[charlie66]

I agree with you 100% on everything except that you cant fix the crushing problem in the aluminum head . I don't think its a band aide at all. I have fix it 100% . I run 35 psi everyday as a street driven car with zero problems now. I'm not trying to start anything with you, just stating a fact that I have produced by trying it.. Just don't want the people with this problem to think it cant be done/fixed....

[mgarblik]

If you have a fix that is working and would be willing to share details, I am all for learning and trying it. Never meant to say it couldn't be done. What I did was oversize the holes slightly and insert a seamless stainless steel tube into the hole. Wall thickness of the steel was only .030" . Then I used a steel step washer on the top of the hole. These repairs did help some. What did you do to solve the issue?

[charlie66]

Drilled into the head until a inch from going through . Flat drilled the bottom of the hole and inserted a steel 1/8 wall sleeve. I messed up on the back one drilled too far where it broke into one of the threaded holes for the accessories . So I had to screw a bolt in and flat drill it again. Took like 4 heat cycles till the bolts finally stopped creeping and now the bolts never move. Had the boost up to 44 psi with a Cometic 3 layer gasket.

I have a whole thread on it here.... With pictures..

Thanks for not taking offence ....

[frbformula]

Thank you all for your input. I am still about a year away from building my turbo motor as i am in the process of putting a manual trans in the car. It looks like cast heads are a good choice and one i am going to greatly consider.

A question about the aluminium heads. Even at lower boost does the bolt tower between the exhaust ports still become a problem? I am thinking it will take about 10 or less lbs to make my hp goal. Add to that i will most likely want to increase the boost because it will be addicting. So at say 15lbs is there still a concern with the bolt tower or does that issue only come up in high boost applications?

[Tom Vaught]

The Boost Guys seem to have far more issues with the center bolt boss (and other bosses) vs say a NA engine guy with normal cylinder pressure loading or a low boost level street guy. At 860 hp (using a Vortech Supercharger) and less than 14 psi of boost a basic 455 2 bolt main engine was just staring to see possible head sealing issues with a aluminum head. The conclusion, after tear-down was, the wrong bore size gasket was used in the test engine (too big of a gasket cylinder bore) vs the engine actual bore.

It might have made even more HP with the correct gasket bore size.

Tom V.

[mgarblik]

I would think careful assembly with Cometic gasket or other premium gasket, insert washers in the aluminum heads, and re-torque of the gaskets would seal fine at that power level. We really didn't start having serious gasket, head column crushing issues until we were at 1100 HP and above with Nitrous Oxide. The repair/fix Charlie described is also a nice option if you decide to make more power with aluminum heads.

[Torment]

Having built and raced power adder Pontiacs at and well above the power level desired by the OP... there is absolutely no way I wouldn't run a well prepped set of iron heads for this application. Iron head, iron block, make everything reasonably flat, straight and smooth for the MLS - no special machining required... and you're done. It'll run for years. My 2 cents.

[charlie66]

Originally Posted by frbformula

Thank you all for your input. I am still about a year away from building my turbo motor as i am in the process of putting a manual trans in the car. It looks like cast heads are a good choice and one i am going to greatly consider.

A question about the aluminium heads. Even at lower boost does the bolt tower between the exhaust ports still become a problem? I am thinking it will take about 10 or less lbs to make my hp goal. Add to that i will most likely want to increase the boost because it will be addicting. So at say 15lbs is there still a concern with the bolt tower or does that issue only come up in high boost applications?

I would says yes to your question. But not as noticeable. I ran 15 psi for a year or so before I went crazy with the higher levels and after a few months at 15 I was getting signs of it. The main sign is you will get water spraying out of the overflow of the radiator. That is when you will know for sure you need to re torque.. I only know this because of the learning curve I went through. It took me along time to actually figure this out.. For a long time I thought that it was at the limits of the head gasket. But then I started to realize the studs were losing there clamp. Then I went though a period of thinking it was the ARP studs that was going bad from the heat . At the time I had a EGT gage set up and was getting readings of 1900 degrees . So in my mind that was enough to convince me that the heat was killing the temper of the bolt. Then one day it came to me and realized the head was crushing and had to come up with a solution. after a lot of days and nights of contemplating I came up with drilling and pressing in the towers. It was one of those things were I had tried so many things and had so many different beliefs over the years of being wrong, that when I finally got it I almost didn't believe it... lol But now I have zero issues , thank god... and just so you know, I drive my car all the time and I am very hard on it....

Oh, I started out with 5 psi and then 10 psi. At those pressures I had no issues..

[taff2]

A smart company would take a set of their ali heads,get them expertly ported and then copy them in iron. Sell them as a boosted head option for the same cost as their ali head,so the company would have a good profit margin and the boost guys get what they want. Options could be o rings,CNC'd chambers
I'm at just under a 1000hp with my 96 iron heads and intend going up to around 1400hp,but it took a lot of work to get what I wanted-weeks of porting,new guides/seats cut/spring pads cut/chambers relieved/gasket surfaces ground/dry decking/o ring grooves etc etc. I went through all this because I believed an iron head would be better and more reliable for my needs. It would be nice to just be able to buy a new iron head and virtually bolt it on.

[TimeWarp]

I wonder if the CV-1 heads with convertible exhaust option will be free of this problem. Its more than just a curiosity...I just purchased Tom McQueen's IAII 555 ci engine with the CV-1's. He's decided to do an aluminum block and warp 6 heads in his GTO.

I also wonder...rather than drilling and putting an insert, what about a wider washer under the head of the bolt to spread out clamping force? Realistically would that be doing the same thing the insert is doing?

