Retighten head bolts

[motavated]

Well long story short. My manifold hits speed bumps pretty hard. So I decided that it was a good idea to retighten my head bolts right? Some where I read that its recommended to re-tighten head bolts every oil change especially in the napz engines. Well I have this l20b right. So I took off the valve cover and loosened all the bolts and coolant started to leak from the block side. I re-tighten the head in the correct way at 60 pounds. But it had trouble starting since some water got into the cylinders. After a while it started and ran. I then changed the plugs and let it idle for 30 minutes...

 

So my question is... Do you really have to re tighten head bolts? If so, how often? And if you do, what is the right way to do it. Thanks!

 

 

My engine is still ok I guess. It feels better than before. I just didn't like that coolant leaking..

[Dimerforlife13]

Well long story short. My manifold hits speed bumps pretty hard. So I decided that it was a good idea to retighten my head bolts right? Some where I read that its recommended to re-tighten head bolts every oil change especially in the napz engines. Well I have this l20b right. So I took off the valve cover and loosened all the bolts and coolant started to leak from the block side. I re-tighten the head in the correct way at 60 pounds. But it had trouble starting since some water got into the cylinders. After a while it started and ran. I then changed the plugs and let it idle for 30 minutes...

 

So my question is... Do you really have to re tighten head bolts? If so, how often? And if you do, what is the right way to do it. Thanks!

 

 

My engine is still ok I guess. It feels better than before. I just didn't like that coolant leaking..

 

On a Z24, your supposed to loosen one bolt and then re-torque it. Loosening all of them could very well cause premature headgasket failure. On a lot of motors when it calls for a re-torque, your just supposed to re-torque them to spec. You might want to do a compression check/cooling system check in your near future. Just my 2 cents...

 

-Brett

[I'm BLUE]

I was under the impression you are just to "re-torque" not to "loosen and re-torque" ? I guess there is a special procedure for the Z24 series then , hmmmmmmmmm now i have to research this( never owned one so IDK ? )

[Dimerforlife13]

I was under the impression you are just to "re-torque" not to "loosen and re-torque" ? I guess there is a special procedure for the Z24 series then , hmmmmmmmmm ( never owned one so IDK ? )

 

Z24's had headgasket issues. From what I know, usual procedure is to just re-torque.

[motavated]

AWW FUCK... Any who lets see wtf happens. Have a extra head just in case... I need to buy a new gasket head and intake just to be safe..

[I'm BLUE]

Z24's had headgasket issues. From what I know, usual procedure is to just re-torque.

 

thanks, good to know either way man :D

 

I need to buy a new gasket head and intake just to be safe..

 

Good Safe way to go ^^^ , don't worry at least you weren't like me and put on a Fucking Fram Oil filter that clogged up , and bypass valve failed as well :blink: ( last one in the garage then I decided to use then no more after that point ) that starved my engine , and having a problem with a rocker arm/cam lobe now :angry: --- :o --- <_< ( It happens man no worries :D )

 

So I too am planning on using an extra head/valve train at least :lol: ;)

[izzo]

on a naps z, every oil change you should loosen one at a time, in no particular order, then retorque to specs...

 

on an l20? lol i doubt it would ever need it but you could check it now and then

[I'm BLUE]

Head Studs Anyone

[Grey_Matter]

aren't head bolts one time use...once you loosen it, you need to replace it as they are stretch bolts.

im pretty sure you just retorque it to make sure it clicks at the right final torque without loosening them

[motavated]

Any more input? Well what is done is done. I hope the head gasket holds ok for a while...

 

I might add that rockauto has a closeout deal on a l20b head gasket kit. I bought the headgasket kit and a intake gasket for less than 35 dollars shipped while also using the special code. Yes the gasket kit has a intake gasket... But the l20b kit has circle exhaust ports. so I also bought a square one...

[I'm BLUE]

aren't head bolts one time use...once you loosen it, you need to replace it as they are stretch bolts.

 

Yes Sir you are correct :D but I usually use them until the head comes off , then replace if need be ( as my understanding or if I have the moneys/ feel I need to ) :D , but I don't know many people that do it ( including myself usually :lol: )

 

I have found with a few newer cars that I have been around ( like the Acura MDX ) that you have no choice but to replace the head bolts when the head is off or face the consequences :mellow:

[metalmonkey47]

aren't head bolts one time use...once you loosen it, you need to replace it as they are stretch bolts.

 

oh shitttt really??

 

Never heard that

 

Glad I'm on Ratsun. lol

[banzai510(hainz)]

I reuse the head bolts all the time. yes there stretch bolts but otherwise we are back yard mechanics and dont have time and extra cash just to rebolt a head down. Esp a L16 that only needs 40pounds. Torq it to 45 and that takes care the stretch.

