Bill

I now am a member of the blown head gasket club.

My head and intake now reside in a plywood crate ready for shipping. I want to have the head o-ringed. I also want the head and intake ported.

I am looking for recomendations from you guys as to who I should have do this work.

I spoke to Powerhaus in Ariz. They extrude hone the intake manifold and hand port the intakes in the head to match. They said that they do not open the runners up larger than the stock gaskets. They also clean up the area in the exhaust ports that are not ceramic coated.

They charge $1,700 for the porting, o-ring and gasket set. They also recomended getting a larger throttle body.

Has anyone had experience with Powerhaus. Good/Bad? Any suggestions on other shops?

While out, I am also going to have my exhaust manifold ceramic coated at Swain Tech (as recomended by Geo, George Roffe)

Konstantin

save your money and buy a bigger Turbo or a wastegate or a maf or chips or something else
you just waste your money with head polishing and intake manifold honing etc. It makes almost zero extra HP
I do not know of a single 951 that show HP gain from a Powerhouse head.

Konstantin

Dave E

If you do have to port the head, I would go to John Milledge, or at least give him a call or email and get some advice from one of the best.

white 944 turbo

You will get no power with that head and I am living proof. I agree go to JME or someone that knows how to make power with the 951 head.

Steve Lavigne

Bill, that sucks.

I assume that along with this head, you are going to get an aftermarket engine management system and wideband lambda sensor so you can keep your new better flowing head happy and detonation free.

TonyG

Don't bother. "O" ring the head, get a good 5 angle valve grind, replace the seals and the guides, and any valves if necessary.

Do not surface the head unless absolutely necessary because this will raise the compession.. which is NOT what you want to do.

You could port the intake, extrude the intake manifold, and bore out the throttle body... but unless you have the exhaust ports done (which you can't on a turbo head), install a good aftermarket cam, go to a this and go to a that...(you get the point...) YOU WILL SEE NO MORE THAN MAYBE A 5HP+ INCREASE. WOW!!!

rcldesign

Its all about the 16V ... <img border="0" title="" alt="[Wink]" src="wink.gif" />

Bill

Thanks for the good advise guys!

I guess I will just have the head o-ringed and do the valve job. You guys just saved me a $1000 bill.

Can any of you recommend a good machine shop that can do this work. If I remember correctly, Garrity no longer is in business.

Konstantin,

Thanks for the advise.

I have a Garrett ball bearing turbo with K26 hot side and T04e compressor, that I got from SFR. Guru 65lb injectors. Tial 46mm wastegate. SFR ss exhaust/test pipe. MAF. Guru chips. ARCII. Apexi AVCR.

Steve,

Yeah, stand alone would be nice. I am waiting for Danno to come out with his plug and play stand alone system.

TonyG,

Is a wide fire head gasket a worthy upgrade? I know that if the head needs to be surfaced, the Factory make a thicker head gasket to compensate. I do not think that it has the wide sealing rings though.

Danno

"Is a wide fire head gasket a worthy upgrade? I know that if the head needs to be surfaced, the Factory make a thicker head gasket to compensate. I do not think that it has the wide sealing rings though."

How about one of these headgaskets?

<img src="http://www.gururacing.net/images/Headgasket1.jpg" alt=" - " />

From the study of failures presented in my <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=002511" target="_blank">headgasket dissertation</a>, I've found most of the failed compression rings where still perfectly circular (both standard & widefire). But their surfaces facing the combustion chamber had been burned away. Since this was only a 0.1mm thick steel layer in both standard & widefire gaskets, once this was burned way, combustion pressure was free to burn through the fibre in between the top & bottom layers of the compression ring and... pfffsstt, one blown headgasket. This is especially evident on the widefire gasket where the majority of the 'wide' part was still perfectly intact, yet the part facing the chamber had been completely burned away and the fibre core blown out.

Adding an O-ring with double-grooving helps provide a secondary barrier when the first layer of the compression ring fails. I wanted to find something easier and even more durable:

<img src="http://www.gururacing.net/images/Headgasket3.jpg" alt=" - " />

I found a supplier to make these all-metal headgaskets. It is comprized of two strong spring-steel top & bottom layers with compression ridges molded to contour to around all the sealing surfaces. A plain steel middle layer is used to build up the proper thickness.

<img src="http://www.gururacing.net/images/Headgasket2.jpg" alt=" - " />

So you get all the benefits of a solid-copper headgasket with none of the headaches:</font>

• <font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">all-metal construction is much stronger than thin compression-ring & fibre gaskets</font></li>
• <font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">solid metal layers conducts heat away from hot surface much faster than thin compression-rings (with fibre insulating core), similar to copper headgasket</font></li>
• <font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">spring compressibility is more tolerant of block & deck mismatches (no milling of head & deck required like with copper headgaskets)</font></li>
• <font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">available in standard 100mm sizes and 106mm for 2.5L blocks from Anderson Motorworks</font></li>

<font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">To complete the package, we'll be coming out with a set of high-strength head studs as well. Made of super-strong alloy throughout, unlike the coated plain-steel studs sold through a popular brand-name. These will also feature metric threads and metric nuts.
I'll update our website with this new product and better photos over the weekend...

