308 Spark Timing

[Deleted User] · July 2009

I'm still having lingering problems with my 4-barrel setup and spark timing.

The one thing I'm finding is that these engines are very, very specific in what works and what doesn't. Particularly true with its spark timing. When I set the timing to work at high rpm, the low rpm range isn't right. Vice versa.

Generally, I can set the timing at idle with a vacuum gauge and its close. Keep jacking it up until you get the highest vacuum reading, then back off 1" Hg. However, I had never known my mechanical curve characteristics or how it was behaving through its rpm range.

I had assumed I was running fairly close to the factory mechanical movement. This made me believe that my 1" less rule was landing me at 8* BTC at idle speed 750 rpm. I had the fortune of finding a man in my community with 6 distributor machines, and made a discovery.

We ran my IAT-4203A, and found this:

2* @ 500

10*@1750

15*@3100

20*@3600

crank degrees at engine rpm

The info I have is for a IAT-4009, book specs

0*@1000

2*@1350

8*@2300

16*@3650

18*@4000

crank degrees at engine rpm

The little number stamped on the arm of the vacuum advances are the degrees of movement in distributor degrees, which is half what you'd read on the flywheel.

I'm getting alot of mechanical advance early. My alledged 8*, evidently is only 6* with the distributor already giving me at least 2* at 750 rpm. The engine runs great with enough torque to pull any hill in my country with a 3.07 rear end in 3rd. The problem appears when I get into the 3000 rpm range and the engine begins to surge like it wants to keep revving, but something isn't right. When everything is right for cruising below 3000 rpm, I can't get the engine over 3000 without this "surge" in any gear. When I jack the timing up to get over 3000, it pings up there and is piggish at the lower rpms.

Let me take out a couple of things. No vacuum leaks and the exhaust is hooked up on a digital A/F meter with O2 sensors and is running perfect numbers in terms of fuel mixture all the way through. 13.5 idle, 14.5 cruise, 12.8 low vacuum primary acceleration, 11.8 secondaries in at WOT. (Ralph will like that last number - McCulloch here we come!) I have worked my carb to death, and there just isn't anything left to fix in that dept.

What say you, super tuners of the Hudson world. Do I need to slow the curve down and get a vacuum advance of more movement for cruising? I'm running the 3.5* canister now.

Mark

dougson · July 2009

At what rpm do the secondaries open? Did this >3000 rpm problem exist before the four barrel was installed?

[Deleted User] · July 2009

Its an older mechanical secondary AFB. No air door secondary etc.

It does it whether I'm running it on the primaries or the secondaries. It seems to be purely an rpm related thing.

This engine hasn't had anything but a 4 barrel on it. My Wasp had a similiar problem running a 2 barrel, just adding some initial timing cured it right up. The Wasp engine is a very tired old 308 with a 262 iron head on it, the 308 w/4 barrel is a fresh overhaul running a reworked aluminum head at 8.2:1 compression.

I have no idea what the timing curve is on the Wasp distributor either. Might not be a bad idea to swap them, or at least have the Wasp distributor mapped too?

The 2 barrel engine will run a higher vacuum at 3000 rpm than the 4 barrel.

I'm also running a modest "344" camshaft on the 4 barrel engine.

Somebody else suggested that it might be the fuel pump not being able to keep up with the demand?

RL Chilton · July 2009

"Somebody else suggested that it might be the fuel pump not being able to keep up with the demand?"

That could be a very strong likelihood. You can always find out how much pressure you have at the carb. If it's close to stock, which I don't remember off of the top of my head, then it probably won't be enough for the 4-barrel. If your floats never stop the flow, you very well could be starving. A lean engine will also run hotter, and often too hot. Better to have slightly too much fuel pressure than to starve an engine. .02

[Deleted User] · July 2009

I need to rig up something to check the fuel pressure. The only clue I have that it may not be the problem, is that my A/F meter is running at 11.8:1 when this starts happening. Which is kinda rich.

It hangs there, right on 11.8. If I back out of the secondaries, it hangs at 12.8 running on the richened up primaries at low vac.

If I didn't have the A/F meter, I'd swear it was leaning out.

[Deleted User] · July 2009

Hudsonator,

if you remember I locked out the mechanical advance and vacuum advance both in the dist I am running in the supercharged 308 PaceMaker.

