1993 Yukon crate motor hydraulic roller lifter cleaning and adjustment journey - (Solved)

[Hipster]

Must be something wrong with me because I have a sizeable itch to do this as soon as I can again...lol

It's a virus for which there is no cure. lol Have had it since childhood. lol

 

[Road Trip]

I cut my Teeth so to speak doing valve adjustments on shaft mount adjustable rockers where the adjustment screw is on a cupped pushrod. There is no running adjustment that can be done. All kinds of lifters out there and have come across stock replacements that hold the valve open @3/4. Pretty much do everything cold these days and never find a need to to do a running hot lash even when replacing parts. Most stock stuff @1/2 turn. Some hi-po stuff that calls for .003, fast bleed anti pump ups you can't feel where zero is and out comes a dial indicator and I check plunger depth at each end and come up with an average to set all at based on adjuster thread tpi vs movement measurement. 100 different ways to get there but whatever way accuracy is paramount. What's the differnce on hot/cold lash on a solid .010 give or take? Won't matter with most haldraulics unless hydo-solid .003 type.

Hipster,

As soon as you mentioned getting out the dial indicator I knew that we are on the same page
even if we are using different ways to achieve the same answer.

****

No doubt to those in the audience who are working with all new OEM-quality parts on
professionally machined blocks and heads think that I am a loon when it comes to this stuff.

In my defense what I'm describing is someone showing up with a mongrel amalgam of new &
used parts, each one chosen because it was the most affordable option, and now they can't
get it to run right? Or it runs OK, but it's a clattery hot mess? I didn't always have to work
on junk, but there was a steady stream of it in my ecosystem. Hated it at the time, but in
retrospect I learned a lot of valuable lessons, mostly in the form of what not to do when
assembling the good stuff. :0)

Some would point to the non-adjustable Gen VI big blocks as an improvement over the
individually adjustable SBC design. On the Vortec 7.4, you crank everything down and
Voila! your valvetrain is all set. And as long as everything is within original factory tolerances,
then the stock length pushrods are going to work. But if I deck the block and choose a head
gasket to optimize the quench *and* I have the heads milled to true up the faces, then when
it's all said and done now the stock pushrods are too long, and if I don't realize this
I may end up with one of those mystery big block rebuilds that just won't idle smoothly...because
the valves are just barely being held open a crack by the internally bottomed out lifters?
Not enough to affect medium/full throttle, but just enough leakage to affect the idle, where the
tiny intake charge was delivered under 19" of vacuum?

And finally, here we have the situation where we have the next generation of GMT400 enthusiasts
starting out with their very first engine builds/rebuilds. And they are experiencing difficulty in
getting the valve adjustment settings correct. It was a learning process for me, but I was
fortunate to have a mentor right at my shoulder showing me the way. Now it's our turn to
mentor, but we're trying to do it remotely, with all the extra challenges that this method causes.

****

Pulling this all together, I for one am glad that this conversation is being had. My hope is that
by reading all this a newcomer to the old truck hobby will realize that an engine with solid
lifters (old flat tappet SBC, modern roller-solid Vortec, or even a Honda K24) is facing a
relatively straightforward valve lash adjustment...and that they should appreciate their
good fortune. (See attached.)

By contrast, setting the proper preload on an engine featuring hydraulic lifters (SBC or BBC)
involves figuring out the ideal length of the pushrods, and does this ideal length match the
parts you have in hand? And they need to be familiar with the internals of their hydraulic
lifters. At the very least how much preload can be added for a particular brand before they
bottom out? And figuring out the leakdown rate (if for no other reason than to see if they
all agree, or if there are a few faster outliers) would be nice, but realistically very few are
going to bother.

When working with all good-enough parts, even I can get a good cold-preload adjustment.
Actually I've done it several times in the past. But here in Funkytown 2024 I find myself
elbows deep in some weird combos where all the competing variables can only be sorted out
via a running lash adjustment.

