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Odd stripped thread fix

1993 4WD PU, MT, 22RE engine (no air cond)

Milestones:

120K: threw timing chain, bent valves, etc. 240K: using a QT of oil every 1K mile, rebuilt engine. Most of the cost and damage was due to the real crappy work done at the 120K incident. 300K: present time, replace radiator and fix minor oil leak up front.

This is the first time that I've done engine work since the two incidents mentioned above are beyond my time limits to do the work - I only have the one vehicle. My previous experience was all on cast iron American short blocks, back in the day.

So I see I have a pretty slow oil leak up front - no running oil, just accumulated dirt and oil, very thick and negligible oil loss per the stick - but I have to replace the radiator and I figure I may as well replace the front main and oil pump gaskets. It's all going well, but when I take off the oil pump housing, I see this:

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The upper left and lower right bolt holes have sleeves sticking out of them. I finally realize that these must be fixes to stripped threads, but I've never seen anything like it. In fact, I think it's a damnable thing to do, as they had to bore out the oil pump housing in order to accommodate the sleeve sticking out and the bores have partial sleeves in them to make up for the slop. But, I probably will never need a new oil pump housing, so I guess so what.

So I'm putting it back together and torquing the bolts per the manual and - oh hell - the lower left bolt is spinning. I can't pull it out, but I back it out and sure enough, there is about 3 turns of thread that came out on the bolt. Well, when I took that bolt out I noticed that there was fresh oil on it and I figured that is where the oil must of been leaking past and now I know that it probably wasn't torqued correctly.

I am at a total loss of what to do - the right thing to do.

I hope that somebody has seen this type of fix before and has some advice.

thanks for listening, jim

Reply to
Jim Graf
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Nope. Those are installed by the Toyota factory to precisely locate (position) the oil pump with respect to the timing chain cover (specifically, with respect to the crankshaft). A normal bolt (or set of normal bolts) are incapable of precisely locating a part do to their required clearance fit (and imprecise manufacturing tolerances). Therefore, you need two high-tolerance, close-fit parts to do the precise locating. These are often ground and polished dowel pins, but can also be precision sleeves as in the case of your 22RE oil pump.

That there were only three turns of stripped thread that came out with that bolt (rather than say 6-10 turns) suggests that only three threads of your bolt were engaged when the stripping occured. It's been a while since I did an R&R on my oil pump housing, but I'm guessing that the bolt lengths are not all the same and you inadvertantely put a short bolt in a hole that required a long bolt. If so, then the bolt was only engaged by three threads and that's why it stripped under torque.

The right thing to do would be to remove the oil pump and the timing chain cover and properly repair the stripped threads in your cover. You can use Heli-Coil or a similar thread repair insert; these inserts typically produce threads in aluminum alloy parts that are stronger than the original threads (provided they are installed properly). But considering the problems you're having and your lack of recent engine repair experience, you might want to simply stop and hand this job over to a professional.

Regards, Michael

Reply to
DeepDiver

Thank you, I should have figured out that those sleeves were locater's, but the 93 engine manual didn't really show them and I don't believe I've ever seen that before, but I have seen locater pins. But they sure do precisely locate the pump.

I wish I had seen this before:

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I used the right length bolt - just verified it and it's the shortest of the set anyways - what is odd is that the bit of threads that came off were a little less then mid bolt, I should have mentioned that. I can get 4 ft/lbs on it before it starts spinning (I actually use a in/lb wrench for these small bolts) and I figure that is all the last person put on it before they handed it back to me.

I've heli-coiled threads before, but what worries me is that the bad threads are in the lower right locater (I misspoke and typed lower left prior. bad proof reading skills).

I certainly don't mind pulling off the timing chain cover and handing it over to a machine shop. A new one goes for $160 (online) and $234 (toyota!), so anything that a machine shop can do would be worth a shot. I just wonder how they will handle the sleeve/locater.

In the past I've had less time, more money but that is somewhat reversed right now, so it's pretty fun getting my hands wrenching bolts again. After this is done, I'm going to replace the entire exhaust system. It's still OEM.

thanks again, jim

Reply to
Jim Graf

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