Build OL'BETSY ZX: 1991 HZJ77

[Loober]

Hmmm. I had my OEM rad recored last summer. Wasn't cheap so I was hoping I could leave it for a bit.
And of course new water pump, shroud in place, and new fan clutch.

Good to know about the gauge.

The 79 series is a bit taller so how's that obvious benefit, but its also built using different materials and internal structure which may also work towards improving its efficiency. I had my original re-cored as well with no noticeable affect, not until I switched to the new radiator.

 

[coldtaco]

Yikes. But that was 12ht right? Hope I'm not there! Guess I'll see.

I am curious what effect timing and fuel has on water temp. I've been planning to back off timing slightly (had it advanced some when I was suffering cold start issues and haven't moved it back yet). But I'm hesitant because my egts are very reasonable and almost no smoke whatsoever. Which is remarkable at this altitude. But water temp does get a bit higher than I'd like... And not dependent on egt to get there first which is the way my diesels always operated previously, so I'm wondering if the timing advance is bringing up water temps?

It was the 2H-T that was in it before I broke it on the drive up from Georgia I saw the factory gauge about 3/4 up a couple times. I hate to think what temps those were.

 

[JDM Journeys]

Mucked around half the day installing my temperature gauge indash (and another voltmeter for rear 12v system) and then went to hook up my rad hose adapter thingy only to realize that the probe was way too big for the threaded hole. So for now I taped it onto the upper rad hose. Not optimal but still gives me a reading...?

I also bled the system just in case, and I tightened the belts on the fan pulley/alternator.

Then I went on a drive and tried to lug it up some hills to get some heat going, but I couldn't get it above 160f on the upper rad hose. The factory gauge sat at a half and went a little bit over that when I had the egts at 1200 for about 5 seconds. Of course I don't normally drive like that but this is testing day.

After I got it as hot as I could I pulled over and did some laser temperature checks. The upper rad hose was exactly what the new gauge said it was at 160 degrees. That was the highest I could get it. The head just under the valve cover was 215° approximately, the upper rad tank was around 182, and the lower rad was somewhere in the 130f range. None of these temperatures are particularly alarming, I don't think?

So overall somewhat inconclusive. I might plumb my new guage into the block when it cools down... It looked to be same thread as the sender on new guage.

The sender for the temperature is now a new one, so what else is part of that gauge? I know it's a guide only and not to be trusted, but I hate seeing it registering even a little bit high.

 

[coldtaco]

I usually see around 180F with normal driving. Going up a long hill at max boost I see around 195F. so you are doing better than me. Maybe the difference between a 12HT and a 1HZ?

 

[svsisu]

I usually see around 180F with normal driving. Going up a long hill at max boost I see around 195F. so you are doing better than me. Maybe the difference between a 12HT and a 1HZ?

Your numbers are very similar to mine (1Hz+T) with similar adapter/probe (Auber instruments) in the upper rad hose. I sit pretty steady at 183 until a long hill climb. I have not verified it with any other measuring device but my oem gauge never exceeds the extremely accurate just below the quarter range.

 

[AirheadNut]

Just so you know, the thread for the sending unit in the block is almost certainly a BSPT thread, whereas your new sending unit is probably an NPT thread. Similar, but not compatible. You can probably get an adapter to go from one to the other.

 

[JDM Journeys]

Just so you know, the thread for the sending unit in the block is almost certainly a BSPT thread, whereas your new sending unit is probably an NPT thread. Similar, but not compatible. You can probably get an adapter to go from one to the other.

Yeah... I checked it this afternoon and found out the hard way, so I appreciate the confirmation that I'm not losing it. Well... In terms of this anyways.

@svsisu thanks for the numbers. My non OEM sender is getting pitched once I get a real one. I know better than that but was impatient/dumb.

 

[JDM Journeys]

Some parts showed up today. Replaced the crappy non oem temperature sender with a genuine factory part. Also plumbed in an aftermarket water temp gauge to the upper rad hose (properly).

