[AWDbandito]

Hey guys.....I know I should be shot, but changing a head gasket with no service manual. Only thing I'm worried about is torque specs on head bolts. Could someone post the proper order and torque specs on these bolts.....or anything else that may be helpful. Thanks in advance.

 

[KingSapper]

610 kg/cm (44lb/ft, 60Nm) torque as per TSRM for 4AGE (AE86 corolla manual I have)

Tightening of head bolts are in this sequence:

Bolts are numbered from front (#1 cyl) to back:

Exhaust: #10, #6, #1, #3, #7
Intake: #8, #4, #2, #5, #9

Torque to 35 - 40 lb/ft first, in sequence, then go back over the top and torque to required 44lb/ft in sequence. This will insure a good gasket seating, if I remember correctly. It's been a couple of years since I did a HG on a 4AGE

Hope this helps!

Will

 

[ITA-MR2]

Clean out, chase, and blow out the bolt holes completely - before you put the head or gasket back on. Clean the bolts (yes, even new ones). Lightly oil the bolts with engine oil prior to inserting. Test fit every bolt for binding / tightness. You should be able to bottom out every bolt cleanly using almost no torque. If you can't, recheck the bolt (or stud) and the hole, remedy the problem, and try again.

I torque in 4 stages; to about 5 ft/lb, then 20, then 40, then 44 (using the sequence provided by Will for each step).

 

[Skyline]

I torque mr ARP's to 65 ft'lb's for my own reasons ..

Toyota manuals are notorious for underating Torque Specs .

 

[Emiel2]

posted by Skyline


Toyota manuals are notorious for underating Torque Specs .

Not if you torque them at 60nm, then run a 500 miles without coming above 3500rpm and then 60nm them again.. they wil last perfect then.

 

[TomsMR2]

waait waait..

i dont think you torque head bolts like that... i remember ITA correcting this the last time too :S

you do the torque sequence as said.. but after the last torque spec, you go back and turn each bolt 1/4 turn or something like that? am i off?

 

[woodc]

Yeah...the BGB I used had you torque to X ft-lbs then do two sets of 45 degree turns....put little dots on them...the whole nine yards?

Coty

 

[ITA-MR2]

That started in '88. Don't know if they changed the head bolts, or what.

 

[azmr2]

posted by ITA-MR2
That started in '88. Don't know if they changed the head bolts, or what.

May be because of the SC model? I'm getting ready to retorque my 88SC head again and the 89 book is different than the 87 BGB. Remember the 1/4 turn is really 90 degrees.

 

[Suwipotato]

waait waait..

i dont think you torque head bolts like that... i remember ITA correcting this the last time too :S

you do the torque sequence as said.. but after the last torque spec, you go back and turn each bolt 1/4 turn or something like that? am i off?

True I have also done it like that in the past

 

[TeeKom]

Remember to always use NEW head bolts. 4AGE uses torque to yield head bolts that stretch during the torqueing process.

 

[TeeKom]

This is from the BGB.

EX: 7,3,1,6.10
IN: 9,5,2,4,8

1) Tighten head bolts in numerical order shown to 22 ft/lb 29 N-m

2) Mark the front of each cylinder head bolt with a paint mark.

3) Tighten each head bolt 90 degrees in numerical order shown

4) Tighten each head bolt an additional 90 degrees in numerical order shown. Verify mark is now facing rearward on each bolt.

 

[mikemo]

Remember to always use NEW head bolts. 4AGE uses torque to yield head bolts that stretch during the torqueing process.

Well, no, they are not torque-to-yield bolts. The 1988 factory service manual does NOT show them as single-use items. If they were, the manual would clearly say so. It does not.

New bolts are not necessarily a bad idea, but they are not required. Clean the old ones, check the threads, chase the holes, and verify that they don't bind (as listed in a much earlier post). From there you will be good to go.

Obviously, the head and block surfaces need to be clean and straight before reassembling. Maximum head warpage is 0.05mm (two thousandths of an inch).

 

[TeeKom]

Well, no, they are not torque-to-yield bolts. The 1988 factory service manual does NOT show them as single-use items. If they were, the manual would clearly say so. It does not.

Ok, you are correct on that, they are actually stretch bolts. That's why the torque specs have the torque and then 90 degree turn. Yes, you can reuse them as long as they have not stretched past their usable range but you'd have to measure each one and verify.

 

[rmeller]

I think that the torque to angle spec was introduced just because it is more accurate. It is less sensitive to friction on the threads.