The Stovebolt Site Forums The Shop Area Engine Shop 235 - Head / Crank / Flywheel Bolts - Need Market Opinion

With rebuilding two to four 235 engines per year,
head bolts, crank bolts and flywheel bolts are a
real problem, at least a worry; I do NOT like
using the same bolts again, and you should not.

I have made contact with ARP engineering and they
have offered to manufacture those bolts for me.
Currently, I need four sets (four engines) and
am considering ordering between ten to twenty
sets for a surplus.

Rod bolts, as you know, are a different beast
and I am still giving thought to what can be
done there.

Would you mind affording a quick opinion for me?

I will be testing the market for brand new engine
bolts (not the pretty ones) for 235 engines. This
will be head, crank main, rocker arm and flywheel
bolts, only. Rods are out for now being a pressed
knurled fit with a T head.

My experience is there is no source for these
bolts. They cannot be found brand new. Do you,
the reader, have a need or will have a need for
bolt sets like this? Quick answer will do and
your efforts are appreciated.

Thanks,

Billyray

Hmmm ,, well I've only done 8 of the 216 engines , but I've never heard of an internal bolt failure , so I guess thats a NO from me.

Just finished putting my 235 back together. Had removed the head while determining what needed to be rebuilt. Had the long block and head rebuilt by a pro and then I put the head back on using the original bolts -- must say I wasn't comfortable doing it. Did insure that they went back into their original holes. Did read a post somewhere about ARP bolts that could be used though not exactly the original length -- sounded scary to me (I didn't have a high enough level of confidence in my experience to make the decsion). I guess this is a long winded way of saying -- Had the correct bolts been available I would have purchased them. The same hold true for the internal bolts. So, YES!!!

Yes, you must use the correct length, always.
Too deep, cracked head or broken bolt. Too
shallow, bolt or head stripped threads.

Another danger is not cleaning threaded holes.
Just a little oil or grease can crack a block.

A "dirty" hole, when a bolt is torqued down,
can create so much hydraulic pressure a block
can easily crack. Rocks, during construction,
are often split this way. Drilled dynamite
holes work the same way.

Torque bolts, such as head, crank and rod,
must be replaced after use. They are designed
to stretch a bit on torque which holds them
in place. They do not "rebound" and return to
normal after being torqued. Almost all manuals
suggest you "throw away" your bolts upon a
rebuild, especially head bolts.

Ok, one "no" and one "yes" on this question,
so far. I hope others will add their thoughts.

Thanks,

Billyray

I'd be interested in a set of head bolts.
Dave

I don't know if 45 years of experience makes a difference, but unless the bolt is a "torque-to-yield" design, stretch isn't a factor. Try this experiment: Chuck a rod bolt in a lathe, and, using a small center drill, put a seat for a ball bearing in both ends of the bolt. (ARP bolts come with these holes already drilled.) Stick a BB-sized ball bearing to each end of the bolt with a little wheel bearing grease, and measure the length with a micrometer or a dial caliper. Torque the cap on, to specification, and measure the amount the bolt stretches. (ARP specifies .014" stretch on a Chevy 3/8" rod bolt) Repeat the procedure 50 times and see how much, if any, the unloaded dimension changes. Then, tell me whether or not I should re-use rod bolts. I do this on the 600+ HP, 7,500 RPM Chevy 350 race engines I build, and generally re-use the bolts several times. Head bolts are a no-brainer, unless they're rusty or have damaged threads, re-use them!
Jerry

The flywheel bolts are the same as for Chevy small block V-8,dime a dozen.The head bolts can be found for $2.25 each at Mcmaster Carr industrial supply online. They have many sizes of grade 9 special bolts.On a 235-261, a guy I know used Ford 351 Cleveland rod bolts,grind the side of the oval shaped head,use a washer under the nut,use those bolts when you have the rods sized at the machine shop.The mains? precision part, the grade 9 won't work unless you machine the bolt true like a dedicated main bearing bolt.

I would buy an ARP bolt set for my application before I (with little experience) would go to 2 or 3 different sources to get what I think I need. Comfort Zone....

