Lash adjustment ?'s

[wil7483]

Well today I went outside and started from the beginning in an attempt to correct a very noisy lifter (in my opinion). I took the advise from others here on the forum and got an old valve cover and cut an opening in it to be able to adjust the rocker arms with the engine running. I started on the number 2 cylinder and worked to the far end of the head. Almost immediately I could see that they were too tight. When I got to the # 8 intake valve I had to loosen it almost 5 turns to get it too clatter and when it did the engine immediately gained almost 600 rpms on the tach and you could hear that it was as if it breathed a sigh of relief. Oh, that annoying noise went away instantly also. Once I got it tightened 1/2 turn I moved to the exhaust valve but every time I touched the nut with the socket the engine would die. I mean very minimum pressure on the nut would kill the engine. I did this like 8 times before I was able to get it loose to the point where it would clatter then it took me like eight attempts to get it tightened 1/2 turn.

Why do you think my touching this valve was killing the engine?

Also, after I got it almost where it sounded like a sewing machine I checked the timing and it was off. So I actually removed the distributor and reinstalled it by the instructions I got on here from another post. Then I set the timing again to 8 degrees BTDC. The engine sounds a lot better although once I got everything back together I started hearing a much more dimmer and fainter tick. Unlike the previous noise though this one goes away as you increase rpm's. Before it just made the tick louder.

Another question that I now have is, could the fact that the # 8 intake valve was so tight be the reason why I couldn't reach WOT rpm's with the 19P prop I was trying to spin? After much testing I settled on a 17P prop that would get me at about 4400 rpm's and 39-41 mph depending on conditions and trim settings. I have this strange feeling that now that I have adjusted those valves that I will be able to spin that 17P well above 5000 rpm's. Any opinions? I actually sold the 19P prop so I could invest in a 16P 4 blade prop but hope that I don't need it now. Hopefully the rain will end soon and I will be able to get the boat to the lake to see what difference all of this work has done.

 

[a70eliminator]

Re: Lash adjustment ?'s

Watch the #8 rocker closely through a cycle and make sure it's not toching on the spring retainer at any point, if it is then the valve tips are worn or mushroomed, the rocker dancing with a spring retainer can release a valve keeper and disaster happens. I'm thinking about this because of how tight that rocker was.

 

[wil7483]

Re: Lash adjustment ?'s

That wasn't good news to hear. So what do you suggest? Should I forgo taking the boat to the lake and just have this head redone completely? I'm no machanic so I i'll not pretend to know everything that needs to be done. I'd be more comfortable just having a mechanic come out and look at it and advise me on what I should do.

I have sent Raul at Rapido Marine 4 emails regarding this ongoing problem and he hasn't responded to any of them. I will probably just call him on Tuesday and tell him all the issues that I have had with the engine and see what he advises.

 

[wil7483]

Re: Lash adjustment ?'s

No other opinions?

 

[coastalcruiser]

Re: Lash adjustment ?'s

have you taken that #8 valve pushrod out and checked it against a new one?
If you roll em on something flat that checks for them being bent.
Im really glad that the valve adjustment worked!
did you use those oil clips? what was it like?
Rob

 

[wil7483]

Re: Lash adjustment ?'s

If it's not one thing it's always another. I took boat to the lake today to test it out after all of the new adjustments and work performed on it. Well the engine sounds so much better now, it is a totally different sound altogether. The problem now is my oil pressure is reading way to low. I cut the day short because of it to be sure that I didn't damage anything. I had my mechanical gauge with me on the boat but no tools to disconnect the sender and install it to get a true reading. The pressure was reading perfect and then just dropped to 20 psi at idle and increased to 45 psi with increase in rpms.

 

[MikDee]

Re: Lash adjustment ?'s

I've been waiting for you to post back to the original thread, so almost missed this one. Anyway, I told you that engine did not sound right I bet it sounds a whole lot better now. Also, aren't you glad, and satisfied, you adjusted the valves with the engine running now? I bet that engine started to come to life once you loosened each rocker to zero lash. I know it's a bit late now, but hopefully no serious damage was done. Sometimes a lifter will go bad if it's overstressed, that might be the leftover ticking noise you have, or not

Because you had the valves so tight, make sure you didn't crush, or break any valve springs, and, or, that the rocker studs are not starting to pull out of the heads, they are only press fit!

