DOD Delete Question (oil system)

[XxCyberhellxX]

okay to start I have a 06 Trailblazer with the 5.3. I had a DOD lifter fail on me so I did the DOD delete.

New PCMofNC Rob style cam
LS7 lifters
LS7 valley pan replacement
new valve springs
PCV delete
PCMofNC mail order tune

everything else is stock. I'm getting some valve train noise after everything so I have ordered a pushrod length checker and waiting for it to some in so i can check my lifter pre-load. (re-used the stock push rods)

the questions I have is about the oil pump. I'm reading mixed things from different places online.

Do I need to change my oil pump to a non-DOD pump off an LS2?
do I NEED to plug the oil pressure relief vale in the oil pan?
I'm sitting at 55psi at idle with 5w30 (on a cold start then drops back down to about 45) I'm also in Chicago with the cold weather.

this is a daily driver that may see the track here and there.

I did not plug the DOD oil holes under the valley pan..

if I can just get the valve train to shut up after the new pushrods I will be happy..

I don't really want to drop the oil pan as it is a 4WD truck

until I get the pre-load checked I'm not spinning the motor over 3,000 rpm


TL;DR: Do I need to change the oil pump and block off the oil pressure relief valve in the oil pan?

 

[C-ya]

Are the lifters the same length at expansion (under pressure)? You may need a longer or shorter push rod with the lifter change. Are the springs stiffer? (Most likely - if nothing else from being new!) How much noise? Which side? Multiple cylinders on a side or just one or two?

As far as oil pressure and flow paths, that's above me right now, too. This is my first DOD engine, and I plan on killing it via software.

Just a couple of thoughts. Not sure how "standard" the lifters are. I built an old school carbed SBC, but I'd have to really research these newer engines and see what fits where.

 

[XxCyberhellxX]

First off ΜΟΛΩΝ ΛΑΒΕ!!! You want them?!?! your going to get them bullets first!!!

And you and i are in the same boat this is my first LS style engine too. i have built tons of SBC's. the lifters are stock upgraded replacements so i believe the over all length of them are the same. but the cam has a different base circle on it so this is why i think i'm getting the noise. i know one push rod is a little worn (cly 4 intake) so i plan on replacing all of them anyways. i'm just more worried about the oil system now.

 

[jimmyjam]

everything else is stock. I'm getting some valve train noise after everything so I have ordered a pushrod length checker and waiting for it to some in so i can check my lifter pre-load. (re-used the stock push rods)
the questions I have is about the oil pump. I'm reading mixed things from different places online.
Do I need to change my oil pump to a non-DOD pump off an LS2?

there shouldn't be any difference in the oil pump.

do I NEED to plug the oil pressure relief vale in the oil pan?

hmm? where is that? pics?

I did not plug the DOD oil holes under the valley pan..

the valley cover should plug them for you, at least the LS2 one does, I don't know what an ls7 cover looks like.
see the rings, those "plug" the holes

that pic came from here

 

[XxCyberhellxX]

by plugs i'm mean i didnt plug them off with the 1/8 NTP Allen head plugs... just the gasket from the valley tray are plugging them

the LH6 engine comes with a higher pressure oil pump than a non-dod engine so it cam support the dod system. now that its gone i hear from some places i can run into issues

the link you got that pic from..... the picture under the valley tray is what i'm talking about...

 

[chicagotransam]

The LS7 lifters are recessed a bit more. You'll want 7.425 pushrods.

You'll also need lifter trays, headbolts, LS2 chain dampener, and timing chain wouldn't be a bad idea. Oil pump doesn't need to be swapped. Don't forget the obvious gaskets either.

You'll need the truck tuned before attempting to drive it since it will be stuck in 4 cylinder mode until you do.

 

[XxCyberhellxX]

The LS7 lifters are recessed a bit more. You'll want 7.425 pushrods.

Thank you so much for that info this would be one reason i feel that that lash is loose.

You'll also need lifter trays, headbolts, LS2 chain dampener, and timing chain wouldn't be a bad idea. Oil pump doesn't need to be swapped. Don't forget the obvious gaskets either.

You'll need the truck tuned before attempting to drive it since it will be stuck in 4 cylinder mode until you do.

I have already done all the work and have the engine running. and have used all the parts you said above. i sent out the PCM/TCM to PCMofNC when i started the tear down of the engine.


I just got the comp cams push rod length checker today in the mail so i plan and checking it tomorrow. i'm thinking about running a .090 preload on the lifters since its a daily driver and want to valve train noise to sound close to stock.

