2h common rebuild advice (1 Viewer)

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Joined
Jan 26, 2009
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Location
Emu Park, QLD, Australia
Hi all. I have a 2h with 450000KLM on it. It burns a bit of oil and I would like to freshen it up along with fitting a turbo. I am a Plant Mechanic by trade and have worked for Cummins for the past 9yrs, I will be building the engine.

My querie is about the 2h and its common faults. I will need to do the build as quickly as possible, without shortcuts. In order to do so I am afteran idea from you experienced guys as to what is commonly required to return this engine to servicable.

Things like:

Do they require a tunnel bore?
Do the require cam bearings?
Do the require a camshaft?
Will the valve train (rockers, followers, pushrods) need replacing?
Oil pump?
Cylinder head?
Do they have liners and can they be replaced?



Also with the turbo install in mind, are there some options I should be considering in relation to longevity?

Pistons?
Rods?
Head gasket?



Thanks guys
 
If it's a 1985 (1984?) or earlier 2H it will have liners, later versions are parent-bore. You will need to pull the head to determine which you have if you are uncertain as to the year of your engine - gasket sets are slightly different for the early 2H vs late 2H.

As for fitting a turbo, you may wish to consider going to 12H-T pistons, which give lower compression. There are several threads in this section about fitting a turbo to a 2H and lots of good info.

I would bet that the oil pump will be out of spec. and the rocker tips pretty worn - it really depends upon how well the motor has been maintained over its 450,000. It is likely you will find a cracked pre-cup or two in the head. I guess you'll find out when you open it up.

Good deals on rebuild sets and parts can be found in Australia.
 
just a note .. if you gonna use sleeves, be sure get the proper head gasket .. sleeve ready, coz you will found 2 one for slee and other that's not.

Check your oil press and maybe it's a good idea if you can order the oil pump gears ..
 
There's some good info here guys, thanks.

The truck is an '85 but I don't know about the engine, I'll have to try and match some numbers tonight to see if it's original. I am still trying figure out if I can do an inframe rebuild or whether I have to remove it from chassis.

Do these engines have problems with crank tunnel alignment or can I just roll a set of main bearings in? Can liners be replaced with engine still in truck? Anyone know about cam bearings for these old girls?

The 2h workshop manual I have doesn't mention a procedure for replacing liners. Can I pull them with a liner puller? Do they need to be cooled to be installed or just wound in with an installing tool?

All engines have traits common to them when it comes to wear and tear, I'm just attempting to learn about a 2h's traits and traps. I will be changing jobs shortly (maybe a month) and have bought this truck to get me to and from the new job. I currently have a vehicle provided by work so I am aiming to get the build done while I still have it which means I need to act fast. I just want to be armed with as much information as possible so I can proceed with eyes wide open.

Please keep the advice coming guys, I'm all ears. :)
 
advice?
do it right the first time or don't bother and drive it till it dies and replace with a 12HT then...
 
Yeah, pity it's not in context with the questions. :)

Luckily the majority of you guys are a little more forthcoming!
 
so you ask questions that can not be answered till it is tore down.
you ask if it can be done in frame

and you asked for advice, in what context am i missing here?

what, you want us to guess what shape the cylinders are in?
guess whether the cam bearing need replacing?
guess whether teh cam needs replacing or machining?

i have rebuilt many 2H engines or 30 years and each one is different in wear so i tell you how it is and now i am not in context...

good luck.
 
You see?...


i.e. assume everything is cooked and plan accordingly, toal kit is about $1200-$1500 USD.

A factory manual is usually a good idea. Max Ellery etc. are usually a bit on the brief side. They usually don't cover injection pump stroke adjustments and the like. I don't believe that you can re/re the crankshaft without extracating the engine.
 
i have rebuilt many 2H engines or 30 years and each one is different in wear so i tell you how it is

This information would have made your first response more usefull.

you ask if it can be done in frame

Can it? Many diesel engines can be built inframe, of course as long as machine isn't required.

what, you want us to guess what shape the cylinders are in?
guess whether the cam bearing need replacing?
guess whether teh cam needs replacing or machining?

No I don't want you to guess :doh:

I have spent my fair share of time in the workshop and field repairing and rebuilding diesel engines. I have spent time also modifying petrol engines both 2 and 4 stroke. Every single engine I have worked on has a common wear point or flaw. No two are worn the entirely the same, this I realise, but they still have common faults.

ie a 525 N14 Cummins with 1,000,000klm will need main caps closed due to fretting and usually need the deck skimmed due to head gasket fretting.

a 444 Cummins will chew out camshaft lobes faster due to an increase in cam load when compared with a 400 Cummins.

etc

Anyways, keep it coming as I am gleaning some useful information from you. :cheers:
 
You see?...


i.e. assume everything is cooked and plan accordingly, toal kit is about $1200-$1500 USD.

A factory manual is usually a good idea. Max Ellery etc. are usually a bit on the brief side. They usually don't cover injection pump stroke adjustments and the like. I don't believe that you can re/re the crankshaft without extracating the engine.

Yeah, looks like I'll have to pull it apart and find it all out for myself. I have a Toyota shop manual for a 2h but I didn't find any reference to liner replacement. I take a closer look at the manual tonight. Hopefully some time in the freezer will get them in.

Thanks, I appreciate your advice...all of it :D
 
Hey OP, I have rebuilt a 2h with a Toyota rebuild kit. Kit had it all except for pistons. Had mains, conrod bearings, camhsaft bearings, rings etc. My truck is an 87 so parent bore. I pulled the engine out the frame to make sure I make things easy on myself. Upon taking the motor apart I noticed that the cylinders were glazed. The lifters had cracks in the mating surface with the cam lobes, the rockers had indentations in them etc. I think it's best you take the motor apart and then make a list of what you need. I know everyone says that the 12ht is Toyota's mightiest engine, but the venerable 2h takes a turbo just fine. Lets not forget that the 12HT is a 2H with direct injection, a turbo, slightly lower compression and piston oilers for added peace of mind. I have added a turbo to mine and 15k miles later, it's just fine. I did buy a spare engine from a mud member to rebuild along the way, this time with proper Alfin insert pistons, etc. You see, I never thought I'd add a turbo to my motor so I am running the risk of destroying the piston ring lands in the long run. Alfin insert pistons takes care of that problem. I am however only running about 7 psi of boost, so it would take a really long time do damage this engine I think.
Anyhow, if you aren't adding a turbo, a simple rebuild kit from a reputable source will suffice, but I would just take apart the motor first before buying anything.
I hope this helps.
Cheers.
 

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