SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Brad @ SCJB on September 26, 2009, 01:42:02 PM
-
So Josh and I took the southwind out a few weekends ago and as soon as I got on it outside of the marina, it ran like shit. It was ok 1/2 throttle, but anything else it seemed like it was flooding out.
I flipped the engine cover and took the flame arrestor off and had him drive while I held on. As soon as the secondaries came on, it would start splashing gas back up out of the carb. not a lot, but enough to get me scratching my head.
We pulled up on shore and pulled a plug....entire electrode was gone. :sly:
[attachimg=1]
pulled all 8 plugs.....4 of the 8 were destroyed....3 on one side....1 on the other.....we're done. Had a yamaha jet boat tow us back to the ramp.
Called up Terry and he was stumped as well. Swung by his house to tear into it and find out wtf was going on. Did a compression test. I think 2 or 3 cylinders didnt check out. so we proceeded to pull the heads off.....found 1 chipped valve....thats it.
[attachimg=2]
I was pretty bummed about it. I parked the boat on the side of the house and threw the heads in the garage and thats where its sat since.
Jen's out of town this weekend so I decided to tear into it. Strapped on cash, I figured I would see if I can figure out how to do it on my own. I swung by Autozone and rented a spring compression tool and pulled the chipped valve to measure it so i can price out a new set....lap them in and be on my way......until i pulled the first valve.....big ol' crack between the valves. :banghead: :banghead: :banghead:
[attachimg=3]
and after close inspection.....3 of the 4 cylinders on this head have the same crack....and 1 of the 4 on the other head have the same crack. The crack above is the worst of the 4 cracks. the rest are all hairlines.
[attachimg=4]
this thing ran so bitchen when i took it from needles to havasu and back only 2-3 weeks before....wtf happened? :mad:
whats it going to take to fix these? they are bbc 454 990 heads. From what I understand (im not a chevy guy) these are great cast heads and are worth fixing. I was hoping for a cheap fix to get this back on the water, but it looks like my boating season fell short.
on a side note. this motor is unmolested. in its 30 years of use, this was the first time its been torn down. standard bore 454 hardin marine motor from the factory. it has just over 300 hours on it.
-
Did that motor ever get crazy hot? To get cracks that large inbetween the seats, something was smokin imo. Most of the time when cracks are inbetween the seats, theres not much you can do to fix them... some people weld, but I haven't seen it done successfully too many times. Usually you drill on each side of the crack, and insert a bolt, and have it cut off.... but in between the seats are tricky..... Every set of heads that I've dealt with that were cracked inbetween the seats, I've junked them.
Just my 2 cents.
-
"Possibly" might be able to install some new seats on the intake and exhaust side.... but that's probably going to be 400 bones just to get them straightened out.... I'm sure Engine Doctor would give you the yah or nah.... they don't look very saveable to me.
-
You could replace them with some 049's or even some 781's and i seriously doubt you will notice a difference...
990's are great if you spin it enough ;) I dont think you will with that heavy of a boat....
I have some 049's for $4500 ;D
-
Junk.
-
what do the pistons look like? big decision is do you rebuild or just do the top end :-\ ??? either way it sucks >:(
-
on second thought :-X put that damn ferd in it :thumbup:
-
on second thought :-X put that damn ferd in it :thumbup:
Yeah ford boy then sell me the big block
Minus heads of course ;D
-
Junk, and sell the LONG block to 2sav, he needs more projects to get his boat wet >:D >:D
-
Junk, and sell the LONG block to 2sav, he needs more projects to get his boat wet >:D >:D
Well i was thinking more of a short block... I have enough anchors now thanks...
Oh and it would not be going into my boat...
That project is finished ;D
-
Brad, It looks to me like that valve was not closing hard enough and got too hot. the valves need to get some seat time so to speak to cool off...That looks like an overtight valve problem.
I have a good set of cores that are closed chamber ovals, they need a guide repaired in one of heads but might match what you have...I gotta go check it out (I doubt they are 990's now that I think about it).
Lemmeknow :thumbup:
GT
-
Do you think the closed chamber heads will work with his pistons... If they are what i think they are ???
-
Do you think the closed chamber heads will work with his pistons... If they are what i think they are ???
