BoaterEd Store      - Help Support This Forum - Join Today!      Hunting/Fishing Stuff
BoaterEd
Username:
Password:
Save Password


Register

Active Topics | Active Polls | Resources | Members | Online Users | Avatar Legend | Statistics
[ Active Members: 5 | Guests: 213 ]  [ Total: 218 ]  [ Newest Member: DonnaB ]
 All Forums
 Forums
 Engines, Electric, Plumbing, etc.
 MerCruiser 454 Valve cover noise, rocker arm?
 New Topic |   New Poll New Poll |   Reply to Topic | 
Author Previous Topic: Throttle cable question Topic Next Topic: Source of Cablemaster replacement Cable  

SeaingDouble

RO# 32117

Posted - Oct 25 2018 :  15:57:01  Show Profile  Reply with Quote
My 1989 MerCruiser 454 has something banging the valve cover above the number one cylinder. Itís a distinctive tap on the valve cover I can feel it. The engine is misfiring. Guessing I have a broken rocker arms or bent pushrod? Or do I have bigger problems? And please tell me I do not have to remove the exhaust Manifold to get the valve covers off. Mine have the little studs with the nuts Threaded on to them
'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland

littlebookworm

RO# 27413

Posted - Oct 25 2018 :  19:30:28  Show Profile  Reply with Quote
Been there; done that. You can't tell what's wrong until you pull the valve cover. You might be able to sneak the cover out without removing the exhaust manifold. It depends on the exact exhaust setup. I had to repair bent valves a few times on our engines and was able to pull the covers without removing the manifolds. Unfortunately, I had had bent valves due to water intrusion and had to pull the heads, a real PITA. Labor to have someone else do it ran over $1k. Hope your problem is simpler. Don't let it go before it gets worse. Hy


Homeport: New Rochelle, NY Go to Top of Page

SeaingDouble

RO# 32117

Posted - Oct 25 2018 :  20:11:23  Show Profile  Reply with Quote
Stock MerCruiser 454/340 with center rise manifolds. Iíve done a little bit of research apparently it is possible to get the valve cover off with a few special tools. Like a flexible extension and a swivel. We shall see. How will I know if I have a bent valves? Because I am 99% sure Iím going to find a broken rocker arm because I can feel it tapping on the valve cover. Or the rocker arm may have broken and the pushrod is going up and hitting the valve cover. One good thing in my situation, is there is no coolant mixing with my oil at all. Thatís a good sign

'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland Go to Top of Page

alien1952

RO# 32487

Posted - Oct 26 2018 :  11:01:33  Show Profile  Reply with Quote
Mush easier to remove the 2 end bolts, install longer bolts , remove inner bolts and just slide back enough to remove valve cover bolts

aka Bt Doctur

Homeport: nj Go to Top of Page

LouC

RO# 10314

Posted - Oct 26 2018 :  12:39:46  Show Profile  Reply with Quote
Yes that is a good plan, those exhaust manifolds are heavy!
About the noise, it is possible a rocker stud pulled out of the head and is allowing the rocker arm to just contact the valve cover, this would also reduce valve lift so the valve on that cyl is not opening all the way....
You won't know till you remove the valve cover....


1988 Four Winns 200 Horizon 4.3 OMC Cobra
1998 Jeep Grand Cherokee 4.0 Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi Quadradrive II

Homeport: Long Island NY Go to Top of Page

jtybt15

RO# 3300



Posted - Oct 27 2018 :  15:32:15  Show Profile  Reply with Quote
hopefully the valve bolt loosened and not stripped. If stripped you may be able to use a thread insert.
http://www.acmeindustrial.com/insert_comparison.html

BUT YA GOTTA PULL THE COVER

Like alien said adding longer studs allows you easier manifold replacement and for this application, you can back off the manifold for easier manifold removal.





Charlie

There is much to be said, in a world like ours, for taking the world as you find it and fishing with a worm.-Bliss Perry, 1904



Homeport: Ca Go to Top of Page

SeaingDouble

RO# 32117

Posted - Oct 29 2018 :  10:37:03  Show Profile  Reply with Quote
Thanks for the recommendations. A friend of mine just went through this on his boat with the same set up and he manage to get the valve cover off without removing the exhaust. Which would also be necessary to adjust valves. Anyway he let me borrow the exact tool combination he used which consist of a swivel socket and Long a quarter inch drive extension. Going to be attempting this today Iíll know soon enough. If for some reason that doesnít work I will go do what has been suggested with the exhaust manifold. Hoping to find a broken rocker arm and nothing else!

'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland Go to Top of Page

Comogene

RO# 9942

Posted - Oct 29 2018 :  12:11:16  Show Profile  Reply with Quote
Brett:

Really isn't that hard. Only the two bolts behind the center rise will be impacted. The other 5 should come right out and then it is a matter of wiggling the cover off. You may have to remove hoses if you have a closed cooling system. Before you do anything, set the timing at TDC with #1 on the compression stroke as it will make adjusting the valve a lot easier.

