Broken timing belt on my 90 4runner

I had a broken timing belt while driving on a freeway. I had the timing belt replaced and the timing marks set correctly, the engine cranks and try to start but wasn't able to get it running. The engine also shakes and I also heard popping sound while cranking. Any experts out there knows if the valves may have been bented? Are 1990 V6 3.0L 4runner engines interference engines that can easily bent the valves in this case? If so, any idea what it would cost to repair it?

Thanks,

-don

Reply to
Coolguy
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I am not sure, but sounds like the marks may be aligned, but a full rotation off. In other words, the engine is trying to fire while the valves are open. The valves in this engine are not usually damaged when the belt breaks. Did toyota put the belt in - - or a shade tree guy? Hope this helps, Clyde

interference

Reply to
Clyde Hathaway

Thanks Clyde, I'm the shade tree guy :-(. I'm not quite sure what you meant by a full rotation off. The two cam on top is a bigger gear, and the crank is a smaller gear on bottom. The bottom gear has to rotate a few times before the top cam gear can line up. I checked the chilton repair manual and it didn't say anything about the possibility of a full rotation off. Can you explain what you mean?

I hope you're right about the valves not damaged, because it will be a nightmare for me. Are you a mechanic expert? How do you check if the values are ok?

Thanks in advance.

-d>I am not sure, but sounds like the marks may be aligned, but a full rotation

Reply to
Coolguy

If you have the valve timing marks lined up properly then you nreed to do a compression test. This will tell you if you hvae any bent valves.

Reply to
Mike

I have a 90 4runner and had the timing belt replaced at 125k. Some of the links were broke but the chain was still together.

The 22RE engine WILL have internal damage to the valves and possibly cylinders if the timing chain breaks. I don't know about the 6 cyclinder.

Reply to
grinder

The 3vZE is a NON-interference engine.

Reply to
Keyser Soze

Thanks Keyser, that is nice to know. To elaborate on what happened. The

4runner overheated because of leaking water pump. My wife pulled in a gas station and some bozo told my wife the it is low on oil based on the dashboard gage because he couldn't find the dip stick under the hood. He then fill the engine with 4 quart of oil (and also fill the radiator with water). Needless to say, my otherwise fine oil level in the engine is now 4 quarts of oil over the limit. During the drive home, the timing belt groove got stripped by the crank gear on the freeway. Now that I double checked on the timing marks after full rotation of the crankshaft on the newly installed belt, the car still hesitate to start and shake and popping sound. It does sound like a timing problem, but I checked and double checked the marks, so it doesn't seem like a timing mark issue. Since it is a non-interference engine, the valve may not be bent from the timing belt stripped. Can the overflow of oil cause the probelm? Does this still sound like a bent valve or internal injury to the engine? For a compression test, I have to call a tow truck to tow it to a shop which I hesitate to do until the last resort. Any help from you gurus would be appreciated.

Thanks,

-d>>I had a broken timing belt while driving on a freeway. I had the timing >>belt

Reply to
Coolguy via CarKB.com

If you can change a timing belt you sure can check the compression. It isn't difficult. :) Overfilling the crankcase is a no no but I would guess the overheating is a more likely suspect of your new problems. Worse case but not an unlikely scenario is a warped head and or failed headgasket. Get a compression gauge, pull the plugs and get a reading.

Reply to
Keyser Soze

Sounds like the most likely problem is a blown gasket or head. You can get a compression tester at your local auto parts place for about $30-$40 and test it yourself. Just pull out all of your plugs, screw in the compression tester and crank a few revolutions at each spark plug port. The readings should all be within 20% of eachother, if it is more you either have a blown head gasket or warped head, block, or worse a crack! If it looks like it's just the head gasket, have the head checked for warpage or, for about $120 in tools you can test it yourself. Go to

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and buy a 24" precision straightedge and set of feeler guages starting from .002" and larger. Since you've done the timing belt yourself, I'll assume you have a decent shop manual. It will show you how to check the head and block for warpage. If the head gasket looks ok, I'd think about swapping the long block as that means there's deeper problems. Between the overheating and excess oil added, these are sure to have done some damage.

Reply to
MrFixit469

Thanks guys. Here is an update. I did a full rotation on the crankshaft like Clyde said and I was able to start the engine. I also did the compression test and here's what I got: cyl 1 = 160 psi cyl 2 = 120 psi cyl 3 = 155 psi cyl 4 = 150 psi cyl 5 = 165 psi cyl 6 = 150 psi

Looks like cyl #2 is a bit low. The car idles at around 500 rpm which is pretty rough. I use the tachnometer on the dashboard and run it to 800 rpm to set the timing at 10 degree BTDC with the terminals E1 and TE1 shorted according to the manual. However, the idle is still around 500 rpm and running rough. The idle speed on the fuel injected engine cannot be adjusted. The manual says it is automatically adjusted by the cpu. Sometimes it even backfired. When I step on the accellerator, the engine sounds much smoother. When I put it on drive, I can only get the 4runner to crawl and then died. Sounds like the timing is quite off.

I have a few questions for you gurus.

  1. From the compression data, can the cyl #2 still be warp or is it just a bit worn?
  2. Since the car idles low and only crawls when put on drive, does this sound like a timing issue to you guys? How can I do a more accurate timing?
  3. What else should I do to get it to work? Any other comments and ideas?

Thanks in advance,

-don

MrFixit469 wrote:

Reply to
Coolguy via CarKB.com

The reading at #2 shows that, at the very least, the head gasket is blown. You MUST address this issue BEFORE you address any other problems! The only way to check if the head or block is warped is to take the head off and manually check it as described above. REMEMBER...when taking the head off, loosen the head bolts ONLY 1/4 TURN AT A TIME, in the reverse order as the manual shows to tighten thehead bolts. You will be starting at the outside edges and working toward the center. IF YOU DEVIATE FROM THIS PROCEDURE, YOU WILL WARP THE HEAD, EVEN IF IT'S NOT ALREADY!!! Your manual will have the procedure for removing the head, it is pretty involved, including removing both the intake and exhaust manifolds. If you've never done this before, follow your manual's instructions to the letter!!! Keep your fingers crossed that the only problem is the gasket.

Reply to
MrFixit469

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