DOD/AFM Delete Valve questions

[swathdiver]

Sorry I meant a LM7 cam from TSP so I can keep VVT

I guess those guys bought a lot of those camshafts and that's why they keep peddling them. An LM7 camshaft is SMALLER then your stock cam and they never had provisions for VVT.



So, if your engine has VVT, the original camshaft is 12625436 and as you can see from the specs, it's quite different than the old LM7/L59 Gen III camshafts. If the replacement they sent you does indeed share those LM7 specs and has provisions for VVT, it should be the 12625437 LH9 camshaft.

When the earlier 5.3 LMG/LY5/LC9 motors do an AFM delete, we use the L33 camshaft as it has the exact same specs as our original sans AFM. We did not have VVT in these earlier motors. There is no exact equivalent for yours. You might consider an L9H 6.2 cam 12623065 or a BTR Truck Torque cam which is a single pattern grind but don't remember if it is VVT compatible or not.

 

[wsteele]

I guess those guys bought a lot of those camshafts and that's why they keep peddling them. An LM7 camshaft is SMALLER then your stock cam and they never had provisions for VVT.

View attachment 344495

So, if your engine has VVT, the original camshaft is 12625436 and as you can see from the specs, it's quite different than the old LM7/L59 Gen III camshafts. If the replacement they sent you does indeed share those LM7 specs and has provisions for VVT, it should be the 12625437 LH9 camshaft.

When the earlier 5.3 LMG/LY5/LC9 motors do an AFM delete, we use the L33 camshaft as it has the exact same specs as our original sans AFM. We did not have VVT in these earlier motors. There is no exact equivalent for yours. You might consider an L9H 6.2 cam 12623065 or a BTR Truck Torque cam which is a single pattern grind but don't remember if it is VVT compatible or not.

Looking at TSP's website, under the LM7 option it says it will work with or without VVT, (not sure if they mean it will work with VVT engines by deleting VVT or that their LM7 cam works with either).

 

[swathdiver]

Looking at TSP's website, under the LM7 option it says it will work with or without VVT, (not sure if they mean it will work with VVT engines by deleting VVT or that their LM7 cam works with either).

The cam will physically bolt up but if there is not a groove and hole cut into the 2nd cam journal, VVT is not going to work as it will be starved of oil.



Sadly, most cams are not designed to work with VVT. I reckon it requires much R&D time and folks just aren't willing to pay for it compared to what it ultimately delivers.

Worse, he's going to lose horsepower with that cam VVT or no VVT.

 

[wsteele]

The cam will physically bolt up but if there is not a groove and hole cut into the 2nd cam journal, VVT is not going to work as it will be starved of oil.

View attachment 344530

Sadly, most cams are not designed to work with VVT. I reckon it requires much R&D time and folks just aren't willing to pay for it compared to what it ultimately delivers.

Worse, he's going to lose horsepower with that cam VVT or no VVT.

I understand what you are saying about the difference between a VVT compatible cam and one that doesn't support it, it is just odd they would specifically call out that one of their two offered "LM7" cam says:

• GM LM7 5.3L Single Bolt Cam, use w/ OEM Valve Springs - Works with or without VVT (28-12689035)

 

[Darren2014]

The cam will physically bolt up but if there is not a groove and hole cut into the 2nd cam journal, VVT is not going to work as it will be starved of oil.

View attachment 344530

Sadly, most cams are not designed to work with VVT. I reckon it requires much R&D time and folks just aren't willing to pay for it compared to what it ultimately delivers.

Worse, he's going to lose horsepower with that cam VVT or no VVT.

So what would be the closest to stock cam I should go to in order to not lose power and hopefully not have to lap my valves. I’m not trying to be lazy, I’m just on a time crunch as far as the days I have off with my new work schedule and I’m currently driving a gmt800 suburban I got T ***** in.

I understand what you are saying about the difference between a VVT compatible cam and one that doesn't support it, it is just odd they would specifically call out that one of their two offered "LM7" cam says:

• GM LM7 5.3L Single Bolt Cam, use w/ OEM Valve Springs - Works with or without VVT (28-12689035)

That is strange. The way it reads to me is that it would work if you wanted to keep the VVT

 

[wsteele]

So what would be the closest to stock cam I should go to in order to not lose power and hopefully not have to lap my valves. I’m not trying to be lazy, I’m just on a time crunch as far as the days I have off with my new work schedule and I’m currently driving a gmt800 suburban I got T ***** in.

That is strange. The way it reads to me is that it would work if you wanted to keep the VVT

That is definitely the way I read it, worth a call Monday for clarification.

 

[Darren2014]

So after a decent bit of research I’m kinda down to either a LH9 cam in order to keep things as close to “stock” as possible. Or go with a TSP Stage 2 VVT cam. Both let me keep VVT tho I would have to install a cam phase limiter with the TSP. Any other recommendations would be great tho. Heck if there are any good reasons to get rid of the VVT let me know. As far as I can see it’s all pros but I’ve been wrong before lol. Thanks for all the help so far guys. I’m so happy I found this forum and all the help I’ve gotten here.

 

[swathdiver]

So what would be the closest to stock cam I should go to in order to not lose power and hopefully not have to lap my valves. I’m not trying to be lazy, I’m just on a time crunch as far as the days I have off with my new work schedule and I’m currently driving a gmt800 suburban I got T ***** in.

That is strange. The way it reads to me is that it would work if you wanted to keep the VVT

If your heads are not burning oil, I see no reason to lap the valves when doing a DOD delete. Yes, that camshaft was made to work with VVT, so it is backwards compatible. It will work in my older motor without VVT or yours with VVT.

I'd look into using the L9H camshaft is you want to keep VVT working. Note that it is different than the LH9 camshaft, two different motors. I'm in the minority around here, most folks like cams with more than 210 degrees duration for a 5.3 and more lift than the stock springs can handle.

I forget, did your motor fail or is it running fine? If the latter, take your time and don't rush things.

 

[Darren2014]

If your heads are not burning oil, I see no reason to lap the valves when doing a DOD delete. Yes, that camshaft was made to work with VVT, so it is backwards compatible. It will work in my older motor without VVT or yours with VVT.

I'd look into using the L9H camshaft is you want to keep VVT working. Note that it is different than the LH9 camshaft, two different motors. I'm in the minority around here, most folks like cams with more than 210 degrees duration for a 5.3 and more lift than the stock springs can handle.

I forget, did your motor fail or is it running fine? If the latter, take your time and don't rush things.

I have a lifter that’s stuck compressed. I believe it’s cylinder one. So it’s driving like crap and knocking very loud. I parked it just after it started and started driving the clapped out burban

 

[Darren2014]

If your heads are not burning oil, I see no reason to lap the valves when doing a DOD delete. Yes, that camshaft was made to work with VVT, so it is backwards compatible. It will work in my older motor without VVT or yours with VVT.

I'd look into using the L9H camshaft is you want to keep VVT working. Note that it is different than the LH9 camshaft, two different motors. I'm in the minority around here, most folks like cams with more than 210 degrees duration for a 5.3 and more lift than the stock springs can handle.

I forget, did your motor fail or is it running fine? If the latter, take your time and don't rush things.

Also what what benefit does the L9H have over the LH9. I know I’ll loose a little horse power and a little bit of torque with the LH9 but it seems to be the closest thing to a stock cam for my motor minus the DOD. The L9H is impressive with how much more power it would give me, but that worries me since I’m not planning on changing out a ton of parts while I’m in there. I’d prefer to just be able to swap the cam, and lifters, put everything back together and have it tuned. With the L9H I’m worried id need to swap some parts out for others that are beefier than stock.