Twins with Twins, Anyone?

[kidturbo]

You can cut the o-rings in the heads. Just a 5 mil bump makes a hell of a difference.

You can check the coolant flow balance, left and right, by measuring flow on the outlet side of each head. Don't even need to run the engine, just the pump.

Cooling balance inside the head is a bit more complicated...

I picked up a good straight edge and feeler set from a machine shop buddy tonight to check the deck. Started pulling studs, and noticed many of them siezed to where a 3/8 dewalt impact won't break em loose. Gonna have to double nut em.. And that causes some concern.

On the flow direction, what's your thoghts on it ? know GM has been back and forth over the years. Positive side is cools the hottest spots first. Negative side as I've read, it doesn't handle air bubbles in the system well. But running Evans removes that issue best I can tell.

Buddy who loaned me the straight edge told me about this o-ring tool. Preferably we do the block, correct?

https://www.jegs.com/i/Isky-Racing-Cams/609/200GRM/10002/-1

 

[kidturbo]

how's the spray pattern of the injectors on the offending cylinders.espaecially the stream thats squirts to the thin section of the bore betw. cylinders.if it gets to hot on the thin area it will get to hot and fail there,
use to see this on our drag car,600 shot of nos fine,700 and above,,kaboom.

Those 2 holes got washed down with coolant pretty good on that last run. Soot layer didn't have much spray pattern to examine, looking back at the pics. Polishing those piston tops seems to work well at keeping soot from sticking actually.

 

[MarkBroviak]

We do the block so that the heads remain serviceable but like Jon said, you can ring the heads in a situation like yours where you don't want to pull it all the way apart. Polishing the piston tops is allows a great idea in my book as it tends to keep the pistons cooler. Your gasket part numbers that you need to use is #54597 and #54598 from Victor-Reinz(Mahle wave stoppers is the same part#, same gasket), do NOT buy gaskets from GM as they only sell the junk lml gaskets no matter what you order them for...

 

[ikeG]

We ran o ringed heads with only arp2000s for a few years, without issue. No combustion leak specifically, I should specify. Filled block & solid heads.

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[kidturbo]

Found these laying under desk where I'd stashed for later reference, after replacing both sets years ago.

The used gaskets shown, are obviously the GM LML version we replaced. So we know for certain happy child is running "Mahle Origional" C's 54585

What I don't know for certain, what just pulled from Problem Child. When we changed the heads in the boat 2 summers back, I thought we used the latest wave-stopper 97 version. Hopefully it's on the gaskets.

If ya check Summit specs, the compressed thickness is .080 on the 54597 vs .040 on a 54585. Same with volume cc. And both listed as a C grade. Interesting

Tks Mark

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[kidturbo]

Ok with a specialty wrench from The Ridge Tool Co, all studs removed. Couple of them were 35ftlb or so.. Not what I expected, but is what it is.

Glad to say the deck seems straight. Or at least under a 002in feeler range on a common steel straight edge bar. Corner to Corner, top to bottom, see no issues.

The head however, shows a .010 dip in the middle... just cleaned it quick with same razor blade as the block.

As for the gaskets, the crush ring stack around the cyl edge left nice matching ring groves in the heads. Fairly deep. So she was sealed up fairly well at one point..

That's what I know for the weekend. Heading to the bar, then off to deer camp

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[LBZ]

Ha. Specialty tool.

 

[Fingers]

I picked up a good straight edge and feeler set from a machine shop buddy tonight to check the deck. Started pulling studs, and noticed many of them siezed to where a 3/8 dewalt impact won't break em loose. Gonna have to double nut em.. And that causes some concern.

On the flow direction, what's your thoghts on it ? know GM has been back and forth over the years. Positive side is cools the hottest spots first. Negative side as I've read, it doesn't handle air bubbles in the system well. But running Evans removes that issue best I can tell.

Buddy who loaned me the straight edge told me about this o-ring tool. Preferably we do the block, correct?

The air bubbles come from the head being the high spot in the system without a vent there to bleed them out. You have to vacuum purge to get rid of the bubbles. I see no real advantage on a Dmax.

Ringing the block is traditional, and easier to some extent because you have the bore for reference. But, the head works just as well.

Most people use a wire fitted into the groove, but I prefer a copper seal ring.

 

[darkness]

Most people use a wire fitted into the groove, but I prefer a copper seal ring.

softer metal for a better crush?

 

[DAVe3283]

I just pulled the heads on my Suburban, and had the ARP studs stuck like you found. Same when I did the heads on my truck last. I tried double nuts but it ripped the threads off the stud before it came loose, so on the truck I did the same thing as you (but with vice grips).

This last week on the Suburban I tried something new. Installed a nut upside down on the stud so it was just taller than the stud, then beat the piss out of it with a hammer. They backed out just fine after that, for the most part.

The part that annoys me is the ARP studs seem to lose to any Allen wrench I use, round out super easily, and are just softer than IMO they should be. I've roached half a dozen ARP studs across my two engines in the last few years prior to this trick of beating on them. Next LB7 I build is getting Xotic head studs to see if cheap Chinese junk is actually any worse than ARP. I bet it is just as mediocre, but for half the cost...

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[kidturbo]

Yeah I had one that wasn't responding well to the pipe wrench technique. And luckily my buddy had a whole drawer full of variable sizes. The #10 version worked well for all the rest. But on the last one, I hit it with the impact gun on the allen head while torquing on the wrench and it finally popped free. Guess I'll go buy a stud puller, after 40yrs mastering the double nut technique.. lol

IMO, they shouldn't ever be that tight on disassembly. That's just not how studs are designed to seat correctly. Why clean, lube, and then install and back off, or finger wrench tighten each stud depending on your preference, if they are just gonna randomly turn in and bottom out that hard upon final torquing??

