Lean, or excessively retarded timing will do it too.

What would be excessively retarded? I had it at 32-34* all in. I want to say it was 34 but might have went 32.

That's not excessive.

Oil therm , block bypass to therm housing, take valve out of thermostat , #10 lines,big coolers , transom water pick ups
New strainers, bravo pumps, keep block pressure 25 psi or less. Let er rip

I run 34 degrees timing and a conservative 650

Is that supercharged or NA?

Cause of engine damage has been discovered. When I brought the heads in, my guy said the motor went lean. The beating the bearings took also suggested the motor went lean and detonated. Well Here my friends is the answer. The most expensive vacuum cap ever!!
http://i880.photobucket.com/albums/a...IMG_2334_1.jpg

No pun intended but.... THAT SUCKS!!

Ouch!

Yup. I put new head gaskets in the motor 50hours ago. The motor looked good inside at that time. I only pulled the motor to switch to inconel valves. I wonder how long I had been running like that.

That totally sucks - are you doing the rebuild or a shop?

Ryan

That's a good argument for keeping a wideband hooked up all the time.

Anybody running this unit from Innovative DLG-1: Dual Lambda (AFR) Gauge Kit - If so do you like it?

Steve Auto and Machine in LittleValley NY is building the shortblock. Just got my heads reconditioned. $800 for heads re-done with manley Extreme Duty valves.

The build so far:

Block decked, line honed with ARP main bolts, and bored .060 over
New Melling 10778 HV pump
Stock crank had to be turned .010/.010.
Stock rods rebuilt with ARP bolts.
New L2399 pistons.
New Crane 134561 cam and lifters.
Heads received all new seats.
New Manley Severe duty 2.19 intake valves.
New Manley Xtreme Duty 1.88 exhaust valves.
Oil cooler, hoses, and filter mount from HP500.
Mercruiser 525sc Blower, carb, and intake manifold.
DUI distributor.

It should all be assembled in the next few weeks. I am also paying the money to have it broke in on the dyno and tuned on the dyno. Ill post pics and videos as I get them. I hope my 242 runs 75.

Money well spent on the dyno! Keep up the progress!

Since Steve is building the motor, he quoted me $300 to throw it on the dyno and tune it. I felt that the $300 was the smartest money spent on the whole build.

Did this boat come from Massachusetts?

The boat was put together by 86242ls in Illinois, then sold to Shekmark in NJ. I drove to jersey to get it. It was nowhere near as clean as when 86242ls had it when I got it. 2yrs in the salt cost me a few grand to get it back up to snuff.

http://i880.photobucket.com/albums/a...59540007_o.jpg
http://i880.photobucket.com/albums/a...55522934_o.jpg

The heads should be done next week. The rotating assembly got balanced today. Shortblock gets assembled next week. Cant wait for summer!

Sounds like a fun engine for your 242. I used to have an '87 242 LS with 530 +/- hp and it would run 68 MPH gps. The 242 is a great riding boat for its size mainly due to its weight, because of this, it takes a ton of power to make them go fast. I ran a Mirage Plus prop that was 21 pitch at 6100 rpms,

I wonder what I'll actually get with 600hp. The previous owner claimed 78mph with 630hp. We shall see!

I'd say you should be close to 75 mph. Honestly I don't think I would want to go much faster that that in a 242.

At 63 mph mine felt like it was running out of hull and chine walked really bad. It might have improved with 280's rather than the small bennet tabs.

The previous owner had a 630hp in my boat and got 78mph. He flat out said it was a death trap. As soon as I bought the boat I replaced the transom as it was rotted. I also replaced the transom assembly as the one on the boat was super sloppy. The boat rides nice and straight at 60 mph. Lets hope it does well as speeds increase.

Keep us posted on progress !

Current status: Shortblock is complete. Heads are still out being rebuilt. Blower is good to go. I picked up a HP500 oil system.

The only unknown at this point: Fuel lines- I got a nice Earls -8an fuel line on the carb so I need to get the line from the pump to carb. I have never dealt with AN stuff before.

I am hoping to get it on the dyno in february.

Well its been a while since I have updated.

The build is as follows:

Stock forged crank. Reconditioned forged rods with ARP bolts. Melling HV oil pump. TRW 2399 pistons .060 over. The heads I got are stock HP500 Carb heads. They have Manley Severe Duty intakes with inconel exhaust valves. I used a crane 134561 cam with their matching triple springs. The Blower and carb is all stock 525sc stuff.

I have a few questions with my setup.

According to desktop dyno compression calculator, with .005-007 deck height, 17046 Fel Pros, and 2399 pistons my compression will be 9.25-9.33. I am not a machinist so my measuring was with a feeler gauge on top of the piston. Kinda crude I know. What should my timing curve look like with that compression?

What temperature thermostat should I use? I was thinking a 120 to help with the higher compression.

I will be using 91octane non-ethanol only. No exceptions!

http://i880.photobucket.com/albums/a...5dbdf65797.jpg

http://i880.photobucket.com/albums/a...r/IMG_2444.jpg

http://i880.photobucket.com/albums/a...r/IMG_2443.jpg

http://i880.photobucket.com/albums/a...r/IMG_2442.jpg

What numbers are you using for compression? Is the block bore notched? Here are my numbers;

1.2 cc .005 deck
9.5cc head gasket
1.5cc ring
-13.8cc dome
121cc combustion chamber

956.3 cc swept

9.0:1

There is bore notching, but it is very small. You can hardly see it in the pics. Fel Pro lists that gasket at 9.7cc. I forgot about the ring cc. I was also assuming 088 HP500 heads were 118cc. I would prefer to be closer to your number Mr. Maine.

I hope the 'triple springs' was a typo.

Motor looks sharp..

Its has 2 springs and a damper spring. For regular use Crane 99893 is ok. For extended high RPM use Crane recommended 99896 springs. They were $256 vs $89 for the cheap springs. It seems like valvetrain is not the place to try to save money.

Tomorrow is the big day. DYNO TOMORROW!!!!!!!!!

I hope that was a typo on those springs.

The 99896 spring is for a hydraulic roller camshaft, and will have way to much pressure.

99896 is 150 psi @ 1.900,and has a rate of 528lbs lbs/in. With your cam, it would have around 450lbs of open pressure. That will kill the cam quickly.

Those are the part numbers Crane specifically recomended.

My crane catalog shows #99893-16, or 96896-16 for that 134561 camshaft.

my catalog

http://i880.photobucket.com/albums/a...ooer/cam_2.png

Must be some typos.

Irregardless, the 99896 is a heavy spring meant for hydraulic rollers, not flat tappet hydraulics

99896 spring specs

My solid roller springs had a rate of 551 lb/in.
I recommend not starting that engine tomorrow.
Sorry