Chain Housing Removal Without Dropping Engine?

[jjrowe]

Has anyone tried to remove the chain housing cover with the engine in the car? I had an oil leak coming from where the oil pressure sender meets the case. I have since discovered the threads in the case are damaged. This will need to be heli coiled and I have the remove the right chain housing the get a drill in there. Any ideas?



Jesse
76 911S

[Jim Sims]

Looks like someone damaged the threads by trying to "horse off" the oil pressure sender with a crow's foot wrench instead of pulling the mounting block and securing it in a vise for the sender removal.

Yes, but the rear engine perimeter sheet metal piece must come off. It looks like you need to remove the whole chain case not just the cover which means you will have to re-time the right bank.

If you haven't already, see the below thread about repairing this oil line port.

Stripped mag case where oil line go's

[john walker's workshop]

a helicoil doesn't have the fine threads necessary for that repair. in fact, it's a very difficult repair to get right, especially in a soft alloy case. there also is no depth to the hole before it intersects with the bore for the temp sender, so not enough meat to hold an insert. you could weld, drill and tap, but you need an experienced welder to get the magnesium buildup to actually adhere to the case instead of just sitting on top, where it can break off later, and a good machinist to redo the hole straight and true. once i made a special fitting that basically reversed the design of the through bolt that goes through the pressure sender block. it had larger threads on the short end by the hex that screwed into the case, and the sender block sat over the long end with a jambnut holding it tight. then the cam line attached as normal. can't remember the exact details but it was something like that. just oversized the case hole, and maybe the hole through the block too. it was a while ago. better than welding.

[jjrowe]

Jim, John,

Thanks for the replies. This doesn't look good...

Jesse

[Jim Sims]

If you want the part numbers of the OEM bushings John Walker used to made the repair bushing shown in the above referenced thread let me know.

[paslantnose]

Chemical thread repair MAy be a viable alternative.

[john walker's workshop]

and yes, you can remove the housing in the car. be sure the two locating sleeves in the case stay in the case, because if they come out in the housing, you can't angle the housing enough to clear the cam snout. easy enough to twist them out if they do. do a lot of thinking before messing with the hole because you could kill the case in seconds.

[jjrowe]

I am going to check into a solution like the one that was suggested in the above referenced thread. The case I think is throw away at this point since there are several places where the threads are weak. I am hoping to get another 30k out of it if I can fix this. My car has nearly 300k miles, it seems the magnesium starts to rot after that many heat cycles. Oh well, it is nearing time for a 3.6 .

Jesse

[john walker's workshop]

i dug out a prototype fix i made from a common 911 fitting. the hex was machined off and the bore drilled and tapped to the size of the stock through bolt, which is 12x1.0. the large end is 18x1.50. it would be critical to get the new threads perfectly true to the original bore so the sealing ring under the insert will seal. installation tool would be a 12x1.0 bolt with a nut on it.
i would be interested in hearing anyone else's repair for this issue.

[sww914]

I have the same problem on the other side. Somebody had JB Welded the fitting into the case.
It appears that there is plenty of depth for a helicoil or a timesert but I can't find anything in 12X1.0. Has anyone ever seen a kit for this size?

[stevemfr]

Originally Posted by john walker's workshop

i dug out a prototype fix i made from a common 911 fitting. the hex was machined off and the bore drilled and tapped to the size of the stock through bolt, which is 12x1.0. the large end is 18x1.50. it would be critical to get the new threads perfectly true to the original bore so the sealing ring under the insert will seal. installation tool would be a 12x1.0 bolt with a nut on it.
i would be interested in hearing anyone else's repair for this issue.

I did a similar repair years ago - but with a cut-off bolt as the repair piece (no shoulder). I didn't run the tap all the way in so that the threads were conical and inserted the repair piece with 574 on the threads. Worked quite well, but I like your method. I've done similar repairs on other castings and I'm always worried about cracking the casting.

[sww914]

Reply from Timesert
Hello,
Sorry to say we do not carry a M12x1.0.
We only carry the 1.5, 1.25 and 1.75 pitches.

Best Regards,
TIME-SERT