High altitude and no HAC on 2H = engine damage?

[Moodoo]

Hi All,

We are currently in Delhi, Northern India, and about to drive around Kashmir where mountain passes reach 17,500ft. Some last minute research has found my UK 1989 HJ60 Landcruiser does not have a high altitude compensator (HAC) on the 2H injection pump governor.

I have heard lots about black smoke blowing at altitude, but not so much the high exhaust gas temperatures (EGT) which i read can apparently damage and even melt the aluminium pistons!

I really want to drive the famous Manali-Leh highway, but really really don't want to wreck the engine as it still has to get us back to the UK. We are carrying a lot of weight and it is a long route. I dont have a pyrometer to measure EGT either.

- Is it enough to install a new airfilter, gear down and back off the accelerator?
- Should i try to manually adjust the fuel? but based on what, altitude / smoke, as I think too lean a mixture is also bad?

Thanks for your time, and any advice or information would be much appreciated,

Cheers, Andrew

 

[CDN_Cruzer]

I have a 1989 HJ60 with the 2H and I am fairly sure I don't have a HAC. my truck is heavy I recently weighted it on the way home from a trip and I was @ 6200lbs.

I don't have any experience driving @ altitudes that high! The highest I have driven my truck is 6000 feet I have had no problems. I don't lug the engine and (try) to keep it in it's power band = lots of downshifting

I fitted a EGT gauge to see what my temps are like stock someday (hopefully soon) I will turbo it. Here are some observations from driving it around when heavy maybe they will help you make you descion

• when climbing small grades in 5th gear the EGT goes to 1300 and then seems to top out there. this happens even when not flooring it. I don't have a heavy foot.

• in 3rd gear when climbing steep hills if you keep your foot into say trying to maintain 65km/h the EGT will go to over 1400 I get scared and back off the throttle @ that point and slow down even more.

• when driving highways with that kind of weight it's really quite hard to keep the temps under 1100 degrees even when only trying to maintain a speed of 85 km/h

so you have probably already had some pretty scary temps though your 2H already and it has survived. Go for it


Matt

 

[amaurer]

Without a pyro, you'll never keep the temps in the safe range, especially at those altitudes; you wouldn't believe how slow youll need to go. I don't think you'll kill the truck, but I think it will never be the same after a trip like that.

Now, that said, the Leh-Manali is slow going (as I understand it - never done it myself) so that might help you. If you resolve to never exceed 60kph you'll probably come through unscathed.

I'd probably do it.

 

[Moodoo]

Hey thanks for the great replies - definitely food for thought.

Very interesting to see your readings Matt. Like you said, who knows what damage i've already done on previous mountain climbs...
I cant believe I had not even heard of a pyrometer before this, it sounds like an essential modification.

I have a safari snorkel fitted. Aside from putting in a fresh filter is there anything else I can do to increase the airflow?

Tomorrow morning we will go for it and take it extremely slow as advised, otherwise I'll only regret missing out on the opportunity. If anything interesting (i.e. bad) happens to the engine, I'll be sure to report back!

Cheers, Andrew

 

[Tapage]

just back your fuel settings .. ( ideal have a pyro ) if in the mountain pass you see black smoke .. your EGT are high ..

Knowing my truck right now I can drive safe without the pyro, but it's after getting one and know exactly ( or pretty close ) where is the safe point .. just seen my exhaust ( side exit that help a lot )

 

[Wedg3]

I'm from Canada, Quebec and I have a HAC near the Fuel pump.

All That thing does is to lower your fuel ratio. If you know your altitude, turn in down to keep your truck running out of black smoke.

With a EGT, keep your truck on the highway at 750-850 with more then 800lbs of load in it. When you climb a hill with your truck... try to keep it under 1000 degre. Don't forget that your piston melt at 1200 degre. A too low fuel ajust will remove to much of power to climb the hill at a good speed... No domage can be done with to low fuel... just remove power.

 

[canucksafari]

I am with Tapage on this one. Turn down your fuel for the high altitude. While in Ecuador and Bolivia, I saw many diesels without HACs or turbos. They are very slow but run fine.

 

[kim]

I have a 1989 HJ60 with the 2H and I am fairly sure I don't have a HAC. my truck is heavy I recently weighted it on the way home from a trip and I was @ 6200lbs.

• in 3rd gear when climbing steep hills if you keep your foot into say trying to maintain 65km/h the EGT will go to over 1400 I get scared and back off the throttle @ that point and slow down even more.

• when driving highways with that kind of weight it's really quite hard to keep the temps under 1100 degrees even when only trying to maintain a speed of 85 km/h

Matt

Holy hen****! 3rd gear, steep hill, heavy, 1400F!?!

I have crossed Canada towing a trailer and I estimate that my running weight was in the order of 12,000 lbs and I recall climbing into the rockies, from Calgary, and it was all skinny pedal in 3rd, for miles and miles.

I'm amazed that my 2H is still alive and kicking, actually, it runs like a dream with 525,000 kms.

 

[amaurer]

Its pretty easy to hit big numbers - I've seen 1300 accidentally and am sure I could find 1400, but have never dared to go that high.

Some things to keep in mind:

Melting points for aluminum span a wide range depending on the alloy. I don't know what alloy Toyota uses, but the popular "high silicon" piston alloys are said to melt at only 950F. Other alloys are somewhat higher, 1200F+

In any case, exhaust gas temperature does not mean the piston surface is at the same temperature. There is a lot of quite-cool metal nearby that constantly wicks heat away, so you can be sure these is a discontinuity there.

