BJ74 overheating... leads to head or head gasket (real time surgery)

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01:30

Almost done.... exhaust all done up, oil lines done up, coolant lines all done, rad hoses in place, electrical all hooked up, vacuum lines put back, belts on and adjusted.

Just have to adjust the valves (cold setting) and then the valve cover goes on and the batteries go in. Then it's coolant time and a test fire... but that will probably be tomorrow morning.

Last photos for tonight:
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IMGP7730.webp
 
Well, the F'ing thing runs.

Will take it out for a test drive tomorrow.

~John
 
Thanks for posting this John.

It's really common that the JDMs that we see have horrifically poorly maintained cooling systems
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I flushed my cooling system with some CLR, the amount of crap that came out was insane. However like you say, 2 months later I had to replace the water pump, and developed a pin hole leak in the top of the rad.
 
yep, i think them friggin' kiwis were filling the bj42 with seawater before i got it. dammened frost plugs on the top of the head developed pinhole leaks after about a year of me having it. and the rad was about rotted away before it even got off the boat.
 
bj74redrider said:
Could you replace those head bolts with studs? Might make it easier to snug that puppy down.
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Nope, and not worth doing.

It's easy enough to tighten them down, it just takes time to do three steps over 20 bolts - and I go over each bolt at least twice per step...

So... initial tightening 20 + first step 40 + second step + 40 third step 40 = 140 wrench placements.

It actually didn't take that long.


~John
 
BJ 71 said:
Great write up! I assume the problem is solved??
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I haven't had it out for any long runs on the highway, so I'm not 100% sure yet.

The problem only was really showing up after about 5+ minutes at 90+ kph. The last time I had it out (after sitting for three weeks, and after I changed rad) it took about 20 minutes for me to notice it going into the red.

I'll update in a few days once I've had it out for a good run.

The boost hits about 12 @ 2500 and will max out at about 2800 - 3000 rpm. I'll blast the little sucker down the highway and see how when it boosts when I take it out for a better run. Right now the exhaust is still stock. I think a 2.5 or 3" exhaust would wake it right up.


~John
 
Good to see that you used a quality torque wrench for your torques. So many people think they can get away with a cheap one and it ends up biting them. Had a friend lose a tire because of that. It clicked 40 ft-lbs below the setting. And being fairly new to the game just figured well the tool can't be wrong. Well it was... obviously.

When it comes to torquing spend the extra money and get a quality torque wrench. Nice write up. Noticed someone mentioned something about studs for the head. You wouldn't know if there are studs for 1HD-T's? I'm thinking about running around 30-35 psi boost. I want to inspect the bottom end before doing so to make sure it is heavy enough when I rebuild it. And obviously need a new turbo to achieve this.

Sorry for the hi jack.
 
canadian bum said:
Good to see that you used a quality torque wrench for your torques. So many people think they can get away with a cheap one and it ends up biting them. Had a friend lose a tire because of that. It clicked 40 ft-lbs below the setting. And being fairly new to the game just figured well the tool can't be wrong. Well it was... obviously.

When it comes to torquing spend the extra money and get a quality torque wrench. Nice write up. Noticed someone mentioned something about studs for the head. You wouldn't know if there are studs for 1HD-T's? I'm thinking about running around 30-35 psi boost. I want to inspect the bottom end before doing so to make sure it is heavy enough when I rebuild it. And obviously need a new turbo to achieve this.

Sorry for the hi jack.
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I worked in a bike shop and built high horspower high reving ingines like 14000rpm and we ad a cheapo torque wrench that was way way way out of spec...:cheers:'


'~Rob
 
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Rigpig said:
Good thread, but just curious as to why you would re-use already stressed and tensioned head bolts on a head/head gasket issue??
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Sometimes you can get away with it. Just compare the bolts to new ones and if they are the same dimensions you are usually safe. The slightest bit of extra length or loss in diameter it's time for new bolts. I have seen it done before. Although if you don't know what your looking for when it comes to bolt stretch or damage just play it safe and get new bolts.

If you want your truck back on the road fast while doing this just order the head bolts because if you count on the used bolts being good and they are not you could be waiting for some time for new bolts.
 
Rigpig said:
Good thread, but just curious as to why you would re-use already stressed and tensioned head bolts on a head/head gasket issue??
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They are not torque to yield bolts, as such, they do not need to be replaced.

The failure, as I noted in my thread, was not related to anything other than poor maintenance by the PO.

~John
 
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it will be interesting to see the results ...
at least it wasn;t a cracked head, $$$$$$$$$$$$$$.

pretty good for a one day job, long day eh?
 
baxter650 said:
Makes one appreciate the simplicity of the 3B.
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Almost identical procedure, but the turbo adds a fair bit of time to the job.

With the 3B, however, you have to deal with pre-cups & cracking... which is far more of an issue.

~John
 
Thanks for sharing GOOD info.

regards,
helimanBD.
 
Okay, I said I would post an update - I've had the little beast out for a few longer runs now and it's working great. No more issues so far with the cooling system or the head gasket.

It boosts a little better than it used to, and seems to run pretty good when it's warm. I'll check the timing and valves in a few weeks to make sure they're on spec.

~John
 
Moving this up to the top as a friend is doing his job right now and wants to see these procedures.

~John
 
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