Bill, don't worry about having to mill your head & deck. Check them for flatness first then mill as necessary. Powerhaus & Milledge tend to mill off 0.040" for 8.3:1 compression. I've done 0.060" for 8.5:1 compression without any problems, although I did have extra valve-clearance cut into the pistons. This will lower your max-boost potential from 25psi down to 20psi on street gas. But unless you plan on running that high of boost, the extra compression will be fine and will give you better low-end torque when you're off-boost anyway. Will also reduce turbo-lag as well.

Duke

Danno&gt;&gt; I'm just about to get my head reworked with new stems&guides etc. it's also going to be slightly milled for perfect flatness. I'll never run more 20psi, do you think it's safe to use the ordinary 1,1mm gasket?
I was going to order the 1,4mm but if the increased compression with the 1,1mm gasket is safe for up to about 1,3-1,4 bar I'll use the ordinary one!

Thanks for any ideas
Gustaf

NerfRacing

i blew my stock head gasket accidentally running 20 psi. ive heard the stock head is safe everyday to 15 - 16 psi though.

dmoffitt

man i wish you'd had that about 2 weeks ago... oh well, next time (darned 951s, i'm sure there will be... a next time...)

btw i'm happy w/ my head (stage2) from lindsey racing. i bet they could do a like stage 1.5 (the valve job and o-ring but not port/polish) if you asked... call dave or mike and see

white 944 turbo

Danno,
To my knowledge the copper gasket is good once the car heats up. When the car is cold the copper gasket is prone to leak. If this is true will your new gasket have the same problem? Also, is it really possible to run up to 25 psi on pump gas? Lastly, you never emailed me those dyno sheets explaining the chip comparison showing the superiority of your chips compared to the APE and the turbo cup.

Konstantin

I raced 25 PSI and teh rings were still ok. I had to take out the ehad after 13 years sinc ethe fibre was coroded and rusted from the water. The head was lifted in the second cylinder and alowed teh gas blow by and go to the cooling system.
I think if teh ignition timing and fuel is right you can run high boost if you have something like ARM head studs. the OEM are not strong enough

Konstantin
PS danno, the original head gasket for the 100 mm block is 102 mm wide. so you will ned a 102 mm for the 100mm Bore and 106 for the 104 mm block. If JA makes a 106 mm block then you will ned 108 mm if I am not mistaken

Danno

"I'm just about to get my head reworked with new stems&guides etc. it's also going to be slightly milled for perfect flatness. I'll never run more 20psi, do you think it's safe to use the ordinary 1,1mm gasket?"

It depends upon how much you have to mill the head to get a flat surface. First make sure the head hasn't been milled earlier. Do this by measuring the L-shaped protruding marks at the ends of the block. Then index the milling on the flat squish zones next to the spark plugs. This will ensure your head is lying flat just in case the previous person milled it at an angle. If you have to mill off 1,0mm or less, then it should be fine with the standard headgasket for 8.3:1 compression. I wouldn't do the 1,5mm milling that I used for my car unless you have new springs, hydraulic valve-adjusters and some extra clearance cut into the pistons.

"To my knowledge the copper gasket is good once the car heats up. When the car is cold the copper gasket is prone to leak."

Yup, this problem is because the copper gasket doesn't expand and contract very much. And it's not compressible like the stock gasket so there's less spring tension in the gasket. Thus the looseness when cold and it's really the expansion of the head and block around it that provides the additional clamping when things are warmed up (studs don't expand much either).

Our headgasket is more 'springy' using rolled steel like the original gasket, but just more of it! So it will be more like the stock gasket in sealing behavior with the copper gasket's durability and toughness against heat and detonation.

"Also, is it really possible to run up to 25 psi on pump gas?"

Yup, but one quick clarification. Boost is a measure of the restrictions to flow you have in the system. However it's flow-rates and volume of air ingested that determines your power. For example, if you put in a tiny 20mm throttle-body, you'll easily make 25psi boost, but you'll be flowing only 1/2 the amount of air as before for 1/2 the power.

So the examples I've seen of 25psi on pump-gas has been the brute force approach with leaving all the engine internals alone, stock pistons, rods, cams, heads, etc. Thus the overall efficiency is the same. Therefore high-boost was necessary to flow the required CFM for 400rwhp. By increasing the efficiency of the engine through free-flow intakes, larger throttle-bodies, larger valves with P&P head, cams, efficient turbos, etc you can flow the same amount of air at a lower boost level. So 400rwhp @ 25psi or 20psi will still put the same amount of air into your engine and you have to manage the intense heat and combustion pressures that creates.

"Lastly, you never emailed me those dyno sheets explaining the chip comparison showing the superiority of your chips compared to the APE and the turbo cup. "

Well, I wasn't going to give away all of our secrets. Just demonstrating how the APE chips' maps are what causes the tuning headaches with air-fuel mixtures that are way too rich in the mid-range and lean up top. I sent you a reply to take a look at the comparison chart here: <a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=18;t=003592" target="_blank">How to set the MAF kit for adjusting base idle?</a>