Headbolts Torque

[rshimp]

I'm going to rebuild the engine out of my 1980 spider 2000 FI and I was wondering where to find torque specs for head bolts and what not. I saw a website say that the head bolts should be torqued to 7.5 kgm which is about 53-foot pounds. That could be right but when I took them out it took a lot more than 53 foot-pounds to remove.

[Nut124]

My copy of a shop manual says: 83Nm, 61ft-lbs, 8.5kgm.

The original bolts are a bad design and will stretch easily becoming unusable. The problem is that the shank is not waisted and all the clamping torque hits the 1/2" or so of free thread, stretching it. Compare the bolts end to end, mating the threads. Look for any evidence of stretching in the free thread, threads not mating perfectly. Or check with a matching nut. Discard.

I have been using the waisted shank, long free thread torx head bolts and like them better. These may have a different spec. Check w seller.

When torquing, do it in steps and keep track of torque development vs turning angle at each step. If torque does not increase consistently with turning angle, at the last step, then the bolt has yielded.

[wetminkey]

GOSH!! Do what I did,...REPLACE your head bolts with a system that is easy to use, and works right:
https://autoricambi.us/high-performance ... idden=true
Solved my head gasket leak problem permanently.

[focodave]

GOSH!! Do what I did,...REPLACE your head bolts with a system that is easy to use, and works right:
https://autoricambi.us/high-performance ... idden=true
Solved my head gasket leak problem permanently.

+1.
I did the exact same thing as wetminkey.
Blew a head gasket about 2000 miles ago.
Love the new studs -- retorqued them after 500 miles -- very pleased with them -- you will be too -- best upgrade you can do while you are in the mode of working on your head bolts.
PLEASE do this upgrade -- the ROI is well worth it!

[Nut124]

GOSH!! Do what I did,...REPLACE your head bolts with a system that is easy to use, and works right:
https://autoricambi.us/high-performance ... idden=true
Solved my head gasket leak problem permanently.

What final torque value did you torque to?

I tried a set of studs and got coolant leak thru the top nut threads. Some of the head bolt threads in the block are wet, open into coolant.

Did you use thread sealant on the studs?

[tima01864]

I used this sealant on the head bolts, Was recommended
Loctite 1158514 Head Bolt and Water Jacket Sealant, 50-milliliter Tube

[focodave]

Yep.
Loctite 1158514 is the stuff you must use.

I torqued to 55 ft/lbs, on the first go around.
On the re-torque, after 500 miles, I torqued to 61 ft/lbs.

[wetminkey]

The threads of the head bolts enter coolant-filled 'water-jackets' in the engine block and WILL leak coolant if thread sealer is not used.
The head stud kits come with proper torque specs from the manufacturer. Studs require lower final torques than bolts.
I did exactly what focodave did,...55ftlbs, and then 61ftlbs after some engine time.
BTW,...HOWDY focodave!!
Todd.

[RRoller123]

This summarizes what bolt goes where, and what it is exposed to:

[18Fiatsandcounting]

Thanks for the chart, Roller! Do you (or anyone else) have a similar chart for the other engine sizes? The reason I ask is that I don't recall my 1438 or 1608 head bolts going into the coolant gallery, although they do tend to get gummed up with age (just not with coolant). My memory could be wrong on this, and I put thread sealant on them anyway to keep them from locking up.

The other data seems correct. The other ones that I have seen differences with are the 4 bolts that hold the water pump to the block, in that some claimed these went into the coolant gallery whereas my smaller engines seem to have blind bolt holes.

-Bryan

[RRoller123]

I only have this one, made it for my 2L engine.

[phaetn]

I have the same studs, too, bought from Allison's a few years ago. They offer better clamping force than head bolts. I went to them to chase down a head leak that may, in fact, have been coolant getting drawn into #4 intake passage rather than a head gasket sealing issue. Neverthless, I like them.

One time I forgot to use a thread sealant and coolant weeped out of the nuts at the top (having made its way up the threads) as the bottom threads are in a coolant passage. No biggie. I just took them out one by one and applied sealant. I think it was some kind of Permatex sealant.

I lost my torque spec sheet for them so just went to 61 lb/ft, tightening in three stages (20, 40, 61 respectively). This time I just used RTV silicone on the bottom threads. Should be fine.

Cheers,
phaetn