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McLarenLSV

2004 LSV- 380 hammerhead replacement options

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McLarenLSV

Hey guys,

RE: 2004 LSV- 380 hammerhead replacement options

Performed a leak down test on  cylinder #5 and found its leaking out the throttle body indicating an issue with the intake valve. This is a new to me boat and I have hardly had the chance to enjoy it. the boat has 360 hours on it and the motor has 80 after its first rebuild. What I'm considering is a replacement engine rather than a rebuild. I'd like to hear any opinions or options you guys have. Anything is appreciated. Thanks!

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formulaben

Does the motor have a warranty for the rebuild?  Seems way too soon...also, unless you really want to upgrade the motor I would think about just pulling the head and having it rebuilt.  If that valve is the only issue there's no need to pull the entire motor if you were happy with the performance.

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Ballay

Did you pull the valve cover to check?  Is it a lifter, push rod or valve issue. A car mechanic should be able to diagnose and fix the issue for less than an engine change. 

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McLarenLSV

This is the information I received back from the mechanic, I haven't had a chance to have a look at anything myself.

 

From tech: Ran up engine. Starts fine when cold. After letting engine warm up and shutting down, engine is hard to start. Checked spark. Good.
Checked fuel pressure. Good. Went to check cap for cross firing and noticed the distributor is loose. Attempted to hook up diagnostics but
it wont hook up to ECM. Unplugged perfect pass, computer would intermittently hook up. Was able to put it into base timing mode and set
engine timing. Engine runs a bit smoother but still has intermittent starting issues. Engine smells very rich. Removed spark plugs and found
they are very carboned up. Checked compression. Results listed below. Engine has low compression. Lowest on cylinder 6. Performed
leak down test on that cylinder and found its leaking out the throttle body indicating an issue with the intake valve. Inform customer.
Resolution:

Compression results:
#1) 115 #2) 120 #3) 135 #4) 160 #5) 165 #6) 85 #7) 150 #8) 150

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Falko

Those compression numbers would worry me. But given it has only 80 hours on the rebuild, I would check the rocker adjustments, might be too tight. 

That said, these engines do not like to have a higher lift cam installed with the stock valve spring configuration. You have to either fly cut the spring seat or use bee-hive type springs to run higher lift. If they installed a higher lift cam when they did the rebuild, you may have damaged springs and not closing intake valves properly. I would look at the heads first before doing a complete engine change.

Good luck, that is a great engine, odd it only lasted that long.

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Sixball

:plus1: on looking a little deeper before a total new rebuild or replacement. I would finish the leakdown on all cylinders to start with. Some of the other cylinders should be showing problems. If they are all valve issues as said new head rebuild are not hard and way cheaper! 

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