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Old 05-14-2008, 10:30 AM
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Default 22RE Timing Chain

Background: There is a lot of common wisdom that changing timing chains on a 22RE does not need to follow the FSM method, where the headgasket is replaced. In other words, leave the head on, pull the timing cover, pull the pan and clean out the broken guides and any other crap, and put it back together. If the timing cover is grooved or the small tab at the bottom is broken, simply clean out the pan and put on a new timing cover.

As appealing as that is, it has always bothered me. Headgaskets have a service life too, and when they go, ugly things can happen. Not always, but possibly. You are saving (deferring, really) the cost of a headgasket- for why exactly?
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So, my DD needed a rear main seal (I H8oilleaks) so we pulled the motor to do the timing chain. Glad I did.

The PO let the chain go long enough that parts of the timing cover were broken off, and some pretty good grooves were cut into it. Since we were pulling the pan anyway, and I had concerns about where those aluminum fragments went, Squishy suggested we pop a main to look at it.

Scored. Badly. The aluminum got sucked into the oil pickup. Fortunately, the crank was untouched.

Popped a big end, same deal. So now I was looking at a crank polish and new bearings.

Since I was going that far, a light re-hone and new rings simply made sense (the cylinders are good - why not?). I took advantage of the opportunity to get an Engnbldr head with bigger valves and hotter cam, an already planned mod. And since the block was going to be torn down, it also made sense to lightly deck the block, creating a new surface to match the new head, bumping the compression (barely), and working with the stock pistons.

What started out as a timing chain replacement ended up being a virtual rebuild, but it wasn't much more work, just more money for parts and machine work. Frankly I am glad we were thorough.

Think about that the next time someone tells you that you don't need to follow the FSM method and replace the HG, and just pull the pan and clean it out, and replace the timing cover if it's grooved/broken and fuggedaboudit.

Mine would have run, and run well... and either the HG would have failed early, or I'd have thrown a rod sooner or later or at least developed a rod knock and developed an ugly crank. As it is, I can expect another 200K before going back in (except, changing the timing chain in another 80-100K or so) and I can take it to redline fearlessly.

YMMV.
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Heard back from Gunn just now. The cylinders are not in terrible shape, just a bit worn, .001 at the bottom (which is unusual, and the piston skirts show scuffing but are OK). The cylinders show slight ridging, but #3 cylinder is pretty badly ridged, .010. At 139K miles, this puppy was rode hard and put up wet. Oil changes every 8K miles, anyone? Yech.

Their per part cost versus an engine kit means the incremental difference between a hone and a bore .020 over is $40. That is $40 COMPLETE cost. So I will have a new motor. I would have discovered none of this if I did not pull the head, pan, and bearing caps.
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Old 05-14-2008, 11:40 AM
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Good thing you tore into it. Would stink to put all that work in to only have problems in a year.

I agree that the factory way makes sense from the standpoint that the HG is designed by Toyota to match the service procedure they write. IOW, I'd expect that the HG and timing parts to have similar design-service lives. Couple that with the iron block & aluminum head uneven movement and the notorious coolant corrosion, the factory way is completely logical. I mean, either they had a service life in mind when they wrote the procedure or tailored the procedure to the component reliability. In reality, OEM-or-equivalent parts are good out beyond the typical interval, since Toyota tends to over-design things when compared to their recommendations. My HG was still OK at 187K, no evidence of immediate failure but showing definite signs of corrosion. Personally, I think Toyota expected ~125K or ~155K mile (so 200K or 250K kilometer) service lives out of the timing parts and HG (and probably main seals). Most people who have issues with the OEM parts failing are pushing them to 200K miles or more. Aftermarket stuff, all bets are off. There are some really cheap and sketchy parts out there. But sticking with Big Momma parts (be those Toyota boxed or Aisin and OTK branded), I think 100K~115K mile (160~175K km) intervals is not too awful silly conservative, so that's my plan.
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Old 05-14-2008, 11:51 AM
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Doing the engnbldr.com full meal deal, except for using Gunn-supplied pistons/rings/bearings, so we shall see! (Gunn uses Topline, just like Ted at Engnbldr). I fully expect an OEM lifespan. Topline sometimes improves on the OEM design.