Once the thermostat opened, it sat around 180° f.

Then I tried my series of test hills. Bear in mind I already live at 3600 feet. I saw a maximum on my aftermarket gauge of 205 degrees fahrenheit. My factory gauge didn't quite reach a half at my Max Hill climb. Egts were reasonable, except once when I touched 1200° for about a second. Ambient temperature was around 21 c because @Gun Runner 5 loves when I mix units.

Full shroud is on but nothing underneath the rad, owing to the ARB. RTT is up top along with awning and shower room.

So the question I guess I need to be asking is do I have enough "thermal room"?

Part of me is tempted to add some oil to my new blue hub viscous fan. I'm also curious if adjusting my valves will have ANY effect on temperature...I do need to get to this last piece of baseline maintenance. At last.

 

[Gun Runner 5]

@JDM Journeys
That whole metric nonsense is nothing short of voodoo but if I remember correctly isn't
21° (C) where ice forms in your beer.

 

[JDM Journeys]

Oil change day! Added 40oz of hot shot secrets stiction eliminator. No I don't have stiction lol but I haven't done an oil treatment yet so I thought it might be time. May or may not help but it won't hurt...

Also put a new oring on the radiator's leaking petcock.

 

[JDM Journeys]

My new aluminum radiator from the errr... "far east" arrived a few days ago, so I installed it and had a few days to test. In case you didn't see my addition in the "aluminum radiator" thread, it was plug and play, with one modification: No provision had been provided on the RHS for the shroud to bolt to. A quick drill and then nut/bolt solved that, and then it installed like OEM, using the factory bolts, and rubber isolators. I swapped the cap to an OEM one since the shipped one was 1.1 bar, and my newish OEM was 0.9.

Testing showed an improvement. Some long hills yesterday only got it to 200F max, and usually it sat around 186-192 (approx) depending on the gear, grade, speed, etc.

Here are a few pics for reference, if anyone decides they need a new radiator.

(obviously the above was before the shroud was bolted back up.)

And I'm happy to report that the PTO driveshaft was taken into account. Mine was a tiny bit lower than stock because of the ARB bumper integration, so a little more room was very welcome...

Overall, this appears to be a solid replacement for a reasonable price. Longevity is yet to be tested. but I will update at some point.

Also replaced the 76*C thermostat because it was easy access, although probably a complete waste of a new part, since the old one wasn't swapped that long ago.

 

[Gun Runner 5]

I’ve run aluminum radiators on several of my previous Land Cruisers and on day to day driving the temps were very similar to the factory radiators. Where the aluminum radiator paid dividends was the “cool down period” after a long incline. They would return to normal operating temps fairly quickly (at least that was my experience).

 

[Rigster]

My new aluminum radiator from the errr... "far east" arrived a few days ago, so I installed it and had a few days to test. In case you didn't see my addition in the "aluminum radiator" thread, it was plug and play, with one modification: No provision had been provided on the RHS for the shroud to bolt to. A quick drill and then nut/bolt solved that, and then it installed like OEM, using the factory bolts, and rubber isolators. I swapped the cap to an OEM one since the shipped one was 1.1 bar, and my newish OEM was 0.9.

Testing showed an improvement. Some long hills yesterday only got it to 200F max, and usually it sat around 186-192 (approx) depending on the gear, grade, speed, etc.

Here are a few pics for reference, if anyone decides they need a new radiator.View attachment 3362044

View attachment 3362046

View attachment 3362048

(obviously the above was before the shroud was bolted back up.)

And I'm happy to report that the PTO driveshaft was taken into account. Mine was a tiny bit lower than stock because of the ARB bumper integration, so a little more room was very welcome...

View attachment 3362055

Overall, this appears to be a solid replacement for a reasonable price. Longevity is yet to be tested. but I will update at some point.

Also replaced the 76*C thermostat because it was easy access, although probably a complete waste of a new part, since the old one wasn't swapped that long ago.


