Soda blasting engine case

[TT Oversteer]

I just pumped another hundred bucks into the Chinese economy and bought a Harbor Freight soda blaster and I'm getting ready to clean up my 3.2 engine case. I spent a couple hours degreasing yesterday and the case is ready for the next stage of cleaning. I've never used this method before and I'm curious how it will turn out. For those of you who have soda blasted a case, what can I learn from your experience? Should I avoid certain areas of the case? Plug oil passages, oil squirters, etc? I'll post some before and after pics when I'm done. Thanks!

[john walker's workshop]

the soda dissolves in water and the dirt it dislodges and mixes with does not. i don't feel good about blasting cases. cam towers too. too hard to be sure everything is out of the passages. YMMV.

[Cupcar]

I just bought a Harbor freight unit and find it to be magic on suspension parts and fasteners, etc.

My thought would be to blast the engine as a sealed long block before you take it apart. This will get off the hard outside stuff.

Hose it off, compressed air dry it, then take it apart and clean the inside and oil passages by removing plugs and doing the usual solvent based methods for these operations.

I would not be afraid to do individual parts like rockers, rods, piston crowns, etc. with soda blasting.

[docrodg]

I did a full degrease on the case then soda blasted in and out. pressure wash off well then set to soak to make sure everything is dissolved. Another hosing with some bore brushes just to make sure it is clean inside and it will look like new. Degreasing gets the chunks and dirt out, The soda blasting removes the varnish and other discoloration well, and a good pressure wash after makes sure the dirt doesn't try and restick.

Soda blasting is great for many parts as it will not damage them. Just degrease first.

Also... wear a painters suit and a dust mask and goggles.

[Porshaah]

Although it likely wouldn't affect a cylinder wall, I'd avoid hitting it along with any other dimensionally critical surfaces. If you're working outside avoid any overspray to accumulate on cherished vegetation (eg. grass). I thought my wooded lot (i.e. acidic soil) would benefit from the alkalinic soda and it may have but not in the concentration created after shooting a 50lb bag.

[LJ851]

Originally Posted by john walker's workshop

the soda dissolves in water and the dirt it dislodges and mixes with does not. i don't feel good about blasting cases. cam towers too. too hard to be sure everything is out of the passages. YMMV.

I have to agree, it's just not worth the risk. It does not take much debris in the wrong place to ruin your day.

[TT Oversteer]

Today I decided to try soda blasting starting with the non-critical chain boxes:



I was pretty happy with the results and decided to move on to the cam housings. There was some concern about clogging up the oil passages so I decided to plug them rather than worry about cleaning them out after the blasting process. I simply used electrical tape to cover each of the four cam journal oil holes and the pinholes in the spray bars:





Before blasting the parts were degreased with solvent. After blasting I soaked the parts in hot soapy water then rinsed thoroughly and blew all passages out with compressed air then cleaned with chemtool. The soda is a very benign media, dissolves easily in hot water and causes no damage to the aluminum. The mating surfaces of the cam housings cleaned up really nice with no worries about abrasion damage.

On the negative side I used way too much baking soda. I blew through a 50lb bag just doing these parts! It also gets all over everything but cleans up easily with a garden hose. So for occasional use with smaller parts, this system is ok. I wouldn't recommend it for large jobs. Obviously uncontained media blasting has its disadvantages.

Tomorrow I will take a careful look at the engine case and decide whether or not to blast it. If I can cover the oil squirters and plug the oil galleys adequately I may give it a try. I have decided that removing the galley plugs for cleaning is more than I want to do given that this engine didn't suffer any catastrophic failure with associated debris in the oil.

[Porshaah]

You're not actually using baking soda are you? Baking soda is good for baking pies! Theyre's actually a media called soda which is much more abbrasive than baking soda. I setup a tarp and collect the overspray and I'm able to use it at least twice before it turns into talc.

[Walt Fricke]

Well, I used baking soda from Costco. Worked great. Perhaps ignorance is bliss?

[boyt911sc]

Are you doing this cleaning inside a blasting box (cabinet) or open air? I like to do similar project but working in my small blasting cabinet was quite awkward. Could you post a picture of your set-up? Thanks.

Tony

[TT Oversteer]

Originally Posted by Porshaah

You're not actually using baking soda are you? Baking soda is good for baking pies! Theyre's actually a media called soda which is much more abbrasive than baking soda. I setup a tarp and collect the overspray and I'm able to use it at least twice before it turns into talc.

Hahaha! I'm using the soda media Harbor Freight sells that comes in a 50lb. bag for about $35. There is a large "Arm & Hammer" logo on the bag but I haven't tried baking with it yet!

Good idea about the tarp. That crossed my mind as I was cleaning up the mess...

[tom1394racing]

I soda blast cam towers as well as many other parts using an Eastwood blasting cabinet and a pressure blast set up.

With the cam towers, I water flow the spray bars and cam journal oil supply afterwards to clear the oil passages, make sure they flow and flush all residual media .

