I think Frank is on the right track. I, like Frank, like to re-torque the headbolts just from the point of one less worry and a final check. As others have said very seldom have I seen any change. Its that one time that is the whew!!,



Here is a link to the ARP site.

http://video.arp-bolts.com/catalog/ARPCatalog.pdf

It is a pdf file so may take a little time to download.

Scroll down to the tech section on pg 27 and there is info which I think Frank is inferring to.



I always replace the rod bolts, main bolts and head bolts whenever rebuilding a y block. I have worked to many years on John Deere diesels and seen the failures of re-using bolts. The cost of new bolts and studs is cheap compared to doing a re-teardown or grenading an engine.



Whenever I do a Y block I use ARP studs for the mains, new ARP rod bolts and Arp head bolts. Head studs likely will make it to hard to remove a head.



I buy them from Mummerts. He has already done the work of packaging the various length bolts and one stop shopping. He also has done the engineering, has set specifications, done testing and failure analysis which is worth a lot.

marvs

The ARP catalog info sure illuminates the head bolt re-torque controversy (they need to be stretched-in/stabilized). Explains why J. Mummert re-torques 3-5 times during assembly. Likely a requirement if gasket maker claims of "no re-torque needed after run-in" can be validated.

6 VOLTS/POS. GRD. NW INDIANA

I think the thing one has to remember is that the ARP info refers to new bolts or studs. If the bolt has been stretched already then re-stretching is not required. Torque only or stretch measurement, the way I read it.



If you install new rod bolts or main studs by the time final assembly happens one has probably hit the 5 times torqued/released between installation, resizing, clearance checking, final assembly etc.



The one one I would be concerned is head installation with new bolts. It may require torquing, releasing etc without head gasket until stretch is met??? or bite the bullet and waste a head gasket. You would have to make certain bottoming did not occur



marv

Interesting point. If a new gasket IS re-torqued several times (would at least help make certain the fire ring is adequately compressed) and not heat cycled, is it truly wasted? WILL successive re-compressions actually reduce it's final thickness, or is that entirely dependent on total force used?

6 VOLTS/POS. GRD. NW INDIANA

 In my mind that would depend on the actual Gasket construction and material. Modern (Best in particular) may not compress anough for it to be worthwhile. I had an "event" at the pure stock drags a few years ago where I blew both head gaskets in the same pass. Too much timing, not enough octane booster. We ( Feistritzer, Gordon Payne, and I )removed the heads and installed two of John Feistritzers spares in the pits. I thought I was being super careful on the torque readings, which is difficult with the engine in the car. Things like the hood and the heater get in the way. When I got home I re-torqued everything, found several loose. Doesn't prove anything except that I personally need to check my work very closely. Guys like Mummert and Eaton and Feistritzer (and others) probably don't, and that may be the actual reason for the discussion. Not the gaskets.

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank:

Don't include me on your "don't" list.  I always retorque after a few heat up/cool down cycles.  Often find one or more have relaxed.

John - "The Hoosier Hurricane"

I understand that to retorque after a few heat cycles means to simply take off rockers, and torque bolts or nuts to spec in proper order.

But when torqueing a new set of gaskets 3 plus times to make sure the fire ring compresses, are the bolts supposed to be loosened before retorquing?  That is the process I went through, and if wrong may be the cause of the initital seepage.  And yes I worked up to the torque spec in three steps, 30 55 and 70 lbs each time.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Okay, I know there is no such thing as a dumb question, but this may be a dumb question; When you re-torque, do you just unbolt the rocker shafts without loostening the  rocker adjusters or do you leave them set? I think I have it both ways.

Thanks,

Rono

  Ron Lane,  Meridian, ID

When I re-torque the heads I leave the rockers in place and use an offset extension which goes around the rockers these can be bought in 11/16 for original bolts or 1/2-12 pt for the ARP head bolts.



For the ARP bolts with a 12 pt 1/2" drive head. I have gotten around the rockers with a 12 pt 3/8 drive socket or a 1/2 dr 12 pt socket with a wobble extension. If using a 3/8 drive socket it has to be a quality socket such as Proto or Snap-on as others I have broken.



I re-check rocker clearance afterward incase clearances has changed. Adjust the rockers final.

marv

I take the rockers off without loosening the adjusters.  It's only 8 bolts per side.  Leave the pushrods in, and after re-installing the rockers (make sure all the pushrods are seated on the adjusting screws), the clearance should be unaffected.  I always re-check them anyway, just to be sure. 

John - "The Hoosier Hurricane"