2 valve or 3?
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Trailering
Joined: Jan 2022
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2 valve or 3?
Any consensus on the difference in durability between the 2 and 3 valve engines? So far, all the engines I've seen that destroyed themselves have been the 3 valve ones that spit out a cam follower with the expected catastrophic results when it jammed a valve open. Are the 2 valve engines known to do that also? I see that the 3 valve head engines installed in Class A motorhomes call for 5W-20 oil while the 2 valve head engines in the Class C rigs are speced for 5W-30. Anyone know why the difference?
Fleet Mechanic
Joined: Jul 2019
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I will “never say never”, but 2V engines don’t seem to have the valvetrain oiling issues that come with the 3V doing its typical self destruct sequence.
As to the oil spec difference, I’d have to wager a guess that it’s a matter of a class A manufacturer needing to milk some CAFE brownie points versus the class C. That’s assuming same year of manufacture. Those specs change over the years in F-trucks alone.
As to the oil spec difference, I’d have to wager a guess that it’s a matter of a class A manufacturer needing to milk some CAFE brownie points versus the class C. That’s assuming same year of manufacture. Those specs change over the years in F-trucks alone.
Fleet Owner
Joined: Aug 2010
Posts: 21,253
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From: Reynoldsburg, Ohio
Are the two different classes of motorhome built on the F- or E-Series? It's been my long time understanding the 3v engines never found their way into the E-Series. Perhaps that might have changed if we're dealing with the cutaway cab-chassis vehicles?
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Trailering
Joined: Jan 2022
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All the E series only have the 2 valve head due to tighter engine bay space. Are you mixing the F-53 chassis with the pickup based F-100+ series? Both of those were able to switch to the 3 valve when it came out.
Fleet Mechanic
Joined: Dec 2021
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Used to maintain a fleet for a friend that had many 3V engines and they all went 350k plus and were retired because the truck bodies rotted away. The engines in those trucks were still running without any hicups.
Also own two 3V trucks myself and have had them since new with no issues. The mileage is in my signature.
2V after the cylinder head spark plug thread redesign is a bulletproof platform 4.6L, 5.4L, and 6.8L. 3V 6.8L is also a great engine with more power and a better transmission.
Also own two 3V trucks myself and have had them since new with no issues. The mileage is in my signature.
2V after the cylinder head spark plug thread redesign is a bulletproof platform 4.6L, 5.4L, and 6.8L. 3V 6.8L is also a great engine with more power and a better transmission.
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