Thread: newbie bbc owner in jetboat

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I'll mix a little thought for you---

Change the springs( In a jet boat engines are easy to work on) now and run it for the month then take it down over the winter---I have seen engines in jet boats hammer all the valves up into the ports so bad from heat/detonation from pulling all that power/load at lower rpms---the loose springs could be a sign of that

And I do BBC, BBF and others also!!!!!

We started going strictly to stainless steel valves because even on heads that we had rebuilt we were seeing short life with regular valves. They were pulling into the heads. It added about $ 10 per valve to the cost, but we never had another comeback after doing that. Boats are just a totally different animal than cars, even though they are using essentially production line car engines in most cases.

Don

Do these look about right?
http://www.summitracing.com/parts/HR...n/?prefilter=1

yes the 98515 spring and i concur with my esteemed colleague . MR J Clayton . yes boats are not USED the same as car engines . boats are hard on Valve train . i wish i could say i did not know not one thing about boats.... BUT i work at a boat yard one of the biggest in mich over two miles long.. EZ 6 boats a day i work on from 17 foot to very big $$$. even lot of the cheap valves are a mix of alloys some what S steel the new Sbc are very thin from chevy new and most of the time the stock intake valve can not be re ground less you need a new blade to shave your face with. they sure will pull threw the head but if the springs are weak the best valve can go to cup

ok so I am really confused now.........
I did some research and reading and come to find out that I have rotators on the exhaust springs side.... Do I ditch these or run them again? Do you ditch the rotators and run the antirotator with the springs previously mentioned in the earlier post?
Also, how do I figure out what correct spring rate I need or is that not critical in my case? If someone could direct me to the correct part, Id really appreciate it.

THEM ARE STOCK SPRING S you have a stock cam ? use them just put them in .. . if your going to put a better spring in more for hi rpm them you would ditch the EX rotator eliminators how you want to do it thats up to you if your pulling the heads at the end of the year then that is time for the upgrade

What you are trying to do is just get a little more time out of the engine before you need to pull the heads and do it correctly. At that time you can decide what upgrades you will make, but for now just buy some springs like the ones you are looking at and put those in. I would just put them back the way they were installed originally to avoid any hassles. When I worked in the marine business we sometimes had to do things to buy a customer a little more time, until they could simply get no more use out of the old setup, then it was time to break out the checkbook.

You might consider just buying a set of something like World Product heads down the road as the cost of doing a good valve job with related upgrades comes pretty close and most times the aftermarket heads are superior in flow and performance. They also usually come setup for roller rockers.

Pat may have a different take on doing that, and he would know best.

Don

the heads you have are good heads the world O ports are very very heavy i not sure i would be to fast on the gun to ditch the old head casting i do not know what shop rate is like were you are so thats your call on new casting .if fresh water engine alum heads would be a good move loose some pounds and get a better head . it all money so ?

Are the World Products heads heavier than the originals, Pat?

Don

Originally Posted by Itoldyouso

Are the World Products heads heavier than the originals, Pat?

Don

yes very much so there O port heads is one casting mold for there O port and rect port heads so the roof is about 3/4 thick iron on the O port head so this and the head has more iron over all makes for a very heavy head. were gm has two casting molds and the ports are much thinner on the roof of the ports, there is other things i have seen that i will not post on here so if you want to know more you will have to pm me

Hey thanks for the advise everyone. Yeah i went ahead and just did the quicky setup with new springs and all is good so far.
What heads would be a choice? Im looking to go aluminum?
Im leaning to just go up to a 496ci with a single holley.
Other choice that I like is to run a small blower. Ive got a buddy thats running one and it runs pretty strong. I think that if I get around 600hp I will like the outcome. Looks like I could build something that strong without too much expense.