No compression with rocker arms torqued

04fxdwgi25

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It is great when that "tada" moment hits, isn't it.

Non adjustable valve train should not be in these engines. A changed head gasket can throw them off. Just a way for the factory to save $3.00 in assembly labor.
 

tpenfield

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Glad you found the issue. The Gen 5 454's were not fan favorites because of the valve train. Now with the conversion kit you should be good to go. Just make sure 1/4 turn beyond 0 lash is enough.
 

snowbrd84

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Glad you found the issue. The Gen 5 454's were not fan favorites because of the valve train. Now with the conversion kit you should be good to go. Just make sure 1/4 turn beyond 0 lash is enough.
What would be a sign that it is not enough?
 

tpenfield

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What would be a sign that it is not enough?
Rocker arm noise. . .Usually it is after the engine is all buttoned up. Not sure what the spec is for the adjustable valves, the Mark IV engines were 1/2-1 full turn IIRC. 1/4 turn seems light. Maybe get everything adjusted and then run the engine for a while to be sure.
 

snowbrd84

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Rocker arm noise. . .Usually it is after the engine is all buttoned up. Not sure what the spec is for the adjustable valves, the Mark IV engines were 1/2-1 full turn IIRC. 1/4 turn seems light. Maybe get everything adjusted and then run the engine for a while to be sure.
Thanks, I'll listen for tapping. Having pulled the exhaust elbows and valve covers about 10 times in the last couple weeks, I can do it in about 10 minutes now. So no big deal if I have to dial in a bit.
 

snowbrd84

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3800 rpm at 26mph WOT, so WAY better, but something is still off. Ive got coN pression close to 150 across the board. This is with 2 adults, 2 toddlers, 40 gals water and 60 gal fuel. 21 p new prop vs 23 p stock spec. Should be 4200-4600 and near 40 mph.

i have the delco EST ignition kit from Sierra in hand, so might go ahead and install that next to see if i had compounding issues.
 

snowbrd84

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Check plug gap, several a little too much gap, regapped. Number 8 plug tip (which I had dropped in the bilge yesterday) had basically no gap. Regapped. Hit 4200 rpm at about 28-30. Still too slower than it should be but I also have a broken anticavitation plate on outdrive lower unit, so maybe that is causing a ton of slippage. Either way, it's running a lot better than before. Slipped year round with failing bottom paint and 2 months since pressure washed, Def a coating of algea, so that prob knocks a few mph off.

Momentary freak out when temp alarm went off after going from wot to idle speed at the marina inlet, temp shot to 170, and oil Pressure gauge showed 0. Neither the fuel pump cutoff switch or oil pressure ignition kill switch activated to kill motor though and that gauge reads low I'm pretty sure. Killed it immediately either way and threw someone a line to tow me in to slip (was 100 feet from marina). Got in, engine bay was HOT (in the 90s here today) but no fluids anywhere, pulled plugs and all fine. Turned key and started with no sounds, oil pressure still showed 0, but none of the low pressure switches activating. Temp came down to 135 once running and pressure came up. Found out the intake air blower was unplugged. Must have been when I bought the boat. Oil pressure hauge reading came up as temp went down.

Edit: reading online I'm seeing the stock oil pressure switch only activates the alarm and doesn't kill motor? I thought it did since it runs through the thunderbolt module. Hoping I didn't damage anything.

Going to buy a new gauge and a new impeller kit. This boat is stressing me out.
 
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kenny nunez

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Most times the sender is the problem. There is a membrane inside that leaks internally, they sometime read normal on start up but after a short time they equalize internally and rear 0.
 

snowbrd84

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Tested oil pressure sender vs mechanical guage, it was sending 20 psi below my gauge. So didn't lose pressure, it just went below 20 and looked like 0.

Water pump impeller was torn too which prob contributed to overheat. No pieces came off luckily. So I think, fingers crossed, that I am good to go.
 

04fxdwgi25

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If you overheated, don't be surprised the thermostat will need replacing. Stats often fail / go wonky after an overheat
 

snowbrd84

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170 deg, no higher. Shut down within a couple seconds of alarm. Ran today wide open fantastic with new water pump impeller and no temp issues. Mid 90s air temp too. But yeah, going to order a new thermostat just because I have no idea of how old current one is.
 
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