28 replies to this topic

[928s]

Guys it is my first post, so Hi! I don't know if I'm posting on the right website for this question but I have read some really in depth technical discussions on this board an as such thought I might try to borrow some of your brain power and collective knowledge. First let me tell you what I am doing so I can put this in some type of perspective.

I have been building a Porsche 928 for some years now and (it has gotten well out of hand) now the engine is the next item on the agenda. Rather than go the convential route and use the 4 valve head I have chosen to use the early 2 valve heads. (I like to be different) Anyway I am having the crank made by Moldex as we speak, it incorporates current technology which is what I am trying to achive here, modernise an old engine (1984). I have had the heads developed and they will support 600 hp at max lift. To achieve this flow I had to increase the valve size, especially on the intake. It is now 2.1" and Ti for lower weight as I also plan to rev this engine a 1000 rpms higher than stock.

Lots of mass reducing techniques have been employed in this engine along with friction reduction. Where I got my ideas from predominately was the new Zo6 Corvette, with its Ti intake valve and steel exhaust. My exhaust valves are super alloy and I believe they are nimonic metal, rated to very high temps. My valves seats like the LS7 Chevy engine are also interlocked, this means that both the intake and exhaust seats should be made from the same material because of expansion reasons. Dissimilar material have been known to cause cracking according to Del West.

Del west also advise me that the LS7 intake valves are Cr Nitrided. Apparently they didn't supply the seats. I cannot find a supplier of the Chevy seats, I cannot find what the exact material is that Chevy is using, I do know that it is a copper infiltrated powdered metal seat.

I believe that if I was to use Berylium Copper I may kill my head guys and the seats wont last in a street engine. I have also heard of a material called Ampco 45. Again these are very soft with Rockwell hardnesses in the B range, where as Del West advice that certainly upto Rockwell 32 C is acceptable and given my light spring pressures and the fact of the Cr nitriding will chang the properties slightly.

Can anybody shed some light here? Please, my apologies if this forum is not appropiate for this question.

Thanks Greg

[phantom II]

Why not go down to your local Holden store and git yerself an LS2 and drop it right into place where the boat ancher sits. It will save you a lot of trouble and money. Even the local Ausie boys can get 600 hp N A out of the Chevy engine with ease. Is there anybody else who has done what you propose doing?
I owned a S4. Junk, junk, junk. I can put you onto a guy who provides a kit for LS1,2 and 7 engines for this car.

Originally posted by 928s
Can anybody shed some light here? Please, my apologies if this forum is not appropiate for this question.

Thanks Greg [/B]

[imaginesix]

wb PII

[McGuire]

You are sort of on your own here. You have essentially a race engine on the road, so either approach will be a compromise. You can go with copper beryllium but the wear will be sort of excessive... but then the rest of the engine is on a relatively short fuse as well. The other materials will work too but will tend to be harder on the ti valves. So either will work pretty ok but there is no ideal choice. The LS7 seat is a special process, which is why the info is not floating around out there.

[rgsuspsa]

Originally posted by phantom II
Why not go down to your local Holden store and git yerself an LS2 and drop it right into place where the boat ancher sits. It will save you a lot of trouble and money. Even the local Ausie boys can get 600 hp N A out of the Chevy engine with ease. Is there anybody else who has done what you propose doing?
I owned a S4. Junk, junk, junk. I can put you onto a guy who provides a kit for LS1,2 and 7 engines for this car.

Phantom:

By the letters, "git" and "ancher", did you in fact mean the words, "get" and "anchor"?

[Engineguy]

Originally posted by rgsuspsa


Phantom:

By the letters, "git" and "ancher", did you in fact mean the words, "get" and "anchor"?

rgsuspsa,

By the query, "did you in fact mean", were you sincerely inquiring because you were incapable of figuring that out on your own, or were you just being a jerk?

