Oil drain treads worn

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Bernard Fahimian
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Joined: Tue Sep 03, 2002 1:15 am

Oil drain treads worn

Post by Bernard Fahimian »

This is the second time this has happened; the first owner told me he had to buy a new oil pan for $1400 as the oil drain treads were worn out. The service man who is changing my oil tells me he can put a " hielio coil!? " in the drain hole so the oil plug will seal 100%. Is this a good remedy or there are better ways. Happy Holidays to all. Bernard
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tyang
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Post by tyang »

Hi Bernard,

Kerry (330GT) addressed this issue recently:
http://www.parrotbyte.com/kbc/ferrari/OilDrainPlug.htm

Helicoils are a common fix for bunged up threads, but Kerry's solution is a better one. If your mechanic uses Helicoils, make sure he doesn't break off the "tang" inside the sump. He'll know what I mean. I wouldn't want any loose metal particles kicking around in the bottom of my sump!

Tom
Bernard Fahimian
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Joined: Tue Sep 03, 2002 1:15 am

oil drain treads worn

Post by Bernard Fahimian »

Thank you Tom, but i can not get into Kerry`s site since my internet is an AOL Co. What is Kerry`s E-mail? Bernard
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Yale
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Getting on to Kerry's site with aol

Post by Yale »

Kerry has a new aol freindly adress that now works! Go Kerry! Here it is:

http://209.128.90.174/kbc/ferrari/

Best,

Yale
Bernard Fahimian
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Post by Bernard Fahimian »

Thank you Tom and Yale, After a year i am now able to get into Kerry`s site. The problem i have is in the drain hole of the sump cover. If we go with helicoils would it not be better to take the cover off first? Or is it better to weld the original hole and tapp new threads? Bernard
Pontiac
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Post by Pontiac »

Here's the site for those that Can't view it.

Oil Drain Plug

One of the things on the 'to do' list was to fix my oil drain plug. At some point, a previous owner had high centered the car, breaking several fins on the sump cover and causing one or more cracks. From the evidence of the welding, one crack went through the drain hole area at the rear of the cover
Image

The drain plug had been replaced with a 1/2" standard pipe plug. This was probably due to the welding and the lack of a 16mm x 1.0mm tap that would have been needed to use the original plug. So I suspect that it was tapped to size where a standard US pipe plug would fit.

Image

My original plan was to remove the sump cover, get some aluminum rod, thread the outside to the 1/2" pipe thread, screw a chunk in and weld it in place. Then machine the surface smooth, drill and tap a new 16mm hole. In discussing this with Lowell Brown's machinist friend, he was worried that welding in the plug would anneal the casting and make it too soft. As it had already been welded on, whatever damage could be done probably had already occurred. However, he did have a simpler solution that didn't require removing the sump cover. Just get a brass 1/2" pipe plug, drill and tap that for the 16mm plug. This leaves an adapter with 1/2" pipe thread on the outside and 16mm on the inside. Then Loctite the adapter in place, leaving the 16mm hole for draining the oil. There is some difference between the expansion characteristics between aluminum and brass, but for the temperature range and size involved, it can be ignored (Lowell is a physicist and looked all of this stuff up). In looking for a brass pipe plug, I found that the current ones are hollow where the inside threads would need to be. However, I did find an 1/4" to 1/2" adapter which was solid beyond the 1/4" threads so there would be enough material for the 16mm threaded hole. Further this had a six sided head which fits well into the normal three jawed chuck on a lathe. So Lowell chucked it into the lathe, bored the proper inside hole, tapped it using a 16mm x 1.0mm tap and then cut off the head.

Image Image

I first drained the oil overnight and then cleaned the threads in the sump cover with brake cleaner so the Loctite would set up properly. I had to use a cut off wheel on a Dremel to cut back the welds by the hole and at the top so the head of the new drain plug would clear. Then I installed the adapter by putting a couple of washers on the 16mm drain plug, screwed that into the adapter and then using the drain plug, screwed the whole thing into the sump cover after putting Loctite on the outside. After letting it set overnight, I removed the drain plug. The adapter was purposely left a little higher than that face of the sump cover. The 1/2" tapped hole wasn't quite square with the face on the sump. I was originally going to use a cut off wheel on a die grinder to make everything flush, but there's too much difference to deal with that way. So right now, I hope that the copper washer will seal properly against the adapter. If not, I'll probably have to take the sump cover off and have a machine shop use a milling machine to true the face up with the threads.

Image

The last item was to drill a hole in the drain plug for the safety wire. Since this was a new plug, evidently Ferrari no longer makes them with the safety wire hole.

Image

A few minutes on the drill press gave me a 5/64" hole that I chamfered so the safety wire wouldn't catch and break on the sharp edge.

Here's the final installation, safety wire and all.

Image

A month later and no drips at all. So I'm quite happy with the final result[/url]
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tyang
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Post by tyang »

Hi Bernard,

Using Helicoils keeps you from having to take the sump cover off, but taking it off to do this proceedure with the cover off the car, insures that metal particles don't get inside the sump.

If you choose to have the cover helicarc welded with aluminum, and re-tap the threads, it will certainly look "correct," but understand that it takes only one "ham-fisted" oil changer to bung up all the work! The brass insert that Kerry used will be slightly harder than the aluminum, and more resistant to cross threading.

Tom
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330GT
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Post by 330GT »

I didn't have to take off my sump cover to put in the brass insert. However, I had good threads to start with. Cleaning up the cross-threaded mess could leave some aluminum pieces in the sump.
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