4.3L valve adjusment

[JustChilling]

I am almost finished rebuilding my 4.3L mercruiser Engine model A615896 and running into a problem with my cold valve adjustmet. According to the manual I got (CLYMER 86-94) #1 piston is at TDC. Timing cover is off and lined up for TDC.Book says adjust Intake 1,2,3 Exhaust 1,5,6.Problem is #2intake is in the raised position and so is 6 exhaust.set valve and rotate crank 1 turn and 1&6 are way too loose. I have installed a new camshaft sierra part #18-1486 which I sure hope is not for a LH motor. any help would greatly be appreciated.

 

[Bondo]

Re: 4.3L valve adjusment

If the Timing Cover is Off,.........<br />What are you using for Timing Marks,..???....<br /><br />The Cam Gear setting Marks,.. Are NOT the Engine's Timing Marks.............<br />

I have installed a new camshaft sierra part #18-1486 which I sure hope is not for a LH motor.

Without looking up your part#,.... <br />No Problem There,....If it's a Standard Cam.....<br />Lefthanded rotation Is Standard rotation......

 

[tashasdaddy]

Re: 4.3L valve adjusment

Just chilling, i'm in jax also. just did my 98 4.3 vortec. what year is your engine. i'm checking my manuals

 

[Don S]

Re: 4.3L valve adjusment

Tashasdaddy, He has a 1986 Mercruiser model 185 V6. His valves ARE adjustable.<br /><br />When you have the timing marks on the crankshaft and camshaft lined up, you are NOT on #1 TDC on the compression stroke. You are on #4 TDC on the compression stroke.<br />Once you get the timing cover on and the vibration dampner so you have timing marks, just bring up #1 to TDC on the compression stroke and go through your adjustment process again.

 

[tashasdaddy]

Re: 4.3L valve adjusment

i realized that Don, thats why i didn't repost. i knew you would be along.

 

[ron7000]

Re: 4.3L valve adjusment

If you're unsure of having the correct cam, rotate engine by hand and watch sequence of how valves open for a given cylinder. Exhaust should open followed quickly by the intake followed by a lot of hand rotation with nothing happening. If not then that would indicate the cam/engine rotation is not correct. Double check to make sure the valve you think is intake or exhuast actually is. Mark it with tape if you have to, it's easy to forget.<br /><br />another valve adjustment method is EOIC.<br /><br />exhaust open intake closed, say it many times to remember it.<br /><br />rotate engine by hand, work on one cylinder at a time. For a particular cylinder, when it's exhaust valve just starts to open set the intake. continue rotating engine by hand and when the intake valve on same cylinder just closes adjust do exhaust valve. Purpose is to be sure your adjusting the valve when it isn't being opened by the lobe on the cam. The other way is to get the piston at tdc on compression stroke like was said, then you can do both at the same time. Either way works, just matter of preference.<br /><br />Tightening the rocker arms to set lifter preload is completely independent of cam timing, cam timing marks, or the ignition timing mark on the crankshaft pulley. Don't go by them to do a valve adjustment.

 

[JustChilling]

Re: 4.3L valve adjusment

Thanks guys I went out this morning and put the timing cover and dampener on timing mark did line up to 0. Rotated crank 1 turn to bring 1 up to compression and preset valves just fine. I thought I was fine with timing marks alighned because before I put heads on #1 was on top. Learn something new every day that is the fun of it!! thanks again guys this forum is so helpful

 

[Don S]

Re: 4.3L valve adjusment

The piston is at the top of the cylinder twice to complete a full cycle. (4 Cycle Engine)<br />Check out this link.<br /><br /> http://www.keveney.com/otto.html

 

[tashasdaddy]

Re: 4.3L valve adjusment

don that site needs to be on 'new poster read first'

 

[Boatwizard]

Re: 4.3L valve adjusment

I just bump it around and snug em down and repeat 4 or 5 times till there's no loose ones left. You have to crank it and reset anyway. Close enough counts when cold.<br />When you warm it up, loosen till it clatters, tighten till it stops and go 3/8 turn. If it's too tight it will turn up so far and quit pulling like it hits a wall.

