Need inputs on my 2789 Oxy project

[Stripped66]

http://www.cal-look.com/forum/index.php ... #msg250722

Pat Downs said they have 'em...I suppose that means they are on the shelf now!

[Piledriver]

You can get 95>101.6mm pistons what weigh <300g... From WISECO, 22mm pin, ~32mm pin height, flat tops. (for an ATV, but have been used in big wassers before)

Set you back ~$500, could probably get custom versions or about the same price.

If you are only revving to <6K, why H-Beams? I beams are stronger <7000 RPM, and a heck of a lot cheaper.

Consider pulling the vents on those 48s and stick injectors in the manifolds+ MS, should be good for more power than you desire easily.

[Der_Butzelmann]

http://www.cal-look.com/forum/index.php ... #msg250722

Pat Downs said they have 'em...I suppose that means they are on the shelf now!

E-mailed CB about this now, again.
Hoping for posetive feedback.

[Der_Butzelmann]

You can get 95>101.6mm pistons what weigh <300g... From WISECO, 22mm pin, ~32mm pin height, flat tops. (for an ATV, but have been used in big wassers before)

Set you back ~$500, could probably get custom versions or about the same price.

If you are only revving to <6K, why H-Beams? I beams are stronger <7000 RPM, and a heck of a lot cheaper.

Consider pulling the vents on those 48s and stick injectors in the manifolds+ MS, should be good for more power than you desire easily.

I allready have eight of the 4" pistons, so I will use them on this and another engine. Wisecos are nice, but costy, and the ones I have laying around should be more than strong enough for my application, just a bit on the heavy side, but for this engine I guess it ill be ok. The set of eight is "guarantied" to take 500-700 hp in a v8, so half of that power on half the amount of pistons will be about the same load I guess = no problems.

About the rod question, the reason why I am considering H-beams in the first place, is written in the posts above. I allready have I beams ( Porsche 912 "616" ), but am getting advised to ditch them because of their weak design and because of the heavy pistons I`ll be putting on them.

If you have a tip about where to get "affordable" I beams with Porsche journals, I am all ears. My self, I can not find that many to choose from, but my eyesight might not be the best

[Piledriver]

Look here for your rods... and maybe some other bits.

http://www.volkszone.com/VZi/showthread.php?t=421018

[Piledriver]

Hmmmm... If they are undrilled, could the bore centers be redone for T4 usage ala the T4 910s for T4 big bores/studs???

(Enough meat?)


IIRC the T4 bore center is 124mm, T1 is ~112?

The PR tubes would be a PITA, but that's ~normal, 910/split ports are the same way, some engineering required.

[Badbugtwo]

Okay, I will make a couple of comments after reading your initial post and only skimming the rest of the comments....

Both the 48X40 CE`s and the 50X40 910`s were found too big and then way too big for my intentions by "the pro`s".

Your racing will most likely be "apples to oranges" to mine, but I will tell you what I have found with my 2789cc engine both 1/8th mile and 1/4 mile drag racing. I have run two different sets of 910 heads. One was with some what of an oval port port with 50 x 38.5 valves and then later opened up to 51 x 40 valves. The other was square port with 51 x 40 valves. For drag racing, they ran awesome! As a matter of fact, I believe that I could go bigger with this large of a bore.

CAM: Engle FK-89
ROCKERS: 1,4:1 With needle bearings

I use 1.6 Pauter roller rockers. I have run a couple different cams larger than FK-89, but to give you a comparison....

When I ran the FK-89 I would launch at 7,000rpms and shift around 8,800rpms. The engine pulled awesome to redline and I am sure it would have pulled higher. I tried launching even as high as 7,800rpms, but didn't really need to. If I tried launching much lower, it would bog! Even with a big engine!

When I tried an FK-10 I could launch as low as 5,000rpms with no bog and I might have launched as low as 4,000rpms, but would have to check my records for sure. It would still pull higher rpms, but I shifted at 7,500rpms (to save the engine!) and it ran almost as strong as the larger cam!

When I tried a V-26 cam, it was like hitting a rev limiter at 7,000rpms, it would not pull past it! (When I had used this same cam in a 2275cc engine with smaller rockers and smaller heads it would rev to 8,500, although I am sure it stopped making power way before.)

STATIC COMP. ESTIMATED: About 10-12:1 or higher

Depending upon the cam, you might want to run a little higher, especially if you run the E-85.

CARBS: HPMX 44 with Pipercross foam filters and homemade linkage ( yes, they are a bit small )

Unless you run really low rpms, you might choke the engine down, but it would make a cheap rev limiter!

When I first ran my 2789cc engine, I used a set of 48 IDAs that had been bored to 51mm. The engine ran good, but really lost power on the top end. (I think above 8,000rpms, but it has been several years, so I don't recall for sure.)

Once I stepped up to a set of 58 Berg carbs, it really pulled great and dropped 2 tenths in the 1/8th mile.

I'm changing over to EFI and unless I decide to go turbo and a single throttle body, I will probably be going with 62mm throttle bodies and bigger heads.

...EXHAUST: Merged Collector ( cant remember how big it is. 1,3/4” / 1,1/2” ?? with a ”full flow” carbon silencer from a motorcycle

I've only run 2" exhaust on my engine, but I would think either of those two would be too small, but then again, rpm range, cam, heads and intake will determine what you want to run.

Remember, it is a properly matched combination that will give the best results.

A 2.8 liter with too small of cam, compression, heads, carbs and exhaust may not run any faster than a high strung engine that is much, much smaller, but it could last a lot longer!

Good luck with your project!

[Der_Butzelmann]

Thank you for your inputs!
I hope that it works out in the end, and a BIG yes to this line of yours:

"A 2.8 liter with too small of cam, compression, heads, carbs and exhaust may not run any faster than a high strung engine that is much, much smaller, but it could last a lot longer! "

That`s my EXACT idea about this project, and finding the right combo for this and my wallet at the same time is what makes me wear out my thinking cap these days

[Der_Butzelmann]

Look here for your rods... and maybe some other bits.

http://www.volkszone.com/VZi/showthread.php?t=421018

Thanks for the tip

[Stripped66]

Thank you for your inputs!
I hope that it works out in the end, and a BIG yes to this line of yours:

"A 2.8 liter with too small of cam, compression, heads, carbs and exhaust may not run any faster than a high strung engine that is much, much smaller, but it could last a lot longer! "

That`s my EXACT idea about this project, and finding the right combo for this and my wallet at the same time is what makes me wear out my thinking cap these days

Then you've got to get a smaller cam!!!

[Der_Butzelmann]

Thank you for your inputs!
I hope that it works out in the end, and a BIG yes to this line of yours:

"A 2.8 liter with too small of cam, compression, heads, carbs and exhaust may not run any faster than a high strung engine that is much, much smaller, but it could last a lot longer! "

That`s my EXACT idea about this project, and finding the right combo for this and my wallet at the same time is what makes me wear out my thinking cap these days

Then you've got to get a smaller cam!!!

Or even bigger heads, and carbs