head bolt

[Anonymous]

I read that 1 head bolt on the small 6 was a smaller shank or maybe ground for oil passage. Just took my head off and all the bolts are the same. The one where the oil passage is no different than the others. I carefully looked at them all to see if anyone had them out and put one in the wrong place, but that isn't the case.
L.D.

 

[Anonymous]

I believe that this is a mod that can be done to the bolt yourself. Others know better but I am pretty sure this is the case.
Paul

 

[CZLN6]

Howdy LD:

Early Pre-'75 head bolts were not tapered. A trick mechanics did was to flatten one side on the oil transfer head bolt a little to allow more oil to pass up along side the bolt to the transfer slot in the head to get more oil to the rocker shaft for distribution to the rocker arms and pushrods.

FoMoCo began using tapered head bolts from '75 - '83 on all 200/250s to accomplish the same thing. If you were to replace your #11 head bolt with a later, tapered style head bolt you will have accomplished the same thing.

Adios, David

 

[Anonymous]

Do you think think this is necessary? Mine is pre 75 and it is a 170. Just because Ford made that change doesn't mean it is a better idea. Many of their changes have not been but this one could be. Was there any problem with with this engine not getting enough oil to the rockers under normal conditions. Is there a down side to making this change?
L.D.

 

[simon]

Was there any problem with with this engine not getting enough oil to the rockers under normal conditions. ?

dunno, but take a look at those pictures of this C9-coded 250:

here and there.

Thats the reason why I´m always looking to improve lubrication, plus being so crazy about tight clearances, hardened and ptfe coated shaft, chamfered oil holes, and weight matching, deburring and nitriding the replacement rockers.

 

[jwb68c]

yeow!! that could be a problem eh.

 

[CZLN6]

Howdy All:

were those photos of the rocker shaft? If they were, I'd say you had a plugged up oil delivery somewhere. The tight places are, along the head bolt and in the transfer slot between the block, head gasket and head relief channel.

The other spot that gets gunked closed is inside the rocker shaft and the oil holes in the rocker arms.

In an otherwise perfectly clean engine interior, the tapered head bolts may not be necessary. In a less than clean interior engine, more volumn of oil could help to prevent plugging up and the damage in the photos. The extra volumn of oil helps to push through a blockage and dilivers more oil to the top.

Is it necessary? Probably not. Is it cheap, easy insurance? YOU BET!!!

Other precautions-
*When milling the head, be sure to re-establish the oil transfer channel in the head. Aftermarket composite headgaskets add to this dimension also.
*Make sure the inside of your engine is a clean and cared for as the outside.
*Use as light a weight oil as possible and a high detergent, cleaning additive regularly.
*Use the larger style oil filter whenever possible to increase oil capacity.

Adios, David

 

[simon]

Howdy All:

were those photos of the rocker shaft?

yes, those are from my rocker shaft after disassembly.

surprisingly, the rockers arms held up pretty well against all that wear, the bore diameter still was within the tolerance given in the shop manual.

forged iron castings, pretty awesome material with good dry running properties. ..virtually ate the shaft, which is hardened steel !!

Nevertheless, most are beyond their lifetime- their bores, though within specs, show deep scars and craters from particles.
the surface contacting the valvetip is also worn badly from a lack of lubrication (small front oil hole).