I have never used a new bolt yet. I have a Turbo set for a L20 i plan on building next week to never.

 

My personal opinion is use at least Turbo 280zx bolts if building a somewhat pumped up L20. or a turboed or HI comp L motor. Otherwise save your money

 

If more ARP makes Studs and nuts.

 

 

I hardly never retighten my bolts

[datzenmike]

Re torque not necessary on an L20B but I see no harm.

 

Loosen one at a time and torque to final spec. Loosening breaks the bolt loose and gives a better reading.

 

If you have doubts drain the coolant, loosen all and re torque in sequence in the three stages. If worse comes to worst you have a spare gasket.

[datsunaholic]

You have to loosen them to retorque, since it takes far more torque to get them moving again than it takes to tighten them. I used a torque wrench to measure what it took to break the bolts loose once. They were tightened to 45 ft/lbs many years earlier- took over 120ft/lbs just to break loose (on the easy ones, hard ones went off scale), but went right to zero once they broke free.

 

But don't loosen all at once! One at a time.

[datzenmike]

Also the head bolts are totally reusible as long as in undamaged good shape. A turbo or high performance motor would be an exception but you would likely use studs anyway..

[hang_510]

Head Studs Anyone

ARP FTW!!!

 

 

i would/have/do reuse the OG bolts for a stock rebuild :)

[Buzzbomb]

Well long story short. My manifold hits speed bumps pretty hard. So I decided that it was a good idea to retighten my head bolts right? Some where I read that its recommended to re-tighten head bolts every oil change especially in the napz engines. Well I have this l20b right. So I took off the valve cover and loosened all the bolts and coolant started to leak from the block side. I re-tighten the head in the correct way at 60 pounds. But it had trouble starting since some water got into the cylinders. After a while it started and ran. I then changed the plugs and let it idle for 30 minutes...

 

So my question is... Do you really have to re tighten head bolts? If so, how often? And if you do, what is the right way to do it. Thanks!

 

 

My engine is still ok I guess. It feels better than before. I just didn't like that coolant leaking..

 

Look at it this way...You say it runs better than before, and that probably means nothing was hurt. Water doesn't compress, and if a good amount of coolant leaked in there, you might have hydrolocked your engine if you cranked it over with the plugs in there! Silver lining to every cloud, right? If anything, you're only out the cost and time to replace a headgasket. Cost wise, some people pay $40 for an oil change.

 

I run an L20B, and won't be retorquing my head bolts any time soon. I'm not sure when my truck had a head replacement, but I know it did because it's an L20B with a closed chamber W58 head. That being said, even if that head was replaced before I bought it at 100K, I still got almost 75K out of the head gasket before I replaced it last year. In my case, the only thing I did to teh head bolts was check the tightness as DatzenMike and Hainz suggested to me after a few full warm ups/shutdowns after gasket replacement. That is also what is suggested in the service manual that covers L20B available at Olddatsuns.com.

 

Now the NAPSZ engine, I guess that's another story when it comes to head bolts.

[hessianben]

hey adam, what's that RockAuto code??? i need a hg kit too! :)

[I'm BLUE]

ARP FTW!!!

 

 

i would/have/do reuse the OG bolts for a stock rebuild :)

 

+2 ;) :thumbup:

[Pumpkn210]

aren't head bolts one time use...

Some are and some arent. Check your shop manuall for specifics, mine are repeat use and aren't stretch bolts! Stretch bolts are used mostly on all alluminum engines. Bimetal engines mostly just use regular heavy duty bolts!

[Grey_Matter]

Some are and some arent. Check your shop manuall for specifics, mine are repeat use and aren't stretch bolts! Stretch bolts are used mostly on all alluminum engines. Bimetal engines mostly just use regular heavy duty bolts!

 

gotcha :)

[LenRobertson]

Any opinions on head bolt thread lube/coating? My memory is a dry bolt, one with threads lubed with engine oil, and one lubed with no-seize are actually putting three different pressures down on the head when they are tightened to the same ft/lbs on the torque wrench. Isn't a torque wrench measuring friction on the threads, at least indirectly, and lube on the threads obviously varies the friction? I recall learning this in a "Hot Rod" article about a million years ago, but my memory is iffy at best. Or maybe The Rules have changed in a million years.

 

Len

[Unclejesse88]

Stretch bolts, or Torque-to-yield, are throw away bolts. Generally, you will know you have this type of bolt by the tightening sequence. There is usually a angle torque required as the final torque, for example, tighten to 40 lbs, then an additional 90 degrees.

[hang_510]

Any opinions on head bolt thread lube/coating?

ARP sells an assembly lube thats suitable for stock bolts.

i used it on others, not necessarily high torque specs.

 

 

stock IIRC "a light coat of light weight motor oil" (its in the manual) before installation.