I am off to a Dyno day tomorrow, so I rented a timing light to ck my car(I used to own one and maybe it is still around here someplace). I tried it on all 4 plug wires and never found any timing marks on the flywheel. It did appear that the timing changed at higher RPM. One of my co drivers said timing could be adjusted by checking the vacuum pressure. Anyone heard about this or some other way to check timing? Might there be timing marks on the pulley?
Just checked. There is a small tab on the block with 4 marks on it near the front pulley(must be 30+ years since I timed a car) and a small round green spot on the pulley. I could still use some help here.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
I am off to a Dyno day tomorrow, so I rented a timing light to ck my car(I used to own one and maybe it is still around here someplace). I tried it on all 4 plug wires and never found any timing marks on the flywheel. It did appear that the timing changed at higher RPM. One of my co drivers said timing could be adjusted by checking the vacuum pressure. Anyone heard about this or some other way to check timing? Might there be timing marks on the pulley?
Just checked. There is a small tab on the block with 4 marks on it near the front pulley(must be 30+ years since I timed a car) and a small round green spot on the pulley. I could still use some help here.
Mark
Mark,
Formula Ford timing marks are frequently on the flywheel. Mine is timed on the right side of the engine using the bottom of the "pan" flange as the pointer (my starter is on the left). Sometimes they may be viewed from the top. Most, if not all, Formula Ford engine distributors do not have vacuum advance and who knows where you would find a vacuum port. Keep in mind that if you have points that point gap and the resulting dwell angle must be set also. Full advance timing typically is in the 38 - 40 degree range.
There is a chance that there is more than one set of marks on the flywheel. If so before changing anything find the marks with your timing light to determine which are "in the ballpark".
Ivey's web site has specs. Pegasus may also. Point gap, if relevant, is hard to set with used points but in any case dwell must be correct if you cannot measure point gap accurately. Note that Ivey's recommended gap is less than shown on Pegasus's data. Obviously Jay knows his stuff BUT his recommendations MAY be high rpm race track oriented to maximize dwell. I recommend that if you have points that you buy the "heavy duty" ones that Ivey, Pegasus, etc. sell rather than generic parts store points. Also, you need to determine whether you have the Bosch distributor (common) or Autolite/Motorcraft.
There are timing lights, then there are Timing Lights. If you have no marks, the simpliest way to fix the problem is with a timing light that you can "set" the advance.
You can find top dead center for #1 by pulling the plug and rotating the motor and watching the piston at the top. Even using something like a pencil in the plug hole, you can get fairly close to figuring TDC by repeating the procedure a few times and averaging.
Once at TDC take some time to inspect the engine, front pulleys, flywheel, etc to see if any marks are evident.
If you can't find a mark, you need to make one. Make one where a moving part comes close to a stationary part. Some older cars have holes in the top of the bellhousing to see the flywheel through.
Once you have a TDC reference mark you can set advance if you have a fancy timing light. With the more expensive lights you can dial in the advance you want on the light, but use the TDC mark to time it (the light does the math internally...magic).
Set the timing above 3500 rpm. The mechanical advance unit in the distributor should be fully advanced at that rpm level.
If you don't have a fancy timing light, just an old fashioned light, you need to establish a 38 degree BTDC mark. And that is a bit more complicated to do with the engine in the car. Not impossible but tough... and a whole nother post.
First get it to TDC with #1 firing and craw all over the car looking for possible marks.
Marking 38 degrees BTDC with engine in the car....
Ford motors usually have one of two flywheels. 110 teeth or 135 teeth.
You can count the teeth with patience while slowly turing the engine. I mark every tenth tooth with a marker to try to keep track.
Once you know how many teeth, you have to do the math. (Josh, help me here.) But 38 degrees is some percentage of 360 degrees. Use that percentage to figure out how many teeth 38 degrees represents. Then count that many teeth from the TDC mark, and you will be 'close'. Put a mark on that part of the flywheel.
This will allow you to use a standard timing light.
