I have decided to rebuild a LMG 5.3....... would like guidance
11-24-2019, 06:11 PM
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I have decided to rebuild a LMG 5.3....... would like guidance
I have embarked on the great engine rebuild. I have an 09 Suburban that has the notorious piston slap issue. My goal is to rebuild an engine that will NOT have piston slap, and add a bit of power.
I have purchased a high mileage LMG engine already. Having read some things on the interweb and taking eveything with a grain of salt (because I read it on the interweb) I am looking for some guidance and reassurnaces on a few things.
I already plan on getting a tune for whatever changes I make to this engine and for disabling the AFM.
Feel free to correct me, inform me of things I will need to do that I haven't realized yet, or if I am just a F'n idiot for trying to do what I'm doing.
Cheers Ya'll
John
I have purchased a high mileage LMG engine already. Having read some things on the interweb and taking eveything with a grain of salt (because I read it on the interweb) I am looking for some guidance and reassurnaces on a few things.
- I have read that the best way to avoid piston slap is to get some oversized pistons and have the cylinders bored to fit the pistons. Is this accurate?
- Should I go with Forged or the stock style cast pistons?
- There are many many many camshaft options out there. I will NOT be putting AFM back into this engine. I wishes are to find a camshaft that will increase the low end toque as I do tow on occasion. Fuel economy isn't really a concern. It's a suburban after all.
- I am planning on sending the heads out to be clean, inspected and new seals put in. I have seen the CFM stats of increasing the valve size, but I am a dummy when it comes to understanding and translating this to real world increases. The costs involved to increase valve size vs the reward, is it worth it? I do not plan on adding a power adder to this engine.
I already plan on getting a tune for whatever changes I make to this engine and for disabling the AFM.
Feel free to correct me, inform me of things I will need to do that I haven't realized yet, or if I am just a F'n idiot for trying to do what I'm doing.
Cheers Ya'll
John
11-24-2019, 07:19 PM
#2
If the plan is no boost, forged internals is kinda overboard but if the price it right for a set of pistons you can't go wrong. I can't really comment on the piston slap issue.
You will need to stay small on the camshaft because of your goals with power/torque. You also need to stay on the smaller side to keep the stock stall that works really well for towing. Anything that some of these places call a stage 1 or stage 2 camshaft are probably what you are looking for. Most are at or under the 212/218 cam size and that should add a decent bump in power with a good tune. You will no longer want to run 87 octane either. 89+ octane only. Look at Texas speed, summit racing, brian tooley racing, they all sell camshafts and the whole kits for deleting the AFM/DoD system properly.
Leave the cylinder heads alone, they already flow stupid good for stock heads. Clean them up, new valve seals, consider the trunnion upgrade for the stock rockers and slap it back together.
You will need to stay small on the camshaft because of your goals with power/torque. You also need to stay on the smaller side to keep the stock stall that works really well for towing. Anything that some of these places call a stage 1 or stage 2 camshaft are probably what you are looking for. Most are at or under the 212/218 cam size and that should add a decent bump in power with a good tune. You will no longer want to run 87 octane either. 89+ octane only. Look at Texas speed, summit racing, brian tooley racing, they all sell camshafts and the whole kits for deleting the AFM/DoD system properly.
Leave the cylinder heads alone, they already flow stupid good for stock heads. Clean them up, new valve seals, consider the trunnion upgrade for the stock rockers and slap it back together.
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swathdiver (11-26-2019)
11-25-2019, 02:50 PM
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To clarify, you're not rebuilding the engine that is in the Suburban? You purchased a separate 5.3 LMG engine that you're going to rebuild?
What is the year of the LMG you're going to rebuild? 07-09 LMG engines only had AFM. 10-14 LMG engines also had VVT. This will change cam recommendations and other needed parts. If this has VVT are you going to remove that as well?
1. Yes, if the engine is experiencing piston slap going with oversize pistons and proper boring will fix that. This doesn't mean it won't ever happen again but will prolong it.
- For your goals, forged internals are not necessary. Although, as FFDP stated forged pistons at a good price would be a plus. To give you an idea of cost. Replacement hypereutectic pistons are mid $200 range and you can get good forged pistons for right around $500. This would be a gen IV motor so you would have the gen IV rods which are plenty strong enough for your goals.
