FORD 8n valve replacement

[steve16]

i recently started an engine overhaul on my ford 8n. I got new rotating valves and lapped them and installed them. Someone told me however that i might have grind down the bottom of the valves? is this true? if so how do i know if i have to? I'm kinda new to the engine overhaul if ya hadn't noticed ha.. thanks for any advice
 

[Dell (WA)]

Steve......tulip (seriously) valve stems needed grinding for valve clearance, they have 2-piece valve guides.

Rotating valves are straight-stemmed and the rotating valve lifters have built-in adjusting boltheads that you use with knuckle-buster wrenches......unless you know the "secret trick" of drilling a 3/16" hole in each castiron lifter bore so you can stick a 1/8" rod and stop the lifter from turning while you use a shorty "thin-head" open-end wrench to set valve clearance to 0.010-0.012" intake and 0.014-0.016" exhaust, engine COLD. Piece-o-cake.......Dell
 

[Hobo,NC]

[ZANE]

Tell me about this stem grinding thing Hobo???? I have never done that to a rotating or non rotating valve that is straight stemed and not mushroom head valves as used originally in the N engines. How would you know how much to grind anyway?? The rotating cap that the lifter touches top edge pushes the keeper off it's seat to allow the valve to rotate when open and drops off the keeper when it is closed. How could you measure this???
All I ever installed the valves fit the rotating cap to my knowledge because they would all rotate when the exhaust valve was open????

Zane
 

[steve16]

thats what i figured i would have to adjust them a bit. unfortunatly my rotating valves don't come with adjusters so i have to take them out and grind the bottom of the stem?

steve
 

[Hobo,NC]

[Gaspump]

Yeah, I had to do the same thing to one set I had. If there is no clearance between the cap and the stem they won't work and will wear. I don't use the rotating valves any more, after checking the caps and fighting the clips I now go back with non rotating. Worked for most N's for 50+ years and none of mine will see 50-80 hour weeks again, don't need them.
 

[Gaspump]

I feel there is a lot of confusion here. Incomplete answers in most all replies including mine. Yes the rotating valves must be used with adjustable lifters. The stem caps on the rotating valves must be measured for the correct gap to the end of the valve stem. If the gap is too wide the cap will contact the keepers and hammer the heck out of them. I have found them damaged to the point that they were almost hammer welded to each other and in one case they were gone. If the gap is too small no rotation. To get the correct clearance on those caps that are too long the cap skirt is ground. On the other hand I had to grind more than one valve stem where the gap was too small, not supposed to happen but with some new parts it just happens that way. As Hobo mentions the instructions are clear in the FO-4. It is also outlined in original Ford Tractor manuals. I strongly suggest having one or the other on hand, you need it.
 

[Hobo,NC]

Steve I am gonna recommend that for a new'be with out the rite tools not to tackle the free rotat'n set up, For sure not with out the FO-4 manual. Its money well spent to have a proper valve job preformed on yer engine, in fact the performance of the engine depends on how well the valves seal the combustion chamber.

If you must use the Free rotating set up B prepared for a time consuming job,,, it taint EZ to get'em set up, takes me a hour with the rite tools and I have seen a new'b fudge with them all day with the rite tools but it can B done under the shade tree if you are clever enuff

It helps to understand zackly how the set up werks,,, it does do a good job of keep’n the zaust valves from burn’n

The Valve cap for the exhaust basically supports the spring tension when the valve is lifted by the cam. Allowing the valve to rotate freely. The fit of the retainers to the valve is critical so that when the tension of the spring is carried by the end cap the valve can rotate freely in the retainer (these must not clamp the valve). The length of the end cap is critical so as not to move the retainers to far up the valve stem I.e. .004 thou as per the article.
This how the free rotat’N exhaust vale works

8N TRACTOR SERVICE INFORMATION

Bulletin Subject: New Valves and Adjustable Tappets for the Ford Tractor, Kit No. 8N6546

Over the past year, in certain localities, a few owners have encountered some difficulty with tractor engine valves sticking or burning, particularly the exhaust valve. For the purpose of relieving this condition, new valves and adjustable tappets have been developed for service replacement on the Ford Tractor.
The new valve will relieve exhaust valve failure attributable to excessive deposits of the valve seat and/or valve stem. These experiences are local in character, and replacement of the standard valves with the new valves is not subject to warranty or policy adjustment. Please do not submit S.A.R.'s for replacements.

A kit, Part No. 8N6546, is now being made available. It contains four new valve assemblies and eight adjustable tappets with wrenches. The wrenches are included to hold the tappets while adjustments are being made for length.

