Here's your valve adjustment discussion

[Siddhi]

Hey guys,
Here is a post for discussing the techniques for adjusting valves. I am not trying to start a heated debate so don't take it that way. I think it could be very informative to hear the theories and techniques on how to do this task. I being new to the I/O world! Proper maintenance is something I like to know all I can about.
Some things I would like to know about are:
1. How often should this be performed/how often do they go out of adjustment?
2. What are the pros/cons of not pumping up the lifters prior to adjustment?
3. What are the best ways to pump up the lifters both right/proper tools and cheap/homemade tools.
4. Can you gain any performance by adjusting them closer to one side of the tolerance or the other? Is it worth it?
5. What does the extra 3/4 turn on the rocker arm do? I was told it is spring preload or something!

So please let the discussion being. Inquiring minds want to know! Thanks!
-Siddhi

[Siddhi]

Also if you want to bring cams into the discussion that would be great. I just learned that automotive cams do not really work in the marine industry due to reversion or something. So where and what cams to buy/select and why could be an added benefit. And can reversion be eliminated with aftermarket exhaust manifolds. Seeing how they inject the water into the exhaust in a different place then the stock manifolds or does it have an affect? I have a 7.4L carbed 330hp motor and I might be looking to put a new cam in it once I work out my current running problems. So while we are on the topic it would be some good info for us wannabe's!
Thanks!
-Siddhi

[vinny p.]

This is going to get good...

I guess I will start it off. I hope that we can all learn something...

Let me start by giving my opinion to your questions first. I will assume that we are talking about hydraulic lifters and NOT SOLIDS.

1- While I would recommend checking your entire valve train at least once a year, you probably dont have to. Hydraulic lifters almost never go out of adjustment unless something wears out. However, since I am anal, I back off all my rockers as part of my winterizing procedure. That increases the life of the valve train. In the spring, all thats needed is a good adjustment and your back in business.

2-The pros --- Its the only way to get them adjusted correctly. The cons-- Premature lifter wear, cam wear, loss of power, a variety of engine damage.

3- There are 2 ways to do this. If the intake is off, you can pump up the lifters with an old fashion oil can filled with oil. On the side of the lifter, you will see a small oil hole, push the oil can into the hole and fill it up until oil is forced out from the top. Then drop the lifter in its bore and adjust. If the intake is on, the only way to be assured they get them pumped up fully is too remove the disributor, install either a cut up distributor or a good priming tool. Get that lifter on the cams base circle and prime the engine up for a while. Then adjust.

4- Absolutely nothing to be gained, dont even think of it.

5- Basically thats the reason. While the amount of prelod differs with manufacturers, lifters are designed to run with the plunger about .050" down from the top. That keeps everything happy and quiet.

[vinny p.]

Cams --The single most important piece in an engine. Without the right one tailored to your application, the engine will never be right.

Being that I type painfully slow, I only have the patience to type out a small amount of information on this.

First thing-- Not all cams are created equal. The first choice you have to make is whether you are going to run a solid or hydraulic, flat tappet or roller. Your choice depends on your application. For most of us, myself included , a hydraulic roller would be the best choice. They offer a much better lobe than flat tappet, with a longer life expectancy. If you go for a roller, the next decision is billet or cast. I like billet, but the bad thing about billet cams is that they eat distributor gears for breakfast. The fix... you can have a 2 piece cam made. The entire cam can be billet with the excpetion of the distributor gear and the last bearing lobe. The 2 pieces can be pressed and pinned together. Isky presses and pins, Comp and Crane only press. I have heard of a few that are only pressed have come apart. I would recommend Isky cams. These 2 piece cams allow you to have a billet cam and still run a stock distributor gear. Otherwise, you would have to run a bronze gear that wears out quickly.


Reversion-- A real bad problem with boats and wet exhausts. The problem can not be eliminated with aftermarket exhaust, but it can be reduced. I had this problem real bad when I built my 540. The fix for me was full dry CMI headers and tails. For most, thats not necessary. The right cam and good aftermarket exhaust should be fine. Keep the lobe seperation on the wide side, that will keep the overlap in check, which in turn reduces the reversion.

