Don Terrill’s Speed-Talk

I have a 6 cylinder Oliver tractor engine (Waukesha) that I use for tractor pulling. The engine was originally a 283 CID diesel rated for 67 hp @ 2200 rpm. The engine has been converted to spark ignition, bored & stroked, ported w/increased valve sizes, roller camed, and fitted with a sheet metal intake, dual carbs and headers. When dyno’d it topped 500 hp with almost 600 ft-lb of torque. Although competitive, like everyone else on this forum, I need a little more.

Current upgrade plans include:
• Increased intake valve size to 2.100 and port work
• Change fuel to Methanol w/3 2 barrel carbs
• Change to 2” (larger) primary headers
• Increase CR by 1 number

Although very interested in comments and suggestions on everything, I am particularly interested in camshaft events. Limited to 5,500 rpm by rules I have concerns that with an extra 10% in flow my cam will be too big for best performance.

Current engine specifications are provided below. Thanks in advance for any input I receive.

John


Reciprocating Assy
# of Cyl 6
Bore 4.375
Stroke 4.420
Rod/Stroke 1.71
Displacement 399 CID (Same cylinder size as in a 532 CID V8)

Cylinder Head
Int Dia 2.000
Int Flow 61 @ .100
Int Flow 272 @ .500
Int Flow 293 @ .700
Port Length 5.500
Port Volume 192 CC
Avg Port Area 2.13 in2, 1.647 Dia Equivalent
Min Port Area 1.87 in2, 1.544 Dia Equivalent

Exh Dia 1.650
Exh Flow 56 @ .100
Exh Flow 204 @ .400
Exh Flow 240 @ .700
Port Length 5.000
Port Volume 147 CC
Avg Port Area 1.79 in2, 1.511 Dia Equivalent
Min Port Area 1.68 in2, 1.463 Dia Equivalent

CR 14.0
DCR 10.4
Chamber Disk, Center Plug, 0.254" high

Cam
Type Solid Roller
Rockers 1.78 Rollers, Stud mounted

LCA 106
Advance 3.5

Intake
Dura @ .005 Valve 295.2
Dura @ .020 Cam 282.3
Dura @ .050 Cam 253.6
Lobe lift 0.430
Net Lift 0.738
Centerline 102.5

Exhaust
Dura @ .005 Valve 303.1
Dura @ .020 Cam 293.1
Dura @ .050 Cam 265.0
Lobe lift 0.416
Net Lift 0.723
Centerline 109.5

@ 0.005 Valve Lift
IVO -> 43.5 BTDC
IVC -> 71.7 ABDC
EVO -> 79.9 BBDC
EVC -> 43.2 ATDC
Overlap 86.7 Deg

@ 0.050 Cam Lift
IVO -> 23.9 BTDC
IVC -> 49.7 ABDC
EVO -> 61.7 BBDC
EVC -> 23.4 ATDC
Overlap 47.3 Deg

Intake
Description Tunnel Ram / Log Manifold Cross (For an inline 6)
Carburation 570 Holley Avenger X 2
Fuel VP Q16 Exhaust
Description 3 into 1 X 2 w/Merge Collector
Primary Stepped, 1.75 OD to 1.875 OD, 37" long
Merge Choke Dia 2.5" OD
Collector 3" OD X 18" Long
Performance
Power 532 BHP @ 5100 rpm
522 BHP @ 5500 rpm
Torque 592 Ft-Lbs @ 4200 rpm
500 Ft-Lbs @ 3000 rpm
Comes on cam @ 3600 rpm

got room to fit a big blue bottle on that thing.

yes that is very unique.
I am far from an expert here, but I would love to play around with that. By your numbers you are pretty much optimized. I agree with 3 x 2 bbls, for better distribution mostly, and a little more flow. Some more port flow also, Any more cam timing and it will need to RPM higher. Compression increase will help a little, but not all that much since you are up there already. I would try 3.5 in collectors, and maybe advance the cam some more. well that my opinion for what its worth., good luck, would like to hear your results.

Bumps440 wrote: ↑Sun Oct 10, 2021 9:37 pm I would try 3.5 in collectors

Isn't that a bit big? It's only a three-cylinder collector taking in 1.875 pipes with evenly spaced exhaust. The duration vs length equation probably works out that there's only one pulse going through at a time.

