Let's Talk Turkey --- Head Bolts 'n Stuff

I was getting ready to spend today overhauling the $200 Honda which has
one bad cylinder which I suspect is a broken ring.

At any rate, I have received mixed opinions on the reuse of head bolts
that evidently were a "one use" only type. Especially perplexing was
the price wanted for new ones... $16 apiece, seven total required.

The consensus that I have gathered appears to be that reuse is OK as
long as the bolts are OK. Two outfits, one a machine shop specializing
in racing and the other, a long time independent Honda specialist both
suggested after looking at the bolts I have, to give reuse a shot.

Still, I canceled today's overhaul party, (thus allowing thousands of
mosquitoes live longer), and may opt to overhaul the FE engine that is
currently disassembled and all the internals, (crank, rods, pistons and
cylinder wall condition), have been given the OK to proceed. I should
be able to reassemble the short block this week and finish it next with
the rebuilt head, new timing belt, seals, etc. I also plan on tossing
in the extra five speed tranny to replace the current four speed unit
and will reseal it as well.

At any rate, any comments?

JT

 

$:

Is the head gasket steel sandwiched with teflon, or is it fiber sandwiched
with steel?

And what kind of tightening spec does your manual specify?

 

I've always reused head bolts, mostly because I hadn't heard of tossing them
the first few times I had heads off No problems yet
Mike

 

??? Appears to be fiber sandwiching steel.

25 ft lbs 1st round and 47 2nd round. Doesn't mention a thing about
"one use" bolts.

JT

 

I'm tending to agree. Better that the $16 each end up in my pocket.
The guy up the road said if a bolt was bad, I'd know it pretty quick
during assembly.

JT

 

When we look at the bolts and consider they are torqued to only 47 ft-lbs
and protected from the elements, it doesn't seem likely they have been
stressed in the past. I'm thinking it is one of those things that
professionals have to do as part of meeting professional standards but that
we amateurs can risk.

Mike

 

i'm skeptical about civic head bolts being single use. suggest you
check like this - put two bolts end to end and mesh the threads. if
it's apparent that the threads have yielded [elongation], then they're
single use. if not, then you can safely re-use.

 

I am as well. The reason that I've mentioned it is that they are
"strange" looking in that have roughly an inch and a quarter of thread,
the shank is not smooth buy has a swirling thread-like structure and of
course the head requires a special socket which of course I do not have.

Strangest of all, when I bought the original FE, this engine was in
place minus the head and sat for over ten years this way. Thankfully,
the hood was down and the surface rust that accumulated on the two
center holes, (where the pistons were in nearly their lowest positions),
cleaned right up.

Turns out the pistons are fine, piston to cylinder wall clearance is
well within tolerance, the crankshaft looks like new but it will get new
bearings anyway as will the rods.

I think that I'll be on solid ground here and will re-assemble the lower
end this week.

The more I look at the setup, the more I respect Honda engineering.
It's all quite simple and straight forward.

JT

 

you mean like this?
http://img.eautopartscatalog.com/live/A303064570OES.JPG

afaik, that's a retrofit bolt to be used in the event of gasket leakage
problems. [it's longitudinally slightly more elastic so the head gets
loaded more evenly.]

you will need to re-hone the cylinder bores - not excessively, but to
bust the glaze. when you're done, scrub those things for a good long
time with a natural bristle brush, and plenty of soapy water. do it
thoroughly! reason is that tiny particles of honing abrasive embed in
the surface. left there, they abrade the rings and before too long, the
motor's toast again. it's very common for machine shops not to do this
properly and you can see the results in rebuild lives vs. new motors -
60k miles for a diesel rebuild vs 300k on the original for instance.
done right and with appropriate hygiene, there's no reason a rebuild
shouldn't last as long as the original.

that goes for /all/ your cleaning operations!

as soon as you're done scrubbing and washing, spray with wd40 to
displace water so you get no surface rust.

and remove the carbon deposits in the piston grooves if you're not
replacing. carefully! nicked or scratched surfaces reduce your seal.
too much abrasion lets the rings float too much. again, hygiene means
long engine life. can you not get a cheapo set of new pistons from
somewhere? often, these things sit about on a shelf and get sold cheap
after a while. there can't be many people running that motor any more
so i can't imagine demand is strong if someone's sitting on old stock.

 

Yep, but it is also what is shown in the shop manual.

Yes, I've done quite a few over the years.

The ring lands have already been cleaned and cylinders honed. Not even
evidence of a ridge even though this engine had 110K on it. I use the
old trick to clean the rings, a broken old ring which is even mentioned
in the shop manual. (And all this time, I just taught that I was too
cheap to buy the tool).

All clearances are within tolerance so it looks like I'm in good shape.

I'm kind of looking forward to this experience. All my previous work
was with domestic V8 engines... Mostly Studebaker. I did redo a Honda
CL 450 once back around 1980 though.

JT

 

ok. i'd re-use. you can always replace later if they turn out to be a
problem. but i doubt they will.

good. scrub and clean, scrub and clean....

 

The bolts are not "torque-to-yield". You may reuse them.

Typically specific lubrication procedures will be required (or prohibited)
to ensure proper torque. So pay particular attention to any such
instructions. It's been my experience that it's necessary to lube head bolt
threads with engine oil.

 

I have always used engine oil but since I'll be working on a Honda block
involving disimilar metals, I believe an antiseize grease might be in
order. I'm sure that the Honda guy will know what to do. I'm going to
put it together over there and let him bill me for a little shop time.

At any rate, I'm sleeping a bit better after chatting with you folks.

JT

 

I think you'll find engine oil is specified. Anti-seize will alter the
friction characteristics of the thread mating surfaces. Do not change
Honda's specification when working with such important fasteners as head
bolts.

 

Many engine designs have used a torque-to-yield design where the bolt
actually is stretched when being installed and will not return to it's
original dimensions when removed. I don't know if your Honda used such
a design or not, but if I were rebuilding one I sure would find out!

 

all you do is compare bolts for thread elongation. not hard.

 

Hey Grumpy, you sure started a pretty long thread!

Most of it is correct, and your replies show you are on the right track too.

-Yes, they say those bolts are only one use, but I have re-used them in
D-15 motors with NO problems. IF you have a problem it will be when the
threaded portion breaks off on the final torque. If that should happen,
your $16 ea will be well spent.

Run a tap into each of those head bolt holes. I've pulled out LOTS of
crap from the bottom of a hole that would have screwed up torque values.

Engine oil on threads?? Forget it! I saw an interesting demonstration by
an ARP guy torqueing fasteners with oil and assembly lube. The oiled one
creaked as it was torqued. The other one was quiet, and torqued
smoothly. ARP assembly lube is $15 for a tube but it will last a long
time. I also use nev-r-seize too, and it works well.

I would worry more about the rod bolts. THESE are the ones that snap
when re-used and should be checked carefully.

-SP

 

no they're not.

torque to yield bolts don't work like that. you'd have to go /way/ over
yield to shear these bolts.

torque to yield bolts are typically loaded to 98% of yield, not 90% like
a normal bolt. the remaining 2%+ to actually yield them occurs on first
warmup and the resultant thermal expansion. yield does typically /not/
occur during actual bolt tightening.

you can use whatever you want to lube on reassembly, BUT IF NOT USING
THE LUBE IT SAYS IN THE BOOK, YOU NEED TO USE A DIFFERENT TORQUE VALUE.
if you want to use book torque, you use book lube.

where do you work speedy?

 

If the manual gives a torque spec and doesn't mention using new bolts,
I would assume they are reused. Is this the official Honda manual?

 

Yes.

JT