Engine and Transmission Tech

I thought I'd start a companion thread to the "Serious Cams" thread.
Recently, I've designed several custom cams using the latest version
of the engine simulation software Dynomation5. These cams will be
dyno tested as part of an engine development program I'm running for
a non-Rover V8 (Ford 351C). Before designing the cams, I tested the
software for accuracy using several engines that I've flow bench tested
and dyno'd. The engines I've tested span a pretty wide range from the
small port, small valve, Rover 3.5L V8 at one end of the spectrum to
the large port, large valve (intake valve diameter ranges from 2.04"
to 2.19") Ford Cleveland V8 at the other end of the spectrum. When fed
detailed data, the simulations have been surprisingly accurate, though
the trends that hold for an engine with excess cylinder head flow are
quite different than those observed for the induction limited Buick/Rover
V8's.

> I suppose this whole "romance" of automatically running more exh. lift,
> and or duration, came about by the "grinders" deciding to "prop-up" an
> underflowing exhaust.

I'm not sure where it came from but more lift on the exhaust side is
generally not of use because the port blows down quickly in the lift
cycle. Extra duration is usually of benefit, particularly when
restrictive mufflers are used.

> We're seeing, some heads, exhaust side, now flowing 85+% of the intake
> side.

Vizard suggests, when using the same lobe on intake and exhaust sides,
the rocker ratio on the exhaust is best kept 0.1 to 0.2 of a ratio lower
than the intake ratio. If you check the cams used in last year's Engine
Masters Competition, most of the entries were using more exhaust duration
with either shorter exhaust rocker ratios or exhaust lobes with less lift.
I've dyno tested shorter exhaust rocker ratios (1.73:1 intake with either
1.65:1 or 1.73:1 exhaust) on a 351C Ford V8 and it made the best power and
torque with the shorter rocker ratio. In my custom cam optimizations,
I've notice similar trends. The best results were for split pattern cams
with more exhaust duration but less exhaust lift. One set of heads had
a strong exhaust port but a weak intake port (peak intake flow of around
220 CFM and a peak exhaust flow of around 200 CFM). With open exhaust and
single plane intake, an optimal cam was nearly the same duration and intake
but once muffler back-pressure and a dual plane were installed, the optimal
answer was split pattern with more exhaust duration and less exhaust lift.
Vizard's rules of thumb for optimal lobe separation angle appear to hold
best for single plane and open headers, though it also depends upon the
RPM range over which the cam is optimized. Ramp rate appears to be very
important with small port heads but less so with large port heads. Small
port engines tend to respond positively to high ramp rates. I dyno tested
my TR8 and it the Dynomation prediction was within 2 HP of the dyno result.
The Erson cam in that engine has a 2.0 ramp rate which is similar to an
OEM cam. That allows it to be compatible with the new but stock rate TR8
valve springs but I could make better power with a more aggressive ramp rate
and better springs.

I've been thinking about running a series of cam optimizations for popular
Buick/Rover displacements:

3.5L Rover/215 Buick
3.9L/4.0L Rover
4.2L Rover
266 cube Buick 215 (300 crank in 215 block)
4.6L
4.9L (Rover 3.7" bore block with 300 crank)

With ported and unported head flow data. I'd need to settle on some lift
limits and RPM ranges. For the higher performance stuff, I'm thinking
maybe a maximum valve lift of around 0.550". For less modified heads,
any input on what a good lift limit would be? Maybe 0.5"?

I could also input popular cam profiles (Crane H216, Erson RV10/RV15,
Crower 50232, etc.) and see how they compare to each other and to the
optimized cams.

Dan Jones

Dan, concise as always. We got (10) blanks that can go .397" at the lobe.(2) with "vari-cam" potential,(sbc. belt drive). I suspect a throttle position or vacum controlled, plenum divider,(telescoping), on a good single plane man., could have merit, in concert with exhaust port mismatch(Vizard), and possibly stepped primaries, should perk-up the intake side. I'm saving (1) roller for a 6V-71 roots, on a Rover, perfect fit, blower can run up to 20 lbs. manifold. Thanks for the serious tech. roverman.

Dan, I'm also curious to see how rod ratios play into the calculations. The later Rover engines have different rod lengths. Using shorter rods is supposed to improve torque at lower RPMs. Perhaps the software isn't able to process that detail of data, but it would be interesting.

