NMcruser

I just recently, have started to hear a rattling from up in the front of my engine, pretty sure it is the timming chain. rattle just off idle @ 1000-1200 and again around 2200-2500. After that I can't really hear it. My Question. How long can I drive with it in this condition? What is the worst thing that can happen? I'm in the middle of a road trip and can't really do anything till I get back. (i've got about 500 miles to go) Thanks

Yamaha+Toyota=Fun

If you can, pull the valve cover and have a look and see if the timing chain is accually starting to chew up the timing cover. If its not, i would guess that you should be ok to drive back home before you fix it.

NMcruser

anyone else have any opinons? I am going to be taking off tomorrow...how long does it take to wear through the cover? really any and all thoughts would be appreciated.

Chuki

Before you do anything, check the valve guides...

500 miles you be able to make it home if the guides are busted, but you'll probably have to scrounge up a new cover. If the guides are there, then you'll be just fine on the way home, and it could be low oil pressure or a bad oil tensioner, or just time for a new chain.

MvCrash

If the chain skips, you will bend a valve and then need expensive repairs. I think the worst however would be the valve breaking the top of one of your pistons, which can happen.
Good luck!!

LittleRedToyota

i drove around for at least 5,000 miles with my t-chain guide gone. not that i would actually recommend doing that.

(although i didn't know it at the time, the driver's side guide was munched when i bought the truck, and i didn't know about the whole t-chain thing at that point...motor ran fine and just had a little rattle so didn't think anything of it.)

i had a groove somewhere between 1/16" and 1/8" or so deep worn in my t-chain cover, so i was prolly gettin' pretty close to having a milkshake in my oil pan.

one key is that my tensioner was still functioning properly which prevented the chain from skipping any teeth.

take that for whatever it is worth.

Chuki

His 22RE should be a non-interference so if it did break nothing would happen.

pre 85 on the other hand will colide with the valves.

LittleRedToyota

actually, the 22RE is an interference engine.

(EDIT: apparently i was wrong in this statement and the 22RE is *not* actually an interference engine...see below.)

Chuki

Then I must've seen serveral throw back engines. My bro snapped his chain 86' carbbed engine, no collision. My uncle works at a local yard, plenty of snapped chains in there, no collision.

Hell they get people that just give them there toys, cause they can't figure out whats wrong and why it wont start. Several of them just have snapped chains. They put a new chain and sell it.

I've seen 3 engines with busted chains and none of them contacted the valves. I've seen one 20R and that one barely hit the valves and bent 1 up. I haven't seen a busted chain in a pre 85 22R.

I've seen 1 carb'd 86 that didn't hit, and 2 22REs (in the wrecking yard) that didn't hit. 1 was about an 87 2wheel drive, and the other was 92 pickup.

I'm not gonna call you a liar, because a google search and the common perception seems to be an interference engine. It could be that all the ones I've seen with busted could have been reman'd engines. I know my bro's was, the other 2 I don't know. But my uncle said he's seen many of them, and none of them hit. Ah well.... Either way a snapped chain isn't a good thing.


** EDIT **
http://www.pirate4x4.com/forum/showthread.php?t=20386
http://www.carsurvey.org/review_67557.html

Seems to be a tossup. I know my DOA 20/22R engine is non interference. They hav releifs cut into the pistons.

LittleRedToyota

hmmm...interesting.

i could also post some links from sources i consider authoratative (like 4crawler's t-chain replacement write-up) saying it is an interference engine...

but, re-reading my FSM, it does say that the pistons have depressions built into them to prevent intereference with the valves. i always interpreted this to mean "prevent interference with the valves under normal operation (i.e., not talking about a broken t-chain", but seems like that might be a wrong interpretation.

i wasn't "lying", but it does seem that i (and a lot of very 22RE-knowledgeable people) were misinformed. thanks for setting me straight.

Chuki

Well with that in mind, I would assume that enough of carbon buildup on the pistons and they would hit the valves. I would imagine if the chain snapped and the crank and cam were no longer timed even if it is an non-interference engine, that the gap between the pistons and valves would be very very very small that a mild build up of carbon would come in contact with the valves.

I would come to the conclusion possibly that the Engines Toyota dubbed as non-interference like the 3.0 V6 probably has much larger gap if the cams and crankshaft become out of time.

When I built my new 20/22r hybrid I wasn't sure if it would hit or not so I slowly rotated the crank, and I rotated several times and nothing was going to hit. A 20R engine I had lying around was the exact opposite. But the 20R pistons don't have reliefs cut into the pistons, neither do the Domed top pistons 81-84 22R, in 85 they're dished with reliefs cut.

As I stated earlier broken chain isn't good either way you look at it. So

bike4miles

Keep an eye on it and repair it as soon as you can but if you do wear through the cover you can get a new one for $50 on ebay.

hi-desRunner

hey dont mean to thread jack but i just did the head gasket on my 90 4runner and i put the timing belt back on, adjusted the timing now i crank it over over and i have tis loud rattle noise coming from the bay could it the timing belt? and can someone enlighten me on how this could be? thanks