How cold for cold adjustment of valves?

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sandcruiser

sandcruiser

....back in the saddle again....
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Hi all
my mechanic is an hour away. I don't want to leave the truck overnight...

how cold is "cold" for adjusting the valves?
Keep in mind it is near 100*F here, so the motor isn't getting cold no matter how long I leave it.. I'm just wondering if sitting for 5 hours is enough.

Thoughts?
 
My mechanic made me leave it overnight in summer. I think they want it down to the ambient air temp
 
hmmmm
I think I'm going to try to let it sit for a spell, then hose it down and sit some more

overnight would involve two 2+ hour bus rides... not going to happen.
 
Does it call for adjusting the valves cold?!?

Seems odd to me 'cause you want it right when everything is up to operating temperature. I know the 3B shop manual gives valve clearances hot. I take the truck for a run and then burn my fingers adjusting the valves :)
 
roscoFJ73 said:
..Yes
Click to expand...

Strange! I guess the mechanics don't want to get burnt fingers any more. Hot makes more sense to me but I guess steel has a fixed coefficient of expansion so it can be done right either way.
 
cruiser_guy said:
Strange! I guess the mechanics don't want to get burnt fingers any more. Hot makes more sense to me but I guess steel has a fixed coefficient of expansion so it can be done right either way.
Click to expand...

Funnily enough, on my old Landy engine I threw out, a 2.25diesel, it said 0.10" hot or cold.. Probably didn't matter much to that POS:D.

When I had my HJ60 in Oz I never got round to adjusting the valves, it was close to 40degree C , and you'd burn your fingers whatever you touched.. Don't leave a spanner lying in the sun, you won't be able to touch it after 10min or so...
 
I would do the valves myself, but the challenge is in finding the correct shims in a timely manner.
While my Spanish is pretty good, I've discovered that local mechanics get stuff faster and better than I get it. They leverage relationships, I suppose. And they know of multiple providers, in some cases. That, and I don't have a micrometer. The cost of getting one would far outweigh the cost of having someone do the valves.

Either way- labor is cheap. I expect that I'll pay $20 or so for the work involved, and I would rather enjoy a :beer: while someone else gets his mitts oily.
 
cruiser_guy said:
Strange! I guess the mechanics don't want to get burnt fingers any more. Hot makes more sense to me but I guess steel has a fixed coefficient of expansion so it can be done right either way.
Click to expand...

Found this formula for initiall set-up while trying to search for the dial indicator technique John talked about for adjusting the valves (still no luck). Still says that you have to do a hot adjustmenting if that is what the FSM calls for.


Take the "hot" setting provided to you in the cam manufacturer's catalog or from the cam card that came with your camshaft. Use the figures below to alter the original lash specifications to get a "cold" lash setting.
    • Using iron block and iron heads, add .002"
    • Using iron block and aluminum heads, subtract .006"
    • Using both aluminum block and heads, subtract .012"
Remember this correction adjustment is only approximation, and it is only meant to get you close for the initial start up of your engine After the engine has been properly warmed up to normal operating temperatures you must go back and reset all the valves to the specified "hot" valve lash settings.
 
yes. but the FSM for the hd-t is very specific in that the valve settings are for cold.

which is sort of a hassle. I'd rather it called for hot. Such is life.
 
I've experimented on my B-diesel and found NO difference at all between hot and cold values (by checking clearances as soon as I can after stopping my engine and then rechecking them later after it's cooled completely).

So I am happy to set my clearances to "hot specifications" while it is simply "warm" or even "cold".

Really ...... How can one measure HOT clearances? (By the time you have the air cleaner and valve cover off ... the engine has already cooled down from HOT to WARM.)

:beer:
 
I guess it depends on ambient temps...

when I changed out my injectors recently, they were still damn hot to the touch an hour after turning the motor off, with the hood cracked open.

There is a lot of cast iron there, it cools slowly

Now, granted, my ambient temps are 100 or105. At 50, it might cool down faster (like delta^2 faster, if I recall correctly, so it probably does make a pretty big difference.)

How hot is"hot" anyway? I'd guess the block is around 220* F, right? Coolant temp? Maybe a little hotter?
 
lostmarbles said:
Really ...... How can one measure HOT clearances? (By the time you have the air cleaner and valve cover off ... the engine has already cooled down from HOT to WARM.)

:beer:
Click to expand...

I don't know but mine holds the heat pretty good. Its still hot enough to burn the fingers through the gloves. But I have never tried doing them in winter..
 
lostmarbles said:
I've experimented on my B-diesel and found NO difference at all between hot and cold values (by checking clearances as soon as I can after stopping my engine and then rechecking them later after it's cooled completely).

So I am happy to set my clearances to "hot specifications" while it is simply "warm" or even "cold".

Really ...... How can one measure HOT clearances? (By the time you have the air cleaner and valve cover off ... the engine has already cooled down from HOT to WARM.)

:beer:
Click to expand...

well you could always do like some old-school mechanics with toyota corollas and adjust their valves when engine is running :grinpimp:

that ought to be hot enough....
 
During valve adjustment I note what thickness of shim I put in there.
When it gets to adjusting the next time it's a matter of finding the actual play, checking my notes about the value of the shim in there and then finding the thickness needed.
I then can check or I have the needed shim(s) in stock. If not, it's just a matter of getting them at the dealer and replacing them and make notes about their thickness again for the next time.
Having said that I also have to say that so far (the rig is getting close to 250k kms now) about half the valves still have their original shims in there.
The only adjustment I've done so far was to get the valve clearance back into midrange of the allowed play. I never found one to be out of limits.
I check them about every 50k kms. This is more often than advised by a Toyota mechanic who told me once that checking the valves every 120k to 150k kms was more than enough for a 1HZ engine!
So far (last check was at 200k km) he seems to be right having replaced only some of the shims so far.
Next check is in a few weeks.....we'll see ;)
 
Ron R said:
..I then can check or I have the needed shim(s) in stock. If not, it's just a matter of getting them at the dealer and replacing them and make notes about their thickness again for the next time.
Having said that I also have to say that so far (the rig is getting close to 250k kms now) about half the valves still have their original shims in there. ;)
Click to expand...

Must be quite a different setup (overhead cam?) compared to what I have on my B-engine because the only shims I deal with are those in my toolkit (that I use to check my clearances).

My adjustments are done so:
tappetadj.webp

Radd Cruisers said:
NEEDS to be done at ambient temperature - a cold engine.

2 hours rest is not enough. Overnight is good.

The numbers can and do vary in a huge way with a hot or cold engine. Been there, done that.

~John
Click to expand...

Maybe all this varies depending on which engine you're working on? (Mine's an old "industrial-style" engine :D)

If it must always be done "stone cold" ... then why does Toyota supply "Hot figures" on an engine like mine?:

Valveclearances.webp

:beer:
tappetadj.webp
Valveclearances.webp
 
AFAIK ;) the HDT has an overhead camshaft and is more or less identical to the 1HZ (or the 1HZ to the HDT ;) ) and shims are used to adjust. Is a bit of a P I T A but wear is minimal.

And the adjustment should be done when the engine is cold....

I don't know your engine but a play of 0.20 (in) and 0.36 mm (out) when the engine is hot looks to me as being a lot. I would guess these are for cold setting although the decal gives the impression these are hot values.

Yes there is a 'bit' of a difference to your set-up of the valve-train :D:D:D
 
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