I do not have any surging problems at all.

No ping, no run on.

It is a little hard to start but has always been since I supercharged it but

I believe its a combination of the 18 degrees initial advance & the accelerator

pump in the R2 Avanti carter carb is not squirting enough. the old Autolite

4100 started just fine.

right now I am running 18 degrees total since its all locked out.

before when I was running mechanical & vacuum advance it would tend

to act like it would try to run over its self at higher (3800) rpm and above.

even setting the initial advance to 2 before i would end up with 30+

at the higher rpm levels.

with the vacuum advanced locked out and with just mechanical advance

it was still giving me too much advance at the higher rpm but did respond

better bottom end and ran cooler. i never could get it down below 24

degrees total.

it took me several weeks to finally get down to 18 degrees but the car

was 2 tenths quicker in the 1/8 mile with everything locked out and set

at 18 initial.

i have found that 90 percent of my supposed fuel issues ended up being

ignition related problems.

let me ask you this: You still running 6 volts? is so do you have one of the

high output 6 volt coils from Pertonix? Good chance you are experiencing

some miss firing. I would tighten up the plug gap by .010 and see if that

helps. I can only run .028 on mine before the flame gets blown out by

a combination of boost and the high turbulence in the L-head designed

combustion chamber. (old trick I learned on my first turbocharged car to

prevent miss-fires).

later,

PaceRacer50

dougson · July 2009

Many folks out there know a lot more about these flatheads than I do but from what I've learned these engines are very sensitive to compression ratio. Also, from the mixture data and the "surging" you are reporting I doubt fuel pressure is a problem but it is a good idea to install a gauge. I always do. Low fuel pressure would cause cutting out at WOT. The 344 cam you are using was the replacement for the flat top and was a lower lift/duration? If so I would not rule out that you have too much carburation. With the high (>8) compression, detonation is going to occur with advancing the timing...

[Deleted User] · July 2009

Ralph, I appreciate your insight.

Were you running the 18* without the Supercharger?

I am now running a Pertronix Ignitor and the 45K Volt Flamethrower coil. I hadn't considered spark gap being too wide, I'll check that out. Any particular plug/brand you'd recommend?

I think I know how to fix your pump shot problems. Use an accelerator nozzle off the early mopar 383 version of the AFB #3856S. We probably need to start another AFB thread. You help me on the timing, I'll try to help you hone in that raucous R2 AFB.

Mark

[Deleted User] · July 2009

dougson wrote:

Many folks out there know a lot more about these flatheads than I do but from what I've learned these engines are very sensitive to compression ratio. Also, from the mixture data and the "surging" you are reporting I doubt fuel pressure is a problem but it is a good idea to install a gauge. I always do. Low fuel pressure would cause cutting out at WOT. The 344 cam you are using was the replacement for the flat top and was a lower lift/duration? If so I would not rule out that you have too much carburation. With the high (>8) compression, detonation is going to occur with advancing the timing...

The effect the 344 cam might have is making my running compression high. Its really conservative and traps alot more of the theoretical compression. The 344A I have is 258* duration and .390" lift. The bigger cams bleed off more compression. This started off as a solid, conservative project to be topped off with a low-boost, variable sheave McCulloch. Even the McCulloch is a low-boost Kaiser unit, designed for longevity and durability.

My carb is a conglomerate of different, early AFB carbs. Began as a 2641S, 1-7/16" throttle bores on all 4, off a '58 273LA powered Chrysler. Maybe 375 cfm. I further cut that down by transplanting larger secondary boosters from a #3856S carb. Nearly 1/4" difference in diameter larger than the originals. I would be lucky if this carb is able to pass 340 cfm @ 1" Hg. I was shooting for a single 4 barrel carb about the same cfm as the Twin-H, or barely more.

I guess you could say this engine represents the most basic of parts, with as little internal modification as possible - trying to match bolt-on parts to get the effective use of what's there.

The most amazing thing about this basic setup, its destroying transmissions left and right with its mid-range torque. Twisted input shafts and the one in it don't feel so good, took out a set of universals too. I've never dumped the clutch on it, but I have dumped the throttle on it after its rolling in 1st. All of that and I evidently still don't have all the kinks worked out? The McCulloch isn't on it either - yet! Remarkabale engines for thier time. Hudson should have made tractors based on this engine, its the torquiest thing I've ever seen for the displacement.

