Chefordiac

I looked around and couldn't find much on blocking off the DOD towers on a Gen IV motor. Mine in particular is an LY6. One option was to use pipe plugs but I didn't like the idea of adding the extra stress to the casting. I decided to plug the tower holes with cup plugs but of course no one makes them in the hole size of the DOD feed towers. The closest size was 3/8" from Dorman auto but this required drilling and the motor is assembled. I will try to outline what I did here.

Chefordiac

I took a 3/8" drill bit and locked a shaft collar onto it just below the depth of the cup plugs that I intended to use.

Chefordiac

I then covered the engine internals with furnace tape because a.) it sticks well and b.) it conforms well also. Then I cut the tape around the tower holes and stuffed a wad of paper towel into each hole. After this I rolled the motor over on it's back as it is on an engine stand. I WOULD NOT recommend doing this if the engine cannot be flipped upside down to keep chips from falling into the engine oil holes.

Chefordiac

With the engine upside down I drilled out the holes to the depth set by the shaft collar. I then vacuumed out the remaining chips and cleaned the holes with a gun cleaning brush. After that I removed the paper towel plugs and vacuumed the holes again to be sure. It's tough to see here but the hole is enlarged to 3/8" dia. down about 3/8" in the hole.

Chefordiac

Finally I tapped in the cup plugs flush with the tower surfaces. I think this will induce less stress on the towers than pipe plugs would. Time will tell I'm sure.

LS1MCSS

iTrader: (18)

I used 1/8" allen head pipe plugs on mine.

Chefordiac

I probably would have been fine doing that as well. My only concern was that that the tower castings have no side support and I thought that the pipe plugs might crack them from the pressure exerted. Probably just paranoia.

S10xGN

iTrader: (11)

I'm not seeing this stress ya'll are stressing over, it's simply not an issue. I do like Chevfordiac's method of working on a built engine with minimal contamination though.

rojs234

iTrader: (5)

I'm inclined to agree with you, Russ, although I see nothing wrong with the way *Chefordiac * did the job. We did this on a Gen lV aluminum block 5.3 about a year ago. I checked the factory holes with a drill bit for size and they were the size recomended for a 3/8x16 tap, so we bought 3/8 allen head plugs at Lowes and tapped the block so the slightly tapered plugs would screw down flush. We also used *Chefordiac's* method of turning the block upside down on an engine stand and using a strong shop vac both during and after the process.

litle88

iTrader: (20)

I have mine with Allen screws too and there's no stressing the block what's so ever.

Albertan

I bought a new valley cover and it comes with seals to block off those towers. Or at least I thought that is what they were for. Is plugging these with pipe plugs just extra safety?

rojs234

iTrader: (5)

The valley cover with the o-rings works just fine. I have an LS2 with that setup and have had no problems. The reason we plugged the towers on the 5.3 was that we had the cover plate but no o-rings. They were on national back order at the time and were not available anywhere. We re-used the original cover gasket by cutting out the middle part that fits over the towers because we couldn't buy the flat cover gasket either. I see no reason you couldn't use the DOD cover also if trying to save money. OK....after thinking about this, I may have mis-spoken and I came back to EDIT.!!! I don't have one to look at but I'm afraid the passage to the oil pressure sender would be left open causing ZERO! oil pressure. So.... anybody trying to use the original DOD cover needs to check this. Sorry, my bad.

Albertan

Thanks for that!

S10xGN

iTrader: (11)

And when they are available, you get the privilege of paying $5 each. You can get all 8 plugs for less than that...

TurboMonte100

iTrader: (1)

The DOD cover can be used, simply remove all hardware underneath and then tap and plug the angle channel that supplies oil to the dod system. Good job pointing that out rojs234, in many of the threads I have seen about this, most do not mention the rear oil feed.

BTW I tapped and plugged my towers, they are super stout and I dont see any danger of stressing them.

pastvertical

iTrader: (1)

how do u get the solenoids off the cover? and where exactly do u tap the cover . can u post a pic?

TurboMonte100

iTrader: (1)

Sure can. The first shows the "angle" passage that supplies oil from the rear oil sender to the solenoids to opperate them. This is the one that needs tapped and plugged, many over look this. This can be tapped a standard thread (only go half way), and then use a set screw (or bolt) bottomed out with a little loctite to hold in place good.


The soleniods are just held in with plastic snaps and then rotate them to remove. The rest of the hardware is attached using tork headed screws. Here are a couple showing the hardware and stripped cover. This cover when stripped is a little lighter then the ls2/3 cover.

keith102371

iTrader: (20)

I found a valley cover Gm sells that blocks it off and comes as a kit with the valley cover, gasket, o rings and bolts for 35 bucks, ALOT cheaper that the ls2/3 valley cover. heres the pn#12598832

http://www.performancetrucks.net/for...delete-495725/

S10xGN

iTrader: (11)

The reason most people don't mess with blocking the cover ports is that they ditch the entire cover for a non-DOD version. The top of that thing is fuuugly!

lowrolr

dod does leave passages open.each two t off into one. I was just suggeted to plug them off. TSP uses a ls2 cover on all theres.