[charlie66]

Originally Posted by TimeWarp

I wonder if the CV-1 heads with convertible exhaust option will be free of this problem. Its more than just a curiosity...I just purchased Tom McQueen's IAII 555 ci engine with the CV-1's. He's decided to do an aluminum block and warp 6 heads in his GTO.

I also wonder...rather than drilling and putting an insert, what about a wider washer under the head of the bolt to spread out clamping force? Realistically would that be doing the same thing the insert is doing?

No it wouldn't. I had T-washers and all they did was get driven deeper and deeper into the head.. There's too much heat up high by the exhaust. The clamping force needs to be down low by the deck.. The middle exhaust T-washer sunk 1/4 down on my head. But I do run more boost the most being I only have 4 holes.....

[Tom Vaught]

Possible that the CV-1 head with the exhaust ports removed close to the head gasket surface might help but that is still a open question as I do not think any of them have run any real boost with that mod. Brian H ran the CV-1 heads but with the normal head configuration and a Procharger. Totally different heating deal for the head.

No real experience at all with that head by any boost guy and that mod.

Tom V.

[TimeWarp]

bankbook/doc is running boost with the cv-1 heads and convertible exhaust. Not sure how he's fared though. He doesnt post a lot. Well, I'll get some info on it by next year. The engine should be assembled with twin turbos by end of summer. The car by next year. Not that I plan to run a lot of boost anyway.

[charlie66]

Here are 2 pictures I took of the center and the end bolt holes. Center is sunk and the end even though its alone on the end it still is sinking and cracking. So I don't think it matters whether its 2 together or 1. It will still sink.... Those are T - washers sinking....

[TimeWarp]

Originally Posted by charlie66

No it wouldn't. I had T-washers and all they did was get driven deeper and deeper into the head.. There's too much heat up high by the exhaust. The clamping force needs to be down low by the deck.. The middle exhaust T-washer sunk 1/4 down on my head. But I do run more boost the most being I only have 4 holes.....

You sure do run that thing. lol But I meant a wider washer. Since you cant go wider on that end one I wonder if you can build a support for it off the bolt holes on the end of the head?

[mgarblik]

"A smart company would take a set of their ali heads,get them expertly ported and then copy them in iron. Sell them as a boosted head option for the same cost as their ali head,so the company would have a good profit margin and the boost guys get what they want. Options could be o rings,CNC'd chambers
I'm at just under a 1000hp with my 96 iron heads and intend going up to around 1400hp,but it took a lot of work to get what I wanted-weeks of porting,new guides/seats cut/spring pads cut/chambers relieved/gasket surfaces ground/dry decking/o ring grooves etc etc. I went through all this because I believed an iron head would be better and more reliable for my needs. It would be nice to just be able to buy a new iron head and virtually bolt it on."

I agree 100% with this post and have been advocating for these for at least 10 years in every way possible. Each year at the PRI show, I talk to EVERY single vendor that produces cylinder heads and pitch the idea. 25 years ago, I did the same thing when the only aftermarket Pontiac head was the Wenzler head and after 5 years of badgering from me, the Butlers, Arnie Beswick and a host of others, Edelbrock finally relented and produced the Performer RPM, fully expecting to lose money on the project. The rest is history. If enough of us keep beating on the vendors, one of them will produce some. Iron heads are the simplest, easiest way to overcome the wide spread of the 10 head bolts, the flimsy aluminum castings, and the side by side exhaust valves of a conventional Pontiac head. In addition, many non-boosted Pontiac fans may use them NA in lower power applications as decent iron cores are becoming more difficult to find.

[charlie66]

Originally Posted by TimeWarp

You sure do run that thing. lol But I meant a wider washer. Since you cant go wider on that end one I wonder if you can build a support for it off the bolt holes on the end of the head?

I personally think it will still crack. All the problem is coming from the heat up top.. You have to bring it down into the water where its cooler....

[TimeWarp]

I bet you're right

[charlie66]

Originally Posted by mgarblik

"A smart company would take a set of their ali heads,get them expertly ported and then copy them in iron. Sell them as a boosted head option for the same cost as their ali head,so the company would have a good profit margin and the boost guys get what they want. Options could be o rings,CNC'd chambers
I'm at just under a 1000hp with my 96 iron heads and intend going up to around 1400hp,but it took a lot of work to get what I wanted-weeks of porting,new guides/seats cut/spring pads cut/chambers relieved/gasket surfaces ground/dry decking/o ring grooves etc etc. I went through all this because I believed an iron head would be better and more reliable for my needs. It would be nice to just be able to buy a new iron head and virtually bolt it on."

I agree 100% with this post and have been advocating for these for at least 10 years in every way possible. Each year at the PRI show, I talk to EVERY single vendor that produces cylinder heads and pitch the idea. 25 years ago, I did the same thing when the only aftermarket Pontiac head was the Wenzler head and after 5 years of badgering from me, the Butlers, Arnie Beswick and a host of others, Edelbrock finally relented and produced the Performer RPM, fully expecting to lose money on the project. The rest is history. If enough of us keep beating on the vendors, one of them will produce some. Iron heads are the simplest, easiest way to overcome the wide spread of the 10 head bolts, the flimsy aluminum castings, and the side by side exhaust valves of a conventional Pontiac head. In addition, many non-boosted Pontiac fans may use them NA in lower power applications as decent iron cores are becoming more difficult to find.

I think at one point Ames had some in there catalogue but never came out... don't know why...

[charlie66]

Originally Posted by TimeWarp

I bet you're right

I had the car out today , all day was at 35 psi . I really beat the snot out of it. It was cooled down for about 4 hours and just for the heck of it I checked all the exhaust bolts and they were all good. Didn't budge an inch .... just sayin.....