Obviously this motor was wrapped up tight on old (or cheap, likely both) oil. The hone marks were visible but the wear at the bottom of the cylinder is unusual, along with skirt scuffing. No matter, now. Fortunately the crank is beautiful.

I may wrap it up tight against the rev limiter, but once broken in she shall see good synth and frequent changes. The cost of good oil changed often just ain't that much over time. I notice deals on Valvoline Synpower, which according to BITOG is very decent - I'm a Valvoline guy.
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Old 05-14-2008, 12:21 PM
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Quote:
Originally Posted by Red_Chili View Post
Doing the engnbldr.com full meal deal, except for using Gunn-supplied pistons/rings/bearings, so we shall see! (Gunn uses Topline, just like Ted at Engnbldr). I fully expect an OEM lifespan. Topline sometimes improves on the OEM design.
Nothing wrong with that.

Just as a point of fact, the timing kit I used from DOA appears to have come from Taiwan except for the guides, which I understood to be OEM parts trimmed to fit. I initially didn't note the manufacturer on any of it because most of it did not come in a box. I did not know their source until I tore things apart and wish I'd have thought about it more back then.

The key it seems is that the tensioner and guides must be OE or equivalent. Toyota spec parts have a better plastic in the guides and tensioner foot than typical aftermarket parts spec. It's obviously a cost reduction thing.

My speculation is that the reason my metal backed guides failed was the tensioner was not working correctly, which meant the guide was flexing a lot more than intended. Even steel parts eventually break if subjected to dislocation beyond their fatigue limit and the top of the driver's side guide is gonna flex if the chain is not tensioned. The tensioner was in bad shape, did not operate smoothly and the foot was disintegrating. Personally, I would not use any part that was not made in Japan. The parts I got from Toyota were made there (based on a 'JAPAN' stamp, although no other marks indicating manufacturer) and that means the most likely case is that they are OSK-made, which is who made them originally. I personally also think the DOA guides I got were not OEM. Cheap steel guides that snap are no better than cheap plastic guides that snap IMO, but it's probably also true that if my tensioner was non-op, then it's likely that plastic guides would have given up much sooner.

Be sure that the tensioner piston shaft is bright chrome and not dull-ish silver. The original design used a bright, hard chrome finish, but is not always present (maybe due to the environmental nightmare, in-process changes or 'improvements' or simply the higher cost of chrome plating). Tensioners with that duller finish tend to not work as smoothly and seem to have shorter useful lives. Anyway, that's one major red flag that you might have a less good tensioner.
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Old 05-14-2008, 12:59 PM
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Got the tensioner from Ted.

FWIW, even Toyota tensioners have had failure issues. Shows up kinda quick usually. Also FWIW, Toyota sources these parts most likely from the very same aftermarket vendors. That's where they got the designs - all they needed was permission to resell. Sunk cost already amortized supplying Toyota, so it's free money (well, from a tooling standpoint at least).

As an example, Marlin gets parts from the OEM manufacturers who used to supply Toyota. He advertises as much, too.

Oh, and have I mentioned that BMW gets many of their parts from China these days? It's all a parts potpourri.
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Old 05-14-2008, 03:11 PM
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I didn't care if it was Toyota, I just wanted to make sure to get a Japanese-made tensioner with the chrome piston finish. In my mind that would be most likely OSK, since they are generally believed to be the OEM back when the truck was built. The one Jerry got in met those criteria and so I didn't shop extensively. I know Ted has worked with OSK, so his is probably fine, too. But I couldn't put it in my hands and get my eyes on it before plopping down my money. When I was shopping for the timing stuff, I had failed DOA parts sitting on the bench and had just gotten past cleaning up that alignment hole on the Topline head, so I guess I was particularly sensitive to non-OE stuff at that point.
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