7mgte timing belt issue

[Hacki_sack_kid]

I did a rebuild on my 7m about 11k ago, driving home i stopped at a stop sign and heard something grinding, pulled everything apart on the front and i found the timing belt was being chewed apart from rubbing against the covers. any ideas on why this happened? does the supra have some sort of belt guide to keep the timing belt in place like a corolla?

 

[Supracentral]

Yes, there are guides on the lower pulley:

http://www.supracentral.com/foundation/tsrm/engine-mechanical/

Look carefully at the drawing above, there are both front and rear guides, they sometimes break.

 

[CyFi6]

The crankshaft timing belt gear has two guides staked onto it. There is an older and a revised version of the gear, the new one has more "stakes" in it, basically a punch holding it on. The older ones have been known to break off, that might be your problem. Also, if your machinist machined your block or head off flat, it could cause this too.

 

[gofastgeorge]

I would bet that either one of the guide lips on the crank pulley has went by-by (the front one),
or your tensioner pulley is shot, and tilting to one side.

Also, did you use a name brand belt, or a mystery brand off chinaBay ?

 

[Supracentral]

Also, did you use a name brand belt, or a mystery brand off chinaBay ?

Along those lines, if you're looking to avoid spending a fortune on the belt (i.e. Greddy Kevlar) you can get a really good nitrile belt from Napa for $27.99:

http://www.napaonline.com/Search/Detail.aspx?A=NBH250237_0117502755&An=599001+101992+50070+2070018

I've used these in daily drivers and they are a bit tougher than a standard rubber belt.

 

[IwantMKIII]

Gates makes a decent timing belt as well. i bought mine for maybe 80 from driftmotion IIRC. Supposedly they sell at napa now for 50. Not nearly as good as my previous Greddy for $100+ considering it lasted through a fire and still had tension on the thing (of course the rubber melted off), but a good, cheaper alternative in my experience. IIRC, the only major difference between the two is gates didn't use metal wire as its infrastructure like Greddy did.

 

[Hacki_sack_kid]

if your machinist machined your block or head off flat, it could cause this too.

how could it cause this? and he did by the way, are there guides on the block and head themselves? also i used a toyota timing belt, worked there at the time lol. if i remember correctly i didn’t replace the tensioner pulley because i thought it was good at the time, so basically replace the tensioner pulley and possibly the crankshaft timing pulley if its guides are bent/missing, and that should fix it right? and hypothetically if it were the block or head would i have to replace them and is there a way to tell or do i have to wait for the belt to explode lol?

 

[CyFi6]

If the head or block wasn't leveled in the surfacing machine and it was leaning forward/backward it would tilt the cam gears and make the belt want to ride forward/backwards whatever the case

 

[supra90turbo]

Pull the crank pulley off and see what you can see. No use speculating when you're halfway there.

I'm willing to bet you lost the outer guide on the crank sprocket.

 

[Hacki_sack_kid]

Pull the crank pulley off and see what you can see. No use speculating when you're halfway there.

I'm willing to bet you lost the outer guide on the crank sprocket.

i would have done that yesterday but i got a bad back and was at my limit for the day, but i pulled the rest of it apart and you're right it was the timing gear, i just wanted to educate myself and consider all possibilities. so thanks everyone for all the help and info.

 

[giterboosted]

Sorry to resurrect a dead thread but where am I get a new lower timing gear? As I'm havin this problem with the outer edge popped off, and id rather not spend a million bucks at Toyota

 

[Poodles]

It's cheap from the dealer (and the only place you're going to get it new)

 

[giterboosted]

O really? Thanks!