598 Engine Build
 

Thought I'd share my winter project. Boat is a 28 Nordic Heat. Old engine was 900 HP Whipple engine. I sold that engine, which left me needing one. I wanted to build something a little different and I never really utilized all the HP I had. So, the decision was to build a 700+HP naturally aspirated engine. I ended up with a 10:1 598 with AFR 335 CNC heads, hydraulic roller cam and all the rest of the necessary hardware. The caveat was that I had an old 500 EFI intake sitting around that I wanted to play with. After all everyone knows they won' make any power. I also had a single plane 4bbl efi system not being used. Maybe I could play on the dyno some. Like eveything always does, it got a lot more involved. I decided to build my own plenum and got to talking with "Nordic Flame" about throttle bodies. I came up with a drawing and he machined 4-2 bbl throttle bodies for my intake. The dyno results speak for themselves. first one is with the 4 bbl tb, second was just changing to the new intake, no other changes except A/F tables.

Here are a couple of pics of the engine. The low end torque is truely amazing, and I don't have to spin a ton of RPM. I'm sure a huge intake and dominator style carb/tb would make more peak HP, but you can't beat the cool factor and torque.

By the way I owe a hugh thanks to Dave "Nordic Flame". Not everyone has a CNC machine at their disposal. Again Dave, THANKS!

Nice numbers. Good reliable power. Those carbs look pretty bad ass also! :drink:

I dont think my 598 is making that power with a single Dominator so you are doing something right.

sweet set up looks nice and dyno sheets def look good !

Nice work Bob and Dave, as usual!
Looks very cool and different.
How many CFM are the throttle bodies?
That motor should live forever with the low RPM HP and N/A.
Best Regards,
Steve

That is nice setup good luck!

Never flowed the throttle bodies so I don't really know. We used the same bore size as the 1100 cfm 4 bbl throttle body, so around 2000 cfm would be my guess. I also ported the intake quite a bit. Another cool feature is that I installed 2 large idle adjusting screws in the back of the plenum(plus the IAC). I run the throttle blades all the way closed, that way there is no synchronization needed for idle. The TB's have progressive linkage and the secondaries don't open until past 1/2 throttle so the response is very soft and driveable. So far they work even better than I had hoped.

Bob Lloyd
Full Throttle Marine

That's awesome Bob. I might drive out and take a look.

Clark

That is very slick Bob. I have been wanting to do something along those lines for some time. I just never seem to find the time. I'm sure you know what I mean. I had quite a different plan but that seemed to work very good. Placing the throttle bodies directly over the intake runners is obviously the way to go. Congrats. Very nice.
Eddie

doesn't the off the shelf KINSLER stuff do exactly this same thing ? i used it all the time on the v8 and v6's .

That's pretty awesome.

Very cool, Bob. Nice work. Swing up my way and give me a WOT fly-by at the 17MM. Give me a head's up, and I"ll get you on HD.

Yes they do. Just not exactly what I was looking for. I bought the throttle blades from them.

As impressive as the setup looks, the dyno sheets are even more impressive. I cannot believe the improvement. That is awesome.

tell me about that , please. my experience with their stuff were the factory race motors that came to me to run from chevy and buick and ford... so while i certainly had my hands all over it, it wasn't my design or specification or anything like that... but the stuff was very well executed and simple and worked really well. for the sake of discussion and no other reason, what did you like/ not like achieve/ couldn't achieve ?

am curious in an intellectual and engineering framework...

i mean... it never occured to me to do it because... well... it never occured to me... but on box stock 502 mag mpi's like i had, if you had dumped the manifold that everyone hates and replaced it with the kinsler piece and adapted the factory mpi to it , do you think that would be a net gain , loss or a waste of time ?

Nice Part!
 

Hey Bob, nice work and a great result.
As we all seem to say now, when it comes to naturally aspirated in a marine engine,"THERE AIN'T NO REPLACEMENT FOR DISPLACEMENT!"
We did a lot of development on the 598-600 cubic inch versions of the 8.1L 496 Gen 7 engine as you know and we developed two different intakes that would support 750HP on the big cubes and higher flowing CNC'd heads. One was a redo of our existing 496 manifold that was reasonably priced using two 1200 cfm throttle bodies. The long runners and big plenum developed huge torque like you are seeing in your great creation and the other is our stack in line fuel injection system we built for the HO750 engine. The later obviously has the wow factor but the cost of this type keeps most guys wallets in their pockets!
I am curious what you think your beautiful system would sell for?
You also qualify as an "Official Rocket Scientist" for that amazing throttle linkage set-up- NICE WORK! The design and CNC work on the throttle bodies is really nice and obviously the system works very well as the dyno sheets show.
Congratulations on some nice development work!

