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hi, I would like to know if there are different blocks related to a DOD or non DOD engine criteria? I am not a engine guru, but because of recent engine issues I guess i need to know more about this. Can you guys please explain what makes a DOD engine and what makes a NON DOD engine. please forgive my lack of termanology
thank you for your time...
G ATSMA, thank you for the reply. I have been trying to understand the differences, and if I have read correctly the engine blocks are the same ('07-13). it is how/what GM did to create the difference. I THINK that if the engine was DOD then the valley oil galleys would NOT be capped? and if the engine was non DOD then the galleys would be "plugged" from the factory? also if I have been told correctly? to make a DOD engine into a non DOD the galleys need to be plugged and certain components have to be changed (IE: lifters & springs.....) ?? Ultimately I am looking at how to correctly and completely make a DOD engine into a non DOD engine...
The important part here is the valley cover.
NON-DOD engines use a cover that uses O-rings to cap off the "towers". They are not plugged any other way, BUT many use a rivet kit or drill and tap them for allen plugs.
DOD engines use a valley cover that routes oil to the towers to activate the DOD function.
I gathered that as well... my O.G. engine was a non DOD engine and ECM. my replacement engine I believe was a DOD engine. when the engine was rebuilt the builder I THINK was not aware of DOD/nonDOD and the engine was put together W/O valley cover O-rings AND no galley plugs.... i ended up with low oil pressure hence my investigation into the wonderful realm of DOD/ nonDOD GM goodness!
thank you for the reply.
I gathered that as well... my O.G. engine was a non DOD engine and ECM. my replacement engine I believe was a DOD engine. when the engine was rebuilt the builder I THINK was not aware of DOD/nonDOD and the engine was put together W/O valley cover O-rings AND no galley plugs.... i ended up with low oil pressure hence my investigation into the wonderful realm of DOD/ nonDOD GM goodness!
thank you for the reply.
How in the world would the engine builder not know this? I feel there is no excuse for him not knowing....
Well I learned the above AFTER damage done ( I GUESS my fault: I ASSUMED oil pressure would be good - before gauge hook up) being fresh rebuild.. also he was in the process of "retiring" - closing shop... AND I ! was his LUCKY last customer...... OOHHH -BBOOUUYY!!
anyways I got the gest of all this by the "new" rebuilder after disassembly... he indicated the above as well.
follow up questions.... what are the "stock" build items and steps to make the block nonDOD compliant? I know my ECM is factory nonDOD programmed. what parts are needed to make a stock block nonDOD? the truck will be a emissioned compliant daily driver no performance ad-ons..... that will be another build...another time..
If you swapped in a Gen 4 block in place of a Gen 3 you would know it. Cam sensor and knock sensor location is completely different. And it wouldn't run anyways because it would be a 58 tooth reluctor wheel on the crankshaft and 4 tooth on the cam gear (which you would have to extended the harness to even fit it)
Ls7Colorado, thanks for the reply, I do know for sure that the OG block and the second block were/are both Gen IV, I was told by the chevy house that my OG engine (vin no.) indicated that it was a nonDOD and nonVVT but flex fuel capable. I was not able to get info on the second block, but the pics I took and block no's ? supposedly indicated that the block was acceptable replacement AND my pics I took show the oil galleys not plugged in bare block form. SO... IF I understand correctly, the replacement block should of had the oil galleys plugged and the valley pan should of had the o-rings installed AND that is something the engine builder should have known to do OR atleast ask about right??? Had these been done then my oil pressure would/should of been fine & all right with the world?
thanks again for input and patience as I try to understand...
I have never actually plugged the DOD oil holes in the block, I have used the non DOD valley cover with O-rings and never had a oil pressure problem.
I have seen many people on here recommend blocking the holes though, no way to know for sure if that’s your oil pressure issue without pulling it down. Have you checked the filter for metal?
Ls7Colorado, Yea.. I finally got it to a shop & it was tore down to bare block... the oil had a "little bit" of "pearlesence" to it but no "chunks or slivers" the cam bearings were wore down "brass look" to them and the crank has some very light scoring? he thinks we can get away with polish on it. I believe I will need a new cam though..... The machine shop will check the block & let us know what he thinks and recommends....
it just sucks (really bad) that a guy offers to do something says he can do it AND then screws over the person...... why!! I mean it's not like he isn't/wasn't going to get paid & trusted him to just do his job! if it cost more then I would pay more... I told him this, just treat me fair!
che70velle, I didn't take any pics of the valley pan, but when we unbolted it from the fresh rebuild (using this block) there were no o-rings in the circles of the valley pan. I have attached a few pics of the block when i picked up from the core place. might help?
Ok, that’s a later gen4 block with the good rods. The bottom pic shows the towers that feed oil to the DOD solenoids in the valley cover. You are correct in assuming that you’d need a valley cover with o-rings that will seal those towers. No o-rings and you’ll have no oil pressure. While the block is torn back down, it’s a really easy deal to tap those towers for 1/4” pipe plugs and seal them off that way. It’s a sure seal that will never fail. Pipe plugs are cheap. Here’s a couple of pics of a block that I have that’s been tapped and plugged. This is literally a $40 mod including tap and plugs that anyone can do in an hour when the block is torn down. Be sure to wash the block real good if you go this direction. The tap process will put shavings in the towers.
ch70velle, thanks for the reply, so if my OG engine was set up as nonDOD/nonVVT and being this block used for replacement block then should the builder have known to use valley plugs and install o-rings on the valley cover? neither was done and I am also under the impression that different type of lifters are to be used?? i am trying to figure out what would have caused my new rebuilt engine have VERY low oil pressure to where it caused bearing failure?
ch70velle, thanks for the reply, so if my OG engine was set up as nonDOD/nonVVT and being this block used for replacement block then should the builder have known to use valley plugs and install o-rings on the valley cover? neither was done and I am also under the impression that different type of lifters are to be used?? i am trying to figure out what would have caused my new rebuilt engine have VERY low oil pressure to where it caused bearing failure?
thanks!!
As far as valley plugs go, no he shouldn’t have know to do that, as most builders simply install the correct o-ringed valley cover and send it, without plugs. Just like it came from GM. Regarding lifters, if the engine came with DOD, which is possible, the builder would have tossed the funky DOD lifters and went conventional. The DOD lifters are very long and have a spring out on the end. You can’t mistake them for a std lifter in any way. However, it’s also possible the engine didn’t have DOD and he went back with same style lifter.
On the front of the block,, isn't that setup for VVT as well? I thought only the VVT engines had the pink o-ring and that style of chain tensioning?
I've only torn open Gen 3 so just curious..
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DOD/NON DOD blocks ?? 
I guess i need to know more about this. Can you guys please explain what makes a DOD engine and what makes a NON DOD engine. please forgive my lack of termanology
hence my investigation into the wonderful realm of DOD/ nonDOD GM goodness!
