250 2v in my boat has exploded!!!

  • Thread starter Thread starter Anonymous
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Xdee: Good point, Horrible signature.

Okay i've done my research. Sounds like the XF EFI is the best one, i just need to convert it to carby.
Anyone know where i'd get a marine exhaust manifold for it or can point me in the right direction?
 
The exhaust manifolds are pretty hard to find secondhand. I had to buy mine new thru Rolco and was around $400 a couple of years ago. Go to www.luxfords.com . Also take into consideration your exhaust may need modification. My X-flow manifold exits the exhaust to the rear (engine front). Most IL 6 cylinder marine manifolds I've seen have the exhaust exit in the lower centre. If you do manage to find a secondhand one check the flange pattern fits the head you're using. All the later ones should have a multi-fit flange.
I'm not sure if the pre-xflow and x-flow oil pick-ups bolt to the same spot on the block/oil pump. I'm sure someone can help out here. The pick-up will match the sump so check that too.
Just a couple of things to think about.

BTW, what size/pitch prop do you run?
Joel
 
Take a good look at the crank snout - I don't know about marine 250's, but on the old Chris-Craft marinized auto engines (where the trans/clutch bolted to the "front" of the engine), they used to provide oil for the trans/clutch through a drilled passage in the crank, from the #1 main bearing. Then they used a drilled bolt at the end of the crank to hold the gears on.

An easy thing for a machine shop, but you gotta pull the crank.
 
I've been told that i can't use an EFI block because there's no place for the fuel pump to go... is that true?

I just rang luxfords... a new manifold is $544 !!!!! argh...
 
Also, joel, i don't know what pitch the prop is, i just bought the boat i didn't build it myself.
You say there are different exhaust flanges? Can you elaborate? Are the efi and the carby heads different or something? Or is it the difference between the Xflow and the precrossflow heads that you're talking about.
I don't want to spend an arm and a leg and get the wrong flipping manifold, haha!
 
chubs":41n0lkp8 said:
Also, joel, i don't know what pitch the prop is, i just bought the boat i didn't build it myself.
You say there are different exhaust flanges? Can you elaborate? Are the efi and the carby heads different or something? Or is it the difference between the Xflow and the precrossflow heads that you're talking about.
I don't want to spend an arm and a leg and get the wrong flipping manifold, haha!
Click to expand...
Theres bugger all differnce between the Alooy and iron head crossflows. The ports are differnet and the inlet manifols, the exhaust are the same from memory. Iron head are older then the Alloy and might be better if the boats get the heat going more then the on road applications.
There is a big differnce however between the PRE XFLOW and XFLOW heads and blocks. 2V heads are a limited edition head for the older PRE XFLOW blocks which are bout 1 1/2 inchs narrower then the XFLOWS.
Mounts etc are the same and rotating stuff too, well almost. The main differnce is the XFLOW has inlet passenger side and exhaust drivers side, PRE XFLOW both are on the drivers side, which is what you would have.
If your sump is for your current motor then its PRE XFLOW and youll just have to find a PRE X FLOW block and have the marine crank swapped over and fit your current sump and clutch and maybe freshen the valve seals,lifters,and springs/retainers. If you got the cash get a cam too and the timing set and it will run that bit smoother and the cam will help power over 3500RPM which you will love.
The clutch you have should fit a XFLOW engine with out too much trouble and expense.
OHH and these i6's love tripples set ups :twisted: Do it you know you wanna....Steve
 
The efi crossflow motors have a removeable cover where the carby fuel pump normally goes. But I have heard (if true or not) that the cam may not always have the lobe on it to work the pump - one of the gurus will know.
 
Reality time!

The boat has a maybe damaged motor. It may un-seize with a little TLC. It certainly seems to have had an issue that lead to this problem. Maybe something as simple as running massively lean or retarded.

When everything is set up to run a specific motor, when the damage to that motor is unquantified - why start talking about changing something so radically, to start with? :?

Surely, the first goal would be source a similar short motor in running order, open up the seized one when the two are side by side, assess the damage and go from there.

