416 Conversion questions

LiqTenExp · 09-25-2022, 07:45 PM

Hey,

I'm looking at updating my rotating assembly and stepping up to 416ci displacement. I'm roughly 250-300 whp over stock. I've got almost 30k miles on my current setup.

I'm getting oil on plugs and smell a little oil after coming to a stop. I did new valve seals/springs a couple months ago and that wasn't the source of the oil. It isn't eating oil at any noticeable increased rate compared to typical for it over the years. I don't use a catch can. Some of the smell could be the Metco breather I have. Based on the plugs... is thinking the rings are getting tired @ 15 psi at those miles a good assumption? I did a compression test last year and everything was GTG, going to do one more shortly to just compare it.

I've just started to do research as I don't have much experience here. I see there are a lot of LT4 "packages" from BTR, TSP, etc. I am going to have my local shop do the work and will coordinate this with them but want to educate myself on some of the choices for connecting rods, pistons, rings, cranks, crank bearings.

Any recommendations/suggestions/comments appreciated.

JSH · 09-25-2022, 08:01 PM

Quote:

Originally Posted by LiqTenExp

Hey,

I'm looking at updating my rotating assembly and stepping up to 416ci displacement.

This must be good choice because it seems it's all Pray uses.

KingLT1 · 09-26-2022, 08:19 AM

Do the compression test and if all is good use a catch can... LT4's get quite a bit of blow by through the pcv system.

L78toLT1 · 09-26-2022, 08:38 AM

Did you check your valve guides when you replaced the springs and seals? If you're running an aftermarket cam & springs, I can't imagine your guides are in very good shape at 30k miles

LiqTenExp · 09-26-2022, 10:28 AM

I replaced the valve seals when I did the springs but not guides, I believe technically they were done around 8-9k miles when the majority of the engine work was done. I don't have any smoke on decel that I can see only accel, I should put my gopro on to confirm...

turbo_jimbo · 09-26-2022, 02:59 PM

I would do a leak down. If that's good, a catch can could fix all of this.

LiqTenExp · 09-26-2022, 04:39 PM

Quote:

Originally Posted by turbo_jimbo

I would do a leak down. If that's good, a catch can could fix all of this.

Eh, I know the car, it didn't use to do this. If anything that would be a bandaid. We shall see what the leakdown test says, will likely have time Thurs/Fri this week.

09-25-2022, 07:45 PM	#1
LiqTenExp Drives: 2017 ZL1 Join Date: Jan 2017 Location: NJ Posts: 905	416 Conversion questions Hey, I'm looking at updating my rotating assembly and stepping up to 416ci displacement. I'm roughly 250-300 whp over stock. I've got almost 30k miles on my current setup. I'm getting oil on plugs and smell a little oil after coming to a stop. I did new valve seals/springs a couple months ago and that wasn't the source of the oil. It isn't eating oil at any noticeable increased rate compared to typical for it over the years. I don't use a catch can. Some of the smell could be the Metco breather I have. Based on the plugs... is thinking the rings are getting tired @ 15 psi at those miles a good assumption? I did a compression test last year and everything was GTG, going to do one more shortly to just compare it. I've just started to do research as I don't have much experience here. I see there are a lot of LT4 "packages" from BTR, TSP, etc. I am going to have my local shop do the work and will coordinate this with them but want to educate myself on some of the choices for connecting rods, pistons, rings, cranks, crank bearings. Any recommendations/suggestions/comments appreciated. __________________ 2017 Camaro ZL1 Coupe M6 (847whp Dynojet on 93) Last edited by LiqTenExp; 09-25-2022 at 07:57 PM.

09-26-2022, 08:19 AM	#3
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,800	Do the compression test and if all is good use a catch can... LT4's get quite a bit of blow by through the pcv system. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

09-26-2022, 08:38 AM	#4
L78toLT1 Drives: Hyper Blue 2016 2SS 6M Join Date: Sep 2017 Location: North Ga Posts: 1,787	Did you check your valve guides when you replaced the springs and seals? If you're running an aftermarket cam & springs, I can't imagine your guides are in very good shape at 30k miles __________________ Baby Blue 2016 Hyper Blue 2SS/6m/MRC/NPP/Silver Rally stripes/ZL1 wheels & brakes/GForce DS and axles/ZLE Cradle Bushings/FE4 ARB front & rear/SEMA Grill/Rotofab dry/95mm TB/Magnuson 2300/Full LT4 fuel system/JMS boost-a-pump/E85 Sensor/Ported CID heads from LME/Cammotion PD cam/Thompson Motorsports forged shortblock/catted Kooks 1 7/8 headers /JRE remote tuned

09-26-2022, 10:28 AM	#5
LiqTenExp Drives: 2017 ZL1 Join Date: Jan 2017 Location: NJ Posts: 905	I replaced the valve seals when I did the springs but not guides, I believe technically they were done around 8-9k miles when the majority of the engine work was done. I don't have any smoke on decel that I can see only accel, I should put my gopro on to confirm... __________________ 2017 Camaro ZL1 Coupe M6 (847whp Dynojet on 93)

09-26-2022, 02:59 PM	#6
turbo_jimbo Drives: 2022 ZL1 1LE Join Date: Jul 2022 Location: Vegas Posts: 34	I would do a leak down. If that's good, a catch can could fix all of this.

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