6.2L Winter Refresh

[SpareParts]

I had some piston slap on start up but went away pretty fast, but 1 was slapping even hot very slightly.

Here are some valve pics. All valves look like the pics

 

[j91z28d1]

I can only guess the exhaust valves look that way from burning oil thru the pvc?

I'm pretty much convinced that dexso oil is such a hard spec to hit, because it's gotta be oil that can be burned by the qt thru the intake and not foul out the cats for atleast 100k miles like old school oil would if it burned as much thru the old school pvc valves. seems once the oems when to this full bore pvc setups everything eats oil stock. the di engines are nightmares because of it on the intake valves.

 

[SpareParts]

I could be wrong, but to me the valves indicate a healthy running cylinder. Maybe slightly lean though.

 

[j91z28d1]

I was thinking it looked like the white fluffy build up on spark plugs when they burn oil. maybe not thou.

 

[SpareParts]

Thanks to Amazon now delivering on Sunday i was able to measure the block.
Looks like the bottom measures 4.065 and the top measures 4.068 at the largest point i can find.

 

[SpareParts]

Decided to take the block to the machine shop today.
He said .020 was pretty much the standard overbore and he had to deck it to get a good hone.
He will deck it. Bore it .020 over and torque plane hone it. He will order pistons/rings and pins. Rough estimate is between $900 and 1K and will take about a month as he is busy, so need to wait my turn.
Not much gonna happen till after Christmas i believe.

 

[SpareParts]

Anyone happen to know what a stock STD size piston weighs?

 

[SpareParts]

Machine shop called and said pistons will be in next week and my block will be done the week of Christmas.
Trying to keep as budget as possible, i wanted to weigh the rods.

After a day and a half of watching videos and trying to build something that would give me repeatable results i could trust with stuff i already had in the garage i got it done
Used a piece of aluminum strap, angle iron, a quad transmission bearing and an OS 1.20 engine bearing. The part hanging from the ceiling is a hanger and another OS engine bearing.
Seems to work pretty good after i got it figured out and now i have the information i needed.

Now i know that between all the rods there is a 2 gram difference between the heaviest and lightest.
There is a 1.9 gram difference on the big end
And 1 gram difference on the little end.

I'm pretty sure i can get the total reciprocating weight the same.
The rotational weight im not sure if i want to mess with that.
With there being 1.9gram difference on the number 1 rod journal i just don't know if it's worth the effort on a stock engine that will never see over 5.5K rpm?

The next thing i really need to know is the weight of a stock piston. I don't want to order a $50 piston just to weigh it when i have no use for it.

 

[strutaeng]

Are you planning on getting the rotating assembly balanced?

Or are you trying to avoid that?

 

[SpareParts]

Trying to avoid it but it depends on the weight difference between stock pistons and the new pistons.
It's my understanding that replacement pistons should weigh the same as the original pistons. I just wanna make sure.

 

[SpareParts]

Was looking at my old cam yesterday and i noticed the #2 wear pattern. It's no wonder that bearing is always shot.
Measuring the left side of the groove is contacting the bearing 0.160 and the right side is 0.120
The original bearing is 0.630 in width. CH-10
The new style is 0.775, CH-25
Measuring the cam, the bearing surface is 0.755 also, with the new style bearing depending on alignment, it is 100% supported.

 

[SpareParts]

After much thinking i believe i will go with THIS cam.
Still waiting on the machine shop. Should get the block back soon now that the holidays are over with.

GPI - Low Lift VVT LS Truck Camshaft L92 / L94 / L9H / L96 / LY6 / VVT (6.2L) - Gwatney Performance

Our camshafts are our most popular product, and for good reason - they are pound for pound - the best on the market. These low lift VVT Performance Truck cams are specifically designed and engineered to take your: 2007-2013 Cadillac Escalade (L9H for MY 2009, L94 for MY 2010-2013) 2008-2009...

gwatneyperformance.com

 

[SpareParts]

Ordered the Cam, lifters and cam phaser limiter today.
Still have more to order but the list is shrinking for sure!

 

[SpareParts]

I think i'll have the block back sometime next week finally. After discussing a couple of things it sounded like he planned on next week but i actually forgot to ask.
I'll be ordering everything else to finish off the short block next week. Not much left actually.
Turned a couple old lifters in solid lifters so i can check piston to valve clearance with the new cam.
Have all the parts cleaned but will clean them 1 more time before installing.

Thinking about getting the heads rebuilt. There is almost no play in any of the guides with the valves at or near full lift. Spec is .0037 and im sure there is less than that.
All the valves lapped in with no pits but the seats are measuring a little big after lapping.
Valve seat width for intake is .050 after lapping all the imperfections out they measure .070, Exhaust spec is .070 and after lapping measure .095.
Other than the seat width heads are in good shape.
Wider seats will transfer more heat from the valve to the head. I think the biggest drawback is flow but how much it is affected on a mostly stock rebuild i don't know.

 

[SpareParts]

Forgot to mention my helper was watching my every move as usual from her favorite perch when im in the garage messing around.

 

[SpareParts]

Got my block and new pistons back from the machine shop today.
This weekend i can start measuring crank clearances. Should be good to go as the crank measures within tolerance.
Still waiting for my cam to ship.
I did leave the heads at the machine shop to get a 3 angle valve job. Stock heads have a 2 angle valve job.
I was just going to use them after lapping in the valves but the seats ended up to wide after getting all the pits out. Intake spec is .060, After lapping they measured about 0.80
The exhaust calls for .080 seat width. After lapping out the pits the seat measured about .100 so i thought it best to get the heads at least surfaced and a 3 angle valve job.

 

[SpareParts]

Little miffed at the machine shop.
Was looking over the receipt and noticed they ended up boring the block .030 over when it was supposed to be .020
Called them up to ask about this. They said supply issues with .020 pistons and .030 was all they could get They also said it would not be a problem ever as they do .030 all the time on 6.2s.
I'm thinking BS. I can order them without a problem.
I'm thinking they messed up the .020 bore and had to go to .030 to fix it and that is what took so long, who knows.

Anyway, after doing a bunch of reading .030 bore is not uncommon and doable after sonic testing. I don't know if that was done or not.
When i go back to get my heads i will for sure check them over before i accept them. I will also take the block back with me so i can make them sonic check it so i can see the numbers.
I also can't find minimum wall thickness. It is listed everyplace for 6.0s and 5.3s but not 6.2s. Maybe someone here can tell me?
The other bummer about that is I am certified in Sonic thickness testing and Eddy current NDT testing but have 0 access to the equipment.

I'm kinda stuck though as i don't have a different block and they are telling me this one is good at .030 over. I could take them to court but no guarantee i would win over something that might never be a problem as others have done it without a problem.
I also can not find any post any place i have looked of an actual failure from being bored .030 over on a stock engine running normal compression so maybe that warning is overhyped and aimed at the boosted mob?

In the meantime, i am going to continue with checking clearances and cleaning. Nothing else i can do.

 

[SpareParts]

Well now after posting i have found that .100 thickness is recommended minimum for a NA 6.2.

 

[j91z28d1]

I hate that kinda stuff. they should have atleast called and ask you before doing it.

 

[SpareParts]

Measured the mains and rods this morning. All good.
Main spec is .0008 to 0025. My largest is .0021
Rod spec is .0009 to .003. My largest is. 0023
All on the bigger side but within spec.

New pistons: 5 weigh 511 grams, 2 weigh 512 grams and 1 weighs 513 grams.
Piston pins weigh 172 grams each.

Still need to check ring end gap but i don't anticipate any problems there.