Gotta do some more reading on this, cause half those nuts were loose to me, and head has a nice warp in it. Maybe that half of the block is getting hot as Jon believes.. We will find it, cause according to the ring grooves in the heads, they were dang tight at once.. I'll run a torque wrench on the other engine before I start to crack it open...

 

[kidturbo]

Checked the other side deck and head. Deck is also under .002 and head looks to be about .005 in the middle. Drops to around .003 as ya move up towards long edges.

Studs over there all about the same, hit or miss. Half required the specialty tool. So we can deduct a few things from that I guess..

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[Chevy1925]

It won’t matter the brand, they will all bottom out into the threaded hole. I believe the only point is to allow the stud to move a touch so the head can slide down the studs easier. When they get cranked in tight, they are not perfectly 90* to the block surface and can make lining the studs up to the heads a bitch.

I ran A1 H11 studs in my old truck and it still has them. They have 7 or 8 torque cycles on them at this point and been in 3 different blocks. They were never a bitch to get out but every single one would bottom out into the block as I torqued the top nut to spec. I liked that they were were speced to 150ft lbs but I feel they were the demise to the OG LLY heads I ran. They were bad ass studs, wish the company didn’t go under.

I’ve done other engines with 2000’s prior to my own block issue. They all bottom out into the block as I torque. I hate that damn feeling of torque building then letting loose becuase the stud turned (ptsd of when my block let loose and blew a chunk out lol) so I finger tighten the studs all the way down or lightly with an allen after the heads on (all hole bottom tapped and cleaned prior). I go as far as making sure the studs are damn near the same height after bottoming out with a caliper juuuuust to make sure there ain’t an issue under them lol.

 

[1FastBrick]

I still think there is something going on with that block. I wonder how it would look on a decking machine?

 

[kidturbo]

I'm with ya James on the trying to set all the same at start. No matter what your approach. Personally, old school back em out a 1/4 turn. Others say lightly tighten with allen wrench. So long as all are done the same, torque values should be equal.

When I put the exhaust studs into these heads, I double nutted them, and purposely cranked em down into the threads at 30-40lbs so they wouldn't back out when removing the nuts. The fit is so tight we had to custom cut the studs, and order special acorn nuts to clear. If just a couple studs back out, ya can't get the nuts off, and would likely require a cut off wheel to remove these tubular manifolds. Originally designed for Wagler heads with larger ports, and it takes 3 custom modified wrenches just to R&R the manifolds. Hope I still have those wrenches.. lol

Back to the block and heads. Last thing to do is look for a crack in the block. Gonna be a little tricky to magnaflux the deck with bottom end fully loaded. But gonna give it a try just to be certain. I once had a Cleveland block that cracked between two cylinders, and didn't show up till it got good and warm. Was betting on same situation here, and only reason I fed it a couple bottles of goo to see if it sealed up..

But speaking of heat, and thinking back, this engine has seen 240F a few times prior to these gaskets failing. Once a couple years back when we plugged a sea strainer coming out of a channel. Then again right after the CP3 failure, the coolant reservoir tank bolts came loose and dumped all the coolant while cruising. Then when the Port turbo let go, we ran aground again and plugged the Stbd sea strainer. I may have idled it at 220-230F for a a little bit that day trying make it into the boat ramp on one engine. Like a half hour or so. Almost forgot that one...

Because we was always running that Evans, it never once boiled over. So lets just say a couple times she was pretty warm.. Then last trip out at LOTTO, on regular coolant, and well after the fact IMO, she went off like a tea kettle when I shut her down. As where the Port engine has yet to ever see 230F on the gauge. Could be onto something.

 

[PureHybrid]

x2 on the bottom tapping like James said, and ideally if you're going to bottom a stud into a hole the last 3 or 4 threads should be missing

 

[Fingers]

I guess I do Studs differently that some/most of you.

• Clean holes. No oil.
• Blue Loc-Tite.
• Run them down and then back off at least 1/4 turn.
• Put an orientation mark on the top of the stud.
• All studs should be the same height.
• Put the head on and hand tighten all the nuts while making sure the stud does not turn.
• Let Loc-Tite cure over night.
• Remove the head and clean up any excess Loc-Tite.
• Now assemble as normal. Check the orientation mark after torque passes.

The Loc-Tite willl keep moisture off the threads, Keep the studs from turning, and is easily free up with a little heat to the stud.

 

[Fingers]

softer metal for a better crush?

More consistent squeeze and there are no gaps when using seal rings. Wire always has a gap.

 

[1FastBrick]

More consistent squeeze and there are no gaps when using seal rings. Wire always has a gap.

Are these custom made per application or is there some where they can be ordered in traditional sizes?

 

[Chevy1925]

I guess I do Studs differently that some/most of you.

• Clean holes. No oil.
• Blue Loc-Tite.
• Run them down and then back off at least 1/4 turn.
• Put an orientation mark on the top of the stud.
• All studs should be the same height.
• Put the head on and hand tighten all the nuts while making sure the stud does not turn.
• Let Loc-Tite cure over night.
• Remove the head and clean up any excess Loc-Tite.
• Now assemble as normal. Check the orientation mark after torque passes.

The Loc-Tite willl keep moisture off the threads, Keep the studs from turning, and is easily free up with a little heat to the stud.

you've never had the loc-tite let loose and still let the stud turn? is that only on the 2000's ore have you tried it on something like the 625s or different studs that can hold higher torque?