my story; removing the cylinder head 80 series 1HD-T

[lockie]

well let me start by saying, what i did this weekend was (what i thought) slightly beyond my mechanical knowledge. So you may have to excuse me... i might not be calling certain parts by the right name.

And why was i removing the head you might ask.... for the past 4-5 weeks i've noticed that the radiator was over pressurising and pushing all the coolant out the overflow, and on two occasions it started to get a bit hot.

Saturday about 10:30 is when i kicked off, in that day i got everything off that was in the way - fuel lines injectors, rocker cover, timing belt etc.....
Injector 6 had a little bit of green/white crystals building up on it. Not a good sign, all the others however didn't look too bad...
That took my brother and me a couple of hours (over a few beers, and we definitely weren't rushing)
along with a shit load of pictures.

Sunday was the big day (i didn't realise how much i had left to do) i thought i was going to be gone by early afternoon.... wrong! I left at 7pm.
We took off the turbo, the dump pipe, outlet manifold, camshaft and finally the head!
Unfortunately upon inspection i found that piston no 6 had a nasty little surprise on it (all the pictures should be attached below)

So now i'm having the head sent off to get crack tested tomorrow and then i guess ill see if its possible to replace just one piston, try and save myself the cost of a full rebuild (i'm only an apprentice so im not exactly rolling in it)

 

[Michael Montgomery]

I'm no expect but can see your issues on the pictures shared.
Maybe others here can assist you better with precise advice.
Hope you get it fixed swiftly without to much cost baired.

 

[frank rabbets]

It looks kike the piston has been hitting the valves so replacing the piston will not help. The usual cause is worn big end bearing on the affected journal/pin. Usually , on this engine, a ticking noise is heard just before more dreadful terminal banging noise. You DEFO need to take the big end bearing caps off to inspect the shell bearings. Also DEFO need to measure Number 6 crank journal/pin with a micrometer all the way round ( 8 places ) to make sure it's still round to within .001 ".

Now the water loss is, unfortunately, another story. Turn the engine over so you can inspect the bores for cracks with pistons right at the bottom. Number 6 gets hottest especially with debris build up. Pocke a weak probe down the water jacket of each cylinder. It should drop to the bottom equal height on each cylinder. Leave the block full of antifreeze. If you cannot see a crack leave pistons 2 by 2 overnight at the bottom of the bores and see if antifreeze seeps through the walls of the cylinders onto the piston(s).

Keep us informed. Very interesting.

 

[clivehorridge]

Fingers crossed for no more cracks.

New BEBs is a good move anyway, but replacing a piston is a bit more of a strip-down.

Still it's worth it.

Money is only time, so IMO, you should take your time and get it right.

 

[Towpack]

Agree 100% on checking the BEB's. If the head's already off then changing a piston is an easy next step when the BEB's are accessed. If that cracked piston is due to it hitting the valve caused by a badly worn BEB then you have been very fortunate indeed and caught it just in time. If the cooling issue is just the head gasket then, assuming the crank is OK, with a new piston and BEB change you should be home and dry. I'm crossing my fingers for you, good luck!

 

[StarCruiser]

You've come to the right place Lockie, and got some gold star advice. Take your time and inspect thoroughly being top of the tree. No point rebuilding an engine with a cracked cylinder. Hope it hasn't got that. It does have green coolant though. Toyotas like the Toyota Red stuff. Not sure if this is significant. Looks like the head gasket has seen better days though, thankfully, I haven't seen one 'in the flesh' so don't know what it's likely to look like on one of these.

Good luck with it.

 

[lockie]

thanks for the replys and advice guys!
BEB's are on order, head is getting sent away for testing and a reco today.
also got a few other little bits on order (head bolts, timing belt spring, few other bolts etc...)

ill be heading back to my brothers this afternoon or tomorrow to check out the cylinders and do the antifreeze test that frank rabbets mentioned (thanks again for the tips!)

ill keep everyone up to date with pictures etc...

anyone know of a place i may be able to order a piston within australia?

 

[Michael Montgomery]

thanks for the replys and advice guys!
BEB's are on order, head is getting sent away for testing and a reco today.
also got a few other little bits on order (head bolts, timing belt spring, few other bolts etc...)

ill be heading back to my brothers this afternoon or tomorrow to check out the cylinders and do the antifreeze test that frank rabbets mentioned (thanks again for the tips!)

ill keep everyone up to date with pictures etc...

anyone know of a place i may be able to order a piston within australia?

I ordered a kit from Austrailia for my rebuild and it was deemed very good quality.
Just have to know the size of your pistons.

Only thing if I can recall the kit didn't have is the exhaust valves so I bought them from the UK. They were also cheaper from what they offered.

Hope this helps

https://www.ebay.co.uk/itm/321546024506

 

[lockie]

a little update after a day of calling around and researching on the internet.
one of the companies i was talking to about pistons and rings, said that if i was to only replace one piston, it could throw off the weight and make the engine unbalanced.
BUT i've also been told that if i was to replace the cracked piston with genuine toyota part it would be ok.
here is the catch... ONE genuine toyota piston - $500
a set of 6 pistons and rings (aftermarket) $700

So i think ill just place them all, (and the BEB's), hone the boar/cylinder (correct terms??) and leave it at that...
quote for the testing and reco of the head is $1200, plus all the other little bits and pieces. so the bills are getting bigger at a rapid rate!

