maistroyoda

I was having a hard time starting my 82 4x4 after it sat for a while. I couldn't get it to start at all. I tried many things including changing the igniter and coil but no luck. I gave up and took it to a shop that specializes in Toyotas. They do good work and I do trust them. They got back to me today saying that I had the three rear rock arms on the intake side broken. I went to check it out and sure enough, they had completely broken off right where they make contact with the springs. The guy told me that the valves under those rocker arms were probably shut not allowing the gas and air to enter. He said that he would like to do a compression test to see if there has been any further damage to the engine. Here's the question to you all, if the three rocker arms broke, what is the likelyhood that there will be damage to the engine or valves? I figure I will get a more honest answer here. He said that if there is damage to the cylinder then I may need a new engine. What would cause three rocker arms to break off? Please help.

JustDSM

Wow! That's pretty signifigant. A rocker arm isn't likely to just fail during normal operation. And even less so, three of them in the same motor!

My guess is something kept the valve from opening, or opening all the way, and as the cam came around to open those valves, the cam was pushing on one end of the rocker, and the "mechanically locked" valve was in a fixed position, and something had to give somewhere, so the aluminum rocker arm gave way.

I'd definately investigate the cause. Don't just throw new rockers in and go.. I've got a spare rocker assembly here somewhere. It's out of a '82 22R. You are welcome to stop by and pick it up ($20) for the whole deal if you would like some spare parts.

xxxtreme22r

if the rockers broke, I have no doubt it caused a flat spot in your cam as well. I'd be changing that too. Also I wouldn't just change out the rocker either. It could have very well bent the rocker shaft(s) too.

The tops of the valves might have survived, just make sure it hadn't "mushroomed" the top of the valve.

While I am thinking of it you said broke where it meets the spring, did the rockers themselves snap or did the rocker faces fall off? That's more common then anything.

maistroyoda

I might take you up on that offer Justin. Today they called and said they did some cylinder air leak test which failed indicating that there is valve and/or piston damage. It isn't going to be a simple replace the rockers repair. Good thing I got that engine from you. The plan is to get the truck back, swap engines with the one I got from Justin, and do a complete rebuild on the old one. By the way, the rockers are steel not aluminum. I thought the 22R came with aluminum.

maistroyoda

I'll try and get a pic of them tomorrow.

engineguy

looking forward to the pics.

igotit

3 broke rockers tells me she may have jumped timming,causing the piston to strike the valves,id pull the head.

1stgenboy

....x2

maistroyoda

Yeah I'm gonna pull the head and inspect. I was under the impression that the double timing chain would prevent the timing from jumping tho. I thought it could have been revved to high. The PO, my brother, didn't take care of it too good and ran it HARD. I parked it immediately after acquiring it from him so they could have been weak when I got it and the next time I fired it up they broke. I might pick it up tomorrow and will post pics.

xxxtreme22r

Still haven't mentioned if you broke the rockers in half or if just the faces fell off the end of the rockers. I think we are all assuming right now that you completely broke them in half.

My guess is over reved too. Since this is an 83 and carb'd there is no rev limiter, and without upgraded valves and valve springs you'll have what called valve float if you rev it to high and since these engine beyond popular belief ARE interference motors, it's not all that hard to kiss the valve off the piston by valve float itself. Especially if it has a 20r head and/or the head/block surfaces were milled.

Now onto the steel rockers, the 20R's had steel rockers, toyota changed to aluminum when they started making the 22r, however the 20r and 22r rocker assemblies are interchangeable along with the cam. My guess is somewhere along the line the P.O. switched rocker assemblies. Also, maybe even put a 20r head on there.

Easy way to tell if you have a 20r head on there:

1975 - 1980 20R Cylinder Head
Round Intake Port
Round Exhaust Port
80/81 C.C. Chamber
Intake Valve Diameter 43mm
Exhaust Valve Diameter 35mm


1981 - 1984 22R Cylinder Head
Square Intake Port
Round Exhaust Port
82/83 C.C. Chamber
Intake Valve Diameter 44.5mm
Exhaust Valve Diameter 36.5mm

maistroyoda

Makes sense what you're saying XXXtreme. BTW they broke off in half. Maybe a little more to one side than the other. I never thought of the possibility of it having a 20R head on it but that is certainly a possibility. Only one way to tell. I wanted to pick it up today from the shop but I don't have anyone to help me. I should be able to get it tomorrow with my dad. I'm going to inspect the cylinders, pistons, crank, valves and the head. If it appears that the head is the only part damaged then I'll replace with a rebuild. If there's cylinder damage then I'll need to replace the entire engine with the extra one I got.

xxxtreme22r

just remember it could be a 22r head and a 20r rocker assembly as well. In any case, I would ditch that entire rocker assembly and get a new one.

maistroyoda

Here are the pics:

JustDSM

Wow.. That's not good my friend. Quite interesting these rockers are steel.. I notice the dual row timing setup. Is this by chance a 20R that had the 22R valve cover?

If you're planning on fixing this motor, I'd strongly encourage you to do a tear down and inspection, as those rockers don't just break.

That 22R (Aluminum) rocker assembly is yours if you want it. It's not going anywhere

maistroyoda

Thanks for the offer. I really wanted to remove the head and inspect the internals, but I'm starting to think that maybe I should just remove the engine and replace it with my extra one (thanks JustDSM). Then I can take my time and really look into the current engine and rebuild if I need to. Right now it's hard to say exactly which engine it has without tearing into it a little. It could be a bunch of different parts thrown together.

Mr_Random

That looks like a 22r... Are we 100% sure that year never came with steel arms? Either way it definitely jumped timing... Good luck with it! I'd be surprised if the pistons weren't mangled themselves.

igotit

im just about sure my 82 has steel rockers on my 22r.

cancel that.....i got aluminium rockers!

xxxtreme22r

Just because he has 22r head on his truck, doesn't mean the P.O. didn't put a 20r rocker assembly on there. They are interchangeable.

smogman

My guess is after sitting the valves are stuck. When you tried to start it the rockers break because they are the weakest link. This is how you verify. get a piece of wood and push down on the valve. If they don't move they are stuck. This happens a lot with vehicles that sit for a long time. if the carb dumped gas into the intake or a little water got in there, the valve will stick to the seat. Take 2 hammers, yes 2 hammers. DO NOT USE 1 HAMMER, you will screw up the valve tip. Place one hammer on the valve tip and use the other to tap the other hammer. spray some wd40 down the intake first and let it soak. The odds of the timing chain jumping are slim and none. Your leak down check is going to fail because you have dry cylinders. You can tell if you have a bent valve really easy without a leak check and without pulling the head in about 5 seconds. take a flat piece of steel (big carpenter square works best) and lay it across the tips of your valves. they should all be very close. You must back off the adjuster so the cam is not holding it open. you can do this with the rockers on if you back off the adjusters you just lay it across the back of the adjusters.

maistroyoda

Makes sense what you're saying. I didn't really feel that it was the timing chain either.