Which heads for the 351C were you going to model?

Art, the stiffness of the lifter bores might limit the ramp rates we can use on our roller cam project. This is information I just learned last night. I'm still trying to process the information and how to accommodate it; weld up a brace, use a bolt-on gypsy rig, prayer.

Dan
Can you model a custom cam for me?

3.7 bore with 3.4" stroke Rover.
Ported 64 Buik 300 heads with stage 1 valves.
12 to 1 compression running on e-85 with willpower single plane and 600 to 650 cfm double pumper.

Cam is solid roller Net lift .536 intake .551 exhaust

IVO 33 IVC 69
EVO 74 EVC 38

> Dan, I'm also curious to see how rod ratios play into the calculations.
> The later Rover engines have different rod lengths. Using shorter rods
> is supposed to improve torque at lower RPMs. Perhaps the software isn't
> able to process that detail of data, but it would be interesting.

The software does simulate the rod ratio/length. I know that, all
things being equal large port engines prefer shorter rods than small
port engines. Theory says that induction limited engines would
like longer rods but in what I've seen so far, the effect is minor.
I spoke with multiple time EMC winner Jon Kaase about this and he
said to run rods at least 2" longer than the stroke. He say's that's
worked well on every thing they've built form small port 289's to
big port IHRA Mountain Motors.

> Which heads for the 351C were you going to model?

We have a bunch on hand to flow bench and dyno test. All will
modeled in Dynomation as well. The list includes:

U.S. open chamber 2V iron
Australian closed chamber 2V iron unported
Australian closed chamber 2V iron ported
U.S. open chamber 4V iron unported
U.S. closed chamber 4V iron ported
Boss 351 closed chamber 4V iron
ProComp 3V aluminum
CHI 3V aluminum
CHI 4V aluminum
M-6049-A3 Ford Motorsport aluminum high port aluminum
M-6049-C3 Ford Motorsport aluminum high port aluminum
M-6049-C302 Ford Motorsport aluminum high port aluminum
M-6049-C302B Ford Motorsport aluminum high port aluminum

For those not familiar with the canted valve 351C heads,
the designations 2V, 3V and 4V do not mean the number of
valves per cylinder. They refer to the size of the ports
2V are smaller than 3V which are smaller than 4V.

We're also testing a boggling number of intake manifolds
and several different carbs including these:

[www.bacomatic.org]

Dan Jones

I use a European touring car cam[Tom Wilkenshaw SDI], which has a very limited lift due to the race regulations, runs a lot of overlap/duration. With my 3.9 it does make good power, 290hp and similar Torque, also a lot of compresson, 14:1.

Paul and clan, how many trashed, broke or worn-out, Rover lifter bores have we seen ? I suspect the reduced friction of the "roller" shall help the bores. I shall address, if/when it becomes an issue, ie billet alum. "spyder" that would interlock with "dogbones" ? Afterall, "Caddy" uses Bolt-In lifter tray ! How much force-really ? Of course rod ratio will affect dynamic compression at overlap and afterward. This explains difference in torque produced at various rpms. I'm getting quote for cast/forged, stroker cranks. Hopefully-someday, we'll have heads that need them. roverman.

Dan, Thanks. I have an Australian Cleveland block and Oz closed chamber heads and 4bbl intake for another project. Just a coincidence.

Yikes! Autolite in-line 4bbl. That's a rare carb.

Art, I glanced through a book on hopping up Buick engines and there was some discussion about the lifter bores needing reinforcement for aggressive cams. I'm thinking that a section of aluminum pipe could be fitted on top of the bores and tacked into place if need be.

Edit; Dan asked about lift limits. It looks to me like the Buick/Rover heads have an inflection point in their flow just above .400", something like .420" or so. Porting improves this, but porting mostly improves flow below that inflection point. I am going to aim for a max valve lift of .450 or slightly above that. I'll need to check valve/piston clearance to see what the limits are.

My 'design' goals are to come up with something that doesn't require a complete engine rebuild to make work. Trying to avoid changing pistons, working with stock heads, stock intakes, etc. I do expect to have to change valve springs.



Edited 1 time(s). Last edit at 05/05/2010 12:21PM by pcmenten.

