96 5.7L Mercruiser - no compression, water in

[tpenfield]

To add to what Rick said, pressurizing the cylinders and listening for air leakage is known as a cylinder leak test, that requires a special gauge to measure the amount of leak. Each cylinder is tested when it is at TDC on the compression stroke and the gauge measures the pressure that the cylinder can hold versus the supply line pressure being used.

A 'good' cylinder will be under 10% leakage in this type of test.

 

[96RinkerCaptiva212]

dang, I'm an idiot. That's pretty obvious. Sorry, I got the parts off and it was getting dark on me last night so I started rushing to get to the test. Also recovering from Strep so just super tired right now with everything going on, haha. Thanks guys, great forum with great members!

 

[96RinkerCaptiva212]

Is this the manual yall use on your boats or is there a better version? There was a link on this site.

http://www.iboats.com/Mercruiser-St...7112464--session_id.372493987--view_id.373441

 

[Scott Danforth]

that is a seloc manual. not worth the paper its printed on.....sorry iboats, however the late Don S would use them as knee pads. clymer manuals not worth anything either

you can view the factory manual on-line for free here http://boatinfo.no/lib/library.html

pull drive
disconnect motor
pull motor


specifically as I posted in post#13 Manual 17 covers your motor. .... http://boatinfo.no/lib/mercruiser/ma...iser17.html#/0

 

[96RinkerCaptiva212]

that is a seloc manual. not worth the paper its printed on.....sorry iboats, however the late Don S would use them as knee pads. clymer manuals not worth anything either

you can view the factory manual on-line for free here http://boatinfo.no/lib/library.html

pull drive
disconnect motor
pull motor


specifically as I posted in post#13 Manual 17 covers your motor. .... http://boatinfo.no/lib/mercruiser/ma...iser17.html#/0

Thanks! Thought maybe it was a cheap "haynes" copy. I may buy a actual hard copy.. or just post my laptop up in the garage. I like to have something tangable in my hands. No way I'm printing 968 pages lol

 

[tpenfield]

that is a seloc manual. not worth the paper its printed on.....sorry iboats, however the late Don S would use them as knee pads.

You know, I tiled the kitchen floor a month or two ago and certainly could have used a couple of Seloc manuals . . . my knees were killing me

 

[Scott Danforth]

Thanks! Thought maybe it was a cheap "haynes" copy. I may buy a actual hard copy.. or just post my laptop up in the garage. I like to have something tangable in my hands. No way I'm printing 968 pages lol

I keep a tablet in the garage when I need to look up something

Short of using the manual to pull the drive and the sequence to pull the motor, its a small block chevy. there are better manuals on the SBC than those by mercruiser when it comes to rebuilding them.

 

[RaceCarRich]

You could back off the rockers on #5 and put air to it. No need for a leakdown gauge or %'s. That's more for evaluating engine condition not a cause of catastrophic failure. I'd just focus on the dead hole. The airs gonna go somewhere it's not supposed to (crankcase, adjacent cylinder, intake, exhaust, coolant system).

My guess is the cause will be apparent when you get the head off so I would be disassembling not diagnosing at this point.

Sorry for your luck.

 

[96RinkerCaptiva212]

Ok Update - stopped by Harbor Freight on the way home and picked up a leakdown tester. Probably handy to have around anyway but was scared it may be irrelevant at the end of this process anyway since I assume the worst has occured. So just came in from ATTEMPTING to leak down, lol

Test didn't get far unfortunately. Started on the passenger side with the dead cylinder. Made it to the 3rd cylinder (dead cylinder) and rotated piston to TDC (as close as I could tell) and put air to it. Leak was 70% but air was rushing out exhaust ports of head. I thought ok! this seems promising. Went to move to the next cylinder, rotated the engine, seemed like nothing moved even though I turned the crank over. Thought I kicked a tool into the bilge area as I heard metal drop. weird.. Ok, rotated again, weird, nothing moved. rotated again, no pulleys rotating over. I pulled the crank bolt and it's not stripped or stretching. Put the bolt back in and tried to crank over again, just the crank bolt turning. Piston in Cylinder 5 (dead cylinder) is not moving. Pretty sure what I heard was the connecting rod dropping down. Motor seems locked up now... all I can think now is the threads are stripped going into the crank? I would expect the bolt threads to strip before crank. It honestly wasn't hard to turn over by hand the entire time. Pretty sure this thing is TOAST.

