Assembled my 88 fuel injection motor. When checking the rocker to valve stem clearance, it is way too much. (Around 120 thousands)

The static gap without pulling the rocker up away from valve stem and down on pushrods is closer to spec at about 30 thousands. Still a bit wide though.


Can this be checked properly with dry lifters or do i have to wait till they are pumped up and collapse them then?

I redid the shortblock but the head was freshly done when i bought the donor truck. So I didn't do anything to it but clean it up. Checked the pushrods and they are all 10.14 stockers.

Thanks
Brigart

 

1° Gap between valve and rocker has to be measure with dry or totally collapsed lifters AND piston in compression stroke.

2° Recheck gap as indicated above if still been so big then it sounds like:

a. shorter valves where installed
b. valve seats were adapted to cylinder head and valve deep was not properly done
c. Excessive wear between pedestal and rocker
d. Excessive wear between/at lifters & camshaft

Let us know what you find...

 

The valves have a fresh machined surface on the stem end. Either they are new or were touched up.

Is there a way to verify their protruding length from on top of the head?

Looked through the chiltons and couldn't find a valve length spec.

Cam and lifters are new. Pushrods are all straight and stock length.

Would love it if I didn't have to pull the manifolds and head back off lol

Thanks Brigart

Wonder if this is gonna bite me in the ***.


Intake & Exhaust Valve Length Change On
1985 Ford 4.9L (300 CID) Engines


Ford Motor Company has changed the length of the intake and
exhaust valves used in the company's 1985 model year and later
4.9L (300 CID) engines. The earlier style valves had an overall
length of 4.810 long while the later style are 4.750 long.

The Ford Motor Company part numbers for these valves are:
E5TZ_6507A for the intake valve and E5TZ-6505A for the exhaust
valve.

The change in valve length was necessitated by a change in the
engine's rocker arm styles. The 1985 model year and later
engines are using the boat style rocker arm configuration that is
similar to the Ford 351W and M series engines.

At this time, AERA is not aware of any aftermarket suppliers for
these new length valves.

(Insert Illustration)


The AERA Technical Committee

 

Somewhere I have seen "assembled height" specs,but I don't remember where,they use that spec to tell if valves were seated too deeply in the head after grind in.I would call a local shop that does head work,they should have that spec.I know it used to be common to dress valve tops if needed when they were ground,but it was a very minimal amount.It sounds like if they used the wrong valves (older) that they would be long and your clearance would be too tight.At any rate,I wouldn't wait until I fired it up to find out.What a mess,it would be better for tear down now,if needed.Good luck with all that.I have been running 300's for over 10 yrs now and Ford V8's over 20yrs before that,and I have never heard so much about valve adjustment until I came on this forum,I guess I've just been lucky.Most all of the ones I have dealt with just had a torque spec on the fulcrum nut that seated on a shoulder,and if everything else was correct,the lifters pump up and adjust,like they were designed to do.

 

Thanks 300B if you or anyone finds this spec i'd appreciate the info. Off working in California (live in OR) so projects on hold for a bit. Gives me a chance to hit the junkyards down here.

Thanks
Brigart

 

Rocker arm bolts torqued to 17-23 ft. lbs.

With the lifter on the base circle of the cam and fully collapsed, the clearance between the rocker arm tip and the valve stem should be between .10 and .20 inches.

Ideal clearance would be .125 - .175 inches. So your clearance is with in spec. with the standard pushrod.

Rotunda tool t70p-6513-a is used to collapse the lifter before you take the clearance measurement.
You hook the tool on the front of the rocker arm and then you pull back on the tool. This will collapse the lifter.

 

F150XLT you are a lifesafer!
Went back and reread it again. Somehow I registered it as .0125 to .0175 when I read it the first time.

Thanks a ton.

Brigart