What feeler gauge should I use for a cold adjustment. It's a rebuilt engine and I need to do an initial setting on the valves. I am thinking adding .002 to the .014 and .008 to get things rolling. This sound right?
Cold valve adjustment?
- Thread starter joeyg1973
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Cruiserdrew
On the way there
Yeah-Don't second guess the factory. You will need to warm it up and reset anyway. Set it to spec, run until warm, reset to spec. Don't over think this.
adding clearance.....
Are your thoughts that you have a weak valve job thus causing the valves to "sink" (tighten-up) prematurely?
Are your thoughts that you have a weak valve job thus causing the valves to "sink" (tighten-up) prematurely?
Leave the cold adjust to the flat fours.......
- Thread starter
- #7
My thoughts are that it is cold and that the metal hasn't expanded yet so therefore I would need to compensate. From what I can tell here I don't.
Thanks.
Thanks.
I've done it the way you thought for the same reason. And it is better to have loose lashes than too tight. But I've always ended up closing up the gaps later when I did it that way, so I've gone to just starting out with factory gaps the way the FSM says. I've had to loosen a couple, but not all.
I last adjusted my valves hot and then checked them cold to see what the difference was. The gap increased by about .0015.
I have an RV ground cam in my '77 2F. I heard somewhere that RV cam's take a different valve clearance setting, but can't work out in my head why that would be if I am using a stock head assembly.
Can anyone confirm/deny that?
Can anyone confirm/deny that?
Seeing as Joey has his answer another valve question.
I just finished stripping down an engine from a spares vehicle, '76 2F unknown mileage. Bottom end OK looking top very sludgy, cam badly worn and ALL the valve clearances 0.15 to 0.2 at least. I never ran the engine, it was incomplete and had sat for a long time.
I was wondering how the engine would have run with such wide gaps, poor power, poor starting, could the sludge be a result of low running temps from the clearances? Anyone ever had an engine like that running?
Picture of the cam below.
I just finished stripping down an engine from a spares vehicle, '76 2F unknown mileage. Bottom end OK looking top very sludgy, cam badly worn and ALL the valve clearances 0.15 to 0.2 at least. I never ran the engine, it was incomplete and had sat for a long time.
I was wondering how the engine would have run with such wide gaps, poor power, poor starting, could the sludge be a result of low running temps from the clearances? Anyone ever had an engine like that running?
Picture of the cam below.
hot vs cold
hey Joe,
I'm with you as far as the start up cold settings should be greater than hot engine setting. All the metal components will definately expand with temparature rise and that can only shrink the gap.
I reckon that .001 over is enough.
When I run tools in an well down there beyond 10,000 feet, I expect a length difference of 1 meter or so due to thermal alone - even more in a geothermal well.
How about "you tell us" after you re-adjust when hot.
cheers
hey Joe,
I'm with you as far as the start up cold settings should be greater than hot engine setting. All the metal components will definately expand with temparature rise and that can only shrink the gap.
I reckon that .001 over is enough.
When I run tools in an well down there beyond 10,000 feet, I expect a length difference of 1 meter or so due to thermal alone - even more in a geothermal well.
How about "you tell us" after you re-adjust when hot.
cheers
What?!
DesertPat- You are oilfield I can tell... Need any experienced hands over there???
The whole reason for having a different valve lash spec for the exhaust valve is HEAT! You will have a difference in valve lash from hot to cold NO QUESTION about it.
I've set my stuff up cold added a few thousands (better to loose than too tight), warmed it up to 185-190 and allowed that heat to sink in for a few minutes then shut down and reset to oem specs.
If you adjust to oem with a cold engine you lifters and cam lobes will prematurely wear and you can bend pushrods in some engines.
My lifter faces had shown some premature wear and I sure it was from a PO tune up as the wear was specifically found on the exhaust valves on number 4 and 6. Damn lazy fool...
The whole reason for having a different valve lash spec for the exhaust valve is HEAT! You will have a difference in valve lash from hot to cold NO QUESTION about it.
I've set my stuff up cold added a few thousands (better to loose than too tight), warmed it up to 185-190 and allowed that heat to sink in for a few minutes then shut down and reset to oem specs.
If you adjust to oem with a cold engine you lifters and cam lobes will prematurely wear and you can bend pushrods in some engines.
My lifter faces had shown some premature wear and I sure it was from a PO tune up as the wear was specifically found on the exhaust valves on number 4 and 6. Damn lazy fool...
This is an f, or 2f engine right? Not an extremely close tolerance, tempermental, high tech, race bred powerplant......
I wonder if Toyota set an initial adjustment, then went back and adjusted after warm up?
I wonder if Toyota set an initial adjustment, then went back and adjusted after warm up?
Or did the initial running in on the engine, cam lifters, pushrods, valve stems etc cover that?
Temp Effect
Well put F-Junker.
I like the way you are thinking - you gotta be oilfield trash too.
In case some of you are wonderring, the formula for expansion or contraction of steel is .0000828 inches per degree (temp change) per foot of length.
What distance are we talking about in a F or 2F from the cam lobe to the valve seat?? - a few feet. But in the exhaust valve, the delta T is significant.
Ocdbeetle - Good question about how Toyota handles this @ the factory.
Experienced oilfield hands remain in demand everywhere - the demand just isn't the greatest at this time. The downturns of the industry removed a lot of talent over the decades. Those who toughed it out and survived, reap the benefits. But the benefits haven't kept up proportionally with the price of oil over the decades.
Well put F-Junker.
I like the way you are thinking - you gotta be oilfield trash too.
In case some of you are wonderring, the formula for expansion or contraction of steel is .0000828 inches per degree (temp change) per foot of length.
What distance are we talking about in a F or 2F from the cam lobe to the valve seat?? - a few feet. But in the exhaust valve, the delta T is significant.
Ocdbeetle - Good question about how Toyota handles this @ the factory.
Experienced oilfield hands remain in demand everywhere - the demand just isn't the greatest at this time. The downturns of the industry removed a lot of talent over the decades. Those who toughed it out and survived, reap the benefits. But the benefits haven't kept up proportionally with the price of oil over the decades.
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When the lobe is spalled as shown, it erodes the bottom face of the tappet. This cause rapid increase in the valve clearance. Even if the valve lash is tightened back to spec, there is a significan loss of valve lift and duration, so the engine will feel very lazy. starting & idling is not adversely affected, but WOT operation is degraded because the cam becomes the airflow limiter instead of the carburetor.
That makes sense, the lifters looked OK surface wise but had quite deep a concave dish effect.
I was wondering about starting, thinking if the clearance became large enough it might reduce compression.
With the bearings looking OK I am guessing it was a lack of oil changes or poor / wrong oil that killed the cam.