[Deleted User] · July 2009

I sure am enjoying all this hi-tech stuff and am trying to learn, will be interested in trying out some of these setups when ya'll get the bugs out. I really am enjoying reading these, no kidding. Bob

464Saloon · July 2009

`Hudsonator wrote:

The effect the 344 cam might have is making my running compression high. Its really conservative and traps alot more of the theoretical compression. The 344A I have is 258* duration and .390" lift. The bigger cams bleed off more compression. This started off as a solid, conservative project to be topped off with a low-boost, variable sheave McCulloch. Even the McCulloch is a low-boost Kaiser unit, designed for longevity and durability.

My carb is a conglomerate of different, early AFB carbs. Began as a 2641S, 1-7/16" throttle bores on all 4, off a '58 273LA powered Chrysler. Maybe 375 cfm. I further cut that down by transplanting larger secondary boosters from a #3856S carb. Nearly 1/4" difference in diameter larger than the originals. I would be lucky if this carb is able to pass 340 cfm @ 1" Hg. I was shooting for a single 4 barrel carb about the same cfm as the Twin-H, or barely more.

I guess you could say this engine represents the most basic of parts, with as little internal modification as possible - trying to match bolt-on parts to get the effective use of what's there.

The most amazing thing about this basic setup, its destroying transmissions left and right with its mid-range torque. Twisted input shafts and the one in it don't feel so good, took out a set of universals too. I've never dumped the clutch on it, but I have dumped the throttle on it after its rolling in 1st. All of that and I evidently still don't have all the kinks worked out? The McCulloch isn't on it either - yet! Remarkabale engines for thier time. Hudson should have made tractors based on this engine, its the torquiest thing I've ever seen for the displacement.

Mark, sent you a PM did you get it?

[Deleted User] · July 2009

464Saloon wrote:

Mark, sent you a PM did you get it?

Just PM'd you back.

Mark

[Deleted User] · July 2009

mark,

yes I did run this 308 with the locked out dist and 18 degrees total timing without the McCulloch on it. noticed it did run cooler and performed better

at the track like this. funny thing was driveability went way up once I locked

out the timing.

you are right about the torque being tractor like. so far i have only destroyed

one race built 350 turbo, one driveshaft, ripped the spring perches off the

8.8 rearend I installed and balloned one 10" diameter 2800 rpm stall

converter! And all of this was before I added the supercharger...

right now I have excellent driveability. the bog i had is still there right off

idle but not noticeable because it is much shorter than before. usually i

do not hammer her from a dead stop without the converter loaded up

some and the big is no longer a factor then.

my only issue is getting her started when cold or after she has set for a

few days. a little shot of starting fluid always works for now.

on the McCulloch supercharger, I am seeing my boost vary between 4.5-

5 lbs while on it. I checked the belt & pulleys to make sure its not slipping

and that does not appear to be a problem. I think the engine is a little large

for this old modded VS57 I have. Next step is to a SN92 or newer Paxton

with a upgraded impeller and better ball drive. I read that one of the guys

makes ceramic balls now for these to better handle the heat.

apparently they are able to be packed tighter, do not gall up the bronze

ball drive or the impeller shaft. a cooler is recommended but thats next

on the list of mods. i really would like to get up to 7lbs of boost with the

supercharger.

later,

PaceRacer50

[Deleted User] · July 2009

With me being on the street, I think the vacuum advance still has a place.

Actually, given the 18* situation - I'm seeing that place pretty plainly. I'm throwing back to my tractor days, I actually had to set a distributor up like this before due to hand cranking. Where the mechanical was really quick and spaced out over about 2500 rpms. It allowed me to run 4* retard at cranking (by hand) then would jump up to 4 BTDC once it fired. I'm seeing a similiar curve applying here.

If I can get it all in at 2800-3000, 20* total mechanical - that would put me 2* retard at starting rpm. Jumping up to probably 8* by 750-1000rpm at idle. 12*@1500, 16*@2500, all in 18*@2800-3000.

Here's where I see the vacuum advance. Evidently, I have been running real well in the mid range 1800-2800 rpm at high vacuum/low load in the 23-28* advance range. So, given the projected new curve - I'll be in the same range at high vacuum/low load with a 7* canister. In high load/low vacuum - I should be in Ralph's range with +/- 2* of initial to play with.

