Yet one more timing belt Q....

[tkremin]

Just bought a 1990 4runner SR5 (4x4, 3ltr V6, automatic)

About a week ago on my way home, and almost home, the water pump decided to commet hari kari and dump the contents of the coolings system. Thankfully about a block from home.

I got the most pleasant surprise of finding the water pump BEHIND the timing belt. Timing belt was a little old (the engine had the recall performed about 50k miles ago - with an overhaul ( new hone, rings, etc) but figured as long as I was in there... and teh radiator had some seepage, so a new radiator as well.

The engine now seems to run slightly rough and doesn't make as much power as it did before. I tried checking the belt alignment, assuming that the crank mark is at 0 degree TDC so I didn't have to completely dissasemble ( is this true?), it and the upper pulleys seemed alined with their marks.

so my question (finally): could the belt alignment be one tooth off on the bottom pulley and the engine still run - just rough and with little power?

I shut it down ASAP, and it was just peaking on teh quasi temp temp gauge, and I popped teh hood to try and let as much air flow through as possible, but could that short of an over heat bother the engine that much?

I was just reading through some of the other posts. Is the distributor ran from the timing belt or directly geared?

I had assumed directly geared, but if it is belt related, could it just be timing from a less stretchy new belt?

I moved out to Cali here about six months ago, and regretfully all my good tool sare still there waiting to be rescued, so I had to pick up and extra set of craftmans that will become tag along tools, but am wondering if I should invest in a new timing light now to check this out???

Thanks in advanced for any help - and sorry for teh long post - but the devil is in teh details, and something might trigger a brilliant solution from someone!

[reb]

A timing belt off by one notch can cause the symptoms you describe. The mark for aligning the crankshaft is on the crankshaft timing pulley, inside the cover. That might not exactly coincide with the timing marks.
The distributor is driven from a camshaft. It wouldn't hurt to check the timing, tho I wouldn't expect it would have changed.
Good luck.

[tkremin]

bummer - so have to all the way back in again. I was hoping for a simpler answer.


anyone know how many teeth there are on that crankshaft timing gear?

If the distributor is driven off the camshafts, and the belt is off one notch, the timing should be off by 160/#of teeth, correct?

[tkremin]

FYI - first time dealing with a belt - used to gears/chains, so if you have any tips on working with belts - that is appreciated too!

[alltrac165]

No idea how many teeth, but you can figure the dizzy is off by the same percentage of 360 that the cam pulley is if it is indeed off. My guess is that it's off by a tooth. Could be either cam pulley or the crank pulley that's off.

[reb]

If you have to go back in, it would be worth your while to find a manual. The Toyota manual devotes about 15 pages to the operation. One hint is to check the idler pulleys. Mine had to be replaced with the second replacement belt. It's a bummer to have one go bad shortly after a new belt is installed.

[Toysrme]

Yep, paint on the block, pullies and belt the position they are in before you take them off and you won't have that problem ever!

[tkremin]

have a chilton. I am going to order a full set of official manuals. regardless of what others on this board may say, they are worth the investment, unless you like breaking things, and getting things almost right is good enough, or have worked on that particular model MANY toimes already and already made all teh usual mistakes. I would rather not have all those learning experiences - kinda like now!

and I did make sure of all the marks. I was just using that timing mark as a check after reassembly and starting to see if it was close at all. Even made matching marks on old belt before I removed it and transferred those belt marks to the new belt (using tape so it shouldn't affect the belt).

It was really tight getting the marks to match on both upper pulleys though, I assumed because of the old belt having streched a little. want to check teh valve lash, so I may just go in and do that as well - find piston TDC and make sure cams are timed with that. This was much easier on airplanes, just take the cowlings off and you got access to everything! And a builtin lever for rotating the crank!

The idler seemed really solid, I did check it, but guess it could be a little worn.

I put a timing light on and the timing was at 0 BTDC, so retimed and it seems much better. Do these have a "usuall" spot on the adjustment range? I know all teh old Chevy V8 I used to work on always came in at about the same point on teh adjustment clamp bolt, if everything was installed right.

pretty sure I will just go back in, when I get time and redo everything.