If you have a Mark IV (I think GM changed to Gen V after 1990)your valve train set up consist of a stud, pushrod guide plate, rocker arm, pivot ball and nut. The nut should have nylon threads. It is conceivable that the nut loosened or that the stud loosened but then the pushrod would be loose. It is also possible that the pushrod guide plate broke (happened to me). All parts are readily available and you will need a new valve cover gasket and a torque wrench to reassemble. Shouldn't take you more than 2 hours from start to finish. Don't forget to put assembly lube on the pivot ball and pushrod to rocker arm contact point.

Gene



Homeport: Beverly, MA Go to Top of Page

SeaingDouble

RO# 32117

Posted - Oct 29 2018 :  13:08:07  Show Profile  Reply with Quote
Just tried my friends contraption that worked on his 450 for a MerCruiser. Not even close, not sure how the hell he got it to work. Looks like Iíll be pulling the manifold. Itís really unbelievable to me to have to do this to remove a valve cover.

'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland Go to Top of Page

SeaingDouble

RO# 32117

Posted - Oct 30 2018 :  12:39:20  Show Profile  Reply with Quote
UPDATE I was able to get the valve cover off just had to remove riser. Anyway what I found was the number five exhaust rocker arm had simply come off of the pushrod. Pushrod does not appear to be bent and the rocker arm itself not damaged or broken. The lock nut on the rocker arm doesnít appear to have loosened just by comparing to the others. So, how can This have happened? Can I simply re-install this rocker arm and adjusted the valve and that is it? Or am I missing something?

'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland Go to Top of Page

Comogene

RO# 9942

Posted - Oct 30 2018 :  14:26:36  Show Profile  Reply with Quote
Worst case, you have lifter that is not working properly and that requires pulling the intake manifold. But before you jump to that, pull out the pushrod and make sure it is straight. Roll it on a flat surface and check that there is a "ball" on each end. Possibly the rocker arm stud loosened? Specs call for torgue of 50#s with thread lock. Reinstall all with assembly lube. Rotate the crank until you get #5 on the compression stroke and adjust the value. Half a turn on the nut could be the issue.

If your down for the winter, I'd pull the intake manifold and take a look. All it costs you is a set of gaskets and time.



Homeport: Beverly, MA Go to Top of Page

SeaingDouble

RO# 32117

Posted - Oct 30 2018 :  16:01:26  Show Profile  Reply with Quote
Well what Iíve decided to do, is adjust all the valves on both sides. If itís still missing and spitting and sputtering Iím going to pull the intake and check the intake gasket and inspect lifters. Iíve already checked the pushrod it is not bent. I reinstalled the rocker arm with no issues. Unfortunately I didnít notice A hint of moisture in the oil. Not detectable on the dipstick but I can see it on my socket when I am adjusting the rockers. Already did the risers thatís why Iím thinking possibly intake gasket. Iím not thinking head gasket at this point. I donít see any signs of any freeze coming out of the exhaust

'89 Wellcraft Gran Sport
'98 Proline 21 Sportsman

Homeport: Maryland Go to Top of Page

littlebookworm

RO# 27413

Posted - Oct 30 2018 :  21:50:08  Show Profile  Reply with Quote
We used to find that problem with GM engines on cars in our shop. In all likelihood the valve rocker stud has pulled out of the block. Check the height of the stud compared to another one. The solution is to pull the stud and either replace it with a new pressed in stud or to tap the hole and use a thread-in stud. Any good marine or auto mechanic can do it.There are even kits available for you to do it yourself. The cause is usually a stuck valve or over-tightened rocker. Since it happened suddenly, it's probably the result of a stuck valve. Try tapping the valve with a hammer to see if it moves. If not, it may be bent or stuck from some rust, particularly if it's one of the valves near the center of the head. That would require pulling the intake manifold and the head to repair. Hy


Homeport: New Rochelle, NY Go to Top of Page

jtybt15

RO# 3300



Posted - Nov 07 2018 :  14:07:51  Show Profile  Reply with Quote
If it's a collapsed lifter, you may be able to get it out with a magnet. The only problem is the magnet sticking to every surface. Otherwise, you'll have to remove the intake manifold.

you also might be able to check of collapsed lifter by pushing down on the push rod. The lifter is spring loaded as well as hydraulically. The oil should drain down so you can feel the spring. Mark the height. Turn the engine over til the lifter fills with oil and measure again. Might have to do this procedure a couple of times in case the lifter is on a cam lobe when you measure. It's a PITA but easier than pulling the intake. Oh, and get a one piece intake gasket. They used to be about $55 but well worth it as they're reusable.





Charlie

There is much to be said, in a world like ours, for taking the world as you find it and fishing with a worm.-Bliss Perry, 1904



Homeport: Ca Go to Top of Page
  Previous Topic: Throttle cable question Topic Next Topic: Source of Cablemaster replacement Cable  
 New Topic |   New Poll New Poll |   Reply to Topic | 
Jump To:
BoaterEd © BoaterEd Go To Top Of Page
This page took 0.44 seconds to load
Forum Guidelines and Privacy Notice

    

Boatered.com