slate blue

Hi Warren, my pistons will need approxiamatly a 5 cc dish in them. This will give 12 to 1 comp ratio. We have high octane fuel commonly available here. There is several different pistons available with 6cc like mine to 16 cc and 26 cc. All of these I believe you could slightly alter also. I was quoted about $200 for this. It just depends on how much stroke you are chasing as to what you do. I wish I had taken a photo of the bottom of the piston, it is a very modern design.

You will need some very dished pistons if you want to supercharge and stroke. When I was going to drop the N/A project because of a mishap and low power simulation figures, I worked out if I used the 26cc pistons and only stroked to 5.4 liters, this would yield about 9 to 1, which is roughly where I would want to be with a forced induction project. I'm glad my project is still N/A, we have achieved great results so far with all our development work and obviously I'm hoping the end result atleast equals the sum of the parts.

As to costs, in AUD I was quoted $425 for the offset grinding, welding was going to be about $275 and the new "chevy drillings" were unquoted at the time. But if you allow $500 for that and then a pretty substantail balancing procedure say $300 you're at $1500 aussie or about $1150 USD.

Hope this helps

Greg

Herr-Kuhn

It's okay Brendan we all know you are waiting to turbocharge it, right?

BC

I have three engines completed or planned.

The 78 is done, and kinda for Sale
The 89 is pretty much part-planned,
The "Third engine" is now just a GTS crank and some crazy ideas.

slate blue

An interesting thing about the bolts is that they don't suffer from stress corrosion or hydrogen embrittlement. This is quite unique to the multiphase material. This material according to the ARP website is the same material used in the F1 connecting rod bolts. This must be why the rods are good for 10,000 rpm. The bolts are rated at 285,000 psi versus the standard Porsche bolts at 156,000 psi. ARP 2000 are rated at 215,000 PSI but can suffer from corrosion problems. The multiphase bolts aren't cheap at $50 a bolt!

FlyingDog

Greg, why are you selling your Honda rods?

slate blue

I have two sets, I bought the other set to do the GT engine but due to a screw up and the costs incurred by that I will never do the GT engine. The other honda rods are Carrillos with forced pin oiling, they are 0.940" wide and 6.2" long and use the 0.866" pin. They weigh 575 grams There are perfect for future use. My other set are Lentz, Here's a photo of the Carrillos.



I'm chasing $400 for them, you may be able to buy them cheaper on Ebay but it is a lottery. These are good ones that have not been overheated, they will need closing and honing, but I would never fit a second hand rod without doing that anyway. I will probably sell them here is Oz for more as they are not exactly common place down under.

BC

What would the rest of the engine need for these rods? What are the specs again for the crank and piston?

slate blue

It depends Brendan, but I bought these rods for my GT engine, they would need custom pistons. I would have Mahle make these, with the smaller Nascar pin, you should be able to get the compression height quite high also the pin is smaller and lighter. I don't like the convential strokers because of the rod ratio. The motor I was planning was going to be a higher revving 6.1 liter with a rod to stroke ratio of 1.75 to 1. Not the 1.56 that most strokers use.

As to the rod to stroke ratio, this is not such a big deal in an auto. My car is a manual and as such would rev more and this is the way I wanted it. Lower revving torquey engines suit some cars but I wanted a more useable rev range and remember revs mean power. This is not meant to offend other stroker motor guys. I just believe it is a alternative direction one can take.

To get the stroke to about 90 to 91 mm you will need to weld the crank, both on the cheeks and journal, N.B my mini two valve stroker will only be welded on the cheeks (to give correct clearance to the narrower chevy rods) and as such is only a 5.7 liter because of its 86 mm stroke. If you used you GTS crank to do this, not sure I would, you wouldn't need to weld the journals. If you weld the journals you will need to hard chrome the crank.

The first 928 stroker was a welded crank, Honda rods weren't around then so they needed a lot of welding as they used 2.1" With the Honda rods it means a lot less welding and that should mean more inherent strength. Never forget this is an experimental engine, not a standard rebuild as such reliabilty has a question mark over it. If nobody ever does it well never know. This could be a great way to get extra capacity at an affordable price. That was one of the reasons I ran the post about group purchase of Mahle pistons.

If that piston price were to come down due to a standardized requirement 6.1 liter, it would be about half the price of the old strokers and much more advanced design to boot.

BC

Could I use your rods somehow with my GTS crank with the question being the custom pistons? Do you think with the rod length it would still give me enough distance between the pin and crown for high boost? The GTS crank is planned for the larger high boost engine I envision.

slate blue

Hi Brendan I admire your spirit for power, but Honda rods are really designed for N/A purposes. That is revs, revs suit manuals, not autos, so if you are going the auto route forget about my rods, very little to be gained if anything. I am not really a FI guy, I like the N/A engines for what they are, If you go to a F1 race you will see the greatest N/A engines ever built. Love that induction roar, if anybody saw Montoya out drag Alonso down the back straight at Interlagos the other day that was great. If you have seen a F1 race you will have no doubt as to the pure roar that must have been. There were some great incar shots with some really nice noises taken at that time.

If I was you I would consider N/A for the GTS, build the high revving stroker I was going to do! It is 6.1 liters and I planned for it to match the McLarens F1 engine. That was 627 bhp. That would be a great achievement with the same capacity. 6.1 liters also gives quite a nice rod to stroke ratio.

I have also been reconsidering my project, with different pistons I could achieve a 6.1 liter, that is what Bob Devore had, albeit is a different bore and stroke ratio. He produced 580hp according to a article in Excellence (August 1990) I would sell my pistons off cheap if I decided to go this way, I will only get 300cc more so I don't really know if it is worth the trouble. 6.1 liters sounds good though.

I'm waiting on news from Piper as to the cams, if they are successful these are pretty decent cams especially for 280 pounds. My engine builder says I will need 1 7/8 primaries as the exhaust flow requires it, I can understand that, but most of the strokers come off 1 3/4. Maybe this is because they have better flow through the head? It is interesting how my head guys said that the intake was totally inadequite and then I saw Bob DeVores for the first time today and he had changed the runners.

Here is some preformance figures from his car,

60 MPH in 4 seconds
100 MPH in less than 9 seconds
125 MPH in 12 seconds
150 MPH in less than 16 seconds
175 MPH in 21 seconds

Standing quarter in 12 seconds

Not bad!!!!

Cheers Greg

928SS

so how long did bob's motor last anyway?? not trying to be negative, but just curious as we all know power vs reliability are the two big tradeoffs in general....

BC

No Auto. I already blew two up. Only 5spds unless its for my wife and I don't get the keys.

BC

Is there a power rating on those rods? I'm trying to do some money calcs, as what you want for the rods, and what it would cost for the crank change + pistons, and motor work must be compared to leaving the GTS crank alone and buying custom rods and pistons.