Note: The 38 degree advance mark will be counterclockwise from the TDC mark when looking at the flywheel from the rear.
110 teeth: 3.3 deg/tooth between 11 and 12 teeth
135 teeth: 2.7 deg/tooth about 14 teeth
Great info. Any easy way to tell how many teeth with out counting all of them?
Maybe I can borrow a fancy timing light and use it to figure where to put a mark for my cheap t light.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Formula Fords always had 110 teeth. The Ford 2000 (S2, FC) came with 135, but their flywheels were commonly modified when they first started showing up in SCCA competition, to allow 110.
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Keith
Averill Racing Stuff, Inc. www.racing-stuff.com
248-585-9139
counting teeth, only close but may be good......you need a TDC mark and variable light....but be forwarned that one of the top builders sez even the expensive variable lights are not accurate so use that variable advance light on zero and a 38 or whatever accurate mark when out of car.....can u rent a variable light.....then mark as purp or the guys said above while in car and go to markings (38-40) on light.....also call previous owner....may have story on marks on the front crank pulley u found, 2 cents
Then again....play Clouseau and count teeth per Stark n friends and see if the front pulley markings have meaning
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Mike O- Summit,Glen,Rd Atlanta,Rd America,Brainerd, Bryar,LimeRock,New Jersey MP,Trenton,Phoenix,Charlotte, Vir,Mid Ohio,Riverside,Buttonwillow,Vegas,Nelson,Pocono,
West Palm,Mosport,Mt Tremblan,Bridgehampton,Heartland
How much of the flywheel can you see through opening you are using to look for timing mark? If flywheel is marked at full advance timing instead of TDC then you may not see it if checking at idle. If you have not already done so it might be worth the effort to look for a mark with the engine at full advance rpm.
don't forget like BlackBMW said above, to go to 4000 RPM full advance for timing, if u r looking in the right port with a standard light, it might have been there all the time but u didn't go high enough to see or with a standard light u may have to turn the distributer to get it......all this with ear plugs and step out of CO frequently, it's a somewhat violent process.....the variable light lets u rev it til 4K, full adavance and turn knob back and forth to find the builder's mark......thought about this when u said it had been a while since u timed a motor and maybe not a race car at full advance per raciing mark on flywheel.........by the way, this can a pain for most of us, I hate it cause if I can't find it immediatly, I'm eat'n CO and I have sensitive hearing, wear ear plugs on the track or I can't think........we were up in Canada and a friend said something was wrong and thought he was down at 35 degrees and I said u better fix it or I'm whip ur butt......he and a friend went down in the tunnel so he could see his mark, it can be that much of a pain......also on marks I put big gobs of a bright color on both sides of mark so I can find it.......oh damn! group 4 to the starting grid and ur trying to find the damn mark!!
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Mike O- Summit,Glen,Rd Atlanta,Rd America,Brainerd, Bryar,LimeRock,New Jersey MP,Trenton,Phoenix,Charlotte, Vir,Mid Ohio,Riverside,Buttonwillow,Vegas,Nelson,Pocono,
West Palm,Mosport,Mt Tremblan,Bridgehampton,Heartland
How much of the flywheel can you see through opening you are using to look for timing mark? If flywheel is marked at full advance timing instead of TDC then you may not see it if checking at idle. If you have not already done so it might be worth the effort to look for a mark with the engine at full advance rpm.
I did rev the engine and still no marks on flywheel.
We did a dyno event today. My first pull showed 93 hp, but it started to fall off at about 5500 rpm. I advanced the timing(twisted the distributer) a little and got 95 hp plus curve flattened out all the way to redline, up 22 more hp near redline Looking forward to the new top end power!
They also found the motor running a bit lean at max power. I have a 170 main jet. Any recommendations for a bigger jet?
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
careful, u want the white exhaust pipe, at least in RR, don't know if u r autoX which DickR may fill u in, as they say "leaner is meaner" I'm at 165 145 for 2L but relative to air correction jets as jets as well for windup response......sounds good to go!!
