Headgasket

[98gsxtuner]

Yes I did search but....I want to know if the oem 4 layer headgasket will withstand 25 psi with arp headstuds. I was gunna go with cometic but after reading sum threads thats not the way i want to go for the simple reason of resurfacing the head and block.

 

[420a-t]

Yes. Research some on different headgaskets. I'm planning on 30+ psi and I chose a stock headgasket with some arp's. If you're not planning on running more than 25psi, there's no need to buy an expensive headgasket and pay to resurface both the head and block (if needed).

 

[kottyking]

You should be fine, the head studs are the weaker point and you replace those so you should be good.

 

[98gsxtuner]

Thanks for the reply guys.

 

[me612]

I'm at 35psi, over 500hp, and I'm still running an OEM composite gasket with standard ARP's. It's not just the gasket, but the gasket / fastener combo. ARP studs and an OEM composite gasket go a long way. L19's if you're really going to be pushing a lot of power.

 

[95GSXCO]

Yeah I wouldn't worry that much about the gasket its more the studs. I have seen guys push the plain old fel pro HG alot farther then I would have ever taken one. Just make sure you install your studs correct.

 

[nlzn]

ARPs + OE MLS has been holding great for me

 

[94hipsitsi]

me612, how do you not push coolant between the amount of boost you are running and the higher timing from using E85? Is your block or head ringed? I'm on a stock head gasket, that I replaced 3000 miles ago, and ARP head studs as well. I'm boosting 26psi and seem to push coolant if I run 23* plus timing on the top end. New head gasket because I was definitely pushing coolant with the original head gasket.

 

[ed_dogg23]

Im running 30 psi on studs and a cheap felpro. I tryed an ICS titan with the orings and it leaked right away, and yes I re-torqed the head. I think the head surface was not perfect so I just used the composit felpro and its holding and sealing fine.

 

[turboglenn]

I've pegged my 30psi boost guage when my line came of my EBC the other day ( I'm guessing i hit at least 35-40psi or so) and i run a stock style felpro head gasket with ARP studs. I almost went MLS but when thinking about it after talking to some guys at MAPerformance i decided to keep a composite gasket as a purpose "weak link" under the question of what would you rather have let loose... a piston being damaged or a blown head gasket.. I chose the gasket

I also decided against' MLS because my head and block are both virgin in terms of the gasket surface (neither has been machined) and I was told that unless they were machined i would loose some compression ratio as well and i was shooting for a solid 9:1 or better

 

[me612]

me612, how do you not push coolant between the amount of boost you are running and the higher timing from using E85? Is your block or head ringed? I'm on a stock head gasket, that I replaced 3000 miles ago, and ARP head studs as well. I'm boosting 26psi and seem to push coolant if I run 23* plus timing on the top end. New head gasket because I was definitely pushing coolant with the original head gasket.

23* of timing? That alone must be building up quite a bit of pressure in your cylinders.

While I was street tuning, I had my timing set to 20*. On the dyno, we backed the timing down to 17* and hardly saw a power loss, so we left it at the safer level of 17*. For my personal application, I saw no use in running more timing when all I saw were extremely minor gains. My goal wasn't max power. My goal was to find a good compramise between good power and safe power.

Have you put your car on a dyno and verified that you are seeing noticable & worthwhile gains by running that much timing?

Next season I am considering picking up a set of L19's to replace my standard ARP's, but I have no intentions as of right now, to run anything other then the OEM composite HG.

 

[turboglenn]

I"m right there with me612 on timing ( i wish on HP ) But on 2 motors in the last year, this newest on being 9:1 compression. I am running 23 - 25* of timing in the top end and about 18-19 at the very onset of full boost and around peak torque then working up in 500 RPM increments to the25.. and actually i could get away with more up top but am staying conservative with it becuase i'm happy with the power. I do need to bring the timing down under the light boost 3k - 4k RPM range because that's where I see the only knock on E85. This is also tuned at 27 psi (just been to lazy to get all the way to 30 because of the plugs needing changed and re-gapped )

Anyway, a stock headgasket will hold a LOT with good fasteners when torques correctly as long as you start with nice smoothgasket surfaces on both the head and the block and one thing i can say to NEVER DO.. is to use a "whizer wheel" air tool with the scotch brite style pads to clean up the gasket surface. iv'e seen a lot of people F^%k their heads and even blocks up with those... Use onlygasket remover spray and a razor blade by hand IMO. That could be your issue if this is recurring and the surfaces were fine when you pulled it apart and they weren't machined (boy that's a lof of "ifs'' )

hope ya figure it out bud

 

[me612]

Man you guys run a lot of timing. Different strokes for different folks, but I like leaving a good safety margin considering my car is driven every day it's nice out, not track or competition only.

E85 is excellent in preventing knock, but IMO that doesn't mean just keep adding timing until you see knock. You're cylinder pressure's gotta be getting pretty high.

