peckinpah

The grooves in my tensioner and guides were not that deep, maybe a millimeter:



I'm leaning toward overheating being the culprit in my case, or at least the straw that broke the camel's back. It was 105 the day my fan belt broke, and my temperature gauge was definitely in the red, though it could have gone a little higher. I was sure I was gonna blow a head gasket but was stuck in traffic in town and couldn't pull over.

The next day was when my timing chain started rattling noticeably.

theAuthority

you know I was just being a smart alec and agree maintnance is key.

peckinpah

Re "preventive maintenance" I thought that's why we bought these trucks, so we could worry less about doing all that stuff.

Hell, my owner's manual says never to drive the truck faster than 55 MPH. If I did that, I have no doubt that I could prevent all kinds of breakdowns from occurring. But I'm not going to.

davo247d

my thoughts are, the tensioner is worked with the oil pressure? so your pump could have been run dry (because im sure that your suppose to pirme those pumps) which would cause the tensioner to fail wich could i think give it to much pressure and breaking the guide. Thats also why your suppose to clean out the oil pan so teh oil pick up doesnt get cloged or somthing like that but idk if any of that is true just my thoughts

theAuthority

if you're going to ignore your brake problems. I think you should listen to your manual and go under 55. the slower you hit someone the better, and don't aim for their doors. for for the trunk or engine at an angle

theAuthority

The reason I asked is because I just learned something new about 22r's and such, basically a lot of overhead cams.

I'm used to domestic engines with push rods. I didn't know the tensioner was pressurized by the oil?

theAuthority

On another note you live in the same town as my cousin. He is a youth pastor at a local church.

He's a funny guy, plays more xbox than me. Was in the Airforce also for military intelligence

He's been out for 6 years and still won't tell me what he did.

91Toyota

Yeah I would rather not. I know it still has "some" oil on everything, its just not oiling that great.

Thats a pretty good idea though. This is why start-up's are hard on engines.

Matt16

Though I understand why they used plastic guides- as they wouldn't wear on the chain. Metal backed guides are a good idea though as a safety factor.

abecedarian

And the noise from the chain rattling when the guide breaks is a good indicator you need to change the chain before it eats up the water jacket in the timing cover (and dumps water in the pan) or snaps (and leaves you with bent valves).

peckinpah

I would tend to agree that there may be some method to the seeming madness to using plastic guides. For one thing, plastic guides bend, and they only need to bend a quarter inch or so until they're pressed up against the inside of the timing chain cover. So in a sense, the plastic guides are already "metal backed".

And once the chain if flailing around like that, the damned things could be made of space-grade titanium and they'd still get chewed up, leaving metal particles in the oil. If given the choice of pieces of plastic in my oil or pieces of metal, I'm gonna go with the plastic.

So to my mind, the metal-backed guides might even be a hazard to your engine, and only delay the inevitable breakage by a short time anyway.

Windsor

In theory, any metal particles in the oil should be picked up by your oil filter.

TOYOTA 1

^ true.
but only after the shavings are flung to the top of the motor all over the cam and rockers, and then washed back down into the pan. :l

flyingbrass

How long do metal backed guides last? Anyone have 100K miles or close? The rubber-like coating on my metal guide seems relatively thin and soft. I'm not sure how long it would hold up until the chain scrapes metal.

Kiroshu

Toyota Recommends the timing chain to be replaced ever 90,000-100,000 Miles. Theres a reason Toyota wants you to do this.

Matt16

You have a valid point. Good thinking.

thook

The chain is not going to cause the guide to bend like that. It's too rigid considering the anchor bolts in place.

By the time the plastic has worn through on the metal backed guide (which is thick enough to accommodate for the limits of tensioner travel) there will be an audible difference in chain rattle. Even then, by the time you get that rattle, one should stop driving the vehicle and replace the assembly.

One advantage of the metal guide is that "theoretically" it will not break under the same circumstances as the plastic one and fall into the crank gear and possibly cause the chain to jump potentially causing piston/valve collision. As well, the steel is hard enough that the chain is not going to shred the guide so much as you'd think without also making WAY too much raucous to go unnoticed. Or, the chain will simply snap being the guide is steel. In either case, you'd really have to be an automaton to not realize something is wrong before severe damage occurs. As for particulate concern, tri-metal bearings (Toyota OEM) can tolerate absorbing some metal before actually failing and/or causing cam or crankshaft damage. (Not the same for aluminum bearings, so one would need to get informed on that.) Anyway, I said "theoretically" because I know of one person........and only one.......that has had a metal guide actually break. The incidents of plastic ones breaking (and causing said mallady) is far greater, though.

I think one has to realize that no matter who makes what and/or what is made in regards to the timing chain that no product is going to be uniform in every case. In other words, one kit might have a better plastic than the next while the chain might be of lesser quality........or vice-versa. In other words, you can't solely rely on the product or even suggested maintenance intervals. You simply have to pay attention to the vehicle. You're timing chain could fail early for some strange reason. Or, it could last for twice the interval. I have a friend with an '86 22r P'up. Over 200k on his chain and no noise. Go figure. I was surprised.

Donsway

I know the exact min. my guide broke. Was getting onto I-40 just east of Nashville, came up behide a slow non-driving type on the ramp. 40 was full and flowing fast and the guy in front of me is coming to a stop. CRAP!!!! I was in 3rd and did a HARD, high RPM down shift to 2nd to get around the guy. At the next stop I heard the bolts in the can. So that will take one out.

thook

Hmmmmmm.....I did already say that can break. Gave one example. But, the likelihood/incidents of that happen is much less. Probably why most critical vehicle components are made of metal and not plastic........wouldn't you agree?

I don't know........it's whatever what anyone feels best. But, there's a lot of speculation in this thread about the metal guide. Why don't any of you gentlemen with the valid concerns you have give Todd or Ted a call at engnbldr for some input on the subject? Afterall, they do sell the parts and have most likely seen a lot more on the entire subject than any of us.

Kiroshu

One common place is your owners manual. Or you can call Toyota your self.