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Mike O- Summit,Glen,Rd Atlanta,Rd America,Brainerd, Bryar,LimeRock,New Jersey MP,Trenton,Phoenix,Charlotte, Vir,Mid Ohio,Riverside,Buttonwillow,Vegas,Nelson,Pocono,
West Palm,Mosport,Mt Tremblan,Bridgehampton,Heartland
Mark
Typically, I think most run a 165 main jet. The dump tube modification is what is used to cure the top end lean condition. If you run a larger jet, you may become too rich in the low to mid-range which will really hurt at an auto-X.
IIRC, most auto-Xers run pump gas (91+ oct). Someone more knowable than I can probability state this better, but I believe that a lean condition is more prone to detonation than a rich one. I would be careful running lean with pump gas or you may experience the dreaded knock.
Dave,
Thanks for the info. What is the dump tub modification?
I run 1/2 110 and 1/2 87 octane gas to get some lead for my valves.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Dump tubes are small brass tubes that run from the bottom of the float bowl up and into the venturi of the primary and secondary. At high RPM, fuel is sucked out of the tubes to enrich the mixture to prevent running lean at top end. Look into your carb, if you see the brass tubes, your carb has been modified. If not see Pegasus.
"The Ivey prepped carburetors are prepared to the limits of the SCCA rules for FF1600 or FF2000/S2000. They may not be legal for other racing classes -- please check your rule book! The choke mechanism is removed, the power valve is removed and replaced with dump tubes, and a few other tuning tricks are performed by Jay Ivey. They are not for street use."
Dave,
I have the special dump tubes and Ivey prepped carb. I also have an Ivey alum head. I wonder if it flows more air than the iron one that came on the car. I found 170 jets all around. I changed the upper ones to 175 and the bowel ones to 165(it was running rich at lower rpms)
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
I'm no tuner but you need to keep in mind that our Weber has both main jets and air correction jets for both the primary and the secondary. Also emulsion tubes. They all interact in ways that the Weber experts understand (not me).
My Ivey carb (20 years ago) came with PA 165, SA 160, PM 165, SM 170 Etube P F50, S F6. It ran pretty well.
At the recent rebuild and engine dyno tuning on pump gas the only change was PA from 165 to 170 and SA from 160 to 165. The HP increase was not dramatic and some of it may have been that the engine was still breaking in (don't know).
Head is an iron Ivey from 1985.
Be careful. Unless you are tuning on an engine dyno with well controlled conditions it is really easy to get lost.
As DickR points out, the lower (bowl) jets are fuel jets and the upper jets are air jets. Increasing the size of the air jets LEANS the air/fuel mixture by passing more air. Increasing the size of the fuel jets riches the mixture.
As Dick states-jets are best set on a dyno to get the base line.
I had not heard DaveW's technique. That's very cool Steve
I used my dial indicater to find TDC on #1 and then looked through the bell housing hole and there was a line on the flywheel with a 0 next to it(added white paint). I found the easy way to turn the engine was a large screw driver through the bell housing hole pushing on the flywheel teeth. Someday I might get to be pretty good at wrenching on a FF
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Mark
Typically, I think most run a 165 main jet. The dump tube modification is what is used to cure the top end lean condition. If you run a larger jet, you may become too rich in the low to mid-range which will really hurt at an auto-X.
IIRC, most auto-Xers run pump gas (91+ oct). Someone more knowable than I can probability state this better, but I believe that a lean condition is more prone to detonation than a rich one. I would be careful running lean with pump gas or you may experience the dreaded knock.
Dave,
is it worth running a sideband O2 sensor to monitor the AF ratio? Does it make any sense without a "complete" data logging package?
Looks like I got it backwards. Darn. Sure did idle nicely.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Chris
I think it makes sense to always have as much data as you can use. For me, I have Arnie set the jets and timing on the dyno and I don't touch them. I only adjust the valves and clean the e-tubes. And plugs occasionally. The rest is above my pay grade.
