Merc 3.0l head gasket replacement

tinkicker0 said:
Gingie

Err My manual is the official mercruiser manual, not the Seloc one.
It says "torque rocker assembly nuts to 20 ft lbs."

There is a further procedure with the engine running if required after everything has settled down, but the official Mercruiser line is torque them on rebuild.

One other thing, the pushrods come in different lengths for lifter stroke adjustment, so do not mix em up. According to the book anyway.
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So is mine. I been a Mercruiser agent for 20 years and built up quite a few of these from the old 120,140 up til now. Torquing the rockers is not the best way to do it.

Isolate the lash out of the push rod and tighten 3/4 turn.

Even on the courses back in the day at Sowester never torqued. When you do it that way then turn engine over by hand and re check you find valve lash is still out and some of rockers are more done up than the others. You also find the engine runs top end tappy this method.

Dont forget after retorque later to re adjust.

But hey what do i know!!
 
Gary Dont torque.
Adjust rocker untill it touches the valve, then 3/4 of a turn.
Thats from the Horses Mouth from Mercury Marine.
Send me a PM and i have some info that might be useful
 
Gingie.

I bow to your experience.

What a pity you didn't say something along the lines of "Merc says torque 20 ft lbs, but I've been a Mercruiser Mechanic for 20 years and find the following way best" right from the begining. Saved us all a lot of time and in my case a dousing as I opened the shed door in the pizzing down rain to find the manual and give Gary give the best possible advice I could in good faith and helpfulness.

But hey what do i know!!
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I dunno what you know, I don't know you, never heard your username before. You may be a Merc techie, or you may be a 14 year old looking to destroy Gary's engine. I'll accept at face value that you are maybe a mercruiser techie with a better way.
In the end it's Gary's call whioch way he goes with it.

That last line makes your particular post composition look like a troll designed to lead people like me with manuals disagree, just so you could lead us down a literary blind alley before hitting us around the back of the head with the proverbial cricket bat.

Take this as constructive criticism, it is not written in anger, just please give your credentials as you reply. We can then merely read and digest your information, rather than waste considerable time and energy researching the answer ourselves.

Have a beer on me and jolly good weekend. :)

:postapintthroughgingiesletterboxicon:
 
TinKicker.. to be honest mate some if not all the blame sits with me on this one.. I used to maintain fighter aircraft (Phantom F4's, Tornado's and the like) and have stripped car engine's down more times than I care to remember.. I thought boats would be a doddle with my background but forgot that whilst they're similar there's the type training aspect to consider i.e. the mechanical and electrical basics are there but I don't know the numeroous quirks that are potential pitfalls.

Gingie has been an absolute diamond over the last couple of months steering me clear of a good few minefields, he's been nothing but helpful and generous to the extreme in departing his knowledge.

I can see that you're of the same ilk so thank you very much for braving the british weather to find an answer for me to consider, very much appreciated mate..

what I should have said is that I know Gingie and when it comes to things that float, he knows his stuff... my bad.
 
I used to maintain fighter aircraft (Phantom F4's, Tornado's and the like)
Click to expand...

I am not worthy. I am not worthy.

When I finished my HGV techie apprenticeship, I and a few mates went down the recruiting office with a view of maybe joining the RAF. The bloke behind the counter looked at my certificates and said I would be able to go in as a trainee propulsion engineer and would I have a problem with crawling down sooty jetpipes?

Was going to go, but in the end decided against it. Worst decision of my life that. :(

Would have had my 22 years in now, maybe seen the world, enjoyed a satisfying job, made myself deaf, had a fat pension and been working at Manchester airport or somewhere with a very nice salary.

And if any enemy ordnance came my way, dive down a hole in the ground quick smart!
 
not so sure about that mate.. 12 years as a flight systems tech with 3 of them bored out my skull in the Nimrod Software team up in Kinloss... ended up doing another 12 years in IT after 4 glorious years as a mature student at Uni... almost as much social life as the first 9 years in the RAF flitting around the world meeting some 'interesting' ladies ;-) would love to get out of IT and roll my sleeves up again on a flight line.
 
tinkicker0 said:
Gingie.

I bow to your experience.

What a pity you didn't say something along the lines of "Merc says torque 20 ft lbs, but I've been a Mercruiser Mechanic for 20 years and find the following way best" right from the begining. Saved us all a lot of time and in my case a dousing as I opened the shed door in the pizzing down rain to find the manual and give Gary give the best possible advice I could in good faith and helpfulness.



I dunno what you know, I don't know you, never heard your username before. You may be a Merc techie, or you may be a 14 year old looking to destroy Gary's engine. I'll accept at face value that you are maybe a mercruiser techie with a better way.
In the end it's Gary's call whioch way he goes with it.

