EA head bolts - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

08-11-2002, 02:46

Gidday, I'm in the middle of replacing the head gasket on a 07/90 EA falcon wagon GL. (yeah, I know - "groan!!!")
I noticed on some previous message threads that it is neccessary to replace the head bolts due to stretching. Are these special bolts supplied by Ford or can they be sourced elsewhere.
I presume that the streched bolts bottom out thus meaning they won't torque down properly? If so, is it possible to take a couple of thou off the ends (using a lathe) or perhaps using shims/spacers under the heads of the bolts? Has anybody tried this?
It's not the $80 that bothers me so much as replacing the bolts with the same inferior product!
Also I noticed that it was mentioned when tensioning the head down, not to use the workshop manual way (ie torque to spec then go 90 deg in direction of turn. Could somebody tell me the correct tension to use on the '90 ea falcon if not using workshop manual method?
Many thanks for any help.
regards
Simon

Aussiblue · 08-11-2002, 03:43

The bolts are torque to yield bolts and are considered superior to the old style torque only ones so you must:
a) Buy tirque to yield bolts from Ford, Repco, Veales etc
b) Torgue them to spec then 90 degrees as stated in the manual.

With a alloy hed you need to use torque to yield to get the required clamping force.

See http:http://www.aera.org/Members/EngineTe...1296/page2.htm and http://www.federal-mogul.com/felpro/...kets/pg_9.html
//www.federal-mogul.com/felpro/counterpro/essentials_of_engine_sealing/cylinder_head_gaskets/pg_9.html for a discussion of torque to yield bolts.

Aussiblue · 08-11-2002, 03:47

Note what is said here http://www.autobodypro.com/tektips/a...nutsnbolts.htm

"One-time-use, or torque-to-yield (TTY), fasteners take advantage of the torque yield principle. Most torque specifications build in a 25 percent safety margin--they can be overtorqued by 25 percent before damage occurs. TTY bolts do not have this safety zone. They are designed to be tightened just into the yield point but not to the extent that the metal is distorted. The advantage is they deliver 100 percent of their intended strength, versus the 75 percent strength provided by regular bolts. The drawback is that they can only be used one time. Once they are removed from an application, they can no longer support the load they previously did, and they must be replaced with TTY bolts. Installing a conventional fastener in their place will result in a 25 percent weaker clamping force. Because TTY fasteners are used in a variety of applications, such as subframe mountings, it's important to identify these during the estimating process--not just for the additional cost involved but also to alert the technician."

Aussiblue · 08-11-2002, 04:21

buy one of these ACL tools Ref No. ACLHBA001 from Repco or Veales or a Kincrome torque angle guage.

08-11-2002, 16:25

Many thanks for the info and the quick reply Blue. I am now more understanding of the principals involved. (not that I had much understanding to begin with!!!)
Thanks again
Simon