Yes, Buddy

Rebuilt my 235 head earlier this year with new valves, guides, etc.
I had no problems cleaning and re-using my old head bolts.
I didn't worry about getting a new set of screws, because I have been driving my six for about 60K miles in TX/CA temperatures with a clogged radiator and original driveline and 4:11.
Never developed any head problems whatsoever and I didn't even know how long the engine was used before I got it.
And the old head gasket was perfectly fine and would have sealed for many more years.

My point is, that it all depends how far you wanna go for yourself or your client.
The 235 I drove for the past ten years, every day, seems to handle a lot more than screws streching a couple of micro inches.

Hail the old sixes...nothing ever like it.
Can't wait for her 'good morning music' when I fire her up for another ride.

Hotrod Lincoln, thanks, lots of good info. Biggest
350 I have built is a 450 horse sitting in my
old Corvette Mako Shark. For V eights, I always
replace critical bolts with each rebuild, and
I use ARP bolts. My concern is one stretched or
broken bolt can ruin your Saturday night cruise.

Truckedup, I will pull out some old V eight
flywheel bolts and compare. I am sure you are
exactly right on that. Rod bolts, complicated.
I have a 55 - 57 block apart now. Rod bolts are
knurled and have a special T head. Not sure
ARP will make those for me.

Buddy, yeah, I like doing it right, everytime.
Too big of a risk to cut corners. I will go
for the ARP bolts like you.

On the road again, a lot of these trucks I work
on for family and friends, end up in deep snow,
way out in the middle of nowhere, even up in
Alaska where Buddy lives. I want all to be perfect
and dependable. Breaking down in the wrong place
might make you dinner for a grizzly!

A mixed bag so far. Langdon told me he does not
worry about using the same bolts again.

A final comment, many of these engines we work
on have over 100k, over 200k miles, are as old
as me, they have been around and we don't know
what has been done to them. Engine I took apart
this past weekend, rod nuts were loose. Flywheel
had 3 bolts of one type, 3 of another. Not good.

What I have in mind is to order at least ten sets
custom made by ARP. Use three or four here, then
offer the rest to whomever at my cost to test the
market for 235 critical bolt packages. I think
there is a small market for these bolts.

Just have to figure out what to do on those
pesky rod bolts.

Thanks everyone for input. I hope more will
come down from the peanut gallery and comment.

Merry Christmas to you and yours!

Billyray

I have a 56 3/4 ton Napco 4wd

I concur with Hotrod, if it puts your mind at ease, you could mic the length of the bolts looking for a stretched spot. I usually always reuse headbolts unless there was a major overheat in the engines' life that caused major damage. I think the older iron was sometimes over engineered anyway,
Scott

I haven't had a 235 apart recently enough to remember what the rod bolts look like. The old 283's and early 327's had 11/32" rod bolts, and the 350's moved up to 3/8" diameter. ARP uses a super-strong alloy that needs 50 ft.-lbs. of torque, or the torque-to-stretch method of tightening. I'll bet an existing rod bolt could be fitted to the 235 rod, without having to have them custom-made, even if the hole in the rod has to be reamed to fit. The rod will need to be reconditioned after installing the new bolts anyway, something we always do when retrofitting to ARP race bolts. By setting up a jig in a valve seat and guide machine, and using valve guide reamers, I can make the rod bolt hole just about any size you want, accurately.

BTW, to get the correct amount of bolt stretch on a 7/16" diameter bolt in a Carillo rod for a 350 engine, it's necessary to use over 90 ft/lbs of torque. Those rods cost $1,000.00 per set, back when we were using them regularly.
Jerry

235-261's use 1/2 inch main bolts in two different sizes, the rod bolts are 3/8
You never know where bolts have been in over 50 years, more likely than not ,over tightened by a past hack.New bolts are cheaper than running over your own crankshaft.
You can't mike a bolt unless you know the length of each one when it was new.GM didn't machine each bolt to an exact length like ARP does.
The 351 Cleveland rod bolts were suggested to my friend by ARP themselves as the diameter of the machined shank is exactly the same as 235 rod bolts.The grade 9 bolts from the industrial supplier are 170,00 psi, same as the "economy" bolts from ARP.
If you're doing a low cost re ring and bearing job, the old bolts are probably Ok.But today ,with the cost of parts and machining for these old engines on a first class rebuild,it's cheap insurance to replace bolts.

