Can anyone tell me how it's possible to get 3.2 or 3.4 litres from a 968 motor?

Is it all done with sleeving/overbore?

Does it require an off-set ground crankshaft to get the stroke?


Thanks!

 

Mitch,

We are right now working a getting 3.22 liters from a 2.5 liter block. We have the block at the machine shop right now working on a sleeving process that will allow us to go 108mm. If used with a 3 liter crank, I believe this runs out to 3.22 liters. Its a project I'm looking into for our race car.

So, If that much can be had with the 2.5. I would think its safe to run the 3.0 liter block out to 3.3 or even 3.4 on the extreme side, maybe even using a standard sleeving process.

By the way, will you call me at the shop today. I need to discuss a few things about the race upcoming in November...its pretty important.

Thanks!

 

Interesting John...

Why dont guys like Milledge run motors this size?
I dont "think" Kelly Moss,when they were running their set-on-kill NA 968 used this kinda displacment..i might be wrong though.

I'll call later today....

 

That's because AMW knows some secret enging-building tricks that the other guys don't... heh, heh...

 

I could tell you, then I'd have to kill you. <img src="graemlins/oops.gif" border="0" alt="[oops]" />

 

To get a 3.4ltr we start with a 3.0 ltr block and bore to 110mm and offset stroke to 90mm or go with our new billet crank at 90mm. Or we can go to 3.4 ltrs with an overbore to 109mm and stroke to 91mm which yeilds 3396.6 CC or 3.4 ltrs. We have not combined the 110mm bore and 91mm stroke as of yet but don't see why it is not possible in a normally aspirated environment. Boosted might be a bit risky. In any event that would net 3459.2 CC or 3.5 ltrs. We have kept the turbo motors to 108mm bore max for more stability and such but can go to 91mm stroke which makes a 3334.6 CC, 3.3 ltr motor. My own turbo track car is getting a 108mm bore, 88mm stroke 3.2ltr when we find the time to finish the car some day. I kept the stroke a bit lower at 88mm since the car is designed to run 8000 RPM. Anderson learned a lot of engine tricks when he was here but not all of them

 

Actually, Derrek is right...I did not learn all the "tricks" while at Hunltey.

I did gain knowledge at Huntley :-) But when you work that hard for someone, its hard not to walk away with anything learned.

As for engine building knowledge............

Thats another story

"See you at the track"

 

[quote]Originally posted by Huntley Racing:
<strong> Anderson learned a lot of engine tricks when he was here but not all of them
</strong><hr></blockquote>

do any of those involve duck tape? Cuz I think I saw that one.

 

 

That is exactly what I am going to do to my block....when I can find the time to get it apart...the motor is sitting in my office and has been for the last 2 months.

John and Danno have been feeding me info on what to do....

 

Derrick, could you give us some insight as to what was required to make your motor live at 8000 rpm?

Obviously valve springs, lighter valves, and solid lifters (16 valve?) are required. What else did you do?

It definitely makes sense that the last place you would want to weaken in a 3.0+ liter 8,000 rpm motor would be crankshaft rod journals. Are the journals different sizes in the 968/S2/944 crankshafts?

 

Steve,

To get a hi rev motor, especialy in the 8k range, safely.You would want to first, convert to solid lifters...this requires some delicate adjustment, but its not new technology and can be done on the 16 valve heads a lot easier than the 8 valves. The 8 valve head would require that you machine holes in the cam tower that can be used to gain access to the solid lifter for adjustments in the valve lash. This is something we are doing to further our car for next season.

You would also want to run a lighter SS vlave, you can get valves with a smaller diameter stem, and couple that with custom valve springs that are stiffer than stock.

Some dandy headwork would top it all off.

To keep the bottom end stable at the revs, you need to have lightweight rods, that are very closely weight matched! A good crank, that has been lightened and definatley knife edged ( avoids oil froth at high revs.). Be sure to use new studs, preferably aftermarket like ARP etc and new hardware when assembling the lower end.


Just my thoughts.

 

For my 3.2 ltr turbo we had titanium hollow lifters made which are 15% of the stock hydraulic units. The titanium requires some special coatings to live in that environment which we did. The springs are our vanadium coated springs, which are made for most the CART teams. The springs are topped off with titanium retainers and special locks. The valves are inconel 7mm stem on the exhaust side and S/S 6mm stem on the intake side. We did some special work on the chambers to allow very large valves and to minimize hot spots and promote flame propagation. The valve heads, chamber and exhaust ports, and piston tops are ceramic coated, the valve stems are friction coated, as are the piston skirts. The rods are ChMo forged with wire EDM bored piston/pin squirters thru the rod to the base of the piston. The rod/main bearings are friction coated. The rods and crank are oil sheeting coated to promote drainback. The motor is drysumped with a five-stage pump (one stage for the turbo and four in the pan. The car holds 22 quarts of oil. The car runs custom head and main bolts. The intake manifold is a custom-made billet aluminum large plenum/short runner unit with a 1200 CFM throttle body. The intercooler is 36"/24"/3" with 3.5" in/out and is front mounted (the radiator is in the back of the car). The car runs 3 oil coolers (two frame rail tube coolers and one large aerospace cooler in the back bodywork next to the dry sump tank. The turbo is front mounted in the passenger front fender area with custom exhaust being made. The header will run 2" primaries with a 4/2 collector into the split turbine 'T' series custom turbo. The motor will run 8 injectors in two stages. The fuel line feed is 7/8" and the return is 3/4". The car runs two 800HP fuel pumps in parallel with two pickups and twin check valves to a 'Y'. The car runs a 32 Gal fuel cell, which will supply the car for 45min to 1 hour. Very little was spared in this effort.

 

You coated your rods to promote "oil drainback"? And you have a dry sump? Coating the rods makes them slippery, helping them cut thru the oil...either case, I don't see why you coated them.

We use PolyDyn PD-14 it does not allow oil to stick to the rods or the crank. But we do not use a dry sump. We use it to reduce parasitic drag on the crank and rods when cutting thru the oil.

As far as the bearings go, PolyDyn-DL, this is another coating that makes oil stick to the surface of the bearings...Kinda the revers of the -14.

To get really trick, use PolyDyn RP on the piston skirts...this stuff gets real slippery when oil gets to it, reducing any drag of the piston against the wall, this wouold help keep the walls and piston in pretty good shape, even under high revs and side loading.

So, in general, we would both agree, solid lifters, stiff springs, light weight valves.

Take Care

 

You dont want the oil to 'stick' to the rods, you want it in the sump. Your standard wet sump motor is another story since the rods are bathed in oil all the time you just want to reduce windage using this type of coating.