The Timing Belt Myth?

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HEY! there's a '69 Ranchero in that pile, worth at least 10k, more if the cleavland or a 429scj is still in it. Used to have one...don't miss it kept the cleavland though

 

artvonne
the hairs on the the back of my neck were standing .. just reading that ... sweet mate

 

What year Subaru?
Is that Subaru an interference engine? If not then the only risk is towing & an affordable replacement cost.

IMHO, You're overlooking something significant: Evolving Technology.

There was a major change in belt technology in the mid-1980s. The 1st generation timing belts like the 3x8 & even the 348 belts used trapezoidal teeth. The 2nd generation belts commonly in use now have serpentine teeth that are much less prone to the teeth stripping, wear & fatigue, and have greatly improved materials. Search out smg2's excellent research on cam drive systems in Tech Q&A, or the earlier work that Ed Gault did on serpentine systems back in the old Fchat archives.

That's why I've bought smg2's cam belt system.

And the other major factor is the $ at risk. I'll accept a higher belt failure risk after 7-10 years on a $15K daily driver than I will on a $200K car.

 

I had a Subaru GL Turbo in 1988. It was a great car. The car had 42,000 miles on it and the timing belt broke at 70 mph going down I-5 in the middle of nowhere. Turns out it bent the valves. Luckily, Cheech and his cousin Chong were bringing their empty tow truck back from LA and they saw me, flipped a U turn in the median and gave me a lift back to the dealer in Stockton.
The dealer wouldn't honor the extended warranty I bought with the car when new, and after hiring an attorney I ended up with the engine block split in two with 1000 other motor bits and parts in a cardboard box in my trunk. They dented my right rear quarter panel from shoving the block in the trunk. I had to tow the car to another mechanic, who finally fixed the car. The day it ran like it was supposed to, I took it to a consignment lot and put it up for sale.
It cost me over $1,000 and 6 months of aggravation. I even had to drive a Ford Ranger pickup in the meantime. It was horrible! This was almost 20 years ago. On a "reliable" Japanese car, even. When belts break, it is BAD NEWS!

Some peolple need to get over it. You change your oil like you're supposed to, right? Change the belts like you're supposed to. And drive it like you're supposed to. And sleep well.

 

Vinny Baggadonutze of Alpine NJ writes:
"The dealer sez my $250k 575M, with shields, needs 12quarts for an oil change, but I [having no engineering understanding past playing a CD] think this is just a scam, so the dealer's sell more oil.

My ma's BMW 325 takes only 6.5quarts. Which I think was alot but OK, for a European exotic car: Can I use something like sand or spackle to fill up the pan and save a few $?"

 

Pontiac did that with the Fiero. 2.5 liter engine with a 3 quart sump! It didn't work.

Ken

 

HAHAHAHAHAHAHA!

 

Hey Scott, maybe you could make up some solid sprockets to make a less expensive timing belt system for some of these guys? Maybe make up some 348, 355, as well as 365/512 stuff too?

Thats the thing some of you guys cant seem to get into your heads. The belts used on the Ferrari's are NOT the same type of belts used on an 80's Honda. The newer cars use a totally different type of belt that not only lasts far longer, but was designed from the outset to transfer more power. I cant remember exact figures, but IIRC the type of belts used on the 308 were rated for a maximum power transfer of about 25 horsepower. The modern type belts that Scott has made sprockets for are rated at something like 250 horsepower, or about 10 times the energy.

I just cant see why some of you would risk a "minimum" of $15,000 to run your car well beyond the recommended intervals. I understand it even less recommending it to a friend.

 

Had an '87 Subaru RX Turbo. Belt broke at 46,000 on 60,000 replacement interval. Subaru stood behind the repair paying for just over half costs including towing. No engine damage, car down for 2 days, good company.

Overall point though is that they do break, but it was a design issue here.

 

I could but to be honest it would only save you maybe $200 from the adjustable set

 

It would be an interesting comparison between automotive and industrial experience with cog belts.The automotive world experiences deceleration loads where industrial applications would generally not.That is to say stress in both directions and accelerated wear?

 

Damn. I was still married last time this thread was active.

 

Listers,

The age or milage is NOT the thing it is RPM. A 2000ish Honda asks for a belt change around 60k. The car spends its life
running at 1500/3000(max) RPM. A 308 spends tis time running at 3/4000ish. Simple twice the RPM 1/2 the milage on belt change.
If during the pandemic your/my 308 has been sitting a bit I plan to extend the time.

 

"If during the pandemic your/my 308 has been sitting a bit I plan to extend the time."

Uh oh...that's dangerously close to causing a cam belt replacement interval discussion.

 

except,

So a Ferrari is good for 50,000-60,000?

 

Does "severe service" mean poor driving skills? If you can't figure out shift points or match revs downshifting it has to take a toll .Ihave had a 1987Alfa Graduate since new.I replaced the clutch at 70K because I had the engine out...not because it needed a clutch ,but a good time to do itI was at a friend's Alfa shop years ago and saw a Graduate same year as mine with 27K on the clock.Al was doing the clutch for the 3rd or 4th time...Very stupid feet at work!.My 2002 MB 230 Kompressor went it's whole life ,145,000 miles with the original clutch.Mechanical sympathy is important .You fix a clutch ,but not a klutz.

 

When I had my Ferrari I went by the rule of 5 years or 30,000 miles. It doesn't mean if I hadn't of changed the belt by the 5 year anniversary I would park the car but would do my best to hit the 5 year interval. Luckily my two current cars, S2K and WRX, have chains.
I have had people tell me a belt is a belt which is not true. My first snowmobile was a Ski-Doo and I went through quite a few drive belts on that. My second snowmobile, a Yamaha, still to this day has the original drive belt from 2003. It covered 12,000 miles and 17 seasons with me with never even a squeal.

 

So, hope you remember which one she was

 

Oh no! My belts are 4.5 years old now. After reading all this I'm now afraid to drive the car over 2500 rpm.

 

Mine are 12. Dare I even look at the car?

 

I went 14 years once............... mostly out of ignorance. Now I'm at five to six years.

 

NO my comment sorta backs the lower change point......but how much lower? The last time I changed belts at 5yrs and close to 20,000 miles there was really no way to justify it. ALL parts were as new. I guess being safe is always best but........

 

My original timing belt tensioners were changed when I had my 1987 professionally serviced in 1995. After that I began changing the belts myself about every 5 - 7 years. In 2018 I changed the tensioners to the Hill variety (Ricambi) even though there was no roughness or wiggle in the 23 year old tensioners.

 

Yeah - these cam tensioner bearings are the only bearings of any kind that I have ever routinely replaced in my entire life without a REASON to replace them - roughness, noise, etc. I'm still not sure why I do it.

Maybe it's due to hanging around with a bad crowd.