I have a "survivor" '69 400/400 10.75:1, 330hp 4 barrel convertible. Exhaust system is original factory duals with muffler over axle. The car runs okay, but could be better. No evident mechanical issues i.e. smoke, stalling, knocking but acceleration is less than expected for the big cubes.
Carb: 1999 professionally rebuilt QJ 7029268 WF
Distributor: 1111946 with Accel recurve kit with heaviest springs, Crane adjustable vacuum advance
Pertronix Ignitor 1181LSCC and unknown vintage Accel Super Stock coil, wires are new Delco 7mm and plugs are new Delco RapidFire
Head casting number isn't evident under all the power accessories, appears to say K16 (right head) and left head has heat riser shroud but has cast "DN" and "119288" just below valve cover Service manual calls it "Large Valve".
Axle: Limited slip 2.78. Although I know this will reduce off the line performance, my previous 400 'Cuda with a 2.76 posi could turn ProTrac 50s over for 15 feet off the line, so on street tires the 'Bird should do better than chirp.
I installed the Pertronix Ignitor and made sure everything operated as before. Then new plugs, new wires, recurve kit and vacuum advance. Each thing one at a time, then road tested. The spark plugs provided the biggest performance increase, as the old ones were fouled and worn.
Engine idles best at 12 degrees initial timing but hot starts best at 8 degrees or less. Idle vacuum is 15" at 650 rpm, advancing timing increases vacuum but induces knock on acceleration at anything over 15 degrees. At 15 degrees it begins to kick back when starting. When I uncap manifold vacuum port and open it to the atmosphere the engine speeds up and runs smoothly.
I don't believe the engine has ever been opened for repairs. The valve seats are probably the originals and may have recessed. How can I check the valve seating without disassembly, and what should I look at to get some power out of this engine? I'm running premium unleaded 92 octane. Are there any preferred brands for performance cars? I'm not racing, or even street racing, but don't want to be afraid to put my foot down when some punk in a rice burner tries to pass on the right at an intersection.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
I will take a stab and point out you have a relatively mild cam for a 400 combined with high gears.
The heads might be an issue, but I have not an expert there.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
First thing that caught my eye was the initial timing and the "heavy springs" I run a light spring and a medium spring in my 400's.
How long has the motor been acting like this?
Vacuum is good at 15" Nominal is 17"
I would check all cylinders with a compression tester and at same time with a vacuum gauge. You may have a few burnt valves, a valve not seating, leaking valve seats, worn guides..maybe all.
What I would do..address pinging. Siphon all gas from tank, buy 5 gallons of 110-116 octane and 5 gallons of fresh 93 octane for a base of 102-105 octane. That should cure the pinging issue in order to run vehicle time and calibrate properly (not to cure issue). A lean carb will induce pinging, so will a hot range plug. You have detonation at 12 degrees initial. but have to go to 8 for hot starts. Should not have to adj. timing at all once dialed in. Set initial timing. Advance timing should be 32-36 all in by 22-2500. Must adjust your springs to get all timing in by 22-2500 rpm. Heaviest springs I have never used in some 15 years. I do not like to screw around with a known "pinging problem" easiest solution is to raise the octane. If you have a 400 with 72 cc or smaller heads, you WILL be detonating under load with 92 octane, but will run fine at idle. Final CR for that motor, stock bore and 72 cc heads was advertised at 10.75 to 1 but in reality, around 10.3. Maximun CR with pump gas is 9.5 with a properly tuned carb, curved distributor and proper camming. Can go to 10 with real fine tuning.
Is cam original to motor? Has valvetrain been adjusted lately? any broken inner or outer valvesprings?
I say...base 102-105 octane. Check your compression and vacuum through rpm range, recurve distributor for initial of 8-14 with all in total of 32-36 all in by 22-2500. Check that carb is operating perfect..No hung up linkage, adj. bleed screws to optimize idle. (with vacuum gauge plugged in to large carb port) Check to see if secondaries open fully under full acceleration, and with that, the gas pedal linkage, when fully depressed, fully opens the secondaries. A good start for your carb bleed screws in close fully cw seat lightly. Open 3 full turns ccw.
Next step is to replace valvesprings. Can be done on motor. Or if desired, removed for complete overhaul. even though springs may be intact, they loose their tension over the years. While off, take to a shop for overhaul.
You could also have a dirty carb, bad gas, clogged fuel filters, cam lobe(s) wiped out. If rebuilt in 99, how many miles and for how many months was it sitting over those 5 years? Also if that pinging issue has not been resolved, there may be some internal damage with the main bearing clearances. What is your oil PSI at start up and when hot? Any fluctuation at idle? any fluctuation in neutral while revving from idle to say 4000 rpm?
Most 69 400's had 068 and 041 grinds. 335/366 HP. the 067 grind rated 350 hp. It is possible, but a longshot that the bird may be a 350..or a 400 with a 2 bbl. cam and the 2 bbl intake and carb swapped out for a 4 bbl and did not change the 2 bbl. cam and heads. Need the head and motor codes to reference. If you have done all the work, and know what you have done, you have covered some of the more detailed points. However, be cautious what other people do for you nad tell you. As Marvin Gaye once said...believe half of what you see and none of what you hear.