In practice 1250F seems to be agreed upon as a good Do Not Exceed limit. 1400F is irresponsible, but trying to keep it under 1000F is, IMO, unrealistic and overly conservative.

 

[cruiser_guy]

Take it easy and you should be OK. The roads in the Canadian Rockies are not that high when compared to other parts of the world and they are better graded (maybe 6-7% maximum while other parts of the world will be 10% or more). We hit 13,650 ft. here in Guatemala but with the turbo I don't notice it that bad.

My advice is to keep backing out of the throttle until the black smoke stops. It's not a "for sure" method but it's all you got right now!!

My pyrometer has spiked to 1500F once when the turbo hose popped off. Needless to say I stopped immediately to replace the hose.

 

[kim]

Take it easy and you should be OK. The roads in the Canadian Rockies are not that high when compared to other parts of the world and they are better graded (maybe 6-7% maximum while other parts of the world will be 10% or more). We hit 13,650 ft. here in Guatemala but with the turbo I don't notice it that bad.

I figured that my running weight made up for the lack of altitude.

 

[cruiser_guy]

I figured that my running weight made up for the lack of altitude.

Maybe, but not both altitude AND grade. The lack of air really affects the diesels. I was not too eager to get a turbo even after driving around the rockies but once I had been to Mexico and 9000ft I decided a turbo was a "must have". We really do have nice roads at home when compared to the rest of the world. Yes, they might have a few potholes and need some repair but all in all they really are not that bad.

 

[CDN_Cruzer]

Holy hen****! 3rd gear, steep hill, heavy, 1400F!?!

I have crossed Canada towing a trailer and I estimate that my running weight was in the order of 12,000 lbs and I recall climbing into the rockies, from Calgary, and it was all skinny pedal in 3rd, for miles and miles.

I'm amazed that my 2H is still alive and kicking, actually, it runs like a dream with 525,000 kms.

Tell me about it! when I drove over the Rockies I had no pyro either I can only imagine how hot things got! When I drove out east (yes the cruisers has dipped her feet in both oceans) I was pulling a trailer and there where times when it was skinny pedal in 3rd for a while!

I am starting to think the fitment of a turbo might actully prolong the life of the engine or is that just me trying to justify the turbo

I do not make a habit of running the truck that hot I try to not ever go over 1200 I was just pointing out that yes it's easy without a pyro to get the egts way over 1400 in 3rd gear you do not have to be flooring it to reach those temps.


How many people have put a Pyro on a N/A 2H or 3B?

Matt

 

[kim]

Tell me about it! when I drove over the Rockies I had no pyro either I can only imagine how hot things got! When I drove out east (yes the cruisers has dipped her feet in both oceans) I was pulling a trailer and there where times when it was skinny pedal in 3rd for a while!

I am starting to think the fitment of a turbo might actully prolong the life of the engine or is that just me trying to justify the turbo

I do not make a habit of running the truck that hot I try to not ever go over 1200 I was just pointing out that yes it's easy without a pyro to get the egts way over 1400 in 3rd gear you do not have to be flooring it to reach those temps.


How many people have put a Pyro on a N/A 2H or 3B?

Matt

Yeah, my cruiser has met both oceans as well.

I have purchased a pyro but haven't installed it yet.

The mention of 1400 F freaks me out because I KNOW I have pushed my truck hard. On the pin, all skinny in 3rd, holding 60 kph pulling 6000 pounds all the way through the Rockies.

 

[Tapage]

How many people have put a Pyro on a N/A 2H or 3B?

Matt

Me .. my Pyro it's running since 2004 or so .. when I was thinking ( I was right :hillbilly ) Tencha needs more fuel ..

 

[FJn00b]

it is not going to get hot cause the O2 consentration is lower by some 30% at that alt. This where a turbo can come handy to keep the O2 ratio to match with the fuel.

If you have no turbo then lower the fuel to match the air ratio and send me an email. I am taking My Cruiser to do Silk Road and may be go thru Karakrum Highway next year.

 

[cruiser_guy]

it is not going to get hot cause the O2 consentration is lower by some 30% at that alt. This where a turbo can come handy to keep the O2 ratio to match with the fuel.

Actually that's EXACTLY why it gets hot. Excess fuel in a diesel means excess heat. It is the opposite of what happens in a gas engine. The turbo keeps the O2 concentration up because of forced induction but you can still see a rise in EGT's at altitude. I know I do at 13,650 ft. I need to back off just a little at that altitude while at sea level I'd be OK.

 

[FJn00b]

Actually that's EXACTLY why it gets hot. Excess fuel in a diesel means excess heat. It is the opposite of what happens in a gas engine. The turbo keeps the O2 concentration up because of forced induction but you can still see a rise in EGT's at altitude. I know I do at 13,650 ft. I need to back off just a little at that altitude while at sea level I'd be OK.

The OP is not talking about turbo engine

 

[canucksafari]

The OP is not talking about turbo engine

Precisely, and that's why it will creat even higher EGTs if you don't turn down the fuel.

 

[cruiser_guy]

The OP is not talking about turbo engine

That's right!! As John already pointed out, the turbo helps reduce EGT's because it gives more air. In the case of the OP, he doesn't have a turbo so he has no way to make up for the lack of O2 at altitude (which will result in overfuelling for the available O2), all he can do is let out of the skinny pedal till the smoke stops and hope that he's OK.

An HAC works to reduce possible fuel flow, in essence, letting off the skinny pedal for you.