjoy it, loose the OLDS.. While you can make the OLDS work, it's just not worth all the money spent only to still hope it lives, and although it's all built-up the engine still won't out live or out perform a well built Chevy or Ford of the same caliber....

[Bubbledeck2]

572Daytona what type of Tahiti do you have?
Mine is a 76 also .. just bought a GPS today and hope to get to the lake Monday and see how fast I really go. Mine is a stock 460 with a JC and according to my tach I'm spinning 4400rpm
Hallett as for the Olds, I don't know what to say .. some guys swear by them. Personally I have a problem with a motor that you have to spend money on to fix a design flaw. I'd go with a Ford or a Chevy .. in fact when I went boat shopping I'd already made my mind up that an Olds was not on my list. I'd check around to see what all the marine goodies are gonna cost you before you go swapping motors though. It may be cheaper to fix the Olds and hang with it. I just saw a complete set up for sale in the local paper here .. $1650 for a 460 Ford with a JC pump. I have no idea what kind of shape it was in, but that may give you some idea what it costs. Hope this helps.

[572Daytona]

Originally posted by Bubbledeck2:
572Daytona what type of Tahiti do you have?[/
The model is a Super Tiger it is a low profile semi-v hull. Here is a picture that I just took, it needs an interior badly:
http://www.sammythieme.com/images/dscn0552.jpg
[QUOTE]Originally posted by Bubbledeck2:
Hallett as for the Olds, I don't know what to say .. some guys swear by them. Personally I have a problem with a motor that you have to spend money on to fix a design flaw.
I don't know that I would consider it a design flaw since the 455 Olds weren't designed to spin 5000rpm for extended periods of time. I still have the stock pan on my Olds and I've never spun a bearing. Again though I only turn 4700 max and am real careful not to run max rpm for extended periods of time.

[Bubbledeck2]

572 Daytona outside of the seating arrangement and mine being a bubbledeck, the lines on your boat and mine are very similar. Someone told me mine was called a "Thunder Tiger", but I don't know that it is for sure.
Have you replaced the control cables in yours yet? I just did mine and it was fun .. not

[wsm9808]

The olds is a strong reliable engine if used within its limits. The heads only have one small oil drain back hole on each end and at high RPM (over 4500) the oil pumped to the top end can not return quick enough and the bearings get starved for oil, and well, you know the rest. Bigger oil pans and restricters in the oil passages are a popular bandaid and do help, (I personaly don't recomend restricters), but if you want your olds to live a long happy life, limit your high RPM bursts to about 20 to 30 seconds at a time and drop your cruising RPM to less than 4000. I own an engine machine shop and have machined dozens of olds motors over the years for "new" jet boat owners, most with stories just like yours on their first weekend at the lake.
A car motor will work fine, but will not be optomized for marine use. The marine cams are a little more agressive than the cars and if you bore your block be absolutely sure you have .001 to.002 extra clearance on your piston to cylinder wall clearance than a car engine. the cold lake water running through the block will not let the cly walls expand at the same rate as in a car and will gall and ruin a new set of pistons in a matter of seconds. Good luck, and enjoy your new adiction....ooops, I mean boat.

[058]

Olds engines are also prone to detonation due to a combustion chamber design that has very little quench area, almost like an open chamber design. Inaudible detonation will pound at the rod bearings like a ball-peen hammer on a piece of steel curling the bearing ends which in turn will scrape oil off the journal- result: spun rod bearing. If the compresson is kept to about 8-8.5 to 1 the engine can give excellent service for years.