head bolt torque what should i do now?

[fzj80joe]

So, I have never heard of reusing head bolts but evidently its okay on a 80 to do so.

I was just torquing my head down and on the final torque one of the back bolts right after i started turning it felt like it got 30% easier to torque and it continued to feel that way for about 45 degrees then i stopped.


so im guessing i stripped a bolt or the block. i torqued the last bolt and don't know what to do.

should i leave it under tension overnight because i have the new head gasket on there with the form in place gasket maker.

or should i untorque the head now?

should i turn it the final 45 degrees and see if it gets harder again

why doesn't toyota just use a torque value instead of this 90 then another 90 method

i feel like i was putting atlas 85 or 90 lbs on those bad boys.

i did what the manual said. torque to 29lbs then put a dot on there and then do 90 then another 90

 

[nukegoat]

you only used FIPG on the timing chain cover part, right?

 

[nukegoat]

My opinion is that it's unlikely you stripped the threads in the block - the bolt could be failing to apply more clamping pressure, though, as it may be stretching out, or you could have had a hydrolocked scenario (water in the bolt hole) that either cracked the block (worst case) or finally seeped through the threads of the block/bolt interface.

If the bolt is stretching or the hole was hydrolocked or just had gritty threads then you can
a) torque it further (might make it weaker)
b) leave it (might not be torqued enough)

if you think you DID strip the bolt / block, you can
c) remove all the bolts and buy new ones and do it again (the FIPG will probably be fine, but you can remove the head and re-seal it if you're really worried)

and if you think you cracked the block due to hydraulic pressure in the tapped holes you can
d) punch the 1fz-fe in the face and give up for a while

 

[Timpanogos Slim]

I haven't heard of head bolt threads in iron blocks stripping either. Maybe it's possible that the bolt gave up and is stretching? A lot of older engine designs didn't have stretch bolts in the head.

maybe the initial torque was some crud in the threads?

AFAIK nothing wrong with replacing 1 bolt. I even know people who have converted to studs by replacing one bolt at a time. 'course, with studs, you have to chase the threads with a bottoming tap to be sure of your final torque.

 

[scottryana]

Untorque the bolts releasing the pressure on the entire head. Pull that bolt and measure it. I bet you stretched it past yield. Order all new bolts drop them in and torque in sequence.

 

[ChiTown]

Probably bolt stretch or fluid in the bolt hole.

 

[Qball]

Why not replace all the bolts with OEM or arp? You already have it open, it would suck you didn't replace one or two bolts and have to redo the heat gasket again.


I would get arp studs/bolts and apply higher torque per arp spec. Some of the Toyota motors are know to not have enough torque for the head and part of the reason the HG fail. Both 1fz and supra motors from that time frame have that issue.

 

[fzj80joe]

I will go to American Toyota and see Cdan if he's working in the morning and get all new bolts, but just didn't know if i should leave it over night because of the FIPG.

I cleaned all the threads in the block with a wire brush and then brake clean and then blew out with compressed air so i don't think there was anything in the holes other than the little bit of oil on the threads of the bolts.

i will inspect the block side threads and measure the bolt when i take it out.

is it normal to take that much torque i didn't measure but it was at least 85 ft lbs

 

[Rwhat]

Did you measure out your head bolts after you removed them? Out of 14 I had 12 that were 10.83-10.85mm and I had 2 that were 10.78

The ones that were 10.78 were still within spec (10.6 min) although I ordered 2 new ones.

They all visually looked new with no corrosion.

 

[nukegoat]

If we're voting here, I'd say just run it. YOLO

 

[NLXTACY]

^ totally. Wait...it's not at #6 is it?

 

[fzj80joe]

haha thats funny you said all yours looked like new because so did I ! so no, i didn't measure them. i will tomorrow for s***s and giggles but I'm just going to replace them all.

after all I'm dong this in the name of preventative maintenance..

 

[LandCruisinMy93]

Most of the time of there is a torque spec plus an angle torque it means it's a torque to yield bolt and it needs replaced if removed or broken. The bolts do stretch, they're meant to. Some manufacturers allow for a certain amount of stretch, others none at all. I had the same thing happen doing the rebuild on a nissan vg30de, the last bolt felt easier to torque as I angle torqued it, though I had stripped it, backed it out and looked at it and it looked fine with no material in the threads, cleaned the hole out with a modified shop vac and reinstalled and torqued/ angle torqued it.. It snapped off about 10 degrees shy of tight. Easy enough to remove using the broken bit since it wasn't under tension. Long winded way of saying just replace the bolts For peace of mind and as a trouble saver, I know they're expensive believe me, Im rebuilding an isuzu 3.9 diesel to put in my cruiser and the head bolts were $11 each for 14 bolts and $14 each for 2 of them and my pathfinder and altima were about the same.

 

[Howard705]

^ Toyota FSM says CHECK/measure-replace ONLY IF out of spec.

 

[Mighty690]

Yep, same anxious thoughts when I torqued mine. I thought I had sheared a couple! I believe what I felt was the compressing of the metal portion of the HG, but bolt stretch is also possible. I actually carefully un-torqued the bolts in sequence, checked them all again (within spec) without letting anything shift or move, and then put them back in with more confidence. The rotation reference marks I made on the bolts and head were very close to the first torquing, btw. All has been well since too, with a great running engine. But, while new head bolts are a chunk of change, it might be worth your peace of mind!

 

[Whileemptyheadsdream]

If we're voting here, I'd say just run it. YOLO

Thats some wild She Krugman ! LOL !

 

[ChiTown]

Why didn't you use ARP studs for this job?

 

[eimkeith]

So, I have never heard of reusing head bolts but evidently its okay on a 80 to do so.

I was just torquing my head down and on the final torque one of the back bolts right after i started turning it felt like it got 30% easier to torque and it continued to feel that way for about 45 degrees then i stopped.


so im guessing i stripped a bolt or the block. i torqued the last bolt and don't know what to do.

should i leave it under tension overnight because i have the new head gasket on there with the form in place gasket maker.

or should i untorque the head now?

should i turn it the final 45 degrees and see if it gets harder again

why doesn't toyota just use a torque value instead of this 90 then another 90 method

i feel like i was putting atlas 85 or 90 lbs on those bad boys.

i did what the manual said. torque to 29lbs then put a dot on there and then do 90 then another 90

The same thing happened to me today - the #5 (of 14) head bolt gave up a lot of resistance in the last 30 degrees of the final 90 degree sweep. New head bolts, btw.

As much as they cost, this thing is going to have to prove that it's going to leak before I through another several hundred dollars on another set of bolts and HG.

 

[tominboise]

Did you clean the threads in the block with the correct tap, prior to installing the head bolts? When I did mine, I chased all the threads and then carefully vacuumed the crap out of the holes. Then I degreased the threads with brake cleaner and let the holes dry thoroughly prior to installing the gasket, head and head bolts.

 

[eimkeith]

I did vacuum and degrease (did not chase the threads.) there wasn't any weird resistance threading them in - I think I got a bad factory bolt, to be honest.