Universal 5424 Valve Clearance

[Obi Wan]

As I slowly take my 5424 apart to refurbish it, I checked the valve clearance. I measured a fairly consistent .018 inches. However, the manual says .0071 to .0089 inches, or .18 to .22 mm. I wonder if some wonder mechanic got his metric and inches mixed up.

Wondering if anyone else experienced this? I suppose it could be wear but that seems like a lot. I wasn't planning on cracking the engine apart if I don't have to. Tried to do a compression test but the new tester i ordered off of Amazon turned out to be a total piece of chinese crap with threads cut so poorly they don't even screw in. And it was not one of the cheaper ones.

[capt jgw]

As the engine wears the valves recess into the head and the clearance reduces. Doesn't take all that long and is quickest on a new engine as everything breaks in. The manuals all say to adjust after the first few hours, maybe that was never done. If they get too tight they start hitting the piston tops. Check and adjust often.

[brianlara 3]

Originally Posted by Obi Wan

As I slowly take my 5424 apart to refurbish it, I checked the valve clearance. I measured a fairly consistent .018 inches. However, the manual says .0071 to .0089 inches, or .18 to .22 mm. I wonder if some wonder mechanic got his metric and inches mixed up.

Wondering if anyone else experienced this? I suppose it could be wear but that seems like a lot. I wasn't planning on cracking the engine apart if I don't have to. Tried to do a compression test but the new tester i ordered off of Amazon turned out to be a total piece of chinese crap with threads cut so poorly they don't even screw in. And it was not one of the cheaper ones.

Obi, the conversion from metric to imperial is
39.37 inches equals a metre exactly
Therefore .3937 inches or 40 thou converts to a single millimetre.
A tenth of a millimetre is 4 thou of an inch
And so the .18 to .22 mm as quoted is very closely equivalent to .007 to .009..
If that't confusing just remember. 39.37 inches is a metre....just move the decimal places.
Depending on the feeler gauges you have just set the clearances to 8 thousandths of an inch, or
.2mm (decimal 2 mm) .
8 thou inches or .2mm.

[brianlara 3]

Obi, on some engines which have been in service for many hours the valve stems wear away at the rocker arm faces. And sometimes in those cases even though you did a meticulous job af setting the clearances, sometime you still have noisy tappets.
Noisy tappets are nothing to worry about. But valve clearances set too tight will cause valves to (virtually) ride, resulting in burnt valves and seats.
The only repair for worn rockerr arm faces or bushes is refacing the arm or renewing the bushes. On a clients motor this should be addressed but on you motor...forget it. Any diesel engine produces enough rattles that slightly loose valve clearances are rarely a bother.
In a nutshell, let them rattle a bit if thats what you end up with but do NOT set the clearances too tight.

[Obi Wan]

Originally Posted by brianlara 3

Obi, the conversion from metric to imperial is
39.37 inches equals a metre exactly

Uhh, thanks Brian. I actually do know how to convert between the two. I've been doing it for over 4 decades. I even have an app for it now!

I was merely suggesting that someone, when reading the manual, may have misread the decimal mm specs as decimal inch specs.

[brianlara 3]

Originally Posted by Obi Wan

Uhh, thanks Brian. I actually do know how to convert between the two. I've been doing it for over 4 decades. I even have an app for it now!

I was merely suggesting that someone, when reading the manual, may have misread the decimal mm specs as decimal inch specs.

Yeah, right.

[Rorzech]

Originally Posted by Obi Wan

As I slowly take my 5424 apart to refurbish it, I checked the valve clearance. I measured a fairly consistent .018 inches. However, the manual says .0071 to .0089 inches, or .18 to .22 mm. I wonder if some wonder mechanic got his metric and inches mixed up.

Wondering if anyone else experienced this? I suppose it could be wear but that seems like a lot. I wasn't planning on cracking the engine apart if I don't have to. Tried to do a compression test but the new tester i ordered off of Amazon turned out to be a total piece of chinese crap with threads cut so poorly they don't even screw in. And it was not one of the cheaper ones.

It might have had Metric Threads or SAE. You should have a tiny thread gauge SAE and Metric just like feeler gauge .

[a64pilot]

Logical, cause 18 to 22 thou is rattly loose, and would explain how they all got the same looseness.
Valves wear tight as has been said, but sometimes valve trains do wear, but usually not on our low RPM motors, but high speed motors that have very strong valve springs, and to get dead even wear across the board just ain't happening.
It is unlikely to have hurt anything. It does slightly retard valve timing and lift, and ever so slightly reduce performance, but not much.
I suspect you already knew that though.

You probably solved the puzzle that would have had me scratching my head.