Valve Adjustment F150 TXRD

[pstephens46]

When should the valves be adjusted? I have 465 hours on this 2004 motor. Will I notice a difference in performance? Don't hear many people discuss this maintenance detail....

[boscoe99]

An adjustment is performed only "if needed". That is, if the clearance between the bucket shim and the cam shaft lobe is not within published tolerance then a different shim is installed to get the clearance within specifications.

Yamaha recommends that the clearance be inspected every 500 operating hours or every 2.5 years, which ever occurs first.

Unless the clearance is widely out of specification I doubt the operator will ever perceive any difference in how the motor operates.

From I know and have read an adjustment is rarely needed.

[pstephens46]

10-4 Thanks

[fairdeal]

I finally checked my F225 at ~1400 hours

Bought two shims, for adjustments that were juuusst barely out.

(too tight, IIRC)

Had to special order; my local yamaha dealer (with a master tech) doesn't stock them....

[rodbolt17]

we don't stock them. it is rare you need them.

[zenoahphobic]

An adjustment is performed only "if needed". That is, if the clearance between the bucket shim and the cam shaft lobe is not within published tolerance then a different shim is installed to get the clearance within specifications.

Yamaha recommends that the clearance be inspected every 500 operating hours or every 2.5 years, which ever occurs first.

Unless the clearance is widely out of specification I doubt the operator will ever perceive any difference in how the motor operates.

From I know and have read an adjustment is rarely needed.

A well designed engine and specifications in this instance meets two criteria:
1. the cams and cups wear extremely slowly
2. the gap specified (initially there to allow for expansion and oil flow inbetween) does not allow a mallable or beating distortion to occur that will increase this gap (unlike pitting on valve stems that need gradual adjustments to bed them into a stable situation).

[boscoe99]

Zeno, zeno, zeno.

Are you saying that the clearance cannot increase with usage? That the shims do not wear and the cam lobes do not wear in a well designed engine?

Help me to understand please.

[rodbolt17]

its rare to see any wear on the cam or shim.
the heat treatment on the is very good and about the time it could wear past the heat treatment it wipes out RAPIDLY.
the lake 70's and early 80's GM 305 had a run of improperly heatreated soft cams.
some did not make 150 miles some made almost 30,000. most all failed very early.

however over time stems stretch and valve faces and seats erode and recess slightly.
that being said I may have had to change the shims in 5 motors,maybe.

[99yam40]

back in the 70s I had a chevy motor come in to a shop I worked in with one lobe on a cam that had a flat spot on it making a noise as you would expect.
But I could not figure out how that cam made it that far through the process and in a new car

[zenoahphobic]

Zeno, zeno, zeno.

Are you saying that the clearance cannot increase with usage? That the shims do not wear and the cam lobes do not wear in a well designed engine?

Help me to understand please.

Didn't say that at all. Wrote "slowly" equating to allowing large time intervals inbetween inspections even less requirement to adjust gap.

And as Rodbolt pointed out valve stems can stretch, if happens can somewhat offset the wear.

The old (?) rocker shaft to valve stem design would be regarded today as a poor design as the surfaces were small and rotated on each other. As you know, hence why we readily accept regular adjustment for those surfaces to round off. It was important to do gradual adjustments because the adjusting tappet rotates altering its contact everytime.

[zenoahphobic]

back in the 70s I had a chevy motor come in to a shop I worked in with one lobe on a cam that had a flat spot on it making a noise as you would expect.
But I could not figure out how that cam made it that far through the process and in a new car

Yes that clatter is distinct and does not lessen much even after adjustment, is the tell tale that there is a flat spot. Often more so on the rocker follower, just cannot set the clearance correctly to get rid of the noise (ref Honda VF1000F or Interceptor, Magna your world if you might have an interest in motorcycles).

[TownsendsFJR1300]

back in the 70s I had a chevy motor come in to a shop I worked in with one lobe on a cam that had a flat spot on it making a noise as you would expect.

My first car, 68 Chevelle with an in-line 6 had a "popping" when accelerating.

I swapped it for a 350 anyway and gave the engine to a friend. His dad pulled the cam and found a cam lobe wiped/flat and the lifter mushroomed.

For the OP, to check clearances, is much easier than adjusting. Simply getting to the cams, setting to TDC Compression stroke) on the cylinder being checked/ Running a feeler gauge between the cam and valve will get you your clearance...

As a side note, My Yamaha FZ6, (600 cc, about 92 HP) has a 14,000 red line. Factory spec's call for checking/adjusting at 26,600 miles. Most times, adjustment is inside spec's.

Your boat engine, running 1/3 the RPM's of the bikes engine (70 MPH is about 6,000 RPM's) and as noted above, is rarely an issue...

[rodbolt17]

next time you have an F 150 or larger head apart look at the valve springs and stem dia.

now look at my old 455 olds.
springs were massive,stems were about 5/16ths dia.

that's cause a rocker wipes acrossed the stem and the spring had to not only close the valve but keep the lifter in contact with the cam during closing.

now the overhead cam design with a rocker arm was somewhat better it still did not use the light weight simple design like the fiat and jag motors of the late 50's and early 60's. most likely some of the other HP imported motors used it as well.

the advantage?
now the shim bucket riding in a fairly large bore absorbed anf sideways thrust.
now we can make a very small light weight valve,now we can use lighter springs that reduced both weight and wear.

with modern metals and heat treating and the light weight desin of the springs and valves.
wear is almost non existant.
to make my old 455 make power at 7000 RPM took a relatively aggressive cam and a set of crane triple springs with about a 300 lb open pressure.

the F70 will tap 7000 without any valve train issues.

[boscoe99]

Today's technology is certainly impressive.

Consider a NASCAR motor with push rods turning 9000 RPM for hours at a time. Newer manufacturing technology and materials applied to an older design.

Some wonder why they blow up. I wonder why they last as long as they do.

God only knows what the future is going to bring.

[zenoahphobic]

Today's technology is certainly impressive.

Consider a NASCAR motor with push rods turning 9000 RPM for hours at a time. Newer manufacturing technology and materials applied to an older design.

Some wonder why they blow up. I wonder why they last as long as they do.

God only knows what the future is going to bring.

The future will be the demise of the ridiculously inefficient piston engine!