Thanks Ralph, I'm gonna get on this.

Mark

dougson · July 2009

`Hudsonator wrote:

The effect the 344 cam might have is making my running compression high. Its really conservative and traps alot more of the theoretical compression. The 344A I have is 258* duration and .390" lift. The bigger cams bleed off more compression. This started off as a solid, conservative project to be topped off with a low-boost, variable sheave McCulloch. Even the McCulloch is a low-boost Kaiser unit, designed for longevity and durability.

My carb is a conglomerate of different, early AFB carbs. Began as a 2641S, 1-7/16" throttle bores on all 4, off a '58 273LA powered Chrysler. Maybe 375 cfm. I further cut that down by transplanting larger secondary boosters from a #3856S carb. Nearly 1/4" difference in diameter larger than the originals. I would be lucky if this carb is able to pass 340 cfm @ 1" Hg. I was shooting for a single 4 barrel carb about the same cfm as the Twin-H, or barely more.

The most amazing thing about this basic setup, its destroying transmissions left and right with its mid-range torque. Twisted input shafts and the one in it don't feel so good, took out a set of universals too. I've never dumped the clutch on it, but I have dumped the throttle on it after its rolling in 1st. All of that and I evidently still don't have all the kinks worked out? The McCulloch isn't on it either - yet! Remarkabale engines for thier time. Hudson should have made tractors based on this engine, its the torquiest thing I've ever seen for the displacement.

I am familiar with the early square bore Chrysler AFB's, I have two on my '56 Corvette and you're right, there are about 400 cfm each. If you have reduced cfm to 375 then you are near the twin-H cfm, so carburation is not the issue. I did not know that the 344A replacement was .390 lift, which is close to the super 7X except with less duration. It's interesting to note that this cam in a typical OHV V8 would have total lift of .585! I'm still trying to learn more about the various Hudson cams, many earlier posts and websites have conflicting or confusing information. For example I have a '56 engine I am having rebuilt with 7X modifications. The cam that came with the engine is a 309742 (stamped), the supposed flat top cam that emerged in '54 and was replaced by the 344A. The engine has hydraulic lifters. I have seen three different lift characteristics posted for the 309742; .352, .372-5, and .391. The duration has been reported at 268*. I measured the lift of mine and it is .375. Is the '56 309742 exactly the same as the '54 309742 and why would Nash resume use of this cam if it was so troublesome? Maybe the use of hydraulic lifters made it smoother.

I'll be sticking with the twin-H, aluminum head, 309742, plus .060 o/b, 7X valves, and hand work on block. I intend to have a timing wheel mounted at the front so I can actually see increments of degrees with a light. I am sure it will help when it comes time to time my engine.

[Deleted User] · July 2009

The cam we're running is the 344A, which was the replacement for the early '54 "chain stretcher" 742. There was a long discussion about camshafts about a year or two ago, I need to look that one back up.

To be honest, we chose this cam because it showed no wear on the lobes. We chucked it up in a lathe and measured the lift. It was .390-.391". That certainly doesn't mean that it wasn't reground sometime before we got it, so I wouldn't swear it to be a factory grind. The engine we took it out of had been rebuilt at some point in time as it had .060" over cylinders. I have no idea what the base circle is, because we just dial indicated it off whatever the base was.

The 258* @ .390" is probably just good luck on our part. We need some on occasion. I wish I had paid more attention to its numbers. I didn't even really "degree" it in beyond measuring its duration. I have no idea what its centerline is. If I ever have the head back off, I'll do that - I'm happier with the cam than I thought I would be.

I took the distributor out over lunch and built a tool for adjusting the advance springs with the spark plate installed. We have an appointment with the Distributor Dr. tomorrow evening - so hopefully we'll have some results by week's end. If we're lucky, I'll be able to post some pics etc. by Sunday.

For sure, try to rig up some kind of timing pointer arrangement other than the peep-hole in the engine plate. Its not bad, but terribly subject to paralax error with a timing light. I need to make a piece/pointer that shortens the distance from the plate to the flywheel to minimize the chance for error. I think Hudson actually made such a piece, but I don't have one.