Jack up the left rear wheel (only) about 2-3 inches. Place gear lever in 4th gear. Now just rotate the left rear wheel. Takes two hands to turn the wheel forward or backwards while bending over to look for TDC, 38- 40 degree marks, or bottom dead center. Also, use same method to turn engine over to adjust the valves using the combination of 9. 1-8,2-7,3-6, etc. I use type writers white out or some white or silver paint from a fine artists brush on the predetermined hash marks on the flywheel to easily locate.
Most Ivey engines run a jetting combination somewhere in the neighborhood of:
P: S:
A: 165 170
M: 175 180
obviously there are subtle differences between engines depending on intake flow and power output.
Last edited by Albatross; June 27th, 2012 at 12:00 AM.
Reason: punctuation
Jack up the left rear wheel (only) about 2-3 inches. Place gear lever in 4th gear. Now just rotate the left rear wheel. Takes two hands to turn the wheel forward or backwards while bending over to look for TDC, 38- 40 degree marks, or bottom dead center. Also, use same method to turn engine over to adjust the valves using the combination of 9. 1-8,2-7,3-6, etc. I use type writers white out or some white or silver paint from a fine artists brush on the predetermined hash marks on the flywheel to easily locate.
Most Ivey engines run a jetting combination somewhere in the neighborhood of:
P: S:
A: 165 170
M: 175 180
obviously there are subtle differences between engines depending on intake flow and power output.
Thank you. Tire roll is a good idea. I think I will try P A 175 and S A 170 and do Main P 170, SP 175 That should lean the bottom and richen the top. I may need to schedule more dyno time.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Mark.......Find the 38-40 degree mark before Dyno, just a thought, not a sermon!
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Mike O- Summit,Glen,Rd Atlanta,Rd America,Brainerd, Bryar,LimeRock,New Jersey MP,Trenton,Phoenix,Charlotte, Vir,Mid Ohio,Riverside,Buttonwillow,Vegas,Nelson,Pocono,
West Palm,Mosport,Mt Tremblan,Bridgehampton,Heartland
Mark.......Find the 38-40 degree mark before Dyno, just a thought, not a sermon!
Thanks. I ordered one of the adjustable timing lights.
Mark
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1990 Van Diemen, the Racing Machine, CM AutoX, WRX(retired)
You can try to make a street car into an autocrosser or you can do a lot less work and make a race car into a great autocrosser
Every time I ever had my engine dynode and brought it home, I would wake up the next day and say "oh, I wish I had dynode the engine with.....! " Try to get final dyno readings with the gasoline you will be using (Avgas 100 LL), your exhaust system, maybe play with exhaust length, carb filter, etc .
come on guys there is no magic jet to install. Jetting is a constanly evolving process. It changes with track altitude, temperature, air density. If you want to be making full hp on a given day you need to buy a selection of jets and get used to taking the carb top off and changing them frequently. On the other hand if you think keeping up with that might be too much ( be honest) you said you have Ivey parts just call Jay and ask for what he usually installs on his dynos runs and leave it alone.
Case in point at VIR pro race early this year a simple jet change from 1 session to next was worth 2 mph down the straight , no other changes.
Most builders dont want their drivers messing with them becasue they are afraid the clueless driver will screw it up and then call and blame the engine builder when something goes wrong, not becasue there isnt time to be gained.
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Kevin Firlein Autosport,Inc.
Runoffs - 1 gold, 3 silver, 3 bronze, 3x drivers of the year
2004 Star Mazda East Coast series champions
8 Divisional championships 6 Regional championships
Kevin is dead nuts on. Along with the selection of jets (both fuel and air), one will also need an air density gauge and a table stating which jets to use for which conditions.
I go with the 90% rule: "90% of the speed of the race car is determined by the driver" . Just tell the driver to put his foot down sooner-shut up and drive!
Timing
Looking forward to the new top end power!