 

[Don S]

Re: 4.3L valve adjusment

I just bump it around and snug em down and repeat 4 or 5 times till there's no loose ones left.

That's kind of a PITA when you have to pull the risers or manifolds just to be able to pull the valve cover off so you can adjust the valves 4 or 5 time till you finally get it useable, not right, just usable. <br />Wouldn't it be a lot easier to do the adjustment by the book (aka service manual) one time instead of using the "bump it around and snug em down and repeat 4 or 5 times till there's no loose ones left." method?<br />Maybe you should change your handle to boat-trial-and-error-and-hope-for-the-best instead of boatwizard

 

[Boatwizard]

Re: 4.3L valve adjusment

You funny Don!<br />I put everything together but the valve covers. The engine is bolted on blocks, an y pipe stuck on it and water put to it. Add a battery and a switch panel, hey we're running in the shop bay.<br />Set the valves, timing and check for leaks. Stop motor, put valve covers back on and clean. <br />Put in boat and she's ready to run. No screwing around in the bottom of the boat for 2 hours trying to do stuff that can be done in the daylight.<br />I thought of that, that isn't in a book.

 

[Don S]

Re: 4.3L valve adjusment

"23 years of Mercury repair" <br />This was taken from your profile, and if you are what the Alabama boaters in your area have to deal with then I now understand why so many are PO'ed with their experiences.

 

[Boatwizard]

Re: 4.3L valve adjusment

Strange, I don't have a problem with customer satisfaction. <br />You on the other hand seem to enjoy ragging people you don't even know. <br />What's your background in?

 

[Silvertip]

Re: 4.3L valve adjusment

Although running the engine with valve covers off is a valid valve adjustment technique, it is messy. That said, a set of valve covers with holes drilled over each rocker arm nut helps control the mess. A Greenlee Punch makes this a simple process. Of course you need a set of covers for each "adjustable engine" but you only need to do it once.

 

[tommays]

Re: 4.3L valve adjusment

What is it about the service manual method that has caused you problems that you would do the while its running method ?<br /><br /><br />tommays

 

[Silvertip]

Re: 4.3L valve adjusment

If done in the shop it allows a final check of the valve train to make sure there are no sticky or simply bad lifters. Better to hear it run before installation when its a lot easier to work on. It's not generally a problem but it does provide one last running check. I have run into a bad lifter now and then. Lifters with high leak-down rates will rattle at start-up. What better time to fix it.

 

[Boatwizard]

Re: 4.3L valve adjusment

I haven't seen anyone set the valves before startup and not readjust since I was a kid. Can't say I've ever seen a machine shop adjust them and tighten the valve covers. They are run down loose is what they always say. <br /><br />Anywho, to get the maximum RPM the valves can't be "close", they must be perfect. For example, if you want an engine to pull hard at slow speed, you adjust a little tighter than the spec, if you want high RPM, it's looser. Most car mechanics and engine builders set chevy valves about 3/4 to 1 1/2 turns down. Set a mercruiser like that and it quits pulling at less than 4000. I've seen 140's hit a wall at 3400, by loosening the valvetrain you're back at 4400. Truth is, due to the variables in adjusting cold and not running, it's very hard to get them all the same.

 

[Reel Poor]

Re: 4.3L valve adjusment

yyyyaaaaaaaaaaaawwwwwwwwwwwnnnnnnnnnnnnn

 

[Bondo]

Re: 4.3L valve adjusment

Ayuh,.......<br />Running the motor on a stand,.. or even just sitting on it's base on the shop floor,...<br />IS the Last Chance to Fix an Issue,.. Before Accessability becomes a Major Issue in Most boats......<br /><br />And,.....<br />I'm another 1 who'd Rather run the Valves with the motor Hot & Running.........<br />I still use a set of Deflector Clips, which clip over the end of the rockers, on the oil hole, that I bought back in the 70s to do My 1st SBC..........<br /><br />I loosen til they Clatter,+ then Tighten a 1/2 to 3/4 turn......<br /><br />But,........ To Each His Own.......