 

[StarCruiser]

Have a look at this thread especially the pistons that were sourced. https://www.landcruiserclub.net/community/posts/1395912/

The new pistons had the uprated steel lands between the rings similar to the marine version which delivers some 300 or so hp.

You're doing fine with your terms. When honing or glaze busting the bores you must thoroughly wash any and all abrasive/removed glaze out of the engine and prevent it getting into any cavities otherwise it could get in and damage parts of the engine. You seem to be plugging up holes diligently so that's good.

 

[frank rabbets]

I would check the crank journal first before spending money. The crankshaft could be damaged beyond repair.

Use all same brand pistons.

Find out how to "glaze bust" the bores to give the original rough finish. This is contra to common sense but enables the new rings to bed in correctly as they will be a different profile to worn in ones in there.

Carefully have a look at signs of blow by on the gasket. If it's been leaking there could well be witness marks on the head or block to confirm. I doubt if it's head gasket if it's original Toyota and all bolts were tight.

It's vital to get to the bottom of the pressure problem before you put the engine back together. There are 2 unrelated problems.

It's a very tiring and stressful job so if you get punch drunk have a day off, but I know how tempting it is to plough on until the end.

Good luck.

 

[frank rabbets]

Someone on here had same type of engine with same pressure symptoms. Turned out to be a crack low down in number 6 bore. Another cause on these engines is unlikely but it might be a faulty thermostat staying closed. They normally fail open in safe position. Thermostat is located behind the pipe/flange on engine which the bottom hose goes round. Take off this and the thermo lifts out. You can test this by heating up in a pan of water. It should open at the temperature stamped on the thermo. It should open fully along the witness lines caused by pre working correctly.

If you find and cure the leak problem it's essential to test number 6 valves by lightly grinding them in to their seats. There should be an even grey ring around the valve seat indicating the valve is not bent. The seat in the 'head should also have a grey even ring indicating the seat is even all way round.

Also crack test the rockers and clamps on number 6. If the piston has hit the valve it's likely to have stressed the valve gear as this gear would be holding the valve open at moment of impact. Someone on here had shattered valve gear I think when the timing belt broke. Did not need crack detector lol.

You can buy spray cans of crack detector dye and developer. If you crack detect the bores because you can't find a crack they'll have to be dried out first as the dye may not be water soluble. worth checking on can first.

 

[chapel gate]

Number six pot generally runs hotter than the rest due to its location on a straight six, are you running more fuel?

 

[frank rabbets]

That gasket does look a bit messy at pot no 6 doesn't it. Perhaps get an opinion as to whether leaking or not from your 'head expert.

A genuine Toyota gasket has a piece sticking out on the corner by the oil stick. This enables you to tell, by the number of cut outs, which thickness of gasket to order before taking the engine to bits.

I don't think the thickness of gasket is very important but at least you can see whether or not it's a Toyo gasket. If Toyo unlikely to fail.

 

[denboy]

That gasket does look a bit messy at pot no 6 doesn't it. Perhaps get an opinion as to whether leaking or not from your 'head expert.

A genuine Toyota gasket has a piece sticking out on the corner by the oil stick. This enables you to tell, by the number of cut outs, which thickness of gasket to order before taking the engine to bits.

View attachment 114302

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Well - never too old to learn something new.... never knew that!

 

[lockie]

Had a look last night, is it a Gen Toyota gasket...
been busy with work so haven't had much of a chance to do anything more this week...

Star cruiser - I started reading that thread, haven't quite gotten to the point regauarding exactly where the pistons came from.
Pretty interested but I'm on a pretty tight budget, so I probably won't be going down the hi-performance road.


Someone asked if I was running more fuel - no I'm not... or I should say I wasn't.
Completely stock with the boost and fuel.

What I have found out that there is two different sized pistons, I think they were 39mm and 42mm. Which is the size of the hole in the top of the piston (no idea what it's called)
So far my first quote for a aftermarket set is $85 per piston and $110 for the rings.

Feel free to pitch in your thoughts on those prices... will hopefully have Friday afternoon off to ring around and get a few more quotes.

 

[StarCruiser]

Continue reading lad. The pistons were pretty reasonable if I recall.

The depression in the piston is the swirl chamber. Worth researching what the size difference is. Put the best size in. You also need to make sure it hasn't been rebored and got oversize pistons.

 

[lockie]

Continue reading lad. The pistons were pretty reasonable if I recall.

The depression in the piston is the swirl chamber. Worth researching what the size difference is. Put the best size in. You also need to make sure it hasn't been rebored and got oversize pistons.

Pretty sure it's all Orginal inside... it looked like I was the first in the engine from factory.

Got a decent drive home ahead of me this afternoon (I'm just passenger) so I'll get into reading that thread then.

 

[StarCruiser]

The pistons should be marked if they are oversize. It sounds like they aren't but you need to check.

Any sign of coolant through the bores?

 

[lockie]

Not that I can see, the bores are a little glazed but apart from that, they look pretty good.

Haven't put anti-freeze in the water jackets over night to check for cracks yet.