(As an aside, isn't it funny that the simplest stuff to fix is also the most expensive, while
the engine bays full of years of accumulated cheap parts is by far the most complex to
try and figure out? :0)

So I guess I straddle both sides of this fence. Cold lash on a blueprinted motor is perfectly
acceptable, even to me. But when words like hydraulic and preload enter into the discussion,
then I can't help myself -- I start looking for the shop valve covers with the tops cut off.

Cheat to win. :0)

FWIW --

 

[Hipster]

Hipster,

As soon as you mentioned getting out the dial indicator I knew that we are on the same page
even if we are using different ways to achieve the same answer.

****

No doubt to those in the audience who are working with all new OEM-quality parts on
professionally machined blocks and heads think that I am a loon when it comes to this stuff.

In my defense what I'm describing is someone showing up with a mongrel amalgam of new &
used parts, each one chosen because it was the most affordable option, and now they can't
get it to run right? Or it runs OK, but it's a clattery hot mess? I didn't always have to work
on junk, but there was a steady stream of it in my ecosystem. Hated it at the time, but in
retrospect I learned a lot of valuable lessons, mostly in the form of what not to do when
assembling the good stuff. :0)

Some would point to the non-adjustable Gen VI big blocks as an improvement over the
individually adjustable SBC design. On the Vortec 7.4, you crank everything down and
Voila! your valvetrain is all set. And as long as everything is within original factory tolerances,
then the stock length pushrods are going to work. But if I deck the block and choose a head
gasket to optimize the quench *and* I have the heads milled to true up the faces, then when
it's all said and done now the stock pushrods are too long, and if I don't realize this
I may end up with one of those mystery big block rebuilds that just won't idle smoothly...because
the valves are just barely being held open a crack by the internally bottomed out lifters?
Not enough to affect medium/full throttle, but just enough leakage to affect the idle, where the
tiny intake charge was delivered under 19" of vacuum?

And finally, here we have the situation where we have the next generation of GMT400 enthusiasts
starting out with their very first engine builds/rebuilds. And they are experiencing difficulty in
getting the valve adjustment settings correct. It was a learning process for me, but I was
fortunate to have a mentor right at my shoulder showing me the way. Now it's our turn to
mentor, but we're trying to do it remotely, with all the extra challenges that this method causes.

****

Pulling this all together, I for one am glad that this conversation is being had. My hope is that
by reading all this a newcomer to the old truck hobby will realize that an engine with solid
lifters (old flat tappet SBC, modern roller-solid Vortec, or even a Honda K24) is facing a
relatively straightforward valve lash adjustment...and that they should appreciate their
good fortune. (See attached.)

By contrast, setting the proper preload on an engine featuring hydraulic lifters (SBC or BBC)
involves figuring out the ideal length of the pushrods, and does this ideal length match the
parts you have in hand? And they need to be familiar with the internals of their hydraulic
lifters. At the very least how much preload can be added for a particular brand before they
bottom out? And figuring out the leakdown rate (if for no other reason than to see if they
all agree, or if there are a few faster outliers) would be nice, but realistically very few are
going to bother.

When working with all good-enough parts, even I can get a good cold-preload adjustment.
Actually I've done it several times in the past. But here in Funkytown 2024 I find myself
elbows deep in some weird combos that can only respond to a hot lash adjustment.

(As an aside, isn't it funny that the simplest stuff to fix is also the most expensive, while
the engine bays full of years of accumulated cheap parts is by far the most complex to
try and figure out? :0)

So I guess I straddle both sides of this fence. Cold lash on a blueprinted motor is perfectly
acceptable, even to me. But when words like hydraulic and preload enter into the discussion,
then I can't help myself -- I start looking for the valve covers with the tops cut off.

