yota_mkii

Hi, my timing chain broke on the run, and i've cranked it over a few times since. so the cam and crank are totally out. I have it all apart now... i can get the crank shaft to 0 TDC, but the cam is reluctant to move.

i know there is danger of bent valves, but there were no bad noises... i just want to rotate that cam to the 12:00 mark, but not sure how to do this without risking valve damage... any leads?

my diesel mechanic buddy tells me i could loosen the rocker arms and then turn it...

rokblok

iTrader: (1)

If it broke while driving, I dont think I would worry about bending the valves while turning it over by hand...

If its interference, you can almost bet money they got tagged by a piston...

Loosen, or remove, the rocker arms. Keep them together on the rocker arm shafts. And in the same order. If you cant move it then, prepare to remove the head...

snobdds

The only correct way will be to take off the rocker arms and realign the cam. To take the rocker arms off means breaking the seal on the head gasket. Some have taken a ratchet strap and wrapped it around the block and head to prevent the head from raising up, but...most of the time the HG ends up blowing soon after.

To fix this right, take the head off and realign everything. Put in a new head gasket (OEM only) and all the other gaskets in a top end kit from the dealer.

It's not that much more to take off since your already in there for the timing chain. Plus you need to look at those valves to see if ther ok, don't just assume since you didin't hear any "bad" noises there ok. Then you will know everything is done right.

ThatGuy1295

Moter?

rokblok

iTrader: (1)

Yes. Most of our trucks have motErs... Although mine has a motOr... It was another factory option...

ThatGuy1295

No no,, what motEr does he have? Cause they made more then one kind. Apparently they actually made different sized motors with different configurations and amounts of cylinders. And some of these motors the cams can be removed without removing the heads...

yota_mkii

thanks thatguy, its the 22r, 2.4l 4 cyl... sounds nice, removing the cam without removing the head. what if i just loosen the rocker arms, will the head still go?

ThatGuy1295

I believe thats what motor snobdds was reffering to. I would do that.

Just wanted to make sure it wasn't a 3vz or something else.

James Woods

iTrader: (1)

The 22r is an interference motor, I am about 99% sure of that. Which means that you don't have to worry about damaging the valves by hand, it wont make any loud noise when it happens. I bent valves on a car at work once when the timing belt fell off at an idle, so if you were driving, that is a good bet that the valves are toast.

ThatGuy1295

X2. Since youll need to replace the HG anyways, and the valves are probably toast, id just pull the head and do it right.

yota_mkii

any way to check on the valves without taking the head off? compression, for example? oooh i don't want to replace all those valves :|

ThatGuy1295

you could compression check, but you'd still have to rotate the cam to do so, or remove the cam, in which case you still might as well pull the head

ThatGuy1295

And you wont have to replace all the valves, most likely 2 or so, but hopfully less or none.
Once the cam stops and the pistons keep going, only so many valves can be damaged as the other valves are not moving anymore. And not in a position to be damaged.

James Woods

iTrader: (1)

The only way to know for sure is to do one of two things at this point.

1. Just remove the head and check which valves are bent.

2.Put it all together and when it doesn't run, do a compression check and tear it all apart again.

I suggest #1.

yota_mkii

haha when you put it that way. ok my plan for tomorrow is... bring all of the pistons to the mid-point (i assume this is possible - ? or at least close) by checking with a dowel through the sparkplug hole. then try to spin the cam again. with luck it will go around freely. If it does, then i will do a compression test on each cyl to see if the valves are seating properly. and the big $$question ... if the cam spins and there is compression, is it good to go>!? thx by the way, you guys are awesome

oh yes and if it doesn't spin, i get to re-learn even more fun stuff that i haven't done in 16 years ;\\

ThatGuy1295

If by some crazy chance you didnt bend any valves then yes, if you have good compression on all cylinders then your good.

But usually when timing chains break on a 22r theres destruction!!

Let us know what you find.