I really think that will get the boat back in the water again, faster.
 
Okay i'm getting conflicting opinions here.

Will a crossflow block bolt onto my marine sump, engine mounts, and dog clutch, or as TCSTEVE says, will i need a precrossflow block?
 
Very true Addo. I guess its always hard for us when we're trying to spend someone elses money. :wink:
But of course, they were only suggestions.
Good luck Chubs, hope you're back on the water with the minimum of headaches, and cost. And keep us updated.
Wagon, you are right. Most efi motors didn't have the cam lobe.
TCSTEVE, your memory deserted you this time. The exhaust manifolds have a totally different bolt pattern.


Stay golden.
 
The 250 blocks, pre- and crossflow, share the same mount bolt holes/positions.

The 250s all have the same crank, from my understanding. They also use the same bearing sets for mains and big ends.

You may need to compare gaskets to see if the sumps interchange. The timing set is the same; to me that suggests the sump width and bolts may match...

You can't swap head, intakes, exhaust manifolds between the two basic types. To add further constraints, the IRON head crossflows and the ALLOY head crossflows have different exhaust bolt patterns. Many cheaper extractor sets are flanged/drilled for both. I cannot speak for a marine exhaust manifold.

This kind of stuff I urge people to stay focused on; get it going again while you consider your options. Which is better - being in the boat thinking it through over a few weekends, or sitting in the shed cursing something that threatens to go over your head or budget in the short term, and doesn't motor? Maybe we can help later with a planned swap to crossflow or OHC. BA XR6T motor in a boat? :twisted:

Cheers, Adam.
 
Well, first up i'm going to whip the head off this weekend.

Start from the outside bolts, and work my way diagonally inwards, a quarter turn at a time, to prevent warping, so i've read.

And after that, we'll see. If the head is screwed, time for a alloyhead crossflow transplant. If the head is OK, then i'll just swap the block over with a carby crossflow.
 
chubs":3ooojrok said:
Well, first up i'm going to whip the head off this weekend.

Start from the outside bolts, and work my way diagonally inwards, a quarter turn at a time, to prevent warping, so i've read.

And after that, we'll see. If the head is screwed, time for a alloyhead crossflow transplant. If the head is OK, then i'll just swap the block over with a carby crossflow.
Click to expand...

Yeah but if the heads ok you wont be able to use the carby crossflow block the head is to suit a pre Xflow block. The sump will come close between the blocks but if you swap the block you need the head that comes with it and a new boat exhaust manifold to suit.
Does your head have the exhaust and inlet on the 'drivers' side of the motor and is the inlet manifold removeable?
Everyone has different ideas and opinions and we all would love an i6 boat right :D
Read through it all and get prices to help make the decisions to get her back on the water, probally starting with whats wrong with her now
Good luck Steve
 
TCSTEVE":kv3xbp5p said:
Yeah but if the heads ok you wont be able to use the carby crossflow block the head is to suit a pre Xflow block. The sump will come close between the blocks but if you swap the block you need the head that comes with it and a new boat exhaust manifold to suit.
Does your head have the exhaust and inlet on the 'drivers' side of the motor and is the inlet manifold removeable?
Click to expand...

So...... i *can't* put the head on a x-flow block now? Some people tell me i can, some people tell me i can't... does anyone have any hard facts?

and yes, tcsteve, i *do* have a 250 2v head, i' ve done my research. It is non-crossflow, and it does have a removable alloy intake manifold.

Anyway, i took the head off on the weekend. Found some blown out holes in the block and the sump. Two pushrods have vanished, and looking down i couldn't find their lifters either. The head looks to be perfectly fine though, so i'm in luck!!!

One thing though, if i choose to go down the crossflow conversion path, how much could i expect to sell the head for? If they are worth a bit, it might be worth making the change.

Anyone want to see photos?
 
A used 2V head and manifold will fetch from $200 to $450.

The crossflow and pre-crossflow blocks and heads do NOT interchange.
 
addo - you're the man. Thanks.
Looks like i'll be sticking to the pre-crossflow in that case.
 
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