I think I may still do the block pressure test but kind of thinking it's a waste of time now. Might as well pull this thing this coming week and call Rapido. Looks like no way there is enough room to drop oil pan in the boat and see if anything is sitting in the bottom.

Here is the results (only got to 3 cylinders before the lock up):
Driver Bank
2 - 90 - untested
4- 110 - untested
6 - 110 - untested
8 - 110 - untested

Passenger Bank
1 - 150 - 30% Leak - can't tell where air is heading, deep, not out of dipstick either
3 - 110 - 45% Leak - water bubbling when I listen to exhaust manifold hose from thermostat/coolant housing and also #5 spark plug hole (the dead hole)
5 - ZERO compression - 70% Leak pouring out exhaust port
7 - 150 - untested

 

[RaceCarRich]

Pull head or motor. You're spending time and money on tools that could be put towards repair. If you did only strip crank bolt hole you'll want to repair anyway.

 

[Rick Stephens]

If you're turning motor over from front use a crank nose socket or put long bolt in the balancer and turn with a bar through the bolts.

 

[tpenfield]

Usually, for a leak down test you get the #1 cylinder at TDC on the compression stroke for the first test and then follow the firing order around the engine rotating it by hand to the next TDC position.

Not sure it sounds like you did that. . .

 

[96RinkerCaptiva212]

Ok, can check on a crank socket. I've always turned a cars over from the crank bolt without issue.

Correct, didnt following firing order. I can(could) do that but just stayed on the same side. I don't think that would cause any issue as long as I arrive at tdc.

 

[tpenfield]

Ok, can check on a crank socket. I've always turned a cars over from the crank bolt without issue.

Correct, didnt following firing order. I can(could) do that but just stayed on the same side. I don't think that would cause any issue as long as I arrive at tdc.

As long as you are TDc on the compression stroke . . . which sooo much easier to keep track of if you follow the firing order. Then you are only rotating the engine manually 90 degrees for each cylinder (V8) or 120 degrees (V6). Going by the leakage numbers it was not obvious if your were at TDC on the compression stroke . . . it may have been on the exhaust stroke.

 

[Rick Stephens]

As long as you are TDc on the compression stroke . . . which sooo much easier to keep track of if you follow the firing order. Then you are only rotating the engine manually 90 degrees for each cylinder (V8) or 120 degrees (V6). Going by the leakage numbers it was not obvious if your were at TDC on the compression stroke . . . it may have been on the exhaust stroke.

Or pull the valve covers and check valves.

 

[96RinkerCaptiva212]

Yea was on compression stroke. Rotated until air was pushing out of plug holes then shined a light in until I could see the piston top out. Definitely did more cranking than just following firing order, haha. But yea, I think I will just pressure test block tomorrow and then pull heads and take a look. Just had an old friend offer his previous 5.7 for 50 dollars. Yea, 50 dollars except it is the engine that shut down on him. He never pulled it apart to see what happened. Definitely had water in a cylinder though. I think I'd be better off just calling rapido for a new longblock really. Total piece of mind

 

[96RinkerCaptiva212]

OK guys - finally have some real info for you today. I keep trying to get a picture up of my block tester rig job but this site just does not like anything I try to upload. Says every file I try is corrupted. Not sure if that is a normal problem around here. Also tried to just upload into my gallery but same thing there.

Anyway, put 15psi to the valve and water immediately started coming out of the #5 (dead) plug hole. Does that solely mean cracked block or is a head gasket possible here as well? I'm going to start pulling the intake and carb now since I would have to use it anyway with a new block. Will check back in a bit to see if y'all have any advice here. I can pull the heads too and get a visual.

 

[96RinkerCaptiva212]

and another update, when getting #1 to TDC and marking the disty... water also came out of #3 while cranking manually. So, have water coming out of 3 and 5 actually. Pulling intake/carb now

 

[Rick Stephens]

Time to pull the head. Water squirting out means you will see the problem.

 

[96RinkerCaptiva212]

well I sure wish I could post pics. The cylinder top is detonated, some small metal basically welded to it. Kicker, valves on head are PERFECT. Now I feel like something fell down the intake tract (have no idea how that would happen, 3x out prior no issues, the flame arrester is always on). Or some crazy detonation. Pics are worth 1000..

My mechanic friend who builds drag cars a lot said "dude, no offense to your boat but it's not a fn drag setup.. rotate that thing and check the cylinder walls, pour oil in, come get this set of heads or have your checked and put that hefer back together" haha