[Porshaah]

I hung a 20' X 20' plastic tarp from a clothes line with half on the ground underneath a blasting cabinet made out of a large cardboard box from a fridge after trying to do it in a blasting cabinet. Position yourself upwind preferably on a calm day and cover yourself completely sealing any openings in your clothes with duct tape. The spent soda is very fine like talcum powder and gets into everything. Goggles and a good mask are a must. I was thinking of using a snorkel mask the next time attached to a hose for a fresh air supply, cause the mask filters clog up quickly. To collect the overspray,(i.e. most is caught in the box) lift one end of the tarp to collect overspray into a single pile and vacume up the clean soda for reuse. I use a $10 siphon type sand blaster which has a few different nozzels for different media and 3.5 hp compressor from Sears. The only issue I had is the siphon creates a crater in my bucket of media and looses its' prime, so I keep it within arms reach while blasting, so I can agitate the media to restore the siphon. If a pressure type sandblaster is used, one shouldn't have this problem.

[Walt Fricke]

Like Porshaah, I tried making a cardboard blasting cabinet with a clear poly cover. I found I couldn't see anything inside after a short while blasting (with a similar, very low buck, siphon gun). I went back to open air work, and hosed off the mess afterward. A real cabinet must use some kind of fan and filter to deal with this? But being able to reuse 50 or so % of the soda would be nice - I'll have to consider using a tarp next time I decide to do this. And maybe a cardboard box which is just open at the top? To help with the reuse part?

Cylinders, heads, cam towers, chain housings, and various covers are obvious candidates for use in a cabinet (though I just don't have garage space for one. The job this helped me most on was cleaning up a very gunky aluminum 915 case. Did a great job. Those and case halves would take a pretty large cabinet.

[tom1394racing]

In my blast cabinet set up, I use a shop vac and sawdust centrifugal separator to evacuate the chamber and clear the dust.

[Porshaah]

Sorry I didn't provide more details on the makeshift cardboard blasting box but you figured it out by loosing the window. It 's just there to collect the immediate overspray and the tarp catches the remainder. When your blasting just aim towards the opening in the box and adjust the distance of the piece you're cleaning from within to outside the box to maximize what is collected by the box as opposed to what bounces back and into the air to be collected by the tarp. In fact one could probably just use a big tarp with the sides folded up. The idea I had was just to collect as much as possible for reuse and avoid killing the grass as I did the first time, by doing it in the open. I found the window on my real cabinet dusts up quickly with soda but is great for other media such as walnut shells and the fillter in the cabinet to the shop vac clogs up quickly too with very fine soda.

[docrodg]

Originally Posted by TT Oversteer

Hahaha! I'm using the soda media Harbor Freight sells that comes in a 50lb. bag for about $35. There is a large "Arm & Hammer" logo on the bag but I haven't tried baking with it yet!

Good idea about the tarp. That crossed my mind as I was cleaning up the mess...

I thought te same thing after doing some blasting in the driveway.

[KTL]

Those towers look great. But I don't like messing with the rocker shaft bores or the cam bearing bores. Before I blasted the towers, i'd tape off the cam and rocker bores or stick some rubber stoppers in them

The spec'd clearance between shaft and bore in these locations is REALLY tight, especially the rocker shafts. Rocker shaft spec'd clearance is zero to .0001". That's freakin' TIGHT. Cams are 0.0009" to 0.0026" and wear limit is 0.0039" That's obviously a little looser because there's oil pressure in the cam bores.

You'd be surprised what crap can get in the spray bars. It's not a lot of work to pull the spray bars. The replacement plugs are cheap, or while you're at it you can tap the holes for 1/8" NPT and then have removable plugs for the next time you clean the housings.

Those spray bars are critical oilers and you have to be sure that nothing gets in there. Even though you plugged the pin holes, there are also holes inside the cam bearing bores that are exposed. Did you tape those shut? Not trying to be a jagoff here. Just trying to make sure you don't have a piece of FOD mess up all your hard work.

BTW my method to pull the cam bar plugs is to drill & tap for M5 threads and use a length of M5 all-thread and a nut & washer atop a small socket as a press fixture. Just be sure to use a strong screw material & oil the threads to keep the threads from being galled during the pulling. M6 is probably a better choice because you can get usually stronger screw material. But the M6 is very close to the size of the plug.

Also be careful to not drill too far when you go thru the plug. If you break thru and your momentum carries you to the next place the drill bottoms, you're hitting the spray bar itself. There's ample room between the end of the plug and the end of the spray bar. It's a decent sized cavity. So when you're nearing the end of the plug, go slow with no pressure on the drill. Then when you break thru, you don't jump down on the end of the spray bar.

[brp914]

KTL,

I've wanted to do this. Once you've got the plug out how difficult is it to get the spray bar out? Is the spray bar clocked at a certain angle for install? Is it the same end-for-end? What do use to plug the hole?

[ajwans]

Originally Posted by brp914

KTL,

I've wanted to do this. Once you've got the plug out how difficult is it to get the spray bar out? Is the spray bar clocked at a certain angle for install? Is it the same end-for-end? What do use to plug the hole?

The spray bar just slides out once you have removed the plugs. It's orientation is set by the nipple on the plug at the far end of the cam tower.

Here's some good threads to look at:

spray bar orientation

cam spray bar plug replacment

andy