6.2L Winter Refresh

[swathdiver]

GMs spec is a maximum overbore of .020".

If I remember right, bore spacing is 4.4 inches and these have siamesed bores, no water between them.

Melling sleeves are 4.3 inches OD for CSL359F.

Put in some Darton sleeves with 4.1 bores? Imagine the torque? Muahahahaa!

 

[strutaeng]

Is the "sonic wall thickness" test the same as ultrasonic wall thickness measuring NDT?

I used to have an employer that had a few of those instruments (ultrasonic) and when I went to a different employer I found a place around here called Pine Environmental that rents all kids of specialized equipment. And the rates were very reasonable IIRC. I haven't rented from them in many years though. There may be a rental place near you.

 

[SpareParts]

Yes. It is the same.
Im in a small town and would be sure there is no place to rent that.
I'll see what happens when i go back to the machine shop with my concerns.

 

[West 1]

The piston weights within 2 grams are dead on. We sold millions of pistons and the latest technology we were using stated the pistons would be within 2 grams. You are good.
Oil clearance at .21-.23 is good if running 5.30W oil. Would not run 0-20 unless the clearance was under .002.

Ring Gaps. Top Ring. .016 is safe for naturally aspirated engines unless you are running Keith Black Pistons. Keith Black places the Top Piston Ring higher on the piston and because of that they list much wider top ring gaps.
Of all the manufacturers I am aware of only Keith Black does this and needs the wider top ring. Some believe it is because the pistons in the KB series were Hyper eutectic, that is false. It is the top ring located high exposing it to more heat. More heat demands more ring gap.

Second ring. .024 works best to help the top ring seat better. The second ring could be run at .008 but that traps the blow by and makes the top ring not seat as well.
The wider second ring gap was proven to be an improvement as far back as 2005. It has been trusted since then as an improvement.
In Dyno testing engines would pick up 3-5 HP just with the wider second ring gap. 3-5 HP is not much for sure but it is an easy improvement for no cost. The OEM and Racers all adopted the new standard years ago.

If pistons are for sale for the 6.2L at .030 over it is a standard over bore for the 6.2L. The piston companies won't tool up for a piston size unless there is demand.

If Mahle or Sealed Power are offering .030 pistons I would be comfortable running them.

I have no experience with the 6.2L sonic testing so can't share any information on that.
When I left the industry we were not seeing the 6.2L in the shops yet.

 

[SpareParts]

@West 1
Im pretty sure i can get the reciprocating weight on all 8 under 1 gram difference with very little effort. Rotational weight will be two grams or less.
I measured 1 top ring and the gap was .017 I will check them all tomorrow to know for sure they are good to go.

Everyone makes .030 over pistons. Mine are Enginetech piston. Made in Mexico. Nothing tells me the real manufacturer
I would also agree that this is done regularly as all the manufactures make .030 over pistons. They all have to be selling enough to make it feasible so it must be done a lot i would think.
I'm on the fence with .030 over. A lot of posts say don't do it without sonic testing first, but i can't find a single post saying my liners cracked for being too thin on a stock rebuild.
I do see a few posts on engines that were turning 7.5k racing regularly with cracked liners and them being 6L LS. I will never turn it up like that. It will see 5.6K sometimes though.
The machine shop told me they do it regularly and never had a problem.
So i don't really know what to think.
I am inclined to just run it if the machine shop tells me what i need to hear.

 

[SpareParts]

Could not help myself and wanted it painted.

 

[SpareParts]

Got cam bearings installed today. Old cam slids in like butta! Don't have the new cam yet.

Also got rods and pistons matched.
All 8 weigh 1299 grams Reciprocating weight is even, but i don't have a scale that measures 10ths over 1000g.
Rotational weight is within 2 grams. I could get them closer but i don't really know where to take the weight off. Thought about taking off 1 or 2 mm off the bolts but i don't know if that would weaken the clamp force. I could take the weight off the sides by rounding the sharp corners but again. Is that going to weaken them.

 

[SpareParts]

Machine shop called today and my heads are done. Has them surfaced and a 3 angle valve job done. I did not have them reassemble as my new valve springs did not show up till today. I have no problem putting them together, and being apart will give me a change to give them a final cleaning before assembly.

 

[SpareParts]

Got the heads back together today. Checked all installed valve spring height. All measure 1.800 +- .005
I read within +-.020 is acceptable so mine are almost perfect.
Tomorrow i will check the ring gaps and hang the pistons.
Can't really start assembling the block as i don't have the cam yet and we all know cam first no exceptions before anything else, right.

 

[SpareParts]

Cam shipped today finally!

Ordered the BTR V2 Trunnion upgrade today also.

Got to order gaskets soon but close to $400 for them all just P1SSES me off and they don't seal any better than old Chevy gaskets

Got the ring gaps measured.
Top: .017-.018
Second: .022-023
Oil rings: .035

Pistons are all hung. All rods are back in the same cylinder they were removed from. Forgot what a PITA it can be to get the C clips in to hold the wrest pins in place.
After the first piston i took an old pair of needle nose pliers and cut groves in the end of the jaws to grab the snap ring and compress it. Way easier!

Was thinking of ordering .001 undersized bearings for the mains but before i did i wanted to remeasure so i could make sure. Used Plastigauge today. Plastigauge came out to .0015
.0009 smaller than the bore gauge showed. Certainly could be as the bore gauge i have is a cheap one, so a thou difference is possible and i almost trust Plastigauge more.
Any case it's good either way.

Got the plugs installed that block the AFM towers. Don't have to ever worry about seals failing. Seals would probably hold just fine but why take the chance.

Had two helpers in the garage for a while today.

 

[SpareParts]

Anyone know where these two bolts go?
I can not recall where they would go.

 

[j91z28d1]

look like exhaust bolts to me with that shoulder? but I can't say forsure, haven't taken one if these that far down yet.

 

[SpareParts]

Not exhaust bolts. The black part covering the threads is like plastic.

 

[mikeyss]

Anyone know where these two bolts go?
I can not recall where they would go.

View attachment 477859

Knock sensor bolts?

 

[j91z28d1]

Not exhaust bolts. The black part covering the threads is like plastic.

I got nothing

 

[SpareParts]

Me either!.
Just checked and not knock sensor bolts.

 

[mikez71]

The plastic sleeve on the bolts doesn't look completely squared off.
Did they break off of a plastic part as they were removed? (if they're stuck on the bolts good)

That said I still have no idea where...
You sure they belong to this truck?

 

[SpareParts]

That's the way they came off of whatever.
I'm pretty sure they came off this engine and i have tried to keep all the bolts/nuts that came off this engine together in one spot but then again i do have parts for 3 ls engines in the garage.
I'm pretty sure i did not put any bolts in the bin that did not belong to this engine.

 

[Fless]

SWAG: bolts to hold some kind of bracket on the block? Or tranny? (I know, probably not helpful)

 

[PatDTN]

If they looked like they were coated in oil I'd think windage tray.

Instead they look dry and chalky. They look like they're subjected to dry heat. Is there any chance those spacers are not plastic and could be exhaust manifold?