Are the LD 28 cylinder head bolts throwaway? In other words are they the type which intentionally stretch and must be replaced if removed? The 82 FSM calls for a torque spec of 87 to 94 ft. lb. I couldn't find any mention of them being throwaway in the FSM, but I often can't find what I need when I need it.
The hex socket recess looks to be about 10mm. That should put the bolts size at approximately 12mm. 94 ft. lb. doesn't sound like a lot of torque on a bolt that size. I'm thinking they shouldn't need to be replaced every time. I'm also thinking that off the shelf grade 12.9 socket head caps might be all that is needed to replace them. Thoughts?
Matt B.
83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles 82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!
The LD28 bolts are not, AFAIK, torque-to-yield. They are re-usable. They are probably class 12.9 to acheive 94 ft/lbs torque, so I don't know what advantage lay in replacing them.
That's pretty much what I thought. Head bolts are fairly low on my list of parts to procure for a rainy day then.
Matt B.
83 Maxima Sedan, LD28, 5 speed, white, 130k miles. My original Maxima.
83 Maxima Sedan converted from gasser, LD28, 5 speed, 2 tone blue, 230k miles 82 Maxima Sedan, LD28, 3 speed auto, 2 tone Gray/Silver, 140k miles
81 810 Sedan, LD28, 3 speed auto, rust, rust, and more rust!
head bolts can fail.
it just good practice to replace head and bearing bolts.as well as some external bolts.like water pump and thermostat.
but with a LD engine there is no NEED to do so.
if its a first time apart engine i would give it a second thought.
bolts that have been remove can fracture and the thread can be damaged.
do this several times and its possible to have troubles.same deal with the new bolts you purchase.I know of some fanatics that ony use studs.
its not uncommon to have bolt failure with a new car and a maxima is at end of design life age.anything that mass produced can go wrong.
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.
I think it mad to reuse head bolts, especially on a diesel. As a matter of fact, you should get ARP head studs, and throw a steel head gasket in there to boot. [/i]
Head bolts were reusable for decades. The LD28's are not torque-to-yield, and are not particularly stressed. I've heard of ONE head gasket failure on US-spec LD28 engines, and it was likely due to lack of cooling system maintenance (corrosion) rather than clamp force failure.
I love ARP stud kits, and have bought and used them. They are a quality product. But does ARP offer a kit for the LD28?
And by the ONE head gasket failure Al is talking about he is most likely referring to my car and its engine. I did have a bad head gasket and cracked cylinder head due to overheating the car one day. I never ever expected it to happen to me because I had already driven the car basically 33,000 trouble free miles. I think the main reason it happened was because the car sat a good year before I decided to keep it instead of selling it. When I got it back on the road it had a brown colored coolant, no sign of green in there at all and I drove it that way without first flushing that junk out and installing all new coolant. Big mistake and then the day came where I overheated it, but I also think I had a bad fan clutch too that may have caused the whole problem in the first place. It's obviously very hard to tell whether the fan clutch is working as it should when you are driving down the road and can't look under the hood. Either way when I did the tear down work we replaced the head gasket with a brand new Fel-Pro unit and I did reuse the head bolts. Of course cleaned them up very nice before reinstalling them, torqued them to the correct spec, retorqued them again at 100-150 miles after the work had been done, and have had 40,000 trouble free miles on the car since.
Salvy
1982 Datsun Maxima diesel wagon w/ 228k miles
*occasional daily driver*
1982 Datsun Maxima diesel sedan w/ 252k miles
*now off the road as a parts car and sent to the yard *
I have proved it is difficult to diagnose the fan clutch on these cars, especially if you are stubborn and you keep thinking it has to be spinning faster. I actually became quite the master in telling the fan clutch's on and off. Its not as easy as just looking at a larger metal bladed fan.
Personally, I reuse my head bolts twice, unless I know its a torque to yeild bolt, that stretches. I don't think I had ever had any problems with it. I like to clean the threads and lube it with some kind of lighter lubricant, so it would reduce resistance in turning to get better torque readings, and preserve the block's threads.
Does anybody use stuff like permatex on head gaskets? I always have done mine dry. Just wonderin if anybody had had greater success with a sealant.
hylomar was often call rolls royce head gasket the blue hylomar spray on is used as a lubricant and sealer for in and on headgaskets.was common practice is older days to reuse gaskets with an aplication of hylomar or copper product.it worked but i dont think an engineer would recomend it.
some nono tourque gaskets have silica and hylomar impregnated sealers.
interesting thing i found look for a link was the new ACL Aluglide product.
WCJR31 Skyline.3.0 manual.wagon
R31 SKYLINE/Passage GT/PINTARA
LPG Ford Falcon 99-06 93 Disco
Local Shire Southern Zone Mechanic.
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