[Canuck]

Strange - I was just wondering when our erstwhile paranoid was going to return. There was something Z06-related I wanted to ask you but I can't for the life of me recall what the hell it was. How was the trip?

Oh yeah - Z06 as a daily driver. I thought you'd mentioned somewhere else that you drove an itsy-bitsy car or a truck as your daily driver over the 'Vette. Why is that?

[Greg Locock]

Cos a Vette is about as nice to drive as my old TR4, except you get cheap american plastic ambience, instead of cheap sixties plastic ambience. Just watch that long hood flex around as you go over every bump.

I was, quite sincerely, shocked when I first drove a Vette. Admittedly, if I get a contract in the states I'll buy one, but mainly because of the engine.

[NRoshier]

was this a recent model Greg?

[McGuire]

Originally posted by Engineguy


rgsuspsa,

By the query, "did you in fact mean", were you sincerely inquiring because you were incapable of figuring that out on your own, or were you just being a jerk?

I believe that was the Internet equivalent of dialing while drunk. Just don't do it.

[McGuire]

Originally posted by phantom II
Why not go down to your local Holden store and git yerself an LS2 and drop it right into place where the boat ancher sits. It will save you a lot of trouble and money. Even the local Ausie boys can get 600 hp N A out of the Chevy engine with ease. Is there anybody else who has done what you propose doing?
I owned a S4. Junk, junk, junk. I can put you onto a guy who provides a kit for LS1,2 and 7 engines for this car.

Oh stop.

[McGuire]

Originally posted by Greg Locock
Cos a Vette is about as nice to drive as my old TR4, except you get cheap american plastic ambience, instead of cheap sixties plastic ambience. Just watch that long hood flex around as you go over every bump.

I was, quite sincerely, shocked when I first drove a Vette. Admittedly, if I get a contract in the states I'll buy one, but mainly because of the engine.

I seem to recall you were involved with the C4/ZR1. Have you had a chance to drive the C5 or C6?

[phantom II]

You left out ,"yerself". Don't nobody talk right around here?

Originally posted by rgsuspsa


Phantom:

By the letters, "git" and "ancher", did you in fact mean the words, "get" and "anchor"?

[phantom II]

Can't help it, Bill.;)

Originally posted by McGuire


Oh stop.

[phantom II]

Trip was great. Thanks for asking. Africa will be Chinese in 30 years. Saw the rally cars in Dakar. Don't fly SAA if you want to live. Computer services are almost non existent so I really missed you.
My C6 Z06 is a very nice car despite the comments of anti GM, Greg. Although many people use Vettes as daily drivers, it is too impractical for that purpose. Drive it at Homestead or Daytona roadcourses and you will have a mighty fine tme in it indeed. I drive a 03 Chevy Metro daily and my wife drives an 02 Olds V8 FWD. We used to have Suburbans and Pick 'em up trucks as daily cars and I am looking at all kinds of replacement vehicles right now. Id like a Caddy STS SW except GM doent make one. I may make it myself.
I am converting a SSR to an extended cab 2500 Diesel duelly and have my new roadster going with, you guessed it, a Chevy LS2 for power.

Originally posted by Canuck
Strange - I was just wondering when our erstwhile paranoid was going to return. There was something Z06-related I wanted to ask you but I can't for the life of me recall what the hell it was. How was the trip?

Oh yeah - Z06 as a daily driver. I thought you'd mentioned somewhere else that you drove an itsy-bitsy car or a truck as your daily driver over the 'Vette. Why is that?

[McGuire]

Originally posted by rgsuspsa


Phantom:

By the letters, "git" and "ancher", did you in fact mean the words, "get" and "anchor"?

There are three more commas in that sentence than the rules of punctuation can bear. Could you please work on your grammar? We have standards to uphold around here.

