Timing belt walking

[Ivan Skare]

Anybody experienced timing belt walk on the cam sprockets on a 4g63? I noticed my belt was walking while revving up the motor. It wasnt that excessive, although its quite concerning. Im thinking the tensioner is in need of replacement or the idler is messed.

[Matt Mann]

What do you mean walking? wondering back and forth (side to side) on the sprockets? If your tensioner is failing you would have a problem by now. When my tensioner let go, it some bent valves. So If I were you change everything now!!! Do not drive it. Check to see if the idler or tensioner pulley are loosening up. This would cause some noticeable movement but the results would happen quickly in terms of damage. Is there any bearing noises going on that side of the engine? Could be a sign of some worn bearings on a t-belt component pulleys?

When was the t-belt done and what brand of parts were used? These may help to shed some light on what could be the issue too? Either way I STRONGLY suggest not to drive it until you know that its not timing belt related, that is if you do not mind spending $800+ to fix the head.

[Ken Hawkins]

I would second that motion!

I ignored a belt walk, as the belt was cosmetically good, and it was *slowly* wearing away on the engine side (I thought I would have a couple of weeks at least) and wound up broken down on the road, with the whole bent valve pain-in-the-a$$.

As an old motor oil ad used to say: "You can pay me now, or you can pay me later"

Ken

[Ivan Skare]

It's a Mitsu belt and I have no clue when it was changed. May be original (165K)? And yes there is a bit of bearing noise down there.

Looks like i'll be doing that whole side of the engine then. I'll do the balance shaft delete too.

Any suggestions on where to get the cheapest OEM parts? Any local places other than the dealer?

Also, i've never done a timing belt on a 4G63. Some tips would be nice, IE shortcuts etc.

Thanks.

[Ivan Skare]

I'm contemplating on yanking the motor.

[John Hartman]

no need to pull the engine to do a timing belt 

VFAQ for the full directions and parts and other tips.

bshaft delete is quite a bit more work than timing belt stuff tho, just so you know.

And I would suggest just having the rear shaft cut down and turned on a lathe rather than put in a short stub shaft.  More bearing load surface for the oil pump drive and also the length of it, this will have some leverage against the pull of the timing belt.

[Joliesa Lepp]

Recently when we pulled my motor to do the rod bearings, we realized my t-belt walked to the left side of the valve cover and stayed there. Upon inspection, one of the lower pulleys was fucked and was vibrating back and forth during decel. Found a bunch of other gremlins too once it was out. Not saying thats your problem, but look into it. Goodluck! VFAQ is your friend!

(P.S.- T belts and components should be changed *at least* every 100k)

[Ivan Skare]

The reason I was thinking about yanking the motor is I want do a bunch of things to it and wouldn't mind having it out. I have the tools and a garage to do so, and my car isn't a daily driver. I might have the engine bay re-sprayed as well.

I am just a little choked because I wanted to race the car this Friday.

I'm wondering if the idler or tensioner bolts are loose causing the belt to move. Anybody encounter this?

[Ivan Skare]

no need to pull the engine to do a timing belt 

VFAQ for the full directions and parts and other tips.

bshaft delete is quite a bit more work than timing belt stuff tho, just so you know.

And I would suggest just having the rear shaft cut down and turned on a lathe rather than put in a short stub shaft.  More bearing load surface for the oil pump drive and also the length of it, this will have some leverage against the pull of the timing belt.

Yeah I agree with you on the shaft John. Is there a shop around here that's done that for the 4G before?

[John Hartman]

I had Fortins in Chilliwack do mine.  I have good pics of it, so you can see that if you don't quite know what to ask for.  It was $32 tax included.

[Brett Haviland]

And I would suggest just having the rear shaft cut down and turned on a lathe rather than put in a short stub shaft.  More bearing load surface for the oil pump drive and also the length of it, this will have some leverage against the pull of the timing belt.

I would argue the "more bearing load surface for the oil pump drive" as i have before.  

If you use the proper mitsubishi subby shaft i see so reason why it would affect the life of the oil pump.  Mitsubishi put these stub shafts and "balance shaft elimination " STOCK in the 1.6L DOHC 4g61 engines.  I dont see why mitsubishi would engineer something to not last as long.  Plus i have a 4g61t engine in my colt with 350 000 km's and the oil pump has never been touched.  Like i said it uses the "stubby shaft" style of balance shaft eleminination strait from factory.


So show me cases where the oil pump failed due to the stubby shaft being installed.  Most oil pump failures are because someone overtightened the timing belt, or installed a aftermarket oilpump/front cover like a topline.  Its the people that do a b-shafgt elimination and then put a nice new "top line" oil pump to go along with it... then the oil pump craps out a short while later and they blame it on the stubby shaft.... hrrmmmm.

Go with the stubby shaft!! it much more easier then dealing with trying to get your rear shaft turned down properly so it works...... then also having a extra set of bearings that can still go bad to deal with... its also  alittle more rotating wieght that your adding to the engine that will rob you of a tiny bit of HP.

[John Hartman]

its not easier to deal with, its the same.  Plus its cheaper 

And, yes, they come with the stub shaft in the stock engines like you say, no question.  But they are NOT put in an engine with high mileage where the bearing surfaces and the load and coast sides of the gear drive parts of the oil pump already worn into a pattern.  Thats like pulling apart a rear diff and then not setting it up for a correct pattern.  it WILL be noisy and wear out way way sooner.

But hey, I am only suggesting it, anyone can do what they like.    No skin off my nose 

[Ivan Skare]

Ill take both suggestions into consideration. Thanks guys.

[Ken Hawkins]

Hi

Having been down the path of doing the T-Belt in the car, with a bunch of other tasks before & after, I would vote to go with the "pull it and do everything WYAIT"

Its a good opportunity to deal with all the pre-emptive repairs at once. Especially good to replace motor-mounts, and any "soft" stuff that is likely degrading, like all the vac hoses, coolant hoses, etc. I had a Supra & have a 928, that at about 20 yrs, all the soft bits were getting cracked & crumbly.

HTH
Ken

[Ivan Skare]

Hi

Having been down the path of doing the T-Belt in the car, with a bunch of other tasks before & after, I would vote to go with the "pull it and do everything WYAIT"

Its a good opportunity to deal with all the pre-emptive repairs at once. Especially good to replace motor-mounts, and any "soft" stuff that is likely degrading, like all the vac hoses, coolant hoses, etc. I had a Supra & have a 928, that at about 20 yrs, all the soft bits were getting cracked & crumbly.

HTH
Ken

Exactly what I was thinking.