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HP500 valve adjustment questions...

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Mudball

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Discussion starter · #1 ·
Hi all:

I have been unable to find a real manual for the HP500 carb engine. This is a 1999 model.

I did find a Crane document that outlines how to adjust the valves, which is what I did.

The basic instructions are:
1. Install one cylinder's rockers and pushrods, and top nuts just finger tight.
2. Turn the engine over until the exhaust valve for that port is half open.
3. Adjust the intake of that port by letting the adjustment nut just make contact and then 1/2 to 1 turn in and tighten the nut. (I used 3/4 turn)
4. Turn the engine again in the same direction until the intake valve fully opens and then goes half closed.
5. Adjust the exhaust valve for that cylinder, being sure to let the lifter fully extend for a minute or so.
6. Continue one cylinder at a time until they are all done.

Since the HP500 does use Crane stuff, can I assume this is correct?

Thanks for any insight!
Kent
 
Discussion starter · #3 ·
This may be a dumb question but according to that link info, say you put for instance the #1 intake at full lift and then adjust the #6 intake per their instructions.

Since these are ~90 degree V engines, why wouldn't that put the #6 intake at the 'clearance ramp' area of their picture?

Apparently, I'm missing something...

Kent
 
#4 ·
This is interesting, because I've always done them several at a time. The guy helping me with my engines is a Mercrusier Mechanic. He wrote down the valve lash adjustment sequence right out of the HP500 manual. According to Mercruisier, you set the crank to a certain position, do certain valves, then rotate the crank to another position, do certain other valves.

This is exactly how I did it on my Small Block Fords.

Also, I believe his instructions only called for a 1/4 turn past contact.

What I will do once valve lash is adusted is pump up the valves with a drill on the oil pump. Then rotate the engine a few times and check lash again be rotating the rods on the valves with no ramp contact. You should be able to spin that rod with just a little effort.

Keep in mind that those lifters are going to pump up with oil when you start it.

The old timers use a paper clip. They compress the lifter until a paper clip slides between the top of the lifter and the retainer clip.

I would get my hands on a Mercruiser Manual or just call up a Mercruiser Certified shop and have them read you the valve lash adjustments.

Good Luck. I will be posting my procedure as soon as Jim and I do it next week.
 
Discussion starter · #5 ·
Thanks Harddrive!

That's great that you are getting your heads back!!

I did check with the shop that did my heads, and they only know about the machine work on these engines, not the engine itself, such as the valve adjustment.

There are a couple of shops around Austin that do engine work, but noone seems to know about the HP engines, specifically.

I would very much like to hear the way Mercury recommends!

I still have the valve covers and exhaust off, so can still easily readjust. I still have lots of 'other' work to do until I learn how to do this.

Take care and thanks again!
Kent
 
#6 ·
In reading the manual this weekend... for a 2000 they called for 3/4 past contact....... I was supprised it was this much..... It also showed different positions for the crank and doing multiple valves at once... It was interesting reading.... Well, not really....
 
#7 ·
Hey guys, I've got an update.

The guy helping with my valve spring adjustment is bringing me over copies of the valve adjustment procedures. I'm putting my heads back on this Saturday. Jim is coming out Sunday to oversee my valve adjustments.

He told me on the phone yesterday that you rotate the engine to certain mark and adjust 4 intake and 4 exhaust valves. Then rotate 360 degrees and do the other 4 intakes and exhuast. I may mave the degrees wrong on that second rotation, but nevertheless I will have the instructions in my hands tonight.

Also, he confirmed that the lash adjustment was a 3/4 turn past contact.

I'll post all of this on a new thread when I put it back together. Will also take some video of the initial startup.

Finger Crossed.......
 
#8 · (Edited)
I'm with Mudball's (Crane's) recommendations.

This how I have always done it.

Remember, the valves need to be adjusted when the lifters are on the base circle of the cam. Also remember, when the exhaust valve is closing the intake is opening - these events overlap to some degree on all 4 cycle engines.

Therefore, to always make sure a lifter is on the base circle:

As exhaust is just opening adjust the intake valve.

As the intake is just about closed adjust the exhaust.

Hydraulic flat or roller - o" clearance then turn nut 1/2 turn. 1/4 turn is risking too loose and don't go over 3/4 turn. Yeh, they say 1 turn is okay but that is a little tight.


Yes, there are other ways to do it faster but when dealing with cams that have such a wide degree of spec's the above has always been a fool proof way of doing it.

Just my input.
 
#9 ·
The Mercruiser repair manual reads differently. It does instruct the way I described in my last post.

I do understand the valve lash process for making sure the lifter is on the low side of the lobe.

However, roller lifters have a very narrow contact point on the cam, therefore allowing the roller to ride on the low spot much longer than flat rollers. I adjusted lifters on 5.0 roller moters using the same method with no problems

I do always go back through them one at a time afterwards.

This bothers me, because I keep hearing this one lifter at a time thing.

Has anyone on this thread tried the procedure recommended by Mercrusier?
 
Discussion starter · #10 ·
THANKS CFM!!!

I had thought that Crane should be a good source. It is great to know that's how you do it, too!

Now I can install the exhaust!
==========
Congrats on getting your heads back, Harddrive!

Pretty soon, we'll all have our blue babies growling!! I can't wait!!

Take care all,
Kent
 
Discussion starter · #11 ·
Hi HardDrive:

You and I must have been posting at about the same time. I didn't get to read yours before I posted.

My suspicion is that both adjustment methods are fine, for the reasons you posted with roller cams having a larger area of zero lift.

I also suspect after looking at various cams that Mercury does their method during manufacturing, to cut down on time, and passed that along in their manual.