View attachment 3362056

Nice work there Phil! From the angle of the picture, the PTO shaft looks like it is still close, but I see they had a cutout on the lower tank for the shaft already. Hopefully this will truly help with those long mountain hill climbs!

Let us know how it cools under those conditions while running the AC. Hopefully no issues at all!

 

[JDM Journeys]

Its close for sure, but now there's probably 15mm of clearance. With the OEM rad I'd put it closer to 5mm!! I've been running it with the a/c in all my tests so far. Timing is at 1.07 and EGT's are decent, but could always be lower. Thinking about going back in and raising it to 1.09 to bring them down a tiny bit more. This altitude isn't kind to atmo diesels, and that's right out my back door, before I go west into the rockies proper.

Overflow level seems consistent now, so I think I've gotten all the air out, and no leaks to report. I was happy to see that they stuck with the same style cap too, so I could use the OEM one.

So next up, (and I've said this before) are those dreaded valves. When I measured a year or more ago the exhausts were on the tight side so I'm guessing even more so now. My plan is to measure clearances, then pull and measure each shim. At that point I'll know which ones I need, and then cross my fingers that Mr. @Radd Cruisers has a wide shim selection in stock... I'm still curious if there'll be ANY discernable difference with proper valve clearances?

 

[jayp2]

So next up, (and I've said this before) are those dreaded valves. When I measured a year or more ago the exhausts were on the tight side so I'm guessing even more so now. My plan is to measure clearances, then pull and measure each shim. At that point I'll know which ones I need, and then cross my fingers that Mr. @Radd Cruisers has a wide shim selection in stock... I'm still curious if there'll be ANY discernable difference with proper valve clearances?

Valves are easy compared to some of the other stuff you've done.

Order current "Packing" from toyota p/n 00295-00103

1HZ and 1HDT Valve shim adjustment tutorial video

Hi Guys, For those of you who have never done a valve shim adjustment or are a little intimidated about it I thought I would make a quick video that covers most of the procedure, of course you will need the manual while doing this. Here is the video, and please subscribe as I have a bunch...

forum.ih8mud.com

 

[JDM Journeys]

Well, after a long afternoon of getting oil on EVERYTHING, I rechecked all my clearances, and then measured all the shims. Once I had done all my figuring, I only ended up needing to order 3 shims, and I can rearrange the rest of them to get right smack in the middle of the spec.

It's not a difficult job, but you do need to be organized. My method was a piece of masking tape on the edge of the head, labelling each cylinder, intake/exhaust valve, and red for TDC, blue for next rotation. That way I could simply follow my tape instead of having to look at the service manual every time.

My specs were as follows...

So at the bottom or below spec in many cases, with a few aberrations. I'm very curious to see what difference it makes? Especially because I put it off for far too long. Should be able to button it back up later this week, if all goes well.

As an aside, if someone is doing their valve shims the old fashioned way, you really should get your hands on the spreadsheet entitled "you_beaut_shim_calculator_viii" . It makes the work of figuring out your correct shim placement way easier! I don't know who spent the time to make it up, but I raised a beer to you this afternoon.

 

[JDM Journeys]

Here's my cheat sheet. Lol. I now have the Rubik's cube of valve shims rearranged so I only need to fill three spaces when the order comes.

 

[JDM Journeys]

Just finished going over the Rockies from Calgary, up the coquihalla and didn't need fuel until Kamloops @ 11.4L/100kms. Fully loaded, RTT on top, 50l of water onboard etc. Not bad!

New alum rad is legit.

 

[JDM Journeys]

Great time at BCOR. Took the 77 on the advanced driving course, and the high speed driving class. Lol! Did slalom and emergency braking on dirt. Olbetsy did really well.

 

[Gun Runner 5]

@JDM Journeys ….. “high speed driving class”.
———————————————————————————
Are we talking “normal vehicle” high speed or “70 Series Land Cruiser“ high speed?