That said, I don't know what I'd be trying to adjust it to, if anything. His size off the head is near on exactly what Exhausted recommends too so he's either really lucky guessing or got some good math behind it.

FWIW, I'll put that engine into Engine Analyzer tomorrow at some point. It'll be fun.

P.S. What's the length on that inlet manifold? EA will want me to know that and I can't guess well enough from picture clues

BLSTIC wrote: ↑Mon Oct 11, 2021 12:10 am FWIW, I'll put that engine into Engine Analyzer tomorrow at some point. It'll be fun.

P.S. What's the length on that inlet manifold? EA will want me to know that and I can't guess well enough from picture clues

Looks very likely too short for that engine speed.

Inlet tract specifications:
- Inlet to flange 10.750"
- Inlet to valve 16.250"
- Dia at inlet 2.187"
- Dia at flange 1.870"

Are you allowed to run individual stack mechanical fuel injection? There are many old Hillborn, Jackson, Enderle, floating around the internet. Try to find one from a BBC or BBF already set up for alcohol.

I have concerns that with an extra 10% in flow my cam will be too big for best performance.

Another advantage of IR is it is much less affected by cam duration/overlap.

Carbureted only.

mn77spl wrote: ↑Mon Oct 11, 2021 1:20 pm Carbureted only.

One could accomplish the same IR tuning with a pair of the old 3-bbl Webers, but they're hen's teeth and learning to get them right is a too-long process.

How long would the runners have to be to effectively have the same isolation and ram tuning on a plenum as an IR setup? With a 5500 RPM limit, that wants 16" or longer runners, doesn't it? (84,000 / tuned rpm = runner length measured from the back of the intake valve to the start of the radiused entry of the runner with the port cross section area 83% of the valve area in the intake port and taper out at a 3.5 degree angle as it goes toward the entry of the runner.)

Unique Engine – More Power Needed
Post by mn77spl » Sun Oct 10, 2021 7:09 pm

Current upgrade plans include:
• Increased intake valve size to 2.100 and port work
• Change fuel to Methanol w/3 2 barrel carbs
• Change to 2” (larger) primary headers
• Increase CR by 1 number

Current engine specifications are provided below.
Thanks in advance for any input I receive.
John

its not often someone Posts such great detailed Engine Specs as you did !
much appreciated for all your Data !

PipeMax v4.70 correlation of your Engine was very good .

your Engine was also making very close to the correct amount of Peak Torque
for the amount of Peak HP ... which usually indicated Cam Specs are pretty close
and Headers and Induction are close as well .

i also simulated 5500 RPM Limit and Q16 -vs- Methanol

the only problem i see is :
your Cylinder Head Intake Port average velocity FPS is already too fast
and most probably already hurting Peak HP output .

If you switch to Methanol + move the TQ and Peak HP Curve to the 5500 RPM Limit
Methanol will definetly need a larger Cross-sectional area Intake Port
nearly same thing for Q16 @ 5500 RPM

If you go to a 2.100" OD Intake Valve + Port Heads more
increase the Intake Port's CSA enough to slow down the Port's Average FPS
speed to around 310 to 320 FPS

If you can't decrease your Intake Port's 'average Port velocity FPS"
at 5500 RPM Limit after you go to 2.100" Int Valve + Porting .
then by spreading the Cam LSA @ 5500 RPM to an LSA=110 can "help out"
by preventing Exhaust overscavenging that will increase
an already too fast Intake Port CSA's FPS .

PipeMax v4.70 (3)Simulation Files into 1 Zipped File of your Engine at 5100 RPM and at 5500 RPM with new changes :

I’ve got no advice.......but wanted to say that thing is pretty cool

If you don’t have one then make a close fitting crank scraper.
Have you played around with longer spark plugs for better/ faster flame travel?

Only 147CCs for what sounds like a long 5” exh port?

Anyway big time congratulations on the level of power it’s making now!
What you’ve done is no easy feat!!

PRH wrote: ↑Mon Oct 11, 2021 3:21 pm I’ve got no advice.......but wanted to say that thing is pretty cool

Seriously. Made me snicker just reading about it. In an old tractor... just fantastic!

Adam

Vizard suggests (in one of his BBC articles) that all big engines are under-valved (valve OD vs. per cylinder displacement), and that a method of improving VE without increasing the peak power RPM is to narrow the LSA and advance the cam.
Possible?