[McGuire]

Originally posted by phantom II
Trip was great. Thanks for asking. Africa will be Chinese in 30 years. Saw the rally cars in Dakar. Don't fly SAA if you want to live. Computer services are almost non existent so I really missed you.
My C6 Z06 is a very nice car despite the comments of anti GM, Greg. Although many people use Vettes as daily drivers, it is too impractical for that purpose. Drive it at Homestead or Daytona roadcourses and you will have a mighty fine tme in it indeed. I drive a 03 Chevy Metro daily and my wife drives an 02 Olds V8 FWD. We used to have Suburbans and Pick 'em up trucks as daily cars and I am looking at all kinds of replacement vehicles right now. Id like a Caddy STS SW except GM doent make one. I may make it myself.
I am converting a SSR to an extended cab 2500 Diesel duelly and have my new roadster going with, you guessed it, a Chevy LS2 for power.

We missed you too.

[phantom II]

You are very polite NR. I took these pics in Cape Town. The RHD conversion costs over $30 000. It is a 07 Z51. I can't identify this steering rack, but the stock Z51 comes with a pretty nifty variable ration unit. I can't find numbers for the stiffness of the C6 chassis, but physics is physics. You can't put such big holes in a structure without penalty. I recently drove two very stiff cars, my friends brand new paddle shift F430 GTB and a Lotus Elise. Both cost more than my Z06 but their fun factor exceeds that of the Vette. At the limit, I think Id rather be in the Vette. First thing you notice is how stiff the chassis are in these two cars but where do the golf clubs go?.

Originally posted by NRoshier
was this a recent model Greg?

[imaginesix]

Originally posted by phantom II
where do the golf clubs go?

In the Metro.

[Greg Locock]

Yes that was the ZR1. In the same sort of timeframe we were driving things like the BMW Z1, which admittedly wasn't a whole lot better for 'scuttle shake' - whatever a scuttle is. That is one phrase the Pommy motoring journos did to death. Still, so long as everyone knows what they are decribing I suppose the exact terminology is just a matter of taste. I preferred 'structural feel', but these days it just gets in with 'secondary ride', or shake, or as Mazda call it, solidity feel.

We managed to sort the Z1 out, as an exercise. Quite why we never tried to sort out the ZR1 in the same way is a bit of a surprise thinking back. I guess that project had enough on its plate. The Miata/MX5 had just come out, that had a much better ride/handling/chassis stiffness/engine mount combination. But mainly at the time I was working on the FWD Elan, which had its own, complex, issues, although chassis stiffness was fine.

I haven't driven anything even slightly exotic in 15 years, that I can remember. Hmm, no, just an endless procession of sensible cars, admittedly some with silly engines. Oh and a couple of Mustangs. Least said...

BTW I'm not anti GM. I've worked for both the Big 2. I do enjoy sticking the boot into Holden, I think they are lazy in some respects (high speed stability of the previous model dunny-door for example, and interior build quality), and the free pass they get in the LoCal press gives me the irrits, but to be fair their marketing department works very hard for that free pass.

[McGuire]

Having given it some thought, personally I would go with the copper beryllium valve seats as the safest choice. Ti valves are just too expensive to risk.

[McGuire]

Originally posted by 928s


I believe that if I was to use Berylium Copper I may kill my head guys

I don't believe there is a significant risk. Very little beryllium will be going into the air and a shop that is knowledgeable with the material will be taking the necessary precautions. I think your personal responsibility ends with making sure they know what they are doing, and if not finding a shop that is.

[McGuire]

Originally posted by Greg Locock
Quite why we never tried to sort out the ZR1 in the same way is a bit of a surprise thinking back. I guess that project had enough on its plate.

IMO the C5 and C6 are head and shoulders superior to all the C4's including the ZR1 in everything, from ride and NVH to interior materials and panel fits. To me they are world-class sports cars.

In my daily driving I am more of a Cadillac guy than a sports car guy, but in my opinion these are the first Corvettes that a reasonable person would consider a real, no-excuses, everyday car. The LS7/Z06 is especially impressive, as you get 500 hp with no noticeable compromise in driveability.

