VG30 Broken Timing Belt

[LenRobertson]

A friend called last night with a common sad story. His son's '89 VG30 truck broke the timing belt while driving. I have no idea what engine speed when it happened, but it sounds like it wasn't at idle. I told him I would strongly suspect bent valves leading to valves not seating and dead cylinder/cylinders. But I don't want to look like an idiot if they stick a new timing belt in the thing and it runs fine. So what is the Ratsun wisdom here, I'm I right in thinking the odds are slim that just a new belt will fix this? The son doesn't have money or skills to pull the heads and replace valves.

 

Len

[datsunaholic]

Odds are slim, but still there, that the valves survived.

 

Only way to know though is to replace the belt and do a compression check.  Or at least check for valves with suddenly excessively wide valve lash.

[Draker]

Well... I don't know about the VG30e's but the DE's when they break... game over.

 

But it's ususally the upper idler stud that breaks.. or tensioner fails.

[Draker]

I'd do a leakdown on it. But.. if I were to place a bet... it be on 'its fucked'

[MicroMachinery]

Bummer. Interference engine.

[H5WAGON]

And the old L-series just keeps on running... 

[LenRobertson]

Thanks everyone for confirming my suspicions.

 

Draker - I thought of a leakdown test, but the guy with the truck is 250 miles away with limited tools. But I got to thinking that if any valves are bent, they will possibly be leaky enough that any sort of crude leakdown test may work. Even blowing in a rubber hose jammed in the spark plug hole might do it. Blowing in there, he should be able to tell if the valves were holding or not.

 

H5WAGON - I had the same thought. If he had an older truck with an L-series he wouldn't have any problem. Well, maybe a blown head gasket, but that doesn't bend the valves. I've dreamed of a VG30 in my 510, but there is something about an engine with a rubber band driving the cams that is really offensive. Yeah I know if the belt is changed when it should be it isn't a problem, but belt driven cams just seem to me like poor engineering.

 

Len

[datzenmike]

Quieter, simpler, lighter, cheaper, don't need integral metal timing covers... and they last long enough to outlive the warranty.

[LenRobertson]

I got an interesting update this morning. It seems David (the truck owner with the broken belt) got a new belt from Autozone and is going to stick it in the engine. So everyone can place their bets on whether the engine will even start, if we are right about bent valves. I have a feeling he won't do a compression test, he will just try to run it. I'm really hoping it works for him, since he needs the truck, even if I end up sounding like a fool with the bent valve prediction. But I think he is wasting his time. Although he is unemployed so time he has plenty of.

 

Len

[datzenmike]

I assume that the belt only goes on one way? The cam in each head would need to be timed before the belt goes on would it not? Be a shame for the valves to survive this far only to be bent cranking it over to try and start it.

[LenRobertson]

David went to the library and printed out the timing belt info for a VG30. I went to my pile of books and found a shop manual for a Maxima (no idea where it came from. Yard sale I think) and the cam timing looks pretty straightforward. I don't really know how good he is fixing things. I suspect competent enough to do this if he is careful. I'm glad he is far enough away that I'm only giving advice and moral support, not actually working on it out in the cold.

 

Len

[datzenmike]

I hear that. Hell I don't even answer the phone in case it's someone wanting help.....

[LenRobertson]

Years ago I read a humorous piece where the guy said if he is at a party and a light bulb burns out, he doesn't offer to change it because he doesn't want to be known as someone who can fix things. My personal batting average on advising/fixing for people is low enough that they have to be really desperate to call for my help. That used to bother me, but now I realize what a good thing it is. It is dark and cold outside but I'm in front of the computer with a cat on my lap. If somebody is in the ditch or broke down, I'm way down the list of people to call.

 

Len

[Jesse C.]

A properly maintained VG can live for quite a long time. Like any engine, lack of proper maintenance will be the end of it. 

[datzenmike]

Yup they are tough. I doubt at tough as the L series if equally ignored in their maintenance but better than the newer engines. Car makers rely less and less on robustness and more and more on exotic lubricants and electronics.

[LenRobertson]

Yes, I know the VG30 is a great engine, just the timing belt bothers me. I know if the belt is changed every 100K or so it isn't a problem. The farm where I work has an early '90s 4X4 Hardbody with over 200K hard miles on it. It has spent quite a bit of time running in dirt fields without the oil being changed as often as should be. The timing belt has been replaced once. I don't think it is using any oil to speak of. It just runs and runs.

 

Now I'm back to wanting a VG30 in my 510. Fortunately I'm cheap and low on motivation, so it probably won't happen, but nice to dream about.

 

Len

[datzenmike]

Wasn't the VG30 good for 1,000 hp? read somewhere, maybe racing?

[LenRobertson]

Wasn't the VG30 good for 1,000 hp? read somewhere, maybe racing?

I'd settle for half of that HP in a 510!

 

Len

[LenRobertson]

So, I just got off the phone with David's father. David called and said he put the new belt on the VG30 and it started up and ran. I don't know how well it runs, but the fact it started amazes me. I don't even mind looking like an idiot with my bent valve gloom and doom (well, maybe I mind a little), since he really needs a running vehicle. At least there are two more people who won't bother asking my advice on things automotive.

 

Len

[MicroMachinery]

Years ago I read a humorous piece where the guy said if he is at a party and a light bulb burns out, he doesn't offer to change it because he doesn't want to be known as someone who can fix things. My personal batting average on advising/fixing for people is low enough that they have to be really desperate to call for my help. That used to bother me, but now I realize what a good thing it is. It is dark and cold outside but I'm in front of the computer with a cat on my lap. If somebody is in the ditch or broke down, I'm way down the list of people to call.

 

Len

 

"We are dumb, but we are not so dumb. It takes great courage and work to keep from working."

 

-Bill Cosby

[72240z]

The vg30e is tricky, all of the ones used by Nissan are interference but to varying degrees. The ones bought to be used domestically (Mercury) were actually altered to not be interference.

Its not impossible that the belt can go and engine still be derivable though if it turned over at all on a Nissan version odds are excellent that comp was dropped or lost in one or more cylinders. 

[LenRobertson]

I'm really looking forward to finding out how well the engine runs. I understand it started, but hasn't been road tested. It may be David will be satisfied with 4 or 5 functioning cylinders. Over the years I've heard engines that obviously had a dead cylinder or two, but the car still would go down the road, so the owner didn't want to believe there was anything wrong.

 

Len

[MicroMachinery]

Luck happens. You will know if it's got even 1 bad cylinder, though. Hard to hide 17-18% power loss..

[datsunaholic]

I've seen engines run with bent valves after a timing belt break, but usually not long.  The bent valves eventually stick wide open, get hammered by the piston a few times, then the valve breaks off and the piston bashes the hell out of itself and the head with the valve head.

 

On the flip side, my sister had a Honda Accord lose a timing belt at 65 MPH and it didn't bend anything.   I think the fact that it was an automatic and it was downhill ( basically coasting) may have had something to do with that.