Cheat to win. :0)

FWIW --

Agree, with most everything, pushrod length is on the valve train geometry spectrum, and alot of small block chevy guys overlook it. Get it wrong on non-adjustable shaft mounts and stuff can go crash, boom, bang on the first revolution. Where the fulcrum is at on sbc rocker, and pushrod length is something that should be looked at with any higher lift, deck, or head milled combo. And agree, sometimes you're only trying to get a little longer out of some much worn stock stuff. Other engine families have used shaft mount for decades but pushrod length, valvetrain geometry doesn't normally seem to be discussed any great depth in average Chevy circles. Lots of cam questions on this site but not alot on what else is needed. Lots of dude's bolting on aftermarket heads with .100 longer valves.......addressing nothing else. Many, Many failures can be traced back to valvetrain stabilty issues.

 

[Road Trip]

It's a virus for which there is no cure. lol Have had it since childhood. lol

Ditto. I remember the very first time I was given an older non-running
Tecumseh lawn mower motor free to tinker with. Had a few tools for working
on my bicycle and no knowledge. Made no progress despite a lot of fiddling about.

Ended up going to my generation's brick-and-mortar version of the internet
(library) and checked out a book on repairing small air cooled engines. And
once I got my carburetor to match the pics in the book and a hot spark at
the plug, when I actually got the Tecumseh to fire up and make noise...this
blew my socks off! Between this and the sound of my mom's '55 T-Bird (she
drove it enthusiastically) the hook was set. And ever since I've had a thirst for
learning as much as I could about these mechanical marvels.

@scott2093, you have my condolences. Welcome aboard.

:0)

 

[Hipster]

Ditto. I remember the very first time I was given an older non-running
Tecumseh lawn mower motor free to tinker with. Had a few tools for working
on my bicycle and no knowledge. Made no progress despite a lot of fiddling about.

Ended up going to my generation's brick-and-mortar version of the internet
(library) and checked out a book on repairing small air cooled engines. And
once I got my carburetor to match the pics in the book and a hot spark at
the plug, when I actually got the Tecumseh to fire up and make noise...this
blew my socks off! Between this and sound of my mom's '55 T-Bird the
hook was set. And ever since I've had a thirst for learning as much as I
could about these mechanical marvels.

@scott2093, you have my condolences. Welcome aboard.

:0)

I got a bike for x-mas around the 5y/o mark, I took it to the garage the day after and stripped it, It was in my head to "grease bearings". Hours later Mom pops her head out, after the gasp from the vision of the new bike being scattered over the garage floor she said "I don't know why I paid for assembly". Me "What? Santa brought it." I was devastated. lol My parents played hell with me I was forever taking apart anything I could get a tool on. Table legs, chairs, light sockets, etc, Thought it was hilarious to turn my sister's door knob around so when she went running into her room and slammed the door she was locked in. About 6 dad caught me in the back of his Bettle tearing stuff out, after the whoopin' he pulled up a creeper seat.

 

[Schurkey]

All kinds of lifters out there... ...Some hi-po stuff that calls for .003,

I got my ass handed to me by Lunati once upon a time. Ordered the recommended "upgrade" lifters with their cam. Nowhere on the packaging or in the description of the lifters did they mention that they were extreme short-travel plunger design--the .003 style you mentioned.

Ruined a cam because of that. It's one of two reasons that I verify various characteristics of ALL lifters including pumping them full of ATF before assembly.

Agree, with most everything, pushrod length is on the valve train geometry spectrum.

"On the spectrum". I just love that.

Get it wrong on non-adjustable shaft mounts and stuff can go crash, boom, bang on the first revolution. Where the fulcrum is at on sbc rocker, and pushrod length is something that should be looked at with any higher lift, deck, or head milled combo.

On shaft-mount rockers (rocker fulcrum not adjustable, and no provision for lash adjustment as with hydraulic lifters) and BBC Gen 5/6, Olds and Ford non-adjustable stud-mount rockers, etc. the pushrod length affects only lifter preload. Depending on the lifter plunger travel, any pushrod within an eighth of an inch of correct would be fine. The pushrod does not change valvetrain geometry.

