460 issues

« **on:** June 15, 2007, 12:22:52 PM »

Ive got a 460 with a jaccuzi jet, in my 24 foot hawaiian. I recently found water in the oil, so im assuming I blew a head gasket, I did compression check and found that 4 of the cylinders have only 10 psi compression and the others are 50,60,80,and 90. The bad cylinders are are on both banks, so I figure I have another issue, possibly rings or could the heads be tweaked? And it has been spewing oil out the dipstick tube also, so I think it is rings. I havent had the boat very long in it is my first jet, and dont know what to expect. should i rebuild the engine or try replacing the heads?

« **Reply #1 on:** June 15, 2007, 12:54:29 PM »

Quote from: azhwn on June 15, 2007, 12:22:52 PM

Ive got a 460 with a jaccuzi jet, in my 24 foot hawaiian. I recently found water in the oil, so im assuming I blew a head gasket, I did compression check and found that 4 of the cylinders have only 10 psi compression and the others are 50,60,80,and 90. The bad cylinders are are on both banks, so I figure I have another issue, possibly rings or could the heads be tweaked? And it has been spewing oil out the dipstick tube also, so I think it is rings. I havent had the boat very long in it is my first jet, and dont know what to expect. should i rebuild the engine or try replacing the heads?

You say bad on both sides, but you dont clarify what cyl have 10 psi, but none the less their all low.
get a leak down tester and do that, because that will tell you if the leak is on the top or bottom end.

oil out dipstick do you have your valve covers vented? how much oil is in the engine when it comes out the dipstick? how much water is in the oil? what kind of exhaust do you have?

« **Reply #2 on:** June 15, 2007, 02:24:18 PM »

Quote from: rwyyattb on June 15, 2007, 12:54:29 PM

You say bad on both sides, but you dont clarify what cyl have 10 psi, but none the less their all low.
get a leak down tester and do that, because that will tell you if the leak is on the top or bottom end.

oil out dipstick do you have your valve covers vented? how much oil is in the engine when it comes out the dipstick? how much water is in the oil? what kind of exhaust do you have?

the test went 1-10,2-80,3-90,4-20,5-10,6-30,7-70,8-10
yeah both valve covers are vented, it has an eleven quart oil pan with a windage tray and at that time the oil was slighlty low, everything was mikshaky, it is a standard hardin transom exhaust.

« **Reply #3 on:** June 15, 2007, 07:45:27 PM »

Quote from: azhwn on June 15, 2007, 02:24:18 PM

the test went 1-10,2-80,3-90,4-20,5-10,6-30,7-70,8-10
yeah both valve covers are vented, it has an eleven quart oil pan with a windage tray and at that time the oil was slighlty low, everything was mikshaky, it is a standard hardin transom exhaust.

well my concern is that its just condensation if the oil level has not risen. still doesnt explian the low comp squirt some oil down the cyl and retest to see if it comes up. did the engine run bad as in missing that would mean the head gasket was blown bad. or just get a leak down tester.
i am limited on knowledge so you might want to try the 460 forum 460ford.com

« **Reply #4 on:** June 15, 2007, 07:53:26 PM »

Leak down might help determine what happened but with compression like that the engine should be torn down & inspected.

« **Reply #5 on:** June 17, 2007, 01:15:17 PM »

thanks,
I torn it down and found that the head gasket is defanitly blown and had been before we got it. So looks like it will need a rebuild, I have access to a rebuilt 460 with an rv cam bored 30 over built for a truck estimated at 490 hp and 580 torque, any thoughts on using an automotive engine in my jet boat?

« **Reply #6 on:** June 17, 2007, 02:47:03 PM »

I don't know that there is much difference in the block, crank and head castings but the rods, pistons and valve train should be good quality and well balanced. A well build truck engine will last a long time running below 3000rpm all the time, but put it into a boat that is running 3000-5000rpm all the time it may not survive long.
If nothing else, get it and build it up to what you need.

« **Reply #7 on:** June 18, 2007, 10:39:34 AM »

If it isn't a fresh rebuild it might be ok. Once the engine has time to wear out a little the clearances will be a little greater and closer to what you want in a high rpm engine. I'd be happy to "break it in" for you in the old Bronco I bought this weekend for off road fun

« **Reply #8 on:** August 04, 2007, 11:35:42 PM »

chaz, what do i look for in ford 460. i have 2 to rebuild both have dove blocks what head numbers should i look for?

??

« **Reply #9 on:** August 05, 2007, 01:07:29 AM »

not chaz, but this explains the casting numbers for the 460 heads.

http://reincarnation-automotive.com/casting-numbers-descriptions-1-index.html

« **Reply #10 on:** August 05, 2007, 02:07:36 AM »

What Ralph was trying to say is that all of your cylinders are reading low

What everyone else is saying is you need a new engine, or at least rebuild what you got...

You do not want to use a fresh rebuld truck engine in your jet boat, cylinder temparetures are too high and you will smoke those fresh cylinders shortly...

« **Reply #11 on:** August 11, 2007, 09:43:55 PM »

What kind of water regulation do you have comming from the Jet pump to the motor? When I got my boat it had no regulator in between the two and would instantly get water in the motor, so I changed head and intake gaskets. Put a ball valve in there and solved my problem. Just something to check out

azhwn

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