Update & Diagnosis on Honda V6 Timing Belt Failure

[CrackyWainwright]

Originally Posted by clinebarger

The mechanic that did the job should have offered to at least try putting a belt on it......And, I always add a dab of loctite to the tensioner idler nut & re torque it. 18 ft lbs for 8mm nuts & 32 ft lbs for 10mm nuts are good universal torque values. I realize you're not upset with the mechanic.....But this is the kind of crap that gives mechanics a bad reputation, < 2 minutes of time could have avoided this whole thing.

Thank you, sir. You're right and you make good sense!

 

[MCompact]

Back in the '80s one of my friends picked up a nice gray market BMW E9 coupe for next to nothing. It was at a Ford dealer and the salesman told my friend that their mechanics couldn't figure out why it wouldn't start as it had a full tank of gas. My friend towed it home and found that the fuel sender was stuck and the fuel tank was empty. He added a few gallons and it fired right up. Today most E9s change hands at north of $30k.

 

[Nick1994]

Originally Posted by MCompact

Back in the '80s one of my friends picked up a nice gray market BMW E9 coupe for next to nothing. It was at a Ford dealer and the salesman told my friend that their mechanics couldn't figure out why it wouldn't start as it had a full tank of gas. My friend towed it home and found that the fuel sender was stuck and the fuel tank was empty. He added a few gallons and it fired right up. Today most E9s change hands at north of $30k.

Lol that's hilarious. A friend of mine owns a mechanic shop, he had a customer tow in a car that he had bought a month or so before, had put something like 3,000 miles on it. Car wouldn't start. Was out of gas. My friend said it's happened several times that customers have done that very thing.

 

[ZeeOSix]

Originally Posted by CrackyWainwright

OK, here's what failed. It was essentially a parts failure rather than a technician error, although some may disagree. The pre-installed nut on the tension roller/pulley worked itself loose allowing the belt to flop off. The mechanic who did the job a few months ago told me today that he seldom checks that nut because it's always tight from the parts factory. Well, in this case it wasn't apparently. I have certainly learned an expensive lesson, even with what I believed to be OEM parts.

So the belt didn't actually break, but just came off the pulleys because the tendioner fell off due to the OEM nut backing off? Kind of hard to blame anyone but Honda and a rare freak occurance IMO. Guess the take away here is to check the torque on the tensioner nut (maybe even remove it first to put some blue loc-tite on it) or replace the tensioner assy, which you should also check the pulley nut torque on.

 

[02SE]

Originally Posted by ZeeOSix

So the belt didn't actually break, but just came off the pulleys because the tendioner fell off due to the OEM nut backing off? Kind of hard to blame anyone but Honda and a rare freak occurance IMO. Guess the take away here is to check the torque on the tensioner nut (maybe even remove it first to put some blue loc-tite on it) or replace the tensioner assy, which you should also check the pulley nut torque on.

Off of Ebay at below market cost, it's all too likely it was a well disguised counterfeit part. As I speculated in my prior posts. In all my time working on consumer cars back in the day, I never saw a genuine OEM part fail like that.

 

[Silk]

Take the belt off and dohc V6 and see what happens - there won't be a valve open. A slipped belt can damage valves, if it breaks they all just slam shut.

 

[ctechbob]

Originally Posted by Silk

Take the belt off and dohc V6 and see what happens - there won't be a valve open. A slipped belt can damage valves, if it breaks they all just slam shut.

Uhh, no that's not how that works. There's likely no spot on the rotation of a camshaft in just about any engine where ALL of the valves are shut at the same time.

 

[kschachn]

Originally Posted by ctechbob

Originally Posted by Silk

Take the belt off and dohc V6 and see what happens - there won't be a valve open. A slipped belt can damage valves, if it breaks they all just slam shut.

Uhh, no that's not how that works. There's likely no spot on the rotation of a camshaft in just about any engine where ALL of the valves are shut at the same time.

I agree, the camshaft lobes are still there regardless of whether there's a belt or not. The valves can't just "slam shut".

