Stripped mag case where oil line go's

[htbetz]

I was using a little too much muscle trying to remove my oil pressure sender and pulled some threads out of the magnesium case underneath the oil pressure sender. Other that removing the engine and time certing is there any gasket type permatex material that will hold up to the oil pressure? There is some threads there but not enough to tighten real tight.

[john walker's workshop]

this is not good. hopefully there's a 12X1.0 timesert kit to fix that. you can't go deeper or the fitting will hit the temp sender.

[Jim Sims]

http://www.timesert.com/mtrcsert.htm

Don't see a 12 x 1 but check actual thread of whatever you stripped (sender or oil line?) and maybe there's a timecert for it.

Good used 7R Mg case with good steel studs is around $550!

Good Luck! Jim

[john walker's workshop]

that would 12x1.0 as i mentioned previously.

[Jim Sims]

Yeah, the side fitting is 12 x 1 but since he said under the sender I thought he might also be talking about a front of the engine location of the oil pressure sender which I believe in the MFI cars has an oil line to the pump under the sender. I believe that female thread is 18 x 1.5 and there appears to be a timesert of that size listed. Its probably the side fitting though, in which case he's out of luck unless there's other timeserts available which are not listed online or a metric helicoil or Fairchild "keensert" in the 12 x 1 size is available. I wonder about drilling and tapping the damaged hole larger (putting a rag in through the temperature sender oil to catch the chips) and making a bushing out of a bolt by drilling through the center of the head and tapping in a 12 x 1 thread. This would push the whole assembly to the right but the rubber section of the oil line to the cam tower might flex enough to fit . Or the rubber section of the oil line could be replaced by a shorter piece. Just an idea. Jim

[htbetz]

Yea, it is the side threads that are stripped. A time cert looks like the perfect solution but if they don't make it...
I've thought about the bolt solution although I would have to remove the engine. Oh well I was going to take out anyway to adjust valves and other stuff. It looks like I have to remove the right cam case, tensioners and sprockets so I can get a drill in there.
Prematex makes a thread saver epoxy that is resistant to oil and pressure. I'm going to try that first as a tempory solution.
Dam, it was running great.....

[Jim Sims]

It would appear you'll have to take the engine apart (at least the right hand side) to make any kind of repair (timesert or the bolt bushing) where you need to drill and tap. If you try the epoxy, it is imperative to get every last speck of oil and grease off the surfaces (threads) to be bonded; if the epoxy instructions specify something for a cleaner then use it but if not I'd use ethanol followed by acetone. Be careful, both of these solvents are very flammable and make fumes. Have plenty of ventilation and no open flames (like a gas fired hot water heater located in a garage). Of course, once the fitting to case joint is bonded you'll need to protect it from any torque from susequent fitting/oil line installation. Good luck and let us know how well this repair approach works. Jim

[john walker's workshop]

i'm afraid your "glue it back together " approach is a waste of time. just what you need, an oil line ready to pop out at any time. 90# cold and 60# hot oil pressure. there's not enough area around the hole to go oversize and you can't go any deeper. lets face it, you're screwed, sorry. time to come up with another case.

[john walker's workshop]

ok, rather than do work, i made this fitting that could solve most of the problem. every time i say impossible, it gets the wheels turning. the fitting i started with is an early 911 oil pressure switch adapter that mounts over the bellhousing. i drilled it out to 7/16, tapped it 12x1.0, and cut it off on a lathe, retaining most of the original flange for the seal ring. it would require drilling and tapping the case to 18x1.5, which is pushing it, due to the skimpy amount of case material around the hole, but it's probably your only hope if you can't find a 12x1.0 timesert. you can make one, or i'll mail it to you. the one in front is actually the same size as the rear one, but it's closer to the camera, which is on macro.

[Jim Sims]

John, Could one also make a bushing from one of the 18 x 1.5 plugs used to seal the hole over bellhousing when its not used for a sender? This might save some lathe work. I don't know if there's enough stock thickness to make the 12 x 1 thread though without looking at one. Cheers, Jim

[john walker's workshop]

i'm sure that fitting could be used too. the hole you drill would have to be dead center, and once the top part is machined down to the lip, it would look the same. with this fitting installed, the sender mounting block would not be moved outwards very much, allowing the cam line, which is already a tight fit over the curve of the chain housing, to be installed.to install it tightly enough, you would put a stack of washers on the original fitting and use the hex on it to tighten the new one up. maybe red loctite, but it should seal without it. don't get too carried away tightening it, as the case is weaker now with the larger hole. red loctite may make the case more unuseable in the future if it causes the 18mm threads to be damaged when someone tries to remove the bushing later in life. use it as a last resort.

[john walker's workshop]

when you tap the case, use grease on the tap to collect as many chips as poss. you can also push grease into the oil passage to trap chips. taps are tapered on the leading end, and you need a straight cut thread in a very short depth. first run the tap in as far as poss, then pull it out and cut the taper off with a disc cutter, effectively making it a bottom tap. then finish the threads to the needed depth. get the majority of the chips out with a greased screwdriver, and then pack rags around the hole and crank the engine to use oil pressure to flow more chips out. disable the ignition so it doesn't start. put a pan underneath for the mess. the tap must be straight in line with the hole or the sealing ring will not contact evenly. one chance to do it right, so go slow.

[htbetz]

Thanks to everyone especially John and Jim for their great brainstorming idea's. Looks like my only course of action is to drill out case to 18mm and install home made bushing. I'll let everyone know how I made out.

[Glasgow 911SC]

Outstanding help John! You must have saved so many people on this board a huge amount of $$$$/££££ over the years.Keep up the good work!

[davis911s]

Glascow I second that JW thank you again for all your time/effort/patience with us.

Shawn