2.7 Head removal questions

Hi all, I'm removing the head from my 2001 Tacoma and been following the manual and some threads here that have been helpful. But I've run into a few questions. I've got things torn down to the head itself, valve cover pulled, all components out of the way.

1. When taking the camshaft gear off, I see most pics with a tie strap around chain and gear. Do I need to worry about the lower end of the chain coming loose? Do I need to keep tension on the chain (pulling up)? Or can the chain just lay there and be ok? [In my experience the Timing Chain doesn't come loose.]

2. The manual talks about inserting a "service bolt" in the exhaust cam gears, is this because the gears are spring loaded or something? Do I need to find the spec'd out bolt or can I just use some wire or something? [The valve cover bolts will work. I also found out that it spring loads only a couple of teeth, so it's not impossible to torque it back to where it needs to go.]

3. What socket do I need to pull the head bolts? Is that some sort of star? [The 12 point 14mm is the correct size]

4. Is there anything else I should worry about before pulling the bolts in the specified order of removal (cam shafts and head bots)? [Some suggestions from my experience: Take plenty of before pics for reference. Check the exhaust and intake stud threads while the head is off, don't wait until it's back in to find out the threads were messed up. If you didn't remove the exhaust manifold, place the exhaust gasket on the studs when you put the head back on. Be prepared to clean the throttle body and intake manifold, as they will be pretty dirty.]

All I can think of ATM.

TIA

 

Well I can answer some of this.... the exhaust cam service bolt is the same thread as a valve cover bolts, so just use one of those (then you wont forget to take the bolt out when your done too). The head bolts are a star head but I'm not sure which off the top of my head. That's about all I know off the top of my head right now. I have a service manual for the 96 2.7L that is prolly very similar if you need it.

 

OK, that "service bolt" = valve cover bolt, makes perfect sense. Saves me a trip to buy something. Thanks for the tip.

 

1. I don't think you have to worry about the chain coming off of the crank gear. I didn't, but I haven't put mine back together yet! You will know if it's off when you are reassembling it anyway, so I guess if it's able to jump a tooth, you'd be able to get it back to the correct one.

2.The service bolt is a 6mm diameter, 1.0mm thread pitch. You need 16-20mm length. The valve cover bolts may work. You can't just use a wire. The gear is spring loaded.

3.The head bolts are a 12-point 14mm (at least on a 1996). Sound like the same on yours. I had 2 craftsman 1/2" drive 14mm sockets. I used the newer one I had because it fit slightly tighter on the bolt. You don't want to strip these bolts! You're going to need a breaker bar, or extension on the ratchet because they are on tight!

4. Did you remove the chain tensioner? You've removed the camshaft gear from the camshaft already? You have everything lined up at TDC? Checked that the marks on the back of the cam gears are lined up?

You might want to check the valve clearances before removing the cam shafts if you have some feeler gauges. But don't turn the crank without the timing chain gear attached to the camshaft. You don't want pistons hitting open valves. (Not sure if this is an interference type engine.)

When you get the head off don't turn it upside-down with the camshafts off. The valve adjustment shims can/will slide out. Well, if they do you don't want to lose what order they were in. You can turn the head over and let them slide out, then keep them in the proper order.

 

Head bolts aren't reusable, just so you know. They are torque to yield and stretch when you tighten them for the first time.

 

I haven't removed the timing chain yet. I will check the valve clearances before, that's a good idea.

I'll keep track of the buckets and shims, making notes as I go. These are good tips!

 

I had a heck of a time loosening the camshaft bolt holding the chain sprocket on. I didn't have a wrench that could hold the camshaft at the hexagonal part tight enough, so I ended up using the tool I built to hold the power steering pump pulley on the sprocket while loosening that nut. It looks similar to the one in the "crank pulley removal thread"

http://www.tacomaworld.com/forum/1s...homemade-crank-pulley-tool-2.html#post8587334

I used a 6-point socket, 3/8" drive with extension and adapter to a 1/2" ratchet with extension. I didn't want to risk stripping it with the 1/2" drive 12-point socket.

Then once I had the bolt loose, I needed to wiggle and pull the sprocket for 30+ minutes to get it off. Maybe there's a trick to this that I don't know. PB Blaster or something?

 

All bolts stretch when you tighten them. Torque settings are there to make sure your bolt stretches enough, not be tight enough.

 

Yeah I ran into this today. Had a 12" adjustable wrench on the shaft and a 1/2" breaker bar on the nut, with two of us working it for about 20 minutes and it didn't budge. Tomorrow I'll look for some pipe to get more leverage on the adjustable wrench. That nut is CRAZY tight!!

 

I'm aware of that, however the head bolts on a 3RZ are designed to stretch and cannot be re-torqued like a regular bolt. They are marked as a one time use item and I even asked Bamatoy1997 about whether or not you could re use them just to be sure.

 

I ended up using this tool I made:



I had to brace it against the fender like this:



Then used my ratchet with a pipe on the end. I actually leaned over from the passenger side fender with the other tool braced next to me. I must have applied close to 200 ft-lbs of torque before it popped! I had to remove the exhaust camshaft so the tool wouldn't hit the distributor gear. Also, the threads on the bolts on the tool put some small nicks on the sprocket holes, so maybe I should have put something over the threads.

 

Thanks DrZ, your suggestions and pics really helped. In fact the idea of taking off the exhaust cam was just what I needed.

 

Were you able to hold the middle of the camshaft with a wrench like it says in the repair manual? I didn't have a quality wrench that would stay tight enough to hold it there!

 

No, not at all. After taking off the exhaust cam and making a tool like you suggested, I still had no success. The flat steel was bending when I torqued on the nut.

Soo... out of desperation, I inserted a screwdriver in a gear "whole" and wedged it through the half moon knock out. I guess I got away with it, as it didn't mar anything. I know it was a bad idea, but after a couple days of it kickin' my butt, I had to try something!

 

I probably would have tried what you did too if I hadn't already made the tool to remove the power steering pulley. (I needed to take that pulley off to replace the leaking PS reservoir o-ring.)

For future reference you need a 1/4" thick steel bar for it to not bend. I tried with a thinner metal bar also, which bent for me too.

 

Man I am getting ready to do this same thing. I hope mine goes a little easier..