Mark

[Deleted User] · July 2009

Mark,

one thing to remember is that I drive mine more on the street then race her

at the drag strip. You are running way more gear than I am and with the

advance locked I am not experiencing any detonation. The 3:55 to 1's I

have need to be replaced with 4:10's this winter. its only at 3300-3400RPM

at the finish line in the 1/8 mile.

i really love the 18 degrees btdc. it seamed like with the mechanical advance

active the engine would tend to feel flat at the higher RPM's like it had too

much advance.

My old 348's and 409's felt the same way in the upper RPM when screaming

down track. I tried to limit the mechanical advance but it just would not

cooperate! that's why it got locked out...

my next step is to add a MSD starting retard unit to back it down to about

4 degrees BTDC to start then advance it back to 18 once it is running.

Also since I modified the crankshaft to use the SBC harmonic balancer I did

make a pointer for #1 being at TDC. It points straight down at the balancer

and works really good.

good luck and let me know when your ready to bolt the McCulloch on.

later,

PaceRacer50

[Deleted User] · July 2009

Ralph,

If I can't get the curve I want with 20* movement and 2* retard at cranking speed. I'll swap the rotor mount/weight limiter out of a mopar IAT. They are only 16* mechanical. I may even have one that is 14* out of a power unit distributor.

We'll recurve this distributor first this evening, adjusting the spring tabs to set the tension. If this don't get me in the ballpark, I'll start junk diving into other IAT's and getting serious about weight limiting.

We are running a tall gear. Which is why I want to keep the vacuum advance for now and some degree of weight movement.

Getting this straightened out, working on a fuel pump for boost next, then we'll be ready for the McCulloch - FINALLY! You know we'll be talking to you then.

Mark

[Deleted User] · July 2009

Fixed.

I forgot to take pictures. So I hope the description will suffice.

We first tried to re-bend the spring tabs to adjust the timing rate. That did not work at all. The spring movement is so little, the rate stayed the same. We tried one weak spring from a Ford points type distributor for the FE series engines and one stock spring. The rate of advance didn't change one tiny bit from what I first posted. Two of the FE ford type springs - did the trick.

The new curve: engine degrees @ crank rpm

0@750

10@1350

15@2000

20@2500

Retarded the timing 2* initial. Cranks like a charm, runs out great to whatever rpm I want to run, and runs a tad bit cooler. We're also running the 7* vacuum canister, which is also working out very well on the road and load changes. Dad loves the difference, we still have our hill climbing torque at whatever throttle position, with that famous "Instant Action!".

One last note on the AFB, which also helped the situation. We plugged the holes that were factory drilled into the throttle bores just below the venturi and above the throttle blades. These holes went right out to the exterior, and subjected the throttle bore to atmospheric pressure at a place atmospheric pressure has no business. This was messing up the vacuum signal just a tiny bit and was causing some quick lean-out to blips onto the A/F meter. After plugging these, the blips were gone and throttle response improved a great deal.

The timing really helped the most, the additional carb work just made a good situation better.

Jegs part number for the springs we used:

Mr. Gasket #720-925D

Fits 1965-Up, Most Applications, Includes 1-Set of Springs

Mark

[Deleted User] · August 2009

I want to add a little bit of information here. Since we're way off textbook settings, we might as well go all out. I've violated another factory Hudson situation that has worked out pretty well in conjunction with our new mechanical advance curve.

We drove the car around alot Saturday. I was really happy with the setup out on the road in the 1500+ rpm range. However, I noticed something lacking while navigating traffic at low speeds.

With the new curve and the near zero initial setting (+/- 2*), I noticed my off idle rev was a bit slower than before. In the right traffic situation, I'd have a low speed stumble right off the idle. Such as making a slow pull-out from an intersection. Not stabbing it, just easing into it right off a standing idle. I'd have to pat the accelerator to get the car up to 1200-1500 rpm before pulling out. This never happened under the first timing setup, but I was running 7-8* BTDC at an idle speed of 750 rpm to accomodate the previously long timing curve.

Looking at my old curve and initial vs. the new curve and initial, it jumped right out at me. Why not run the vacuum advance off full manifold vacuum? Hudsons have 7* vacuum advance canisters, similair to my lost timing advantage at idle. The stumble was because the engine was actually a bit low in timing with the new curve at low rpm and was having to wait for the throttle blades to tip enough to give it that needed advanced timing.