[phantom II]

Is 'irrits' the same as the 'shits? The C4 chassis was a disaster having its roots dating back to the C2 Vette. Penske and Greenwood performed major surgery to get the cars to work. I blasted all over Europe in my ZR1 and nudged 180 mph on numerous occasions. It is aerodynamically very stable and great touring car.
I understand that even F1 cars at speed twist like pretzels because of the aero package. ( I mentioned F1, I hope you don't mind.)

I saw the new Holden cars in S Africa called, Chevrolet Caprice and Lumina. The fit and finish is up there with Lexus. They are mostly intended for the middle east market. LS2 engines with 6 speed manual and auto. Bob Lutz says Holden is the finest GM division.

http://www.chevrolet...1G/gallery.html

There a plenty French cars in southern Africa. The variety of cars is quite extraordinary, coming from, China India, Korea. The full line of Daimler Chrysler products( American and German) are available in RHD.save for Viper.
There are A and B series Mercedes and 1 and 2 series BMWs. GM builds Opels and Hummer 2 and 3s there. French and Japanese cars abound in Zambia. I was casing some hunting grounds since the country has stabilized somewhat.
There are some really beautiful Alphas in this world. Here is an example of one in Simons Town.



[URL=http://imageshack.us][/URL

Originally posted by Greg Locock
[
Quite why we never tried to sort out the ZR1 in the same way is a bit of a surprise thinking back. I guess that project had enough on its plate.

I do enjoy sticking the boot into Holden, I think they are lazy in some respects (high speed stability of the previous model dunny-door for example, and interior build quality), and the free pass they get in the LoCal press gives me the irrits, but to be fair their marketing department works very hard for that free pass. [/B]

[NRoshier]

Phantom, I try to be polite!
But I also do not know Greg as well as most here and genuinely did not know which vette he might have sampled. After all I expect that each of the manufacturers would try the oppositions products..I would t'were I in their shoes. I have seen a C6 running around Melbourne, yellow looked nice enough.

[McGuire]

Originally posted by phantom II


I saw the new Holden cars in S Africa called, Chevrolet Caprice and Lumina. The fit and finish is up there with Lexus. They are mostly intended for the middle east market. LS2 engines with 6 speed manual and auto.

Couldn't say anything til now because the info was embargoed, but the new Pontiac G8 rear-drive sedan with 360-hp LS2 V8 and your choice of six-speed stick and auto boxes was just announced as a 2008 model. The car is essentially a rebadged Holden Commodore with different bumper covers and trim. I think you should trade in the Olds now.

[phantom II]

Easier said than done. My wife has had Oldsmobiles since I met her after I got out the service in '76. It is really a nice car, almost as nice as yours. Id love to put her in a DTS but our marriage could end abruptly. You just can't beat those large GM FWD cars for comfort. Maybe a '70 442 will do the trick but I think the Olds will get old along with us Im afraid. There will always be a Caddy unit to replace the Olds X axle I would imagine. She wouldnt know.

Originally posted by McGuire


Couldn't say anything til now because the info was embargoed, but the new Pontiac G8 rear-drive sedan with 360-hp LS2 V8 and your choice of six-speed stick and auto boxes was just announced as a 2008 model. The car is essentially a rebadged Holden Commodore with different bumper covers and trim. I think you should trade in the Olds now.

[Catalina Park]

I wonder if Holden has kept up the traditions of all the previous Commodores? The oil leaks on the steering racks and the rattles and squeeks in the interior. Holden has a reputation for quality but every Commodore I have been in has always had squeeks from the trims around the door openings.
If you think the Holden is good you should try a Falcon. (although the Falcons do get a rattle around the gearstick!)

[McGuire]

Originally posted by phantom II
You just can't beat those large GM FWD cars for comfort. Maybe a '70 442 will do the trick but I think the Olds will get old along with us Im afraid.

I thought you were already old??