In Attachment No. 1, you will find a complete description of the valve as well as a drawing and instructions for proper installation and servicing. Complete instructions for' the installation of the tappets are included in each kit. You will note that tappets are to be used for all eight valves; however, the new valves should be used only in the exhaust ports.

These kits are available for immediate shipment as announced in "Service Parts Release and Change Notice No. 502". Dealers should be advised of the availability of the subject parts, particularly in those areas where sticking or burning valves axe now a problem.


INSTALLATION INSTRUCTIONS FOR NEW VALVE IN THE FORD TRACTOR ENGINE



A new type exhaust valve assembly is illustrated and described above. The assembly consists of a valve "A", two keys "B", a cap "C", and a special spring retainer "D"; the standard spring being used with this assembly.

The parts, when correctly assembled, permit the valve to be entirely free of the spring force during the lift portion of the cycle. At the beginning of lift, the tappet lifts the keys through the medium of the cap which, in turn, lifts the spring retainer and spring, thus leaving the valve free of the influence of the spring with respect to cocking and undue sideloading. During the normal travel, the valve can turn, oscillate, or otherwise move in its guide. With this action, the deposits that tend to build up at the head end of the guide and on the stem are constantly scrubbed, thus preventing sufficient buildup to take up the normal clearance. Furthermore, the deposits that occur between the valve face and its mating seat cannot build up excessively or unevenly; the net result being that a much better contact is maintained between the two faces, which insures proper sealing.

INSTALLATION

The successful operation of the new valve assembly depends, to a large extent, on proper installation. The clearance required is controlled by the length between the face of the undercut in the valve and tip end, and the depth of the cap. If the can depth is too shallow, it will not lift the keys and springs and, on the other hand, if the cap is too deep or the length between the groove face and tip is too great, the clearance will be
excessive, resulting in a high wear rate and possible valve breakage.


This clearance can readily be checked after the parts are assembled in the engine, by turning the engine over until the valve is free in the lifted position. It should then be free and the actual clearance can be measured by locating an indicator on the valve head and noting the reading then the valve is moved vertically. This clearance can be .0002" providing the valve turns freely, to not over .004" maximum vertical movement.

RECOMMENDED INSTALLATION

1. Check valve guides after cleaning out the deposits, and if bellmouthed or worn so that the clearance is 50% over the original factory recommendation, install new guides.
2. Reface cylinder seats and check with indicator.
3. Inspect valves and seats to be certain that parts have not been nicked in handling.
4. Turn the engine until the valve is lifted and check freedom by turning the valve head.

SERVICING

The valve assembly should improve valve life so that, under normal conditions, they do not need to be checked until the engine is ready for overhaul. Normally, the greatest wear will occur on the portion of the key that contacts the valve groove face. If this is excessive, the keys should be discarded.

Before reinstalling, check clearance by assembling retainer, keys, and cap to valve. Hold retainer and press on cap. Rotate valve while pressing parts together. The valve should turn freely. If binding occurs, it may be due to nicks, dirt, or cap too shallow. To correct for shallow cap, either use new cap or grind valve tip face.

If valve is free, check clearance by inserting small piece of shim stock .004" thick between valve tip face and cap. Press parts together. If valve does not bind, clearance is too great and should be reduced by polishing the cap open end against a piece of fine emery cloth. Recheck clearance and rework cap until not more than .004" shim stock is required to bind valve.



I have run into a problem with the valve kits. The keepers for the free rotat'n exhaust valves do not fit. All they need is a little polish'n on the I.D. of the keeper. You also can polish the O.D. of the keeper. Take a exhaust valve and slide a retainer on the stem then take the two horse shoe retainers and fit them to the valve, slide the retainer up and check for fit. If they do not fit the retainer polish the I.D. of the retainer. You may also need to polish the O.D. off the retainer to satisfy you. I use a dremel tool with a stone that fits the I.D. of the retainer and a sanding wheel to polish the O.D. I have checked three kits and only 6 of the valve keepers fit. I am sorry for any incontinence and hope yours fit ok with out any additional work. I have also come to find out that if your engine had 2 piece guides the retainers for the intake will not work on the new spring.

I spec haft the kits I have sold I git a call to exchange them for the standard set up,,, I have even got a call stating that the machine shop guy did not want to install’em,,, I don’t know why he could git a nutter hour are 2 to do the job,,, just lazy and only look’s for meat and leave some else the bones,,, if ya gottta have’em they are a nice upgrade just b warned they are time consuming to set up rite,,,, good luck,,, BTW I was to busy to finish up this deal,,, one of those days. I am even out of cold beer so wait’n for the rock salt to git’em cold
 

[Hobo,NC]