 

[chicagotransam]

Thank you so much for that info this would be one reason i feel that that lash is loose.



I have already done all the work and have the engine running. and have used all the parts you said above. i sent out the PCM/TCM to PCMofNC when i started the tear down of the engine.


I just got the comp cams push rod length checker today in the mail so i plan and checking it tomorrow. i'm thinking about running a .090 preload on the lifters since its a daily driver and want to valve train noise to sound close to stock.

Wish I knew you were doing this ahead of time... Have a tuner that'd probably charge you the same or less as the mailorder tune and be done on a dyno

 

[XxCyberhellxX]

Wish I knew you were doing this ahead of time... Have a tuner that'd probably charge you the same or less as the mailorder tune and be done on a dyno

Send me a PM with some info... i'm still going to need to get it re-tuned after the e-fan swap and 160º t-stat. plus the cold air intake. I was thinking about having FAST Motorsports do it in Woodstock as my Girl Friend works 15mins from their shop. she could just drop it off on her way to work.

I'm out in DuPage co.

 

[chicagotransam]

Send me a PM with some info... i'm still going to need to get it re-tuned after the e-fan swap and 160º t-stat. plus the cold air intake. I was thinking about having FAST Motorsports do it in Woodstock as my Girl Friend works 15mins from their shop. she could just drop it off on her way to work.

I'm out in DuPage co.

A) DO NOT do a 160 stat (facepalm) Unless you are bracket racing, this is a major disadvantage. Even if you were, there are reasons this isn't good for combustion or the motor. I'm too tired for the physics lesson though.
B) The CAI won't effect the tune
C) The E-fan doesn't add enough to make it worth the cost of parts and a tune and really, the CAI isn't worth the bang for buck either. I have one for sound and not performance. At $300+ for one that won't LOSE HP, it's silly to do.

If you want to spend the money on bang for the buck, get a converter built instead of the E-Fan idea. I am blanking on the name of the company, but want to say they're out of DuPage. Their converter is backing a 7-8 second Vette right now for it's 3rd season. You can call them and give them your specs and they will build you a converter for half of what an off-the-shelf converter would run ya, and will actually last.

 

[XxCyberhellxX]

A) DO NOT do a 160 stat (facepalm) Unless you are bracket racing, this is a major disadvantage. Even if you were, there are reasons this isn't good for combustion or the motor. I'm too tired for the physics lesson though.
B) The CAI won't effect the tune
C) The E-fan doesn't add enough to make it worth the cost of parts and a tune

If you want to spend the money on bang for the buck, get a converter built instead of the E-Fan idea. I am blanking on the name of the company, but want to say they're out of DuPage. Their converter is backing a 7-8 second Vette right now for it's 3rd season. You can call them and give them your specs and they will build you a converter for half of what an off-the-shelf converter would run ya, and will actually last.

I'm going with a 4" intake with a LS7 MAF there for i will need a tune.

and i'm going with the E-fans mostly to pick up the 1 to 2 MPG. the HP is just a bonus.

Going with the 160º t-stat because the truck will see track time here and there. (grew up at Route 66 raceway...lived 15mins from it) Running the engine at a lower temp allows the tuner to run it a little bit more on the lean side. this will make the engine run hotter. there for the cooler temp is where it will help...

agree on the stall but i'm not planing on dropping the trans any time soon. i will be adding a transgo kit and other bolt on to it.

also keep in mine that the main question i posted about is about the oiling system.

 

[jimmyjam]

be nice.

 

[XxCyberhellxX]

be nice.

Thank you for cleaning that up.

 

[XxCyberhellxX]

So over the weekend I was able to check the preload on the lifters and they are way loose. Need a 7.450 push rod. I'm running 7.400 now. so with the new push rods that should give me a 0.091 pre-load on the lifters. I want to run them a little tight so the noise goes away.

anyone want to check my Math...

11 turns @ 0.05 = 0.55

0.55 + 6.8= 7.35

7.35 + 0.090 = 7.44


7.450 = Comp Cams P/N 7639-16 = 0.091 pre-load.



now I'm just worried about lack of oil when I spin it up to 6,200 rpm..

anyone have any idea's on this?

 

[TimRXUV777]

When did GM first put DOD v8s in the Trailblazer/Envoy? Anything before 2005?

 

[The_Roadie]

Here ya go:
http://bit.ly/1hyl3QD