Best Regards,
Ray @ Raylar

Very cool!!!

Cost was the first driver on my decision. Kinsler could make pretty much anything I wanted, but ended up pretty pricey. I wasn't even sure how well it would work with the intake. Since Dave was able to build them(as a prototype), the rest became moot.

You would definitely gain some HP potential with the Kinsler setup. But, with the really small cam and low RPM limit of a stock 502 you may have never seen it and would have lost a lot of low end torque. Years ago I built a 540 with the mpi intake. It made tons of torque but layed down hard around 4900 rpm. Swapped out to a single plane intake and carb and it lost a lot of low end but gained about 300 rpm on top. I didn't have a dyno at the time, so no good data. The 500efi intake also has much better runners than the 502 MPI intake.

interesting... thanks... and well done again. thats nice work.

Thanks Ray. You may remember, you and I visisted early on in my project about your individual runner system. That's what drove me towards using a small plenum design. Unfortunately using an existing manifold and hatch clearance limitations, I wasn't able to optimize runner length and plenum volume, but it seems to work pretty well.

As far as cost I've not given it a lot of thought. It would be a great upgrade to a 500/525 based engine. The cost of the throttle bodies would be the key. Dave Gilbreath machined them so he'd have to come up with a cost figure. I know it couldn't be done very cheaply. I'm guessing we spent close to $800 on material alone.

Awsome engine Bob and that one of a kind intake design and four throttle body linkage is a thing of beauty. Great job! Sorry I did not see this post until now.

Bill

Question
 

Man after looking at that I don't even feel like a novice:eek:

Bobl, I was wondering what type of air filtration is used on that injection system?

Impressive!

Extremely nice.

Uncle Dave

Those 1200CFM TB's look just like the 1000CFM that came with my Holley MPI kit. It looks like you only needed the IAC and TPS on one TB. Cool idea.........
Were the tubular runners better than using a dual quad intake?

Right now I have just some wire mesh flame arrestor matterial in the throttle bodies. I have clearance issues in the boat. I designed the throttle bodies to bolt oval flame arrestors on them if desired. This winter I plan on building a ram air/flame arrestor system into the hatch.

Bob

Question?
 

Bobl,

I am just impressed, did you fabricate that linkage setup? Also, am I correct to say that I am looking at a custom plenum sitting on top of a square bore type intake manifold?

Do each of the TBs feed a particular bank of cylinders ?

Thanks

I have ram air on mine, gained about 1 1/2 MPH. Maybe free'd up about 20-30 HP, manifold air temps are much lower.

Question - I notice on the dyno charts that one pull starts at 34 the other 3500.

Typically one starts where they can stabilize the load and your mill is just a hair higher than the usual 3000 rpm.

How does the mill idle?



Uncle Dave

The dyno was set at 3500 to start the pull. If I hit the record button a little early, it starts recording there. I did some pulls down lower but was having a tough time holding it steady with the larger water orfices I had installed on the dyno. I always hold the load for a few seconds to stabilize before recording, but the rpm will still fluctuate slightly. A bigger dyno water supply would help that($$$). With lower HP I reduce the outlet orfice size to allow loading it more down low, but it really increases the heat in the dyno if you run up the power without increasing the outlet orfice size. Hope this helps explain.


The cam is ground on 114 lobe separation with 250/258 duration so it's not too radical. It's programmed to idle at 800 in neutral and will lug down to about 675 when put in gear until the iac picks it back up to 800. The exhaust has turn downs that exit right at the water line (84 db). It's very docile. I've got about 35 hrs on it this summer and it's been flawless, once I got it fine tuned.

Bob

It's a 500 EFI intake with 8 crossram runners. I built the plenum. It feeds all cylinders. So, the tb's sit above the individual runners but cross feed all the others.

Bob

I had the pleasure of seeing this work of art this past June. I can tell you it sounds great with the turn downs. Pictures really don't do it justice though. Great work Bob!

BTW, You guys still thinking about coming up this summer? Remember, Joanne still need to see her some Billy!! LOL!