 

[94hipsitsi]

Thanks for the replys me612 and turboglenn. To the OP, sorry if this feels like a hijack but you'll find yourself in the same situation some day, you own a DSM. hahaha. To answer some questions though, yes 25 psi with less than 21* on a stock head gasket and ARPs are fine. me612, my timing at 25* on the top end, is not by design. I was actually running 850s on E85/93 mix to control my timing and avoid pushing coolant. Sure, 120% IDC but I only had 19-20* on the top end and no pushing coolant. I decided to get a chip to control part throttle knock and went with 1150s. Timing jumped to 25* on the top end which I was afraid was going to happen. Now pushing coolant. I tune myself and have never been on the dyno. The butt dyno does not seem to show any power difference so I am having a chip made for lower timing on the top end. Turboglenn, that may be some good advice with not using the ScotchBrite bristles. That is what I used when I replaced my headgasket. I used green for the block and yellow then white for the head. I didnt have any gasket to really clean up though, just gasket imprint. Fortunately no damage so not really sure how you can boost 30 and have 25* without lifting the head or push coolant but that almost seems out the norm.

 

[turboglenn]

Man you guys run a lot of timing. Different strokes for different folks, but I like leaving a good safety margin considering my car is driven every day it's nice out, not track or competition only.

E85 is excellent in preventing knock, but IMO that doesn't mean just keep adding timing until you see knock. You're cylinder pressure's gotta be getting pretty high.

There's really no knock at all in the upper RPM's, it's the lower areas under 4500/5k RPM that needs backed down a little on my car, and it's mostly due to the 9:1 pistons i'm sure.

Thanks for the replys me612 and turboglenn. To the OP, sorry if this feels like a hijack but you'll find yourself in the same situation some day, you own a DSM. hahaha. To answer some questions though, yes 25 psi with less than 21* on a stock head gasket and ARPs are fine. me612, my timing at 25* on the top end, is not by design. I was actually running 850s on E85/93 mix to control my timing and avoid pushing coolant. Sure, 120% IDC but I only had 19-20* on the top end and no pushing coolant. I decided to get a chip to control part throttle knock and went with 1150s. Timing jumped to 25* on the top end which I was afraid was going to happen. Now pushing coolant. I tune myself and have never been on the dyno. The butt dyno does not seem to Turboglenn, that may be some good advice with not using the ScotchBrite bristles. That is what I used when I replaced my headgasket. I used green for the block and yellow then white for the head. I didnt have any gasket to really clean up though, just gasket imprint. Fortunately no damage so not really sure how you can boost 30 and have 25* without lifting the head or push coolant but that almost seems out the norm.

I learned that from an older guy at a dealership i worked at when i was in my early 20's. I was using one on a nissan sentra block and he freaked out on me (freaked out in a friendly way) then showed me on a trashed block how easily they will pull material from the thin areas between the cylinders especially. Withing just a few seconds of removing a little bit of stubborn gasket, the wheel ate away enough metal to show light through a straight edge. I have since banned them from all gasket surfaces at my place and in my work. They strip paint, rust, and do first stage polish work great! But no longer for gaskets...

If you haven't seen it, buy the Permatex Gasket Remover (in the green spray can), spray that on, let it sit a minute or two then just scrape with a razor blade at a 90* angle to the surface.. you don't even have to try and get under the gasket, it jsut falls apart nicely (it will burn your skin FAST though so wear gloves)

 

[me612]

What I was getting at is E85 does an excellent job of preventing knock. But in my experience, that doesn't mean you just simply keep adding more timing simply because you aren't knocking. With E85, since it's so good at preventing knock, it allows you to run a LOT of timing. That doesn't mean you should though, in my experience. Adding timing increases the pressure you're creating inside your cylinder. Add enough timing, build up enough pressure, and you're exposing yourself to the possibility of running into some bigger issues (cracked block).

 

[94hipsitsi]

me612, just for reference sake, what does your timing curve look like? The chip that I am replacing is currently programmed at wot for -
4000 - 18
4500 - 18
5000 - 19
5500 - 21
6000 - 23
6500 - 24
7000+ - 24

 

[me612]

Mines more like this:

4500 - 13
5000 - 14
5500 - 14
6000 - 15
6500 - 15
7000 - 16
7500 - 17
8000 - 17

 

[94hipsitsi]

wow, me612, that's some crazy horsepower for the timing you run. good work!

 

[jrohner]

More hp = more cylinder pressure = less timing. Someone with 400-500 hp can definitely run more timing than someone with 600+.

 

[1SloColt]

More hp = more cylinder pressure = less timing. Someone with 400-500 hp can definitely run more timing than someone with 600+.

I don't really understand what you are saying here. Correct me if I'm wrong, but are you saying more horsepower is equal to running less timing? I'm just trying to follow your equation. Typically an increase in timing will increase cylinder pressure, since you've ignited the intake/fuel charge earlier in the compression stroke.

Just because someone makes 500 does not mean they can run more timing than someone that makes 600. There are a plethora of other factors that determine how much timing a motor can safely take, such as boost, airflow vs. rpm characteristics, fuel, dynamic compression, etc..

As for my setup, I'm running an OEM composite headgasket with ARP studs torqued to 110ft/lbs. My cylinder head had warpage of .003", so it was easily within spec. I currently run about 27psi on shell 93 octane with a t4 pt61. It's tuned to 11.6:1 air/fuels.
Timing map(1g):
4500: 10 deg
5000: 10 deg
5500: 10 deg
6000: 10 deg
6500: 11 deg
7000: 12 deg
7500: 13 deg
8000: 14 deg
8500: 15 deg

I may try and add a degree after 7000 rpms, but 10 degrees is about all I can run right now in the peak torque area. I might give it a couple more degrees after 8k, but this timing map is on the edge of running 1 or 2 counts of knock for my stock 6 bolt.