2. The camshaft and related parts will depend on the clarification of the specific LMG engine you have.
3. As FFDP stated no need for machine work on the heads or bigger valves for your goals. Clean them, new seals, springs if applicable, and a good trunnion upgrade.
What is the year of the LMG you're going to rebuild? 07-09 LMG engines only had AFM. 10-14 LMG engines also had VVT. This will change cam recommendations and other needed parts. If this has VVT are you going to remove that as well?
1. Yes, if the engine is experiencing piston slap going with oversize pistons and proper boring will fix that. This doesn't mean it won't ever happen again but will prolong it.
- For your goals, forged internals are not necessary. Although, as FFDP stated forged pistons at a good price would be a plus. To give you an idea of cost. Replacement hypereutectic pistons are mid $200 range and you can get good forged pistons for right around $500. This would be a gen IV motor so you would have the gen IV rods which are plenty strong enough for your goals.
2. The camshaft and related parts will depend on the clarification of the specific LMG engine you have.
3. As FFDP stated no need for machine work on the heads or bigger valves for your goals. Clean them, new seals, springs if applicable, and a good trunnion upgrade.
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swathdiver (11-26-2019)
11-25-2019, 03:04 PM
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To clarify, you're not rebuilding the engine that is in the Suburban? You purchased a separate 5.3 LMG engine that you're going to rebuild?
What is the year of the LMG you're going to rebuild? 07-09 LMG engines only had AFM. 10-14 LMG engines also had VVT. This will change cam recommendations and other needed parts. If this has VVT are you going to remove that as well?
1. Yes, if the engine is experiencing piston slap going with oversize pistons and proper boring will fix that. This doesn't mean it won't ever happen again but will prolong it.
- For your goals, forged internals are not necessary. Although, as FFDP stated forged pistons at a good price would be a plus. To give you an idea of cost. Replacement hypereutectic pistons are mid $200 range and you can get good forged pistons for right around $500. This would be a gen IV motor so you would have the gen IV rods which are plenty strong enough for your goals.
2. The camshaft and related parts will depend on the clarification of the specific LMG engine you have.
3. As FFDP stated no need for machine work on the heads or bigger valves for your goals. Clean them, new seals, springs if applicable, and a good trunnion upgrade.
What is the year of the LMG you're going to rebuild? 07-09 LMG engines only had AFM. 10-14 LMG engines also had VVT. This will change cam recommendations and other needed parts. If this has VVT are you going to remove that as well?
1. Yes, if the engine is experiencing piston slap going with oversize pistons and proper boring will fix that. This doesn't mean it won't ever happen again but will prolong it.
- For your goals, forged internals are not necessary. Although, as FFDP stated forged pistons at a good price would be a plus. To give you an idea of cost. Replacement hypereutectic pistons are mid $200 range and you can get good forged pistons for right around $500. This would be a gen IV motor so you would have the gen IV rods which are plenty strong enough for your goals.
2. The camshaft and related parts will depend on the clarification of the specific LMG engine you have.
3. As FFDP stated no need for machine work on the heads or bigger valves for your goals. Clean them, new seals, springs if applicable, and a good trunnion upgrade.
I have gone through your site and while there are many options, there are too many options for me to wade through. As FFDP suggested and you suggested, I am probably NOT going with forged pistons. I looked on your site and I cannot figure out what pistons are the right ones for what I need and will fit.
11-25-2019, 09:27 PM
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Summits customer service is great I'm sure they will help you find the pistons and anything you may need. They also have many camshaft options. FFDP as always is dead on with his recommendations a 212/218 cam in a 5.3 suburban would be my exact choice. I love the one in my Tahoe and most members here will agree it's a great option.
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11-26-2019, 11:40 AM
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Correct, I purchased a junkyard core LMG 2009. This engine does not have the VVT system.
I have gone through your site and while there are many options, there are too many options for me to wade through. As FFDP suggested and you suggested, I am probably NOT going with forged pistons. I looked on your site and I cannot figure out what pistons are the right ones for what I need and will fit.
I have gone through your site and while there are many options, there are too many options for me to wade through. As FFDP suggested and you suggested, I am probably NOT going with forged pistons. I looked on your site and I cannot figure out what pistons are the right ones for what I need and will fit.
