Yblock milled heads

[Daves55Sedan]

It looks like the heads had a lot shaven off the bottom. Before I gave the machinist my Heads, there was no material shaved off the part numbers in the recesses on the bottom of the heads, but now the part numbers are partially shaven off. It seems like that's gotta be about a sixteenth of an inch milled off.
So, how much do I need to turn all the rocker arm adjusters counterclockwise before I install the rocker shafts on the heads. If I install the rocker shafts without backing the adjusters off, will there be a danger of bending some of the push rods???

[Daves55Sedan]

Okay, I just did some research and found out that these are 1960 292 engine heads (COTB heads) They are not ECZ heads. All the ECZ heads are not posted so you need to be careful about how much milling can be done. But the COTB heads are posted heads.
Nevertheless, I am still worried about how much to back off the rocker adjusters prior to installing the rocker shafts on the heads.
BTW, I checked the head bolts thru the heads prior to installing and discovered it would be best to install 1/16" thick flatwashers on the headbolts to make sure that the bolt threads would not bottom out on the cylinder block when attempting to torque down. It is possible they were already bottomed out prior to having them milled and that may be why my head gaskets were blown in the first place.
But all is well. I ground the valves, hand lapped them into the seats, reassembled the valve/spring assemblies and have both heads torqued down on the block now.
Doggone those things are heavy for an old man to lift over the fenders

[miker98038]

It's been a long time, so don't trust my memory (I don't). There's a machined pad on the ends of the heads that measured a fixed distance, from the original finish of the heads. Measuring this will tell you the total milled since new. If no one chimes in here who knows, try the y blocks forever site. I've milled a lot of those heads over the years, and never needed a thicker washer on the head bolts.

You'll also find some interesting info on shimming the whole rocker assembly to get the proper geometry, if you've got a high lift cam, or a re grind on a smaller base circle.

I always back the rockers off completely, and reset the valves from scratch. Google "Walt Knuckles" (I think), he had an interesting method to set the valves using the rotation of the adjuster, rather than a feeler gauge.

Yea, they're heavy. Mummert's aluminum ones are a lot easier.

[paul2748]

Another warning - some head bolts are longer than others. make sure you get them in the correct place.

As far as backing off the rockers, I never did this and haven't had any problems. Just bolt the stands down evenly a little bit at a time.

Posted heads came out sometime during 1957 so some ECZ heads are posted.

[Alaska Jim]

the rockers on y-blocks are adjustable and need to be backed off from whatever they were set at before. they will not be correct if you just try to bolt them down without backing them off, and there is a good chance of bending a push rod. the solid lifters will not "give" to allow for the difference of the material milled of the head. back the rockers off and readjust them as outlined in the service manual, you will glad you did. if you get the bolts in the correct holes you should not need washers as spacers.

[Hoosier Hurricane]

Sponsored Links (Register now to hide all advertisements)

The four pads along the bottom of the heads are 1 inch tall when the heads are new. Measuring those pads and subtracting their height from 1" will tell you how much has been milled off the heads. John

[dmsfrr]

Originally Posted by Alaska Jim

the rockers on y-blocks are adjustable and need to be backed off from whatever they were set at before. they will not be correct if you just try to bolt them down
.......... and readjust them as outlined in the service manual, you will glad you did. if you get the bolts in the correct holes you should not need washers as spacers.

I agree. Back off the adjusters and re-set them.

Originally Posted by paul2748

Another warning - some head bolts are longer than others. make sure you get them in the correct place.

from > http://ford-y-block.com/assemblyerrors.htm
"Head bolts. There appear to be 2 different length head bolts in a Y-Block engine, 5 short bolts near the spark plugs and 5 longer bolts under the rocker arms. It’s true that the 5 short bolts near the spark plugs are identical but the 5 under the rockers are not the same! 2 of these bolts are slightly longer and are installed at the outer ends of the head where the alignment dowels are located. Lay all 10 longer bolts (5 per bank) next to each other and you should find 4 longer and 6 that are about ¼"shorter. Installing the longer bolts in the center 3 holes can cause them to bottom in the block which can result in a blown head gasket. Late production engines have only long and short bolts."


.

[Daves55Sedan]

Originally Posted by dmsfrr

2 of these bolts are slightly longer and are installed at the outer ends of the head

I didn't pay any attention as to whether they came out that way, but I definitely did re-install the two longer bolts on the outer edges of each head.

[Daves55Sedan]

These heads were milled before this, I think it was back in 1992, so knowing what the total amount that was machined off won't be helpful. I was hoping to just back off the adjusters by a distance equal to the amount milled off this time. But now that I think about it, that is silly. It doesn't take into account that the new head gaskets might be a different depth, nor the idea that the head bolts might have originally been bottomed out, thus not really tightening the heads down to the proper torque specification.
So darn, I am just going to have to go ahead and bite the bullet. I'm going to back them out a lot and start over with a new cold valve lash adjustment. I was hoping to avoid this. It can be easy to loose a push rod down in the galley when the adjusters are backed off a lot.

[dmsfrr]

Originally Posted by Daves55Sedan

... It can be easy to loose a push rod down in the galley when the adjusters are backed off a lot.

Tie some string around the pushrods so you can pull them out if they slip down.



.

[34pickup]

Did you also have the intake surface milled?

[CrownVic55]

Dave, over the years I have managed to drop push rods several times. Caused by too much lash and valve float. In every case the push rod fell down but is still visible in the head. A piece of wire with a hook on the end and I fished each one out. None were bent and were re-installed. Since this was done at high rpm with no damage, I would't worry about one slipping out of the tappet.

[paul2748]

Another way to prevent pushrods falling into the valley when working on the engine is to put the snap type clothes pins on them.

[darrell]

ive never had one fall in unless it was bent.

[Daves55Sedan]

Prior to seeing your ideas about using string or wire, I got the idea about using cardboard. I cut out a piece of cardboard for each pushrod with a hole in the middle that would allow inserting the push rod through it, but too small for the "cup" at the top to fall thru. The outside diameter was made a little larger than the hole thru the heads so that the whole piece of cardboard could not fall down inside the hole. One side of the cardboard outer cut was squared off so that it could easily be grabbed for tearing out the cardboard after all the valve lash adjustments had been set.
I finished the adjustments yesterday and the cardboard holders worked fine and easily tore out when finished.
I also made a cardboard crankshaft damper indicator, cut out to fit on the front of the power steering pulley in front of the crankshaft damper. The template is marked with four marks at 90 degree angles representing TDC, 90 degrees, 180 degrees, 270 degrees. It has a hole cutout in the middle large enough for a socket to poke thru for turning the crankshaft damper. I used another piece of cardboard cutout to extend the timing pointer so it would be easy to align the cardboard crankshaft damper template with the pointer. The crankshaft damper template was taped to the power steering pulley with four small pieces of masking tape. It all worked pretty good.

[Daves55Sedan]

Originally Posted by paul2748

Another way to prevent pushrods falling into the valley when working on the engine is to put the snap type clothes pins on them.

I thought about using clothespins before I got the idea about the cardboard holders. I believed that the bulk of the clothespins might be more trouble that they're worth, possibly causing the bottom of the pushrods to come out of the tappets and rest upon the galley floor. And if some of them were to do that, you wouldn't notice it unless you constantly went around and twirled the pushrods to make sure they were still down in the tappets.

The suggestion to use little pieces of copper bailing wire is probably better than the clothespins, but if I ever have to do this again, I'm going to cutout an empty cereal box again. I had no trouble at all with the cardboard holders.