[BoatsR4Me]

Lifters: Vinny is correct on all counts. Follow the manufacturer's instructions on the pre-oil, adjust for Top Dead Center, adjust the lash, and forget it. Having played with lash loading for speed, I would advise against any experimentation. Incorrect loading on the lifter will change the oil feed to the springs, rocker, and valves. Not a good idea. In fact, changing the lash load can change the balance between the lifter springs and the valve springs effecting the valve open rate. Again, not a good idea unless you have an engineering degree in combustion and air flow dynamics.

Vinny advises releasing the spring loaded lash in winter. This is commendable but can be frustrating for non-experts who experience bent valve covers, gasket costs, and leaking oil. TDC varies depending on the number of cylinders. but directly effects the lifter loading. For storage, choosing the right TDC with the minimum lifter spring load can save you the time and frustration of pulling the covers to release the lash for winter storage. Postscript..........after five OMC I/Os, I have not messed with the lifters. Zero problems. Use the manufacturer's specs.

I type slow too

[cooperider]

I'm glad you guys type slow, it takes me a while to read some of these posts.

[happy]

I personally pre-lube every engine I assemble prior to valve adjustment. (a commision based mechanic) so I don't get paid to go back and do the job a second time.

The tool I use to prelube is an old distributor with the gear taken off..

I know that there are some people who do not bother to oil up the lifters and have success doing so.. I don't believe that this type of adjustment is 100% effective.. seing that you can miss zero lash to easy.. while the engine may run ok.. and seem to be running with all its got.. may be missing a hundred or two rpm.

Other rules that I follow (my own)
_ always measure pushrod height
_ always use new lock nuts
_ take a moment to read the manufactures instructions... thats why someone wrote them..

I assume this thread so far has only been on the regular lifters/rockers and not the performace rollers often found in big blocks..

[Siddhi]

Vinny,
I was wondering if it is cheaper to buy a primer tool verses trying to find a old distributor. Also I am guessing that if you take out the distributor you will have to make sure you get the timing of it back properly during reinstallation. Is that done by putting the #1 cylinder on "TDC compression stroke" and making sure the rotor button is pointing a certain direction? Or is this necessary? Or is that correct?
-Siddhi

[vinny p.]

Siddhi,
I would just buy a tool from Summit, part# SUM-901010 , that will work fine.
Yes, you have to reset the timing if you pull the distributor. As you said, you get the #1 cylinder to TDC, drop the distributor in while also lining up the oil pump drive, pointing the rotor to #1 on the cap. Start the motor, and set the timing with a light. While base timing is important to get a good idle, some forget about checking the timing at full advance. Thats more important to letting the engine run right and live long.

I just want to say without insulting you, if you have never done this before, I would have someone who knows how to do this actually show you how to the first time. These adjustments are critical. If done wrong, you can experience engine damage. Simply reading this may not be clear enough for you to do this correctly.

Boatr4me,
I agree with what you said about finding a spot where the maximum amount of lifters are on the cams base circle. That may help some guys. However, I like to back off all the rockers, take them and the push rods off to check for wear and straightness. Marine motors take a beating, especially mine. While valve train failure can happen regardless of your equipment or how often you check them out, I try to do all I can to prevent failures. Too much money invested and too short a summer here in the North East.

[BoatsR4Me]

Vinny...............I couldn't agree with you more. My problem is the family fleets up north and south. I could not find the time or patience for 4 I/Os and 7 outboards. Wish they were all mine, and fortunately, I have help. Still, the economics don't work for me. But you have my admiration. Marine wear and tear is hard to keep up with but worth ten times the time and money invested. The southern, salt water I/O is challenging to me and Dad. Talk about care and feeding. Try scrubbing the cyl. head water jackets with a tooth brush to dislodge buildup and improve cooling. Every ride is a freshwater flush, checkup, and maint. We don't like failures in the main drive, 60 miles out to sea. I just don't have the time. Hats off to you.

The only thing better than one Playmate is two Playmates. Still looking for a 3rd..............Boatsr4me