Newbie question on cylinder bolts

[yellowhammerjam]

I am having a problem with oil seeping out in spots between my head and block. At first it was very minimal and now it is more noticeable. I am debating on replacing the head gasket as the possible cause. My question is what is meant by stage 1 and stage 2 bolts in relation to the head cylinder bolts? What is the correct torque on the cylinder head bolts? My head is an E88 head and is bone stock. The previous owner who I called up recently said he replaced the head gasket when he reassembled the engine. He had a ring job and valve job done while apart. The car from what I can tell uses no oil, antifreeze, or has no drips anywhere except for the oil seeping between the block and head. I checked the radiator and no signs of oil. Car does not smoke neither, but acts like it has a vacum leak somewhere as the idle is sparatic between 700-1200 rpm's.

Btw the car is a 72 with an L24 and stock.

I checked the compression by warming engine to normal, removing all spark plugs, and with full open throttle my readings were low (120,118,120,117,118, 120) They were pretty consistent though. Could the low reading be due to the head gasket leaking?

Thanks in advance for any input.

Brian

[Phred]

Brian,

I have not heard of head bolts referred to as stage I, or II. More commonly they are referred to as early, and late, late ones also known as tubo bolts. Unless your bolts were replaced, they will be early bolts. Get you magnifying glass out and look closly at the top, or head of the bolt. The Late, stronger bolts, will have a very small "13" on the outside edge of the hex. These will hold 60 lbs. of torque. I have frequently encountered early bolts that will start to feel a little stretchy at 60, but will usually hold up to 55 lbs. Before you replace the head gasket, try a retorque, and see if that will fix your leakage. Many people do not use a lube on the threads of the bolts, and this will give a false torque reading. Torque is a method of gauging bolt stretch, which is the mechanical means by which the head is held down. If there is friction between the threads, the torque wrench will click early, and the correct amount of bolt stretch, and therefore clamping force, will not be acheived. Use regular motor oil on the threads and under the head of the bolt. Remember, there are two different lengths of bolts. The shorter ones go through only the head, and will feel good when you torque them. The longer bolts go through the cam towers too, and they will sometimes feel a little stretchy as you torque them. This is normal, as a longer bolt will tend to stretch a bit more than a short one. If it were me, I would remove one bolt at a time, clean and lube the threads, and under the head of the bolt, and then replace and retorque it to 55 lbs for early bolts. Continue in a circular pattern working from the center of the head , finishing up with the bolts on the ends of the head. If this doesn't cure your problem, you will have to replace the head gasket. But at least by then you will know how to properly torque a head. also, make sure each head bolt has its required hard washer under the head of the bolt. Also, and again if it were me, I would relace the head bolts with the later style, stronger bolt. They are Part# 11056-P7600 for the short bolts, and part# 11059-P7600 for the longer ones. Good luck!

Phred

[Carl Beck]

I'll add a little to what Phred wrote:

When the 240Z's were new - one of the services that were preformed at 1200 miles - was to re-torque the head bolts. As I recall the procedure was to simply break them loose, then torque them down again.

<pre>

Head bolts should be torqued down in three stages

- in the same sequence outlined in the service manuals.

12 8 4 2 6 10 14

11 7 3 1 5 9 13

</pre>

- first torque them all to 20 ft/lbs

- second torque them all to 45 ft/lbs

- third then torque them all to between 47 - 61 ft/lbs

Lots of people report having no problem if they never "re-torque" the head bolts after initial run engine run in. As I recall some head gaskets were promoted as not needing to be re-torqued. Nonetheless, I still re-torque all head bolts after the first thousand miles, if I've had a head off. {note that I said: "if I have had the head off"}

I am always hesitant to tell a non-mechanic to re-torque the head on his engine. Especially if he didn't do the job in the first place. You have to keep in mind that the possibility exist, that you can twist a head bolt off in the block. Not something you want to deal with if you're not willing to tear the engine down yourself.

If you have a head gasket leaking oil, the possibility exists that whoever put the head on in the first place - may have stripped a head bolt to begin with... or worse.

BTW - For the people with early L24's - they used three lengths of head bolts from the factory. This was reduced to using only two lengths upon replacement and/or on later engines.

FWIW,

Carl B.

Edited January 21, 2011 by Carl Beck

[yellowhammerjam]

Thanks guys for the info. I believe I will try to re-torque the bolts and see if that fixes the problem. Much easier to try than pulling the head. Hope it will fix the issue.

Brian

[zKars]

I'm pretty skeptical that an attempt to retorque head bolts in an old engine is going to 1.) fix his problem, and most importantly 2.) any torque applied to the heads will actually go into any additional clamping force on head.

For those of you who have taken old head bolts out, how many have threads that are clean, well oiled and can be spun out by hand? Answer? 0. How many of you have broken at least one in the process? Answer, likely a few.

Even if Brian does get the bolts loose without breaking any, how even and accurate is the re-torque likely to be given the condition of those threads? Just seem like such a low probability of success and such a high prob of making it worse.... Sorry to be Mr. Cautious this morning...

[Phred]

Thank you all for adding to my post, as I indeed left a bit out. I tend to forget that a quick and simple job for me, may put someone else in an unknown area. I look at it this way, if something breaks while you are trying to fix a simple problem, then you get to learn how to fix a complex problem!

Phred

[z boy mn]

Hey everyone, I know this is an old thread but I have been having a similar issue on my "newish" 3.1 stroker motor.

Oil is bubbling out on the passenger side of the block between the block and the head just in front of cylinder 1 and near the dipstick when the engine is cold. The bubbling stops when it warms up. The head and block were modified by the previous owner (as reported to me anyway). The cylinders have been bored out to 89mm and the stroke extended to 83mm (using a diesel crank). The engine was assembled 14 years ago and it never ran until last year when I drove it home.

So, I can look up the specs on torque (or use them from this thread), but does anyone know about changes in those settings for this sort of engine? It does have ARP bolts in the head, and the engine has 4,000 miles on it now (it probably has leaked since I drove it home, but there were lots of other leaks, so I likely didn't notice). Would I be best off breaking the head bolts free and re-torqing from 0, or just set the wrench to 61 (if that's the right setting) and twist (following the pattern)?

Any assistance / help would be appreciated...thanks!