If you look at a cam side profile for a BBC, Crane's method makes sense as a generic method for all cams. I never did that research before. Each lobe, no matter the mild or radical side of the equation will always be on the bottom of the lobe if you use Crane's adjustment method. It does take longer.

I was just trying to make sure that I wasn't screwing something up!

The 3/4 turn in was my largest concern.

Take care,
Kent
 
#12 ·
Did you guys read the link that jayl gave us? The section that explains Hydraulic valve adjustment? one of the first things they say is to adjust with the engine at operating temp. Not sure how to get the engine there with the valves out of wack? But it goes on to say "quickly" start adjusting, the reason is to keep the lifters full of oil so the don't collapse as you are trying to fine tune the top adjustment.

How long would it take before a Hyd lifter starts to collapse once the engine is shut off?

I am curiouse becuase my guy will be performing this soon. And I will ask him his procedure.
 
#13 ·
I'll input a little tech on this. The plunger on a lifter has a .136" of moveable area. Now a 1/4" turn is equal to .025" of movement. So you you are loading the plunger with .025"of oil passage on top. That is what I have always been taught is good. Now last night pondering what Mud had posted about what Merc does is 3/4 of a turn, I thought that is way to much. But it came to me what they maybe doing. Since a marine engine sees such higher rpm then an auto, Merc may have found that 3/4" of a turn puts the plunger about in the middle of its movement area, (.136') and with the added oil area on top this helps prevent the lifter from pumping up during "marine opperating range".

This is purely speculation, but I will note it for future question.

Chris
 
#14 ·
I'm loving this thread guys.

Cstraub, I'll soon find out, as the head fairy shows up this weekend. Not sure how far I will get in the process, but I will start up a new thread on the assembly.

CJ, I know what you mean. I will be able to see the plunger on the lifter, because I'm leaving the manifolds off during the process.

I'd just pump them up, drop the rod in, hand tighten the roller until it makes contact, then go the 3/4 turn. Hand crank it a couple times after you do all of them, and go back through and and check the rod spin at zero lash. You won't be able to spin the rod, even if they are set right, until the lifters leak down.

Cstraub, does that sound right to you? That has worked for me in the past, but I'm learning more
about this subject every time I visit this thread.

Mudball, let us know how you do it when you get there.
 
#15 ·
HD,
When the refer to "heating up the engine" they are not really referring to the lifter but to the "growth" the engine experiences. Cold lash on a Iron headed engine needs to be set about .005" tigher due to expanision. On an aluminum head engine, it is as much as .015" or .020". So what you set cold will loosen as the head grows from heat.

Chris
 
#16 ·
We've set many hydr cams loose at 1/4 turn for drag cars but with 'human involvement' (ie: is it really 1/4 turn past zero lash?)I would not advise this setting. It's not good to let the lifter pump up fully since the plunger will hit the retainer and probably bust it.

Fact: GM actually wants 3/4-1 full turn! 1 full turn - too tight for higher rpm.

Anyway - this is why GM went to non-adjustable rocker arms for the BBC starting with the Gen V. Seems they where getting way to many warranty claims for adjusting the valves and way too many 'redo's.'

I think the biggest mistake comes with the "twist the pushrod until it get's hard to twist" part of this. Is it always hard to twist when you get to 0 clearance. No. You may be stronger/weaker than the next guy and what exactly is "hard to twist?' + The lifter can relax after a little bit and then you think "Oh, I must have not tightened this one correctly" and then you tighten it further.

How about this - get a feeler gauge that goes down to .001 or .002". Adjust the rocker arm so that the feeler just goes in - barely a turn and it does'nt, then barely a turn it does and the next size up doesn't go in. Then give it your 1/2-3/4 turn and you should then be all set. Just a quick suggestion - it will probably make it easier this way.

Remember, the heavier the oil the more tendency for 'pump up.' Boats use straight 40wt for the most part and autos use 5-30 to 10-40. Stated another way, it's harder to collapse a lifter that has more oil pressure in it then one with less oil pressure. They are hydraulic you know.
 
#17 · (Edited)
This is all good stuff. Thanks cfm, I will keep all this in mind during the valve adjustment process. I am going to print these posts for reference.

Do you guys think that Mercuriser is taking in to consideration a cold engine, by recommending the 3/4 turn instruction? I know I've had to tighten up a few in the past after running an engine.

Just a thought......
 
#19 ·
Hey, I am going to talk to an engineer buddy of mine about marine application on these lifters. He designed the latest hyd. roller lifter for the cam companies about 2 years ago. I will see what he says.

Horses mouth sorta speak!!!

Chris
 
Discussion starter · #20 ·
Yes, some great info is here!!
===========
HardDrive, I used the Crane method when I adjusted mine, and did use 3/4 turn in.

With my adjusters, they were super easy to turn on the threads, so when a valve was in the proper adjustment position, I just ran the set screw out, and the adjuster down until they just barely made contact (very easily felt from the adjustment nut), then in 3/4 turn and tighten the adjuster. The pushrods always turned easily at the first contact adjustment point. It was very hard to feel a difference when turning the pushrod before and after the adjustment nut just made contact.

After adjusting everything, I went back and checked each one. The pushrods spun easily by hand.

Note that I did not pump up the oil pressure on the engine, but could see that the lifter was against the spring clip before adjusting.

Like CFM said, I can see how these can easily be misadjusted, if one has tight adjustment nuts, and/or a heavy touch feeling the pushrod tightness, if you must use that method. At least my pushrods turn rather easily until the lifter starts actually lifting the valve.

One thing that really amazes me is how easy the engine turns over with a wrench (without plugs)! Those roller valve trains sure reduce the friction! It's amazing!

It will be very interesting to hear what your buddy says, Chris!

Take care,
Kent
 
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cstraub
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