I'm in the process of deciding what exactly I want to do with my next motor (fourth in 4 years) and have come to the point where I have to start anylizing the structural integrity of my block and head. I know the benefits, I build race honda's all the time and do it to every single one.

My qestion is: has anyone else on here done this yet? or even reached the point where they feel they need to?

I'm not going to let out all the details of my build yet, I'll just say this...

R&D is what I love to do, I find limits and then push past them. This is going to be a "dyno queen" build if anything, I just need a good test subject because off the shelf eagle rod/je piston combo's and cometic headgaskets just don't stand up anymore. I'm not goin for some outragious HP goals, that will hopefully only be a byproduct of what I discover in the process.


I haven't succeded to lift the head yet... but at this point a new set of pistons is cheaper than finding a new block/head when we start pushing the knock threshold.

I would like to hear some serious thoughts on the subject, I'm not a novice to engines, I am running my own performance fab shop on the side of my full time job, I worked in a race oriented machine shop for quite a few years, and have much experience dyno tuning, both engine and chassis. So the more technical info you have to share the better.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

As I understand it, typically if you're consistently blowing head gaskets or lifting the head at your current boost level, o-ringing the block won't help as much as upgrading to a 1/2" head stud over the 7/16ths bolts we get from the factory (or 7/16ths ARP's we upgrade to). They'll take additional torque with less stretch and be less inclined to stretch under heavy boost loads. With a factory metal headgasket, I don't believe the benefits of o-ringing would outweigh the benefits of a 1/2" head stud if you're approaching power levels that can consistently lift the head.

When a headgasket blows, it is almost always due to cylinder pressure overcoming the sealing capability of the pressure applied to it by the head stud or bolt. A knock event is a perfect example (though there are others, as we know). Rather than applying more pressure to a smaller area by laying wire under it, (while the clamp force applied by the stud/bolt overall is the same), i think it would make more sense to apply greater clamp load overall to offer more resistance to a cylinder overpressure event.

For the record, I don't have any experience with o-ringed 420A blocks. I have, however, seen non o-ringed blocks with overengineered headgaskets and head stud kits take a heavy nitrous backfire and bend rods instead of the headgasket letting go.

I suppose if you wanted to go completely balls out, you'd just do both, run a crazy x-beam rod, throw on a GT42R and feed it methanol.

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'95 Eclipse TurboGS (garage deco)
'95 TSi AWD (restoring a survivor)
'97 Talon ESi-T (poor impulse control)
'99 Eclipse RS-T (daily beater)
'13 Evo X (mostly stock)
'17 Sienna (Middle Aged Dad Mobile)



Factory Service Manuals: http://nawdu.de/files/

I have been thinking about the oversized headstuds, we do it to the B series blocks that come out of our shop if they're intended to make more than 600 HP at the wheels. searched on here for a while and decided to call arp when I get home and talk to them about it. Thanks for the input but I am well aware of the causes of blown headgaskets. Timing killed one so far, 50 HP wet shot of nitrous killed another. The nitrous spooled the 60-1 so hard that we basically didn't have enough fuel to support the amount of boost at such a low rpm because the car had never done that before. our educated guesses weren't close enough to survive the incident and detonation wipped out the HG and snapped a rod. blocked survived it amazingly but the head had a .25 inch wide gouge burned into it where the HG let loose and nevermind what the piston did when it crashed to a halt on my valves... The other two motors I've had in the car where destroyed by other causes but I was able to salvage those.


Do you have any info on wich 1/2 inch studs are used? or are hey special order? I did search the subject extensively the last couple of nights but haven't found to many answers to my questions yet. Mostly I found ?'s pertaining to the use of the stock fittig replacements.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

when i was looking to do the 1/2 for the head and bedplate, i called ARP and told them that i was intrested in the same specs as there 420A kit but i needed them in 1/2 instead. now i've decided to go with a 2.4 so i need to call them back again to make sure it's still the same.

i figured they could cross reference their inventory and figure out what i needed instead of me combing their ctalog and trying to figure it out. needless to say it was a custom order, but i dont think it was a custom fabrication, but its still ARP so id still pay for it

i also figured id let the machinist figure out the overdrilling and thread cutting from the parts i got.

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"Don't fear the weapon, fear the soul of the warrior using it."
"My CEL only goes off when i remove my battery."

Best sum up of working on a 2GNT
DR1665- "#5. Spike that motherfucker on the garage floor and grab a beer. You deserve it."


Ahhhh Priceless . . .
eclipse982nrRST "its actually lightish red"
RoninEclipse2G "yeah, they already have a color for that... it's called PINK"

I know DCR makes 1/2" head stud kits for the srt-4, but I have absolutely no idea if that would work on a 420a.

96' eclipse gs, 2gb conversion
built bottom end, crane #16 cams, hx40 pro billet, MS1 v3 MSn'S-E, 3.55 trans, quaife lsd

I o-ring'd mine and used a custom made-to-order solid copper gasket($75) ( .040). Did 28 lbs of boost with no problems. You do have to make sure the head is true, cuz water has a way of getting to places you don't want.

Sleeve the bitch. Last time i checked, it was only $80 per sleeve at your average machine shop.

That's how much my buddies shop charged him to do one sleeve (piston blew up bad and hosed the bore) in his 327.

Goodnight sweetheart...yes its time to go...bum bum bum bum bum...good night sweetheart yes I am one little a$$hole......bum bum bum bum....

why sleeve a block that is just fine?
too many minuses for me to do that on a whim
you definitaly need a good machinist to pull this off for a high boost race engine
if you dont get the proper interference fit of the sleve or dont get a good seal (or air pocket gaps) with your anarobic sealent then you could introduce coolent leakeges arond the HG.
plus if you take away too much of the origional cylinder bore, a portion of the deck's integrity is also lost, in relation to the head bolts' clamping ability, plus you have to worry about adjacent cylinder distortion especially if you use a good pressing to keep the deck sealing nice

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______________________________________
"Don't fear the weapon, fear the soul of the warrior using it."
"My CEL only goes off when i remove my battery."

Best sum up of working on a 2GNT
DR1665- "#5. Spike that motherfucker on the garage floor and grab a beer. You deserve it."


Ahhhh Priceless . . .
eclipse982nrRST "its actually lightish red"
RoninEclipse2G "yeah, they already have a color for that... it's called PINK"

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!