Question on vehicles timing belt

[34Willys]

The hardest part, besides getting the front engine mount bolts out and then balancing the engine without the front mount is getting the crankshaft bolt loose. The manual states do not use impact wrench. There's a special counter torque socket that fits inside the pulley. I'm 210lbs and I usually have to use a 4' piece of pipe to loosen that bolt.
Patrick

 

[Oaktree]

Not to ask a stupid question, but why would anyone build an engine that would self destruct when a belt fails? Is it just poor engineering or does an interference-style engine have some advantage?

 

[kenmac]

I replaced the timing belt on a Mazda I once owned. Not too bad of a job. Best I remember, it took me about 1/2 day . Don't know about the Honda , but the mazda was a DOHC engine. I imagine the Honda is as well

 

[pmsmechanic]

Not to ask a stupid question, but why would anyone build an engine that would self destruct when a belt fails? Is it just poor engineering or does an interference-style engine have some advantage?

Engineers have some limitations when designing an engine. If you want the fuel economy that comes with higher compression then it's virtually impossible to design an engine that doesn't suffer damage from a belt failure. I'm thinking that point is around 9 to 1 compression ratio. I read it once but I don't remember exactly. I've never seen a diesel engine with a timing belt that was not an interference engine.

There are some engines (Chrysler mini van V6's) that are labeled interference engines but ti depends on where the engine rotation stops. Standard on those is to install a new timing belt. If the engine runs ok then you were fortunate. If it doesn't then you need to pull a head for valve repairs.

You can design an engine with a timing chain which lasts longer than a belt but they are noisier and and more expensive to manufacture. I've also read about one V8 engine that had two right angle drives and the overhead cams were shaft drive. Also more expensive.

The best is to change your timing belt at the manufacturer specified intervals as it's always cheaper to do the belt vs repairing that head. If you have no history on the engine, VW for example gives belt wear specifications in their service manuals that give you a good idea where belt life is at. If the sides of the belt are frayed/worn or there are any cracks between the cogs then it's high time to change the belt.

Sometimes manufacturers will come up with longer belt change intervals as they get experience or do a running design change. VW ALH engine is one example. Early ones were 60,000 or 80,000 miles. Now it's 120,000 miles with the upgraded belt design.

 

[etpm]

Lately, both my wife and I are blessed. Most likely 100-150 hours or more a week between us for work.

I make money to find someone I trust to make my life easier so I don't have to do the work myself at times. I know a mechanic I can trust and we already talked about doing this, and his rate is reasonable IMO.

The family member who has the car REALLY needs the car.

That said, you ever have family that makes unwise decisions? Particularly if that family member is through marriage?

Sidenote, luckily it's not the in laws. Both my MIL and FIL are great people whom I love dearly (FIL passed away a couple of years ago). In part, I'm doing this for my FIL.

Since the person NEEDS the car, I've already told my wife to get the car back to us so I can take care of the timing belt and water pump (those two always go hand in hand if you're doing the work).

What's funny is my wife was wondering how we could get the car back being it's two hours away (how do we drive down there, pick up the car and then drive back home). I told my wife we're not driving down there, they are driving the car to us and they can spend the night. Since we're paying for the car to be more reliable, the least they can do IMO.

 

[etpm]

The family member who has the car REALLY needs the car.

Good grief! Your statement above is all that needs to be said. Please replace the timing belt. The family member will then have a car that can be relied on. You can have it done. And it is a family member. Get the thing replaced. Replacing the timing belt will give you peace of mind. Your family member will also gain some peace of mind. And you will be doing a good thing for someone else. Which should make you feel good. Which is a bonus. If I was in your place I would have the timing belt replaced, even if I felt that the family member didn't, in your opinion, deserve it. At the end of the day you will be doing a good thing for someone else AND keeping a car from being scrapped, which helps the planet. Both good reasons to replace the belt.
Eric

 

[dstig1]

Not to ask a stupid question, but why would anyone build an engine that would self destruct when a belt fails? Is it just poor engineering or does an interference-style engine have some advantage?

Not poor engineering, just...engineering. Engineering is the determination of trade-offs in a design. If I want A, I cannot get B. Or as A goes up B will go down... what is the proper balance between them? As pmsmechanic noted, to get above a certain compression ratio basically requires it.

 

[sd455dan]

Generally speaking, if it’s a Honda, it’s interference engine and if it breaks, you’ll almost surely trash an engine. Back in the early 80s those Hondas wanted changed around 80,000 miles. Sometime later they went to a lightweight belt and lowered the requirement to 60K I think. I wouldn’t sweat too much going and picking one up and driving it home so I would get it changed soon.
The reason I say that is that I had one snap on me and an 88 Honda CRX right about at their 80,000 at the time limit. I was just tooling down the road 80 miles an hour with no load on it whatsoever and when it popped, I hit the clutch would saved the engine. Much of that was pure luck, but I sure noticed that that was an OEM belt and it was in perfect shape and not been abused / raced when it snapped.

About 12 years ago I knew a guy who just picked a Chevy up with one of those type engines. It had 200,000 on it but the belt had been changed at 100. He drove it for about three days going to work the belt snapped and trashed the engine. So if you don’t wanna go around, thinking about this worrying just bring it home get it taken care of and make sure to write down the mileage that It was changed on the sticker and put it on the air cleaner.

When I worked in a small mountain community repair shop a Civic was towed in with a bad belt It was still on but missing Lots of teeth... I retimed ( it was Way out) put the new belt in as ordered and went to start the engine cranked and did not start of course.

I had asked the girl if when it died did she try and restart it?

Yeah just till the battery died, and I was sure it would restart because it bucked several times at first and then just spun real easy till the battery was dead. Put a compression tester on it and had 0 PSI in all 4 cylinders ( has to be a record). When I got the head off it had bent All the intake and exhaust valves , and bent them Good. The small CVCC intake valves were fine since they are enclosed in the pre chambers. We sourced an identical lower mileage head and gaskets reassembled and the car ran great again.

Honda engines you have to be very careful to get exact replacements because even one year difference Honda would change things Unlike older Toyotas, as an example a 1980 and 1981 Accord with the same appearing engine .

Honda moved the transmission flexplate 3/8"s rearward... without having both engines and transmissions right next to each to compare a person would not notice. The transmissions would bolt up as well. But as soon as the car was started it destroyed the pump in the wrong year transmission. Yep, Many Honda's are Interference engines.

 

[Sigarms]

Good grief! Your statement above is all that needs to be said. Please replace the timing belt. The family member will then have a car that can be relied on. You can have it done. And it is a family member.

When one notes "it's a long family story" please refrain on making assumptions on family

General rule I live by is when one is blessed with money that one did not work for, you do not waste that money.

 

[MTGreen]

I swapped an OEM timing belt on a straight 6 2005 Lexus at 96k miles and about 10 years old. Service interval was 90k.

I wish I still had pictures of the belt -it was starting to delaminate and so was a ticking time bomb.

Most all piston type automotive engines made in the 21st century are interference engines. To add to what was mentioned above: belt drives are not only quieter than chain or gear drive crank-cam(s) synchronizers but they are more efficient from a frictional/parasitic power loss standpoint