I intended to mic the diameter of a bolt along it's shank to find the stretched area, not the length. If a bolt stretches, it will "thin" down somewhere. It's also become a service procedure for a carmaker that I work for too.
Scott

Your comments are very much appreciated. Please
continue to add your thoughts.

Appears flywheel bolts for the 235 six will be
a direct swap for virtually all early chevy
engine flywheel bolts, inline and V8 alike.

Based on your comments, after New Year's, I will
send ARP sample bolts. It will be suggested they
compare a sample rod bolt to these,

Chevrolet: 283-327 and inline 6, ARP1346001

Ford: 351 Cleveland, 3/8 in, ARP1546003

My plan, on rod bolts, is if a direct replacement
drop in cannot be found, I will have ARP make
those rod bolts. I suspect most would rather
have a drop in fit rather than having their
rod ends and caps machined to accept a size
other than original stock.

Head and crank bolts should be a simple matter
of having ARP make them.

Biggest question now is cost. I will be ordering
a moderate quantity to keep costs down. Still,
the costs of these bolts will be significantly
less than the cost of rebuilding an engine due
to a crank or rod bolt failure and damage.

Comments on bolt age and fatigue are realistic.
These engines are becoming old like us!

Thanks again and please keep commenting.

Merry Christmas to all!

Billyray

I think there are already Main Studs produced by ARP. I found a part# 132-5402, and was planning on using studs. Not cheap, $65 through Summit. I would be interested in rod bolts, if they fit the 261 rod. I know the rods for 235 and 261 are a little different. Do you thing they use the same bolts?

55 and up 235 and 261 use the same bolts,try this place from the links right here on Stovebolt NOS parts they show 12 new rod bolts in stock#3836670 for 55 and up 235-261.i have bought from them several times, slow but reliable service.
The stock 3/8 rod bolts are quite beefy for the power output,no need to change them unless you suspect they have been over torqued in the past

Godzilla, have you checked Chevs of the 40es?
(yes they have 50es parts to)

http://www.chevsofthe40s.com/

They sell them bolts out of the box. May be cheaper than have them custom made.

yust my 2c

Frank

jbrancheck, thanks! I have saved the ARP part
number and will look at these. Their price is
actually not too bad. I have paid a lot more
for Chevy V8 bolts. That is a cheap price
compared to damage done by a broken main bolt.

Truckedup, what method or system are you using
to find original GM part numbers? That site is
great but you have to pay for a part number. I
will order those rod bolts and compare to what
I have here. Thanks, I may have found at least
one set of rod bolts. Again, how are you going
about finding original GM part numbers? I would
like to find part numbers for head/crank/ bolts.

Stovebold, I sent in email just minutes back
asking about this difference between long and
short head bolts. I don't have a clue which
years or models use long or short bolts. I also
asked them if they have a source for crank and
rod bolts. Appears they have rod nuts. I will
ask them if these are good for 55 and up rods.

Thanks again to all for great information. I am
saving all this information and will share final
results in the future so all will know how and
where to obtain needed internal engine bolts.

Keep those comments coming!

Best,

Billyray

Truckedup, I am "trying" to order those rod bolts!

Everytime I click on their link to submit the
information and order, an email compose page
pops up. I will try to order through email.

Best,

Billyray

jbrancheck, here is what I am finding:

ARP 132-5402 2 bolt main Inline 6,
’54-62, without windage tray

I will order a set through Jeg's and see
what I get! When they come in I will post
and let you know if they work.

Best,

Billyray

Godzilla, their web page is a piece of work, yes, email them.I have several old GM parts manuals as do some other guys here.
head bolts numbers are;3835811 for the longer bolts,3835812 for the shorter bolts.For the mains,839126(1/2) for the rear main bolts,3835867 for front and rear intermediate main bolts(9/16).Flywheel bolts,839756,same for 235-261,283-350.