That last line makes your particular post composition look like a troll designed to lead people like me with manuals disagree, just so you could lead us down a literary blind alley before hitting us around the back of the head with the proverbial cricket bat.

Take this as constructive criticism, it is not written in anger, just please give your credentials as you reply. We can then merely read and digest your information, rather than waste considerable time and energy researching the answer ourselves.

Have a beer on me and jolly good weekend. :)

:postapintthroughgingiesletterboxicon:
Click to expand...

Not on here to have my experience bowed to. Or to big myself up and say na na na na!

I dont have to give credentials to reply to any posting on here. Had i read and answered the post before you then yes it would of saved you atrip in the rain, but as you did so before i posted then that my friend is your own fault. NA na na lol. Take an umbrella with you next time!

Aviation is a path i was looking to tread after school and wished i had. But nothing beats what i do (probably is). I can take critisism on the chin and if im wrong im wrong. Im still learning.

Oh if i was 14 check the time of this posting. How many teenagers do you know up this time of the morning.

As for the beer i can wait for that one and if your in Hythe area you can buy me it. Promise not to hide a cricket bat behind me
 
Hi Gary hope all goes well in your repairs, you seem to have had to have a quick learning curve. I always like to know if there is a reason for something blowing on cylinder heads ie cracked or in need of skimming. Also if you were lucky not to have a head bolt break on removal it might be that they were replace by the last person. Do they need replacing every time they are removed? some engines do. Hope every thing goes well and you are back on the water soon.
David
 
doesn't quite need replacing yet but looks like the engine could do with a replacement Pushrod cover.. still sound but very rusty to the extent that the protective paint's falling off... looks aweful!

The inards of the engine fortunately look to be in far better condition, very little coking (a thin sheen of black) so I'll not be doing anything to clean the pistons. Cleaning the mating surfaces and waterways now so should have it back together this afternoon assuming a head skim isn't needed.

Will be changing the oil & filter too now that I have one of those oil pumps to extract the old oil.

I'll get this b**dy engine looking good and running well if it kills me :-)
 
bugger.. need some help here please guys... I've put it all back together and when I try to start the engine it runs for a moment or two but it's blowing like crazy... I'm checking the cylinder compression in case I messed up the gasket somehow (cant imagine how) but had to stop at number two cylinder due to rain.

the most likely cause is that I've made a mess of setting up these valve clearances.. why? because one of the valve settings was way out (cylinder 3 exhaust) from what it was when I counted the number of turns on removal but instead, I trusted the method above and set the valves using the 3/4 turn after tightening the nut down to zero lash:

With # 1 cylinder in firing position:
No. 1 Cylinder - Exhaust and Intake
No. 2 Cylinder - Intake
No. 3 Cylinder - Exhaust
No. 4 Cylinder - Intake

with # 4 cylinder in firing position
No. 2 Cylinder - Exhaust
No. 3 Cylinder - Intake
No. 4 Cylinder - Exhaust

from the front of the engine, I assumed the following regarding what valve was intake or exhaust

exhaust
intake
intake
exhaust
exhaust
intake
intake
exhaust

i also dropped the #4 cyclinder rods on removing the head but I'm pretty sure I got the back in the right tubes (they're exactly the same length anyway)

Please help, I need to get this tub up and running for the coming weekend and need a fail safe way of setting the valve clearances up or indeed, someone spotting I've got it wrong from the above description

ta v much

cheers Gary
 
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I've done some googling and it seems the recommended way is to adjust the intake and exhaust vlave for each cylinder individually when it's at TDC.. is that the way to go?
 
homing in on the problem now I have the engine turning over again.. cylinder 4 pressure is abnormally high... could this be vlave adjustments causing it or could it be worse case scenario and there's water/oil leaking in to the cylinder? or both? or something lese ;-)

thanks
 
What do you call abnormally high? All my compressions (hot) were within 5 psi of 190. Dont sweat the actual readings as long as they are within maybe 10% of each other.
Gauges can lie, so a comparitive test is the way to go.

Also, in due deference to your high standard of engineering skills, did you remember to take the reading with the throttle wide open? I suffer from "forgetfullness" at times and a simple thing like that can have a profound effect on your readings.

As for setting the valves, whichever way you choose to set them, do them individually with the piston at TDC on the firing stroke, so you need to be eyeballing the position of the rotor arm.
 
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took the boat out for the first time since fixing it (holidays and the like have got in the way).. ran her over to Colwell Bay up to 30knts and the engine ran very well sounding better than it did prior to blowing the gasket.

Did a bit of feather wetting whilst there and then came back in rougher water and the boat handled it with ease.. my face is another matter, copped a face full of salt water as a wave splashed over the bow.

all in all.. happy with the outcome

p.s. didn't get a sniff on the feathers.. seems I've a bit to catch up on wrt to rip tides and weight of the lead.. ours were virtually floating ;-)
 
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