Oversize hypereutectic pistons are the route for you. Before buying the pistons you should have the bores checked to make sure what shape they are in. If this was a running "pull out" engine then .010 in. will likely be the ticket. We have those from Speed-Pro part number SLP-H1132CPA25MM. If you felt the need to go with .020 in. over those would be Speed-Pro SLP-H1132CPA50MM. Make sure to have the pistons in hand before boring.
For the camshaft, we would recommend our Summit Pro LS Truck stage 1 hi-lift. That is part number SUM-8719. We recommend the LS6 springs NAL-12499224 and Summit SME-143008 valve seals. The BTR stage 2 version 2 would also be a good option. That would be part number BTC-BTR31218110. The recommended springs for that cam would be BTC-SP011-16. The recommended valve seals would be BTC-VS-LSHAT-KIT.
Both of these cams will provide increased torque down low and good mid-range and top-end power. They will both work with your stock converter and gears. These are both 3 bolt cams so you will need to swap out the cam gear to NAL-12586481. While changing the gear it would be a good idea to get an LS2 chain SME-143012.
As previously mentioned you need an AFM delete kit. If this has PCV then you would need CMB-09-0031. If it doesn't have PCV then you would need CMB-09-0030. These kits come with MLS head gaskets, valley plate, non-DOD lifters and guides, head bolts, water pump gaskets, and a harmonic balancer bolt.
11-26-2019, 07:39 PM
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Thank you for clarifying.
Oversize hypereutectic pistons are the route for you. Before buying the pistons you should have the bores checked to make sure what shape they are in. If this was a running "pull out" engine then .010 in. will likely be the ticket. We have those from Speed-Pro part number SLP-H1132CPA25MM. If you felt the need to go with .020 in. over those would be Speed-Pro SLP-H1132CPA50MM. Make sure to have the pistons in hand before boring.
For the camshaft, we would recommend our Summit Pro LS Truck stage 1 hi-lift. That is part number SUM-8719. We recommend the LS6 springs NAL-12499224 and Summit SME-143008 valve seals. The BTR stage 2 version 2 would also be a good option. That would be part number BTC-BTR31218110. The recommended springs for that cam would be BTC-SP011-16. The recommended valve seals would be BTC-VS-LSHAT-KIT.
Both of these cams will provide increased torque down low and good mid-range and top-end power. They will both work with your stock converter and gears. These are both 3 bolt cams so you will need to swap out the cam gear to NAL-12586481. While changing the gear it would be a good idea to get an LS2 chain SME-143012.
As previously mentioned you need an AFM delete kit. If this has PCV then you would need CMB-09-0031. If it doesn't have PCV then you would need CMB-09-0030. These kits come with MLS head gaskets, valley plate, non-DOD lifters and guides, head bolts, water pump gaskets, and a harmonic balancer bolt.
Oversize hypereutectic pistons are the route for you. Before buying the pistons you should have the bores checked to make sure what shape they are in. If this was a running "pull out" engine then .010 in. will likely be the ticket. We have those from Speed-Pro part number SLP-H1132CPA25MM. If you felt the need to go with .020 in. over those would be Speed-Pro SLP-H1132CPA50MM. Make sure to have the pistons in hand before boring.
For the camshaft, we would recommend our Summit Pro LS Truck stage 1 hi-lift. That is part number SUM-8719. We recommend the LS6 springs NAL-12499224 and Summit SME-143008 valve seals. The BTR stage 2 version 2 would also be a good option. That would be part number BTC-BTR31218110. The recommended springs for that cam would be BTC-SP011-16. The recommended valve seals would be BTC-VS-LSHAT-KIT.
Both of these cams will provide increased torque down low and good mid-range and top-end power. They will both work with your stock converter and gears. These are both 3 bolt cams so you will need to swap out the cam gear to NAL-12586481. While changing the gear it would be a good idea to get an LS2 chain SME-143012.
As previously mentioned you need an AFM delete kit. If this has PCV then you would need CMB-09-0031. If it doesn't have PCV then you would need CMB-09-0030. These kits come with MLS head gaskets, valley plate, non-DOD lifters and guides, head bolts, water pump gaskets, and a harmonic balancer bolt.