I would also go back over Cyl #8 valve adjustment to see if anything changed from some run in? Actually being anal retentive I'd go back over them all



Check your oil to make sure there's no gas in it to thin it down, just as a precaution, but 20lbs at idle don't sound that bad

By the way, maybe you can make another video, so we can hear how it sounds now, and maybe identify the noise you hear?

 

[MikDee]

Re: Lash adjustment ?'s

One more thing, if you're intake valve on Cyl #8 was that tight, it probably wasn't closing all the way, and when firing on that cylinder, the combustion would go back up into the intake manifold, and you would hear a mild backfire, miss, or loud clicking sound, along with lost power. I believe it's evident in the video you made. Ask me how I know? Been there, Done that!

 

[a70eliminator]

Re: Lash adjustment ?'s

General rule is 10lbs of oil pressure minimum for each 1000RPM's you'll be fine.

 

[FreeBeeTony]

Re: Lash adjustment ?'s

I would be very careful here........if you had to loosen one of the rockers that much I would be worried about that lifter..........I had one come apart as I was adjusting it......it spit the pushrod out and the lifter came apart.

Might not be a bad idea to pull the intake and take a look.

Just my $0.02..........

 

[FreeBeeTony]

Re: Lash adjustment ?'s

Was wondering what happened here??.........any update??

 

[maddog2]

Re: Lash adjustment ?'s

My 4.3L engine came from Rapido Marine in Fla. I paid a couple of non-marine mechanics $1,200. to install the engine. It was backfiring badly when I put her in the water. I took the intake off and found that the last pushrod on the right side was loose...the exhaust valve wasn't opening and I noticed the rocker arn stud wasn't tightened into the head all the way... a .25" of bolt thread was showing.

I later found that it states on the Rapido website to adjust the valves...my mechanics didn't. I called Raul at Rapido marine and left a message concerning the valves....to which I recieved no call back.

I have the engine running smoothly, at my own time and expense.

 

[MikDee]

Re: Lash adjustment ?'s

My 4.3L engine came from Rapido Marine in Fla. I paid a couple of non-marine mechanics $1,200. to install the engine. It was backfiring badly when I put her in the water. I took the intake off and found that the last pushrod on the right side was loose...the exhaust valve wasn't opening and I noticed the rocker arn stud wasn't tightened into the head all the way... a .25" of bolt thread was showing.

I later found that it states on the Rapido website to adjust the valves...my mechanics didn't. I called Raul at Rapido marine and left a message concerning the valves....to which I recieved no call back.

I have the engine running smoothly, at my own time and expense.

This is usually the result of an exhaust valve not opening, "backfire" through the intake manifold.

Rocker arm stud? It was threaded? normally they're just a press fit into the head?

Definitely a concern! Glad you got it all straightened out maddog

 

[m283mark]

Re: Lash adjustment ?'s

I Do auto mechanics for a living. Oil pressure is good but if i was you i'd pull the top end out check valves lifters and cam if they were that tight. question is how long were they ran like that. I'd re-seat the vaves its not that difficult. a little time consuming a new set of valve springs the thing will run like a million bucks. if your not confident in that line of work make sure you take it to someone with a good reputation. on a car i may not be so extreme but a dead boat in the water really sucks.

 

[Silvertip]

Re: Lash adjustment ?'s

Lifters that have been tightened 5 to 8 turns too much have a pretty fair chance of being damaged (collapsed). So they being operating like a solid lifter. Whoever did this probably thought that the rocker nuts were simply run down tight like on some engines. Not the case. If it were mine, the manifold would come off, all rockers, rocker balls, push rods and the lifter removed. The base of each lifter would be examined and then probably dumped in the trash. Push rods should be checked by rolling them across a sheet of glass. Rocker balls and the rockers themselves need to be inspected. These are high stress components. They need to operate properly for engine longevity. By the way, next time you do this, DRILL holes over each rocker nut rather than cutting away the entire top of the cover. You don't have anywhere near the mess.