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1989 Mk3 supra
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Discussion Starter · #1 ·
Hey, just took off the oil filter housing and found a crack. It's not very big and doesn't go very far but it doesn't feel right with that crack.

Do you experts think it's anything to worry about or should I just fill it with jb weld haha
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That is disconcerting. It looks like it's forming a T. If under pressure it completes the circle, it could come off or leak at the O-ring. It might be informative to see how deep the bolt threads go when it's bolted down using a caliper or a hook at the end of a piece of wire and compare it to the bolt length to the sealing washer. I don't remember there being a torque spec for that bolt but I wouldn't be enthusiastic about over tightening it next time. Cast-iron doesn't give you many welding options and since it's oil soaked. Not sure if JB weld or Permatex Ultra Black Silicone will stick. There looks to be some threads beyond the lateral crack. If you could extend the bolt or get a longer bolt to use all the threads the current one may not using without hitting bottom, that then might be your best choice. Shaving a few millimeters off the top of the housing for instance without weakening it unduly if you're not using all the threads there are. These are desperate measures to be sure. Oil flow direction is into the center hole, if that is of any help.

Upon reflection, I recommend screwing in the bolt alone to see if you can get past the damaged area. The casting may be sprung out and not allow bolt to go further than the lateral crack. If you had the correct size tap and a die that would be even better to chase it first. Just be sure and collect any shavings with a magnet and or plug the bottom of the hole with a bit of cloth.
 

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Stock 1989 Supra Turbo w/ Sport Roof
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Oh man, that's a really unfortunate situation. Disconcerting indeed. I'm not sure if brazing that would be doable either. It may be worth asking a machine shop for advice or recommendations.
 

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No bolt goes there. That's where the oil filter hollow threaded tube goes. Further, a leak through the crack will have no real effect on oil flow or oil pressure.

It looks like someone overtightened the tube on install. I believe it's a pipe thread, so it gets tighter as it is inserted and only a nominal tightness is needed but someone didn't get that memo. It's save-able though.

I'd use an appropriate thread locker to reinstall the tube, or if you want the ultimate in safety, use hi temp epoxy to permanently install the tube. After all, there is no need to remove this tube the entire life of the engine. There's enough thread to hold securely as all this tube does is compress the oil filter's O ring when you spin it on and then hold that moderate tension. Once you've done that, you have a permanent fix and can be confident the tube is secure. If you go epoxy, I'd file and clean up the outside of the crack and also smear epoxy into the crack and on the filed outside surface, epoxy the male threads, screw it in firmly (not tight) and let it cure. Done.
 

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1989 Mk3 supra
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Discussion Starter · #5 ·
That is disconcerting. It looks like it's forming a T. If under pressure it completes the circle, it could come off or leak at the O-ring. It might be informative to see how deep the bolt threads go when it's bolted down using a caliper or a hook at the end of a piece of wire and compare it to the bolt length to the sealing washer. I don't remember there being a torque spec for that bolt but I wouldn't be enthusiastic about over tightening it next time. Cast-iron doesn't give you many welding options and since it's oil soaked. Not sure if JB weld or Permatex Ultra Black Silicone will stick. There looks to be some threads beyond the lateral crack. If you could extend the bolt or get a longer bolt to use all the threads the current one may not using without hitting bottom, that then might be your best choice. Shaving a few millimeters off the top of the housing for instance without weakening it unduly if you're not using all the threads there are. These are desperate measures to be sure. Oil flow direction is into the center hole, if that is of any help.

Upon reflection, I recommend screwing in the bolt alone to see if you can get past the damaged area. The casting may be sprung out and not allow bolt to go further than the lateral crack. If you had the correct size tap and a die that would be even better to chase it first. Just be sure and collect any shavings with a magnet and or plug the bottom of the hole with a bit of cloth.
There is actually about a centimeter of thread after the crack(like 3/8 inches for my American helpers) so I'm gonna try to see how deep the bolt goes in and otherwise just ask my machine shop :)
 

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Machine shop will have an expensive solution, I'm sure. Since an oil filter is designed to be tightened by hand (less than 1lb-ft), it's not something that needs the attention of welding cast iron (difficult) and cutting new threads. Which is the only thing a machine shop can recommend due to insurance/liability, and their inherent bias for a solution that is pricey enough to make sense for them to get involved. Epoxy repairs are their competition, though it's worth noting that no less a reputable engine builder than Caterpillar sells an epoxy approved to repair cracks in their blocks. So it's a bit like asking a painter if your house needs painting. "Why yes - it certainly does, sir!!".......

Before I did something expensive like that, I'd buy an oil filter relocation kit if I were still worried about the threads having stress. That moves the clamping force (however miniscule) to a brand new fitting, while using the damaged block fitting as a mere connection point.
 

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Machine shop will have an expensive solution, I'm sure. Since an oil filter is designed to be tightened by hand (less than 1lb-ft), it's not something that needs the attention of welding cast iron (difficult) and cutting new threads. Which is the only thing a machine shop can recommend due to insurance/liability, and their inherent bias for a solution that is pricey enough to make sense for them to get involved. Epoxy repairs are their competition, though it's worth noting that no less a reputable engine builder than Caterpillar sells an epoxy approved to repair cracks in their blocks. So it's a bit like asking a painter if your house needs painting. "Why yes - it certainly does, sir!!".......

Before I did something expensive like that, I'd buy an oil filter relocation kit if I were still worried about the threads having stress. That moves the clamping force (however miniscule) to a brand new fitting, while using the damaged block fitting as a mere connection point.
Plus the big benefit of having the relocation kit! No more needing tiny bendy gnome hands to change your oil.
 

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1989 Mk3 supra
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Discussion Starter · #8 ·
Plus the big benefit of having the relocation kit! No more needing tiny bendy gnome hands to change your oil.
Yeah true, but I'm so done with spending money on the car, I'm not even sure it'll start so Im gonna risk it and if it starts leaking then I'll just get a relocation kit then. I guess I'll just hope that the threads hold up :):, I mean it's just like 17ft pounds
 

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1989 Mk3 supra
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Discussion Starter · #10 ·
What do you mean you're going to "risk it"? You're literally going to not bring it to a shop, not use epoxy, just reassemble it?
No I'm going to epoxy it and see if I can extend the bolt because there should be enough thread.

Machine shops in Sweden are really expensive, balanced my crank, resurfaced and honed my engine last month and it cost me about 3k so whatever I do is gonna be darn expensive at a machine shop :/
 
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