With shaft-mount rockers having a lash adjuster...pushrod length is going to have some effect on valvetrain geometry, specifically rocker geometry. I know that some adjustable shaft-mount rockers have a recommended position for the adjuster, with the gross adjustment done via pushrod length, and only the "fine tuning" done with the adjuster screw. But I have very little experience here.

Ball-stud rockers with an adjustment like SBC, pushrod length has a big effect on valvetrain geometry. Thus the big push for getting the most-narrow sweep across the valve tip so long as the pattern doesn't run off the near or far edge of the valve tip.

 

[Hipster]

I got my ass handed to me by Lunati once upon a time. Ordered the recommended "upgrade" lifters with their cam. Nowhere on the packaging or in the description of the lifters did they mention that they were extreme short-travel plunger design--the .003 style you mentioned.

Ruined a cam because of that. It's one of two reasons that I verify various characteristics of ALL lifters including pumping them full of ATF before assembly.


"On the spectrum". I just love that.


On shaft-mount rockers (rocker fulcrum not adjustable, and no provision for lash adjustment as with hydraulic lifters) and BBC Gen 5/6, Olds and Ford non-adjustable stud-mount rockers, etc. the pushrod length affects only lifter preload. Depending on the lifter plunger travel, any pushrod within an eighth of an inch of correct would be fine. The pushrod does not change valvetrain geometry.

With shaft-mount rockers having a lash adjuster...pushrod length is going to have some effect on valvetrain geometry, specifically rocker geometry. I know that some adjustable shaft-mount rockers have a recommended position for the adjuster, with the gross adjustment done via pushrod length, and only the "fine tuning" done with the adjuster screw. But I have very little experience here.

Ball-stud rockers with an adjustment like SBC, pushrod length has a big effect on valvetrain geometry. Thus the big push for getting the most-narrow sweep across the valve tip so long as the pattern doesn't run off the near or far edge of the valve tip.

You've put it in a clearer frame,

Sometimes there is no paperwork but some have the info for the lifter part #s on their web sites these days. I say .003 but usually there's a range there too,.003-.006 or some such.

I'm an*l/OCD about valvetrain stuff so I might be "on the spectrum" lol When stepping outside of stock it pays to work through the full list of checks and measurements.

 

[Hipster]

Other engines such as shaft mount mopars, there are shim kits and other forms of correcting fulcrum issues, one is undrilled heads, but it's some really high end stuff when getting that deep. Bolt on pedestals can be shimmed etc.

 

[scott2093]

2 and a half hour interstate drive was awesome...

I guess I should be careful what I wish for. When I said I can't wait to do it again, I meant getting some old valve covers cut to adjust the valves again....


Ultra Black says to let set up for an hour before torquing.. I may have rushed it a little ...or didn't get things snug enough initially?or didn't use enough?? combo...

Coolant level looks pretty much perfect at hot level... Haven't checked oil.... levels would be confusing anyway...checked an hour into drive and level was good.I'll investigate tomorrow...

Wasn't any smoke so maybe it is coolant...idk....

did I miss a bolt?weird...
sorry about the hose clamp..lol
what was it we're supposed to use?

 

[Road Trip]

2 and a half hour interstate drive was awesome...

Ultra Black says to let set up for an hour before torquing.. I may have rushed it a little ...or didn't get things snug enough initially?or didn't use enough?? combo...

Hello scott2093,

I looked at your oil weep photo carefully, and the good news is that this leak
isn't a result of you getting any of your recent work wrong. Here's your
photo marked up to show that it looks like you have a leaky front oil gallery plug:

You must be registered for see images attach

Interesting trivia: Not all SBCs have this feature - the Flint SBCs do, while the ones made at the Tonawanda plant did not.

You must be registered for see images attach

Here's a link to download an interesting article about 50 years of SBC manufacturing: (Camaros.org)

****

If you can get that plug out, clean the threads, put just enough sealer, and reinstall it, you should
be good to go. Keep in mind that this plug sees full engine oil pressure, so it wants to weep. :0)

So far so good. Continued good luck!