Go Back  Offshoreonly.com > Technical > General Q & A
Rebuilding top end of 2000 7.4 MPI - a little help please >

Rebuilding top end of 2000 7.4 MPI - a little help please

Like Tree0Likes

Rebuilding top end of 2000 7.4 MPI - a little help please

Reply

Old 06-03-2008, 07:25 PM
  #1
Registered
Thread Starter
 
Join Date: Mar 2006
Location: New York, NY
My Boat: 2000 Checkmate 259 Convincer
Posts: 104
Default Rebuilding top end of 2000 7.4 MPI - a little help please

So I am sure some of you have seen my posts about the rotting exhuast manifolds and the crumbling heads.

Looks Like I gotta do the whole top end and I have a few questions if anyone cares to help out.

I am going to replace Heads, Exhuast manifolds and considering popping in a cam while I am in there. Of course I will replace the timing chain as well.

Re - Heads: Should I just get a set of stock heads? I have spoken to a couple of people who post here and I can probabaly get a nice set pretty cheaply. Am I correct in assuming I have to get the old heads off and get the casting number before I can order the new ones?

Re - Cam: Whats a good drop in that might give me a little more bite without running the danger of sucking water.

Re - Exhaust Manifolds - I am looking at a set of Eddie Marine... they are aluminum with stainless risers... supposedly breath really well and will drop right in with my stock captains choice.

I am just looking for some quick pointers as I have done this type of rebuild on a car but never on a boat... ultimately it all seems pretty similar but I do not want to get too crazy and then have a pig that I cannot rely on. I use this boat pretty heacy all season and like to go on some really long trips.

Any insight will greatly appreciated....

Thanks.

Brian
Plaineman is offline  
Reply With Quote
Old 06-03-2008, 07:50 PM
  #2
Registered
 
jayhawk261's Avatar
 
Join Date: Jul 2005
Location: Tulsa, OK
My Boat: 2000 Superboat 24 Step Bottom - Fresh 501
Posts: 1,729
Default

I would think you'd have to pull the engine in order to change the cam. I can't imagine you have enough room between the front of the engine and the front of the engine compartment to get the cam out.

My opinion, for what it's worth, the bottom end won't cost that much more to do. You're already doing the most expensive part in a set of heads. If I remember correctly, this has 950+ hours on it? If it's apart, at all, do it all and be done with it. I know it can be a strain on the wallet. I did my 800 hour 454 Mag MPI last fall because I needed to replace the gimbal ring. I certainly didn't want to pay to have the engine R&R'd twice for when it was time to do the engine. Yeah, I spent money I didn't really have to at the time, but it sure beat wasting money doing the R&R twice and possibly having my known high hour engine finally give it up in the middle of the lake. Just my $.02.

As far as parts suggestion, if you're going to stick with the 7.4 fuel injection and the cast internals, I wouldn't spend money on any high dollar heads. I'd find a set from a shop that have been freshwater heads and have a fresh rebuild on them. No sense in buying new if you can get a good set of used castings with all new parts.
jayhawk261 is offline  
Reply With Quote
Old 06-03-2008, 09:42 PM
  #3
Registered User
 
Join Date: Oct 2003
Posts: 9,495
Default

The heads aren't going to be that critical. You have to choose between oval port and rectangular. Personally, if you're goingt o go with a warmer but still mild cam, I'd stay with the ovals. Have a good 3-angle valve job done on them and be done with it. I would absolutely spring for stainless steel valves. Look for heads on Ebay- I see them all the time. Or, place a "wanted" on here. Lots of guys upgrade from the ovals. You can also check the classifieds on Boatfreals and Speedwake- alot of the guys from here sell their stuff over there.

On the bottom end- if you're pulling the motor to stick a cam in it, you really should have the bottom end done. If the crank doesn't need turning, you're looking at about $200 in boring. A good set of pistons with rings is going to run you $500 and bearings, gaskets and a new oil pump another $300. You might as well replace the stock rod bolts and resize the rods- another $150. That's going to be better than blowing it up in the first few hours with that new warmer cam.
Chris Sunkin is offline  
Reply With Quote
Old 06-03-2008, 11:57 PM
  #4
Registered
Thread Starter
 
Join Date: Mar 2006
Location: New York, NY
My Boat: 2000 Checkmate 259 Convincer
Posts: 104
Default

So I have thought about this for a while today...

You guys are totally right about just doing the whole enchilada but I am comparing prices here and I think that I am going to be so much better off just finding myself a nice reman. 502 and putting a solid powerplant in place. Seems so much more practical to me to buck up the extra G or two and upgrade. Besides... what's the old addage... there's no replacement for displacement. Of course the forged crank and the 4 bolt mains are a big help as well.

Anyway... I have been checking the numbers all day long and it looks like this is going to have to wait til next year. I do think that I am going to take a shot at just a new set of cheap manifolds and see if I can't get a couple of months of bouncing around the bay out of this thing without casatrophic failure.

All I gotta do is get those busted bolts out of the head... any quick tips on the easiest way to do that???

I do appreciate anyone who takes the time to answer in these posts.

Thanks...

Brian
Plaineman is offline  
Reply With Quote
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Ran-Dom 32
Swap Shop
25
05-06-2011 11:10 AM
Plaineman
Wanted
1
06-04-2008 11:21 AM
29scarab
General Q & A
8
06-29-2005 01:25 PM
pullmytrigger
Fountain
1
04-28-2005 09:06 AM
sonic7175
General Q & A
2
08-08-2004 08:56 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Quick Reply: Rebuilding top end of 2000 7.4 MPI - a little help please


OSO Sponsor
OSO Advertiser
OSO Advertiser
OSO Advertiser