 

[mk378]

A leakdown test can be conducted without a timing belt. If that tests good there's no major valve damage so it's worth trying a new belt on.

 

[Bailes1992]

I've worked on a number of engines where the rockers are sacrificial so in the event of a belt failure any pistons that come into contact with the valves will just break the rocker. Replace the broken rockers, replace the belt and drive on!

 

[exranger06]

Originally Posted by CrackyWainwright

The main problem here (besides the fact that I may have gotten Chinese-made parts packaged to look just like Honda OEM parts) is that I don't have the mechanical knowledge or the tools to follow all the suggestions for fixing or testing my dead Accord in the days after the belt broke: "slap a timing belt on it and see if it will crank," "do a leak down test," "inspect the valves." I'm very good at basic maintenance, but I'm no where near doing any serious mechanical work on an Accord V6. I'm an English professor for crying out loud, so I have no real-world skills such as plumbing or auto mechanics or roofing. I can teach your college-age kids grammar, literature, and linguistics (and I can run a chainsaw and skin a deer). I have to hire all serious mechanical work done by others, so that REALLY handicapped me with this Accord situation.

I understand that this isn't your area of expertise, but that doesn't mean you can't learn. I'm an electrical engineer who sits in a cubicle all day at work. I've taught myself auto mechanics and I've replaced timing belts, brakes, entire suspension systems, air conditioning systems, and much more. The only times I take my cars to a shop are to have tires mounted/balanced and for alignments. Everything else I do myself. If I can do it, so can you. You just have to be willing to learn, make mistakes, and get your hands dirty.

 

[Hall]

Originally Posted by WyrTwister

Originally Posted by ctechbob

I don't remember which youtube mechanic posted it (I know it WASN'T Scottie...) but his opinion was that since it doesn't take much time for him, the first thing he does is put a new belt on the car and see if it will run. He mentioned that he's got a pretty decent success rate with it. Thinking is that, its probably broke, but might not be, so why not check. If it runs, proceed with leakdown testing etc.

I think that sounds like Eric the Car Guy .

Or Eric O from South Main Auto. I think it's the Eric from SMA actually.

 

[Hall]

Originally Posted by clinebarger

The mechanic that did the job should have offered to at least try putting a belt on it.......

Don't think it would have mattered. Cranky just knew the engine was toast and had moved on from the car, sentimental value or not. I realize that he, like most people, don't have the skills or interest to dive into timing belt jobs nor was he interested in having a mechanic check it either.

 

[CrackyWainwright]

Originally Posted by hallstevenson

Cranky just knew the engine was toast and had moved on from the car, sentimental value or not. I realize that he, like most people, don't have the skills or interest to dive into timing belt jobs nor was he interested in having a mechanic check it either.

Yep, that sums it up. I loved that car, but it would have been risky to spend more $$$$ on a 14 year old car that might have transmission issues the week after I paid someone to get it running again. Only someone with good mechanical skills was going to do well with that car in that condition. Sometimes all you can do is walk away and move on. I'll have my Tacoma truck paid off in a year, and after that I'll look for another good road car for my long commute to work.

 

[clinebarger]

Originally Posted by ctechbob

Originally Posted by Silk

Take the belt off and dohc V6 and see what happens - there won't be a valve open. A slipped belt can damage valves, if it breaks they all just slam shut.

Uhh, no that's not how that works. There's likely no spot on the rotation of a camshaft in just about any engine where ALL of the valves are shut at the same time.

On a DOHC V6 with 4 independently driven Camshafts.....It's highly possible to have a "neutral position" or at least very close to it on all 4 camshafts. There are only 3 pairs of lobes per camshaft. While this doesn't exactly apply to a SOHC V6 like the Honda J-Series.....There's still a "close to" neutral position for the camshafts, As in....None of the valves are completely open or even half open.

 

[Silk]

There will be very little lift on the 2 lobes contacting valves, it would be an unusual engine design that would clip valves very nearly closed. Possible, but unlikely.

 

[tiger862]

Mechanic probably used the nut to move tensioner thus loosing it. Just an opinion