Paul and clan, Ok we tack alum. pipe on top of bores, and toss the dog bones ? 215's have measureably less alum. around the bores and valley areas, than later Rovers. Will .420" lift clear "all" std. guides ? I suspect "passenger"(right) side row, of bore to be more problematic. For the cams we bespeak, not an issue. My "Huff GT-1" ran a 215" Buick block with "serious" Engle roller at 8k rpm./ rev kit/no-problemo. "IF" you bounce the lifters, BIG problemo! roverman.

Art, how do we get away from using the dog bones?

I'll have to buy that Buick engine tuning book just for the picture of the lifter bore reinforcing lash-up someone made so that they could use roller lifters on a 455 block. The casting of the lifter bores on the 455 looks exactly like the Olds 215 I have. I'm sure the spacing is different, but they left the area between the banks of lifters open, just like on my 215. The reinforcing bar they put over the lifters had a screw for each lifter bore that would be individually adjusted until it was bearing on the side of the lifter bore to reinforce it. Seemed like pretty extreme measures.

But I'm not looking to make a high RPM, high valve lift, max horsepower engine. I'm just maximizing what's possible in a 3.7" bore engine.

Paul,Dan and clan, In my last post, I did not "embellish", on the durability, of the 215 Buick/3.74" bore,mech. roller,Volvo rockers, running at or near 8K rpm., at Riverside-etc. Comparing the needs of a built 455", has very little cary-over usefulness to a Rover, (David/Goliath)? Why get away from dog bones ? OEM. provides the fast track to affordable hyd./mech. roller conversions for this series of motors. Pick a profile. I believe that a"smart" hyd. roller, will measureably help a Merlin or TA head over best effort flat-hyd. cam. Let's get going. Thanks, roverman.



Edited 1 time(s). Last edit at 05/06/2010 11:54AM by roverman.

What ever happened to this?

wondering about a high lift roller with wide lCA for EFI use..

Tony, I had (10) roller blanks made. Paul Menton bought (5). Retrofit has been covered in this forum and Buick V6 forums,(using the Chevrolet late V6 lifters(short), and dogbones.Good Luck, roverman.

Scheinder Cams has 350 sbb roller blanks, in stock. I'm not ENDORSING or SELLING ! Good Luck, roverman.

If the after-market people would get motivated and R & D a camshaft phaser kit (like the LS motor has) for the early motors, that would solve all of our cam choice problems. I assume that it must be too expensive to consider.......

Jac

Jac, how does adding a phaser to a cast iron "lump", solve all of our cam choice problems ? Is not purpose designed billet roller cams a sound advancement ? I'm glad you mentioned the "phaser", so happens I have (2) round lobe cores to accept sbc belt drives. Do you see where this is going ? All we need now is $10 M.and a parachute.(R&D funding) Cheers, roverman.

Isn't a camshaft phaser just a short stroke hydraulic motor? You'd have to balance it but it seems to me that a gearotor type setup would work and fit inside the cam gear. The cam gear would have to be cut out for it of course. Oil feed could be via the cam button and possibly run on engine oil pressure.

Jim

Jim and clan, since sbc belt is too long for sbb and rover,(shorter crank/cam centerline), this allows for oil pressure/spring actuated dual roller tensioners on belt. This should facilitate ample advance / retard of cam. Driving the distributor off of cam-not good. Onward, roverman.



Edited 2 time(s). Last edit at 02/28/2012 07:43PM by roverman.

Mates, hold on a bit; horsepower and fuel economy are back because of technology such as camshaft phaser (variable camshaft advance) and variable lift split lifters and etc,.

There's a couple of ways to advance and retard a camshaft with a phaser, one is a computer control hydraulic valve to rotate the cam gear, the other is electric movement (I think that Honda uses the electronic/electric system) both achieve the same.

The split lift lifter is also control hydraulically by the computer; it varies valve lift on demand depending on your right foot and engine load. It is also used to knock out cylinders (4-6-8) when cruising for fuel economy.

On my post, I was talking about the phaser only that could control cam advance on demand; again, the R & D cost should not be that bad since the technology already exist. A simple system based on computer control and oil pressure activated valving could work, that it either be controlled through oil pressure valving or electronic movement such as some Asian models........

We have LS series Tahoe and Suburban in our fleet with 6.0 Liters that have camshaft phaser in them; it's a pretty clever set up...... Ford utilizes a phaser on the right camshaft of their mod motors in later years; pretty neat technology...........