Now, we have 2* retard at cranking speed with the engine going immediately to 5* BTDC once fired. It cranks as soon as it turns over and is very "free" doing so. The 2* initial retard is to help me hit that 18* total mechanical in the upper rpm ranges. The slight retard also makes starting easier on my 6v setup. My low speed issues seem to have gone away.

This is why I didn't want to get rid of the vacuum advance. Thanks to a previous discussion with Lance Walker about vacuum advance canisters, they can be found in different amounts of movement. Commonly in 7 and 10 crank degrees. If road trials lead me to believe I'd be better off with 7-8 degrees at idle rpm with 3-2* retard at cranking, I can use a 10 degree canister and tailor my low speed timing with full manifold vacuum without effecting my upper end timing numbers.

Mark

[Deleted User] · August 2009

Mark,

i'm going to go back and print off your info and look at trying this in mine to help her start better. sounds like you are getting close to where you want

to be.

Now lets get that McCulloch VS57 on there!

good luck and talk soon,

Ralph

aka: PaceRacer50

[Deleted User] · August 2009

Yeah, I'm slowly working my way up to that McCulloch.

To be honest, I still have some carb work left to do. When I plugged those open holes that went from below the venturis to the outside, it changed my A/F . Particularly in the secondaries, where I'm down to a wiggly 10.8. I have the feeling that if I were running a later model 9400 AFB, I would be finished with this. The secondary transition circuit and the secondary air door of the 9400 would further smooth out my top end situations. My plan was to have two carbs, the early AFB for the McCulloch and a standby 9400 should I need to go back to naturally aspirated.

I'm also having a small problem with the vacuum canister, its leaking just a little and causing some sporadic lean conditions. Its leak is getting worse and could be a more major contributor to the high end waffling (which has moved well on out beyond 4000)than I'm giving it credit for . I have a NOS 10* canister that doesn't leak - yet. I'm going to put it in and move the distributor a degree or two further at initial and see how that goes before plunking down the big bucks for a rebuilt unit with a newer diaphragm material.

However, yesterday evening I took about the most exhilarating ride in the '49 I've ever had . What tuning is left to do is mainly just to be sure the engine isn't being hurt by some out of kilter situation. I'm chasing very minor little things - which makes me feel better than I did. When I finish this early AFB, I'll tune up a 9400S.

I suppose one could say I'm overly nit-picky about this stuff. That assessment sure doesn't bleed over into the car's looks. Maybe one of these days?

Mark

[Deleted User] · August 2009

LOOKS?!

you have seen mine.... looks like it was feed thru a meat grinder and got stuck half way........

I found that the less I try to tune mine the better it does. Kinda like all the other hot rods I have had.

I am still running the original jetting & rods that came from the Studebaker factory for a 1964 R2 289 4speed car except that I went 1 jet richer on the

secondaries.

My next change will be to a more modern PAXTON supercharger. I am wanting

to step up to a SN92 with a upgraded impeller. it will still fit my brackets, look

like a SN60 and put out about 3-4lbs more boost than I have now.

The AFB is actually jetted for one of these blowers as I am rich now with the

boost level I am at.

anyway I need to go. 3hrs of sleep last night. no power from 1:00pm until

sometime after 12:00am this morning. trying to decide if I want to stay at

work or go home and collapse.

later,

PaceRacer50.....

[Deleted User] · August 2009

I've been working with alot of different point cam plates lately, all from IAT-type distributors. One of the things that has puzzled me is the variation in total mechanical advance experianced by distributors of the same type.

The reason is that only .010" wear in the limit slot and/or the limit pin, adds 2 crank degrees of timing.

My IAT-4203A was supposed to have only 18* total mechanical, it tests at 20*. Measuring the limit slot in its cam plate vs. a really nice IAT-4009 reveals the same slot length. The 4203A's cam plate is worn and you can see it, hence the added 2*.

Just as a rule of thumb, using the limit slot length to determine total mechanical movement.

0.385"=20 degrees on the flywheel

0.375"=18

0.365"=16

0.355"=14

After messing with the IAT, the total mechanical movement seems to = (slot length - limit pin diameter)/ total mechanical advance in distributor degrees. It always comes up to .010" per distributor degree.

Cam plates are hard to come by without buying the whole distributor. If nothing else, maybe that can help somebody get thier own cam plate re-furbished or determine whether its worn or not.

Mark

308 Spark Timing

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