Most likley going to be flattops, no? I can tell you what happens to a 454 with closed chamber heads on open chamber pistons, you get about 13.5:1 and they haul ass for about 15 mins. ;D
-
Most likley going to be flattops, no? I can tell you what happens to a 454 with closed chamber heads on open chamber pistons, you get about 13.5:1 and they haul ass for about 15 mins. ;D
Im probably wrong, but being a Hardin Marine engine... I say dome/pop ups with the 990's ;D
thats what was in mine :sly: but im probably way off O0
Edit: I just went through my pics and there not flat tops but nothing too crazy either.
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi223.photobucket.com%2Falbums%2Fdd269%2F2savage4you%2F004-72.jpg&hash=82b0264c549d613cac175ff0dea8345adcd34035)
-
in our volkswagen motors we just pull the seats out using heat and while the head is hot we weld it. then cut for new seats, heat up the heads and drop in new seats, do a valve job and thats it. some times we even run them with the crack but use a thicker seat, or bigger intake or bigger exhaust seats and they are fine. i would ask someone who does head work, im not a V-8 guy but that is what i think.
The Beav
-
in our volkswagen motors we just pull the seats out using heat and while the head is hot we weld it. then cut for new seats, heat up the heads and drop in new seats, do a valve job and thats it. some times we even run them with the crack but use a thicker seat, or bigger intake or bigger exhaust seats and they are fine. i would ask someone who does head work, im not a V-8 guy but that is what i think.
The Beav
I've seen that a couple times, but aluminum heads are much easier to repair than cast iron.
Once I sunk a valve job in a head a little too deep, and had a friend tig a bead all the way around the seat, sucka popped out with a screw driver. But I think the cost to replace the valves, cut for bigger OD seats, valve job, and repair of the head that is questionable on cast iron..... it would probably be cheaper to just get another set of assembled heads.
-
2 Sav did i read right that you have a pair of 049 heads for $4500 bucks? Or did i miss the joke. Matt
-
2 Sav did i read right that you have a pair of 049 heads for $4500 bucks? Or did i miss the joke. Matt
i think they come with a boat
-
A couple years a ago I ruined a single 990 head, I went to replace it, only to find they were discontinued :banghead:
-
2 Sav did i read right that you have a pair of 049 heads for $4500 bucks? Or did i miss the joke. Matt
No joke, heads are $4500
i think they come with a boat
Yep ::) ;D
-
781's $125
http://lasvegas.craigslist.org/pts/1387389420.html
-
pistons are pop-ups! heads are open chamber because of this! qand from my understanding brads intake being square port will not work with oval port heads...if i am correct an oval port intake will work with square ports heads but not visa versa! i have heard about heads being welded up and being just fine, but i guess you would half to find someone good! i would just keep my eyes peeled for another set of 990's! closed chambers arent going to work with them pistons, what we figure is the motor with the 990's was about 11:1 motor! also seeing the bottom end and pistons and cylinder walls they all look great! no scoring no nothing just smooth! i will do some research i think slapping another set of heads on this puppy will do the trick...honestly the motor screams in that puppy and i would put it back to how it ran before! nordic454's motor is very similar and it tacks at 5800! I wouldnt settle for anything other then what came off of the motor!
-
pistons are pop-ups! heads are open chamber because of this! qand from my understanding brads intake being square port will not work with oval port heads...if i am correct an oval port intake will work with square ports heads but not visa versa! i have heard about heads being welded up and being just fine, but i guess you would half to find someone good! i would just keep my eyes peeled for another set of 990's! closed chambers arent going to work with them pistons, what we figure is the motor with the 990's was about 11:1 motor! also seeing the bottom end and pistons and cylinder walls they all look great! no scoring no nothing just smooth! i will do some research i think slapping another set of heads on this puppy will do the trick...honestly the motor screams in that puppy and i would put it back to how it ran before! nordic454's motor is very similar and it tacks at 5800! I wouldnt settle for anything other then what came off of the motor!
You forgot! Some more of These!!!!!!!!!! !!!!!!!!!!!!! !!!!!!!!!!!!!!!
-
sorry hollywood text messaging has ruined me would you like me to edit in some more? oh well...also to answer your question when this occurance happened there was some heat introduced!
-
'or' maybe 'you' could 'use' some of 'these'
-
thought it was "these"
-
I like "these" just fine, ah-thank you!!!!!! ;D
-
ill make some calls brad...from my buddy in huntington beach...hes got a few sets of heads i think..!!