Engine Case Cleaning

[1972_911T]

Ive seen many rebuild threads where people show pictures of cases that they have obviously spent a lot of time cleaning up and making look like they have just left the factory. What methods do people use? Are there chemicals that can help? or is it all down to elbo grease and hard graft.

I have a case in need of some serious TLC and need some ideas how to go about it.

Steve

[dtw]

Seems like I spent 16 hours cleaning my last case - it was really crusty and dirty. Supplies:
-razor blades - to remove old sealants. careful careful, don't nick sealing surfaces.
-Scotchbrite pads (green) for scrubbing inside and outside case surfaces
-brake cleaner for spraying out holes and piston squirters
-acetone for g/p cleaning
-rifle bore brushes, various sizes for thru-bolt bores and other bores
-wire brushes

I'd also love to hear tricks from anyone else as I have another build starting next month.

[304065]

This case was hot-tanked and then tumbled in ceramic media and then all the oil passage plugs were removed, the oil passages thoroughly cleaned and then the plugs reinserted. It will receive another cleaning by me personally prior to final assembly.

[1972_911T]

Originally Posted by john_cramer

[img]This case was hot-tanked and then tumbled in ceramic media and then all the oil passage plugs were removed, the oil passages thoroughly cleaned and then the plugs reinserted. It will receive another cleaning by me personally prior to final assembly.

Do you have to protect the mating and bearing surfaces when tuble cleaning? wont it remove some of the surface? or is it not harsh enough?

Steve

[304065]

Steve, all fair questions. I did not note any dimensional changes from the process.

[1972_911T]

John did the case show have piston squirters? if so would these need removing te ensure no media is trapped behind?

Steve

[304065]

Steve,

The old aluminum cases, of which mine is one, did not come from the factory with piston squirters. These were added in 1971 to the mag cases. Squirters were installed in my case although I'm not sure at what point in the process- probably after the tumbling and before the cleaning just to make sure any chips got blown out of the oil passage to which the drillings for the squirters connect.

[MatthewBrum]

I used a dry ice blaster to clean mine. We rented one at work so it didn't cost me anything but there are people out there who dry ice blast for a living. It cleaned my 3.0 case to look brand new without putting one nick or ding in it. And the stuff just evaporates within seconds. I was impressed.

[1972_911T]

Sounds promising, no abrasive to clog you oil ways. Do you have nay pics of the results?

steve

[MatthewBrum]

I will take some this weekend.

[MatthewBrum]

Here is the case after dry ice blasting

[1972_911T]

Well the end result certainly looks well, do you have any before pics?

Steve

[MatthewBrum]

no I don't but it had a ton of oil, dirt, and grease on it. I tried using degreasers with brushing but it would have taken me forever. I even dipped one half of the case in a parts washer and it only removed some of the oil not the hard black stuff. If I didn't ice blast it I would have had to get the case professionally cleaned.

[turbobrat930]

As far as cleaning my case, I used a red shop cloth, with mineral spirits. I then used a mild detergent, rinsed with water, blow dryed with shop air. Then, I used about 400 red shop towels and about 2 to 3 cans of the big Mothers Al polish (jewelers rouge), and the buffed to a nice shine. I cleaned all of the oil passages, etc... I estimate that I have between 160 to 180 hours worth of time into the case..... but when you dont have enough money to build the motor right then.... it was time well spent as it kept me interested in the project.....

[sww914]

That looks perfect.

[OldTee]

Lawd, the only people who have this kind of time are either in jail, very single, in a monastery or stuck in the outback somewhere!

Looks great tho.

[robmog]

beautiful,
did you spray it with scotchguard?
hee hee
bob

[88911coupe]

Ok, rather than start a new thread I'll just piggyback on this one. I've been cleaning my '88 3.2 case thoroughly but there is still a faint tan colored anodized look on the inside that does not seem to want to come off no matter what I do. I've even used a brass brush and it barely affects it. Am I safe in closing it back up? As I said, this "almost" looks like a stain or anodizing.
TIA

[turbobrat930]

Originally Posted by 88911coupe

Ok, rather than start a new thread I'll just piggyback on this one. I've been cleaning my '88 3.2 case thoroughly but there is still a faint tan colored anodized look on the inside that does not seem to want to come off no matter what I do. I've even used a brass brush and it barely affects it. Am I safe in closing it back up? As I said, this "almost" looks like a stain or anodizing.
TIA

I am guessing that the faint tan color that you are describing is what I would call "oil stain".... I really dont think it will hurt at all...BUT, if you want it gone....take some Mothers brand Aluminum polish....dab a small bit onto a shop cloth..and run on a small spot. The white polish should turn very black within about a minutes worth of polishing.... clean it off...and buff The oil stain should be gone. I would caution you however... if you use the polish, you need to be DARN sure you get every last bit of polish out of the case before reassembly...... after doing the whole inside of the case...was, wash, and wash it again!!!!!

[DSPTurtle]

Turbobrat... did you really do that by hand or did you use a dremel with polishing wheel. I can't get anywhere near that with just a red cloth. I usually throw my polishing wheel on the bench grinder and get things pretty good but nowhere near that. What is your secret?