What happened to my 1HDFT? Taking bets (1 Viewer)

What happened to my 1HDFT?

  • connecting rod bearing(s) spun, allowing piston/valve contact.

    Votes: 0 0.0%
  • Wrist pins bad, allowing piston to rise to high

    Votes: 0 0.0%

  • Total voters
    5

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Joined
Nov 12, 2003
Threads
160
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1,306
Location
Truckee, CA
the 1HDFT in my (converted) diesel 80 died.

backstory
Purchased truck (11/2008)
truck was converted years and years ago by the infamous Raymond Fourie in Vancouver. Its a factory FZJ80 converted to a 1HDFT/h151. It was stock-ish when I bought it. I added OME, 255's on Toyota steelies, Labs rear bumper, Hannaquality sliders, DIY front bumper, african outback rack with columbus RTT, 3:1 low gears, overdrive high range, intercooler, G-Turbo grunter extreme.

This truck is my long distance explorer. I've been across most of the western states. Wheeled on Rubicon, Moab, Hole in the Rock, Death Valley. It's been to the end of Baja 8 times. I've put 150K miles on it since buying it. I wish I could say it's never let me down... BUT...

The timing belt incident (12/2013)
while changing the timing belt (honestly can't remember why), I forgot to tighten the camshaft timing belt nut. 50 miles later... The timing belt fell off, the cam stopped, the pistons hit the valves, and shattered all the rockers. Long sad story short, ended up with a new head.

The crankshaft incident (4/2015)
Exploring Utah... I noticed a really bad front main seal leak. Turned out, the harmonic balancers on 1HZ, 1HDT, 1HDFT, 1HDFTE go bad. They should be replaced around 150K miles. Mine was out of balance... and wobbled so bad it cracked and also ate the crank nose. I made it home, pulled the motor, and put in a new crankshaft (with new bearings).

The (current) Semi-seized Incident (2/2019)
While in Baja California Sur, the engine... stopped. It gave a tiny bit of warning (I think I might have heard an intermittent squeal) before it shuttered and stopped. I was able to almost re-started it... but then the second try... the engine basically seized. With fresh batteries, I can get it to turn about 1/2 a revolution. So, I towed it home.

So here we are... Engine is out, and I was able to get the head off. The cylinder walls look... ok. The crosshatching is mostly present. There is some streaking. What's interesting is the imprints of the valves on pistons 1, 3, 4, and 6

Picts are in order. Pistons 1-5

1980552


1980553


1980554


1980555


1980556
 
Was the timing belt in the correct position? I was wondering if the squeal was the timing belt tensioner .
If the head gasket was too thin, the problem would have been there from the start after the rebuild.
And I would have thought bad wrist pins would have made a racket before it died
With oil galleries blocked, I would have thought you would have seen oil pressure irregularities, but easy to miss unless you look athe guage every few moments. But again, it would have been noisy.
 
Timing belt wise did the tensioner shift because a key did not get put in?

Piston protrusion could be an issue if you didn’t run the thickest HG Available
 
I didn’t think of the timing belt jumping.
It’s removed. BUT I was able to (barely) turn to engine with a huge cheater bar, to TDC. when I did, the cam was also at TDC.
And a jumping timing belt wouldn’t explain why the crank, even after head is off, is nearly impossible to move.
 
And a jumping timing belt wouldn’t explain why the crank, even after head is off, is nearly impossible to move.

I have low klm 1HZ in my shed that I bought from a mechanics sale. The number 6 cyl was hydrolocked when water entered the air intake but it also damaged the BEB . I cant see any deformation of the conrod, but the #6 BEB is destroyed and the crank is delaminated and it was real difficult to turn with a bar on the crank. So I am suspecting you will find problems deeper down. However , we wont really know until you strip the engine further.
 
As soon as the “new” FT motor is off the stand, I’ll put the old one up and inspect the crank.
 
Photos aren't real clear. Valve/piston contact looks obvious on piston 3, the others, I can't really tell.

If there's contact on multiple pistons, it would suggest a timing problem to me, but that doesn't explain why you can't turn the crank.

You could remove the oil pan and look at the bottom end for clues, bent rods, failed BEB, bearing shrapnel in the oil etc, but I think you're looking at engine out.

I cooked and lightly siezed a 1hz due to a cracked head causing it to overheat.
I couldn't turn it over initially, but took the head and oilpan off, and after things looked ok, sprayed diesel in the bottom end, managed to get it turning freely again, and buttoned it up with a new head, fresh oil, and it's been ok. I think I definitely got lucky.
 
How many miles since you replaced the crank? All new bearings then?
 
If the valve contact was from the timing belt jumping... I would think it would only be either exhaust or intake; not both (all four).

Anywho... little update. I needed the pan off the old motor for the "new" (used) motor. While I had the pan off (block hanginging by the hoist, as the new motor still on the stand), I took the pistons out. And... wow.

1981984


1981986


1981989


IMG_5533.JPG
 
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The holes don't actually look awful.
Picts are weird because of flash on phone. Looking down from the top, Crank and oil squirter are in bottom.
in order cylinders 1-5: (6 in next post)
1981992


1981993


1981994


1981995


1981996
 
If the valve contact was from the timing belt jumping... I would think it would only be either exhaust or intake; not both (all four).


Thats because the engine went through a number of revolutions with an out of position timing belt before it ceased to run. The engine's rotational momentum would ensure that . And then you say it almost restarted, the starter motor has enough torque to turn the engine when its damaged and do more damage.

What condition is the timing belt and idler in?
 
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That is a piece from the bearing cap, the part the rocker arm shaft runs through. You don't see it missing with valve cover off? More impressive part is that it was able to make it down into the pan
 
That is a piece from the bearing cap, the part the rocker arm shaft runs through. You don't see it missing with valve cover off? More impressive part is that it was able to make it down into the pan

The camshaft bearing cap? That makes sense. When the timing belt incident happened the rockers and associates pieces exploded. I guess this was stuck in an oil galley for the past few years.
 
s***... when the infamous timing belt incident happened, I was so mad I had someone else fix it. The oil return galleys from head to pan are big. When I did the crank, I had to pan off… I would have seen this big piece of aluminum. It must’ve been wedged somewhere in the block for years.

Anyway… Moving on. The cylinder walls look pretty dang good for an engine with almost 300,000 miles. The crank spins very smooth now that the #3 and #4 connecting rods are not stopping it.
I’m thinking this will need very little machine work before I put it back together. Fingers crossed.
 

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