2004 250 Project Thread

[slideruleracer]

Hey folks,

I introduced myself some time ago in the intro forum but have been remiss in posting an update. Mostly because I've still really only made progress on the engine... so, I won't have many pictures of the boat yet, but I have lots of pics of the engine work.

To recap - we bought this boat from an older couple that lived in Chesapeake bay. It was exactly the exterior colors we wanted and was in generally good shape on the surface. The gel coat was in good shape and other than a few minor issues with vinyl, the interior was also pretty good. The cover had taken a beating from an Osprey nest near their dock, but after a test ride, I was sold. They brokered the boat through the Cobalt dealer in the area and apparently this salesman had sold the boat twice already. When I bought it, it made it 3 times. The owners and salesman agreed to let me do a compression check when I flew down to test drive it and other than 1 cylinder (#8) which was around 150, all the other cylinders were good - between 165 and 170. Needless to say, he didn't have many customers that flew in on a day trip to check out a used boat bringing a little tool kit to check compression!

I drove back down with my father that weekend on a trailer I had just bought (that's another 'exciting' story) and we brought the boat back to MA the next day. After some cleaning up - which included pressure washing and soaking the poop covered canvas, we were in business. I brought the boat to Lake Winnipesaukee 2 days later and we used the boat for the rest of the summer.

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While we used the boat for the next 1.5 months, I made my wish list of things to upgrade - it was some typical stuff - stereo, sunpad cushions (after a cold night, my oldest stepped onto it from the dock and managed to put a good crack in the vinyl - apparently in the warmer climate of Delaware kept it pliable a little longer), carpet, swim platform Seadek - as well as some maintenance items and hop ups (like a grill).

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[AsLan7]

Yes..we missed you posting SRR. Thank you for those pics.
Feel free to post those engine pics as well. We'll take any we can get.

And document those upgrades with pics too!

.

[slideruleracer]

After bringing it back to MA for the winter, I wanted to get started with my project goals. One of the first was to replace the risers and manifolds.

When I did the engine compression checks, one of the things I noticed was a decent amount of rust around the exterior of the engine. It made me a little concerned about the maintenance of the exhaust components. Chesapeake Bay - where they were, right at the bridge - is brackish, I guess. But the lack of any washdown equipment on their dock made me concerned and I negotiated a set of exhaust components at dealer cost when I bought the boat - my plan being to replace them at the end of the season.

The risers came off easy enough. However, the exhaust manifolds became a bit of a headache. I managed to bust about 8 exhaust bolts. I say bolts, because it became clear that they had been replaced at some point, but the studs/bolts were not replaced with factory hardware. They used some cheap hardware and stacked a bunch of washers to try to make it fit.

After breaking them off, I removed the manifolds and started trying to remove the broken bolts/studs. I got all but 2 of them out while working in the bilge, but the last 2 were broken right at the head. Unfortunately, when I decided to try to remove the head, I found that 2 of the head bolts were corroded beyond recognition and I was not fond of trying to drill them out while in the boat and then reassembling the engine with possible contamination. So, I worked with a local shop to pull the engine for me and put it onto my utility trailer. I got the engine home and got to work.

[slideruleracer]

Here's what it looked like before getting into the insides:

[slideruleracer]

I sharpened a few drill bits and got to work. I was able to remove all the bolts except those 2. Once I drilled the heads back enough, I removed the heads andgot them off with a pipe wrench.

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With the heads off, I could now check out the rest of the engine. Honestly, at this point, my plan was still to just replace the head bolts and put it all back together after vacuuming out the cylinders.. But I found a little bit of pitting in the cylinders and a sh*t-ton of rust-scale-crud in the water jackets.

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[slideruleracer]

I tipped the block over and used a screw driver to loosen and drop some of the scale out of the water jacket. This was the first pass.

[slideruleracer]

Over the next few weeks, I didn't really rush much. I disassembled the entire motor, carefully labeling and packing away each part and bolt. I used a needle scaler and a wire wheel on my grinder to clean up the block and continued to scrape the water jackets clean.

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I also picked up a cheap blasting cabinet so I could bead blast a bunch of the exterior parts.

[slideruleracer]

After getting the block as cleaned up as I could, I worked with a not-too-local engine shop who bored the block out for the new pistons (.030 over), balanced the rotating assembly, swapped the pistons on the roads (my year had the pressed wrist pins, so I decided to let them do it), polished the crank and reassembled the new cam bearings.

After I got the block back with all of my bearings, rings, pistons/rods, and crank, I started the reassembly process.

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[slideruleracer]

I finished cleaning up and repainting some of the most offensive engine accessories.

[slideruleracer]

And then I finally got to the day where I repainted the block!

[slideruleracer]

The last couple of weeks I finished reassembling the rest of the engine.

I drilled and tapped the engine block drain plugs so that I could use the blue plastic drain plugs during the winterization process to drain water from the block.

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I also discovered that the NOS black valve covers I bought ($30 ea on Ebay) which I thought was a great deal (it was practically cheaper than buying just a gasket set) turned out to be from one of the original block models. In the earliest 8.1 motors, they used different coils with smaller mounting spacings. So, my coils wouldn't fit quite right. Good thing I have a CNC bridgeport!

Instead of trying to cleanup and repaint the old covers, I designed and machined up some adapter brackets.

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[slideruleracer]

It made some of the fit of the wiring a little different than OEM, but they look like they belong there. And I'm digging the black valve covers.

[slideruleracer]

And I installed the hot water outlet kit so I can connect up the heater that I intend to install this spring.

[jhnmdahl]

Amazing project - thanks for the updates!

[slideruleracer]

Oh, I forgot to mention some of the most exciting parts!

I also found a seller on ebay selling off a bunch of NOS cams from the Gxi engines. So, I bought one - of course! I also sent the intake out and had the large restriction just behind the throttle body ported out - now I can stick my entire hand all the way in. Raylar suggests it's good for another 20 HP, so we'll see.

Unfortunately (or fortunately?) the only 2 differences between the Gi and Gxi motors are the cam and the ECU tuning. So, I needed a way to change the ECU tuning. The local dealer said they could do it if I could get them an engine serial #, but it would be at least $750. I could buy a new ECU for about $1000. So, instead, I bought MEFIBurn software. They sent me the stock tuning files for the Gi and Gxi engines and now I can adjust the tune for the intake changes if needed. I'm trying to decide if I should install a wideband O2 sensor to monitor the AFR... we'll see.

As of right now, I've connected a fuel tank and checked that I get the correct fuel pressure without any obvious leaks, and reprogrammed the ECU. All that's left is to hook up a hose and try to fire it up in the driveway...Hopefully it all goes OK!

In summary, nearly every part that could wear on the engine has been replaced with new, as well as some that don't normally wear (like the thermostat housing casting).

I only have 1 part left to install on the engine.. to be disclosed later.