I am in Southgate. Would be willing to go through these issues if you can drop the car off for a few days to a week. We could probably address alot of issues while you are here with regards to the basics, but would need some time to get gears in head flowing.
I looked your post over again..There should be no evident pinging at idle (no load) with 92 octane. There has to be something somewhere not right. Possible dampner with timing tabs keyway broken causing erroneous timing reading, primaries too small or plugged up (lean), valvetrian geometry wrong (too high rocker ratio too small/big pushrods) Bent pushrods on intake side (caused by broken/weak valvesprings) I thought once that my 400 was having a detonation problem with 82 cc heads. Actually was 5 broken intake inner springs clicking inside valve cover which sounded like detonation) I ran the car at track in November, trailered it, then started it on a cold day in Feb. I broke 3 on one side, 2 on the other.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
I know it's not a radical cam profile, but it is the stock cam and that's fine as it is a street cruiser. But it's embarrasing to hit the gas pedal and the car doesn't do more than my Durango can do with an extra ton of weight and a 4.7L with gearing in the low 3s. Something isn't quite right, but I'm not sure where to start. The engine is stock except for rebuilt carb with correct numbers, is missing the original snorkel air cleaner and preheater tube and wears an open element chrome cleaner now, and is loaded with ps, pb, air. I'm not looking for a 12 second quarter mile car, but 16 second class would be nice! The emissions equipment (3 port TVS, PCV valve) are intact and connected. An open element valve cover breather cap is installed as the air cleaner has no provision for the tube.
Off the line, the first-second shift comes late on full throttle acceleration but fine under normal acceleration. There is no bog, but rather a slow buildup of speed until about 40 miles per hour, at which time the car begins to accelerate very well and will hit 65 quickly. Second-third shift is fine. Any acceleration from a steady cruise to full-throttle has the same gradual buildup of speed, then a rapid transition to real acceleration.
I installed a fresh paper fuel filter last week with no improvement. When doing so, the car had been parked overnight. I loosened the fuel line fitting and had a rag in place to collect the spilled gas. No gas leaked; the line was dry. When starting, two pumps of the pedal are needed while cranking to provide startup fuel and set the choke. Related problem, or different? Any suggestions?
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
I assume you have a TH400 (auto) tranny, maybe it's slipping? That might explain why you don't have any low-end torque. By the time you hit 2nd and third the torque multiplication in the tranny isn't as high and you have less slipping and good acceleration. Just a thought.
Banshee, I'm about 30 miles north of Detroit in Shelby Township. Engine code is matching numbers YT, is original to car, as is TH400 trans. 72,000 original miles, I'm the third owner. The second owner died and I don't have his receipts. Engine has been a slug since I got the car last April, though once in a while it will turn the tires a bit. It has apparently never had more than maintenance done to it, and sat for at least 3 years in storage with half a tank of fuel, which is long gone now.
I don't have a distributor machine, so setting curve is not a precise science for me. It usually involves a lot of test runs. I have a vacuum gauge, and the idle is smooth at 3 turns CCW from lightly seated, providing 15" of vacuum. At this setting it will idle as low as 450 RPM in drive with the air on (my version of load idle) but is set for 650 rpm.
Pinging is only evident under full throttle or big hill at initial timing over 15 degrees. As spec is 9 degrees I was hoping for 10-12 degrees to start. Original distributor setup was factory weights and springs, but I pulled distributor to deal with oil leak (missing gasket) and found vacuum diaphragm to be very stiff and weights and springs to be a little rusty and balky, so I installed the most conservative Accel parts. If you'd recommend swapping the springs I can easily do that. Do you use the Accel weights or the stock weights? I saved all parts and can reinstall them if necessary.
Had the rocker covers off to replace crispy, leaky gaskets over the weekend. No evident slop, no crud, no loose pieces. Getting in there is a b&%*$ with the A/C equipment.
I am willing to tear down the carb and go through everything. I'll get a can of carb clean and check for base gasket leaks as there appears to be a little discoloration around the base plate. You mention plugging the vacuum gauge into the large carb port. Which one is that on the Quadrajet?
When advancing timing vacuum will reach 17+ inches. However, car won't start and kickback occurs. So the timing is backed off to 11 degrees now, starts easily and doesn't knock at all.
I also just replaced all the vacuum lines in the engine compartment and the check valve on the brake booster as it was leaking a little.
The car is a 92 point show car and doesn't have a gauge set. Can't tell you what the oil pressure or any of the temps are, though I have a digital infrared high range thermometer that I could use to read cylinder temperatures.
We do not have a gas station in the area selling racing fuels. Way out in Auburn Hills there is a BP with Torco 110, but I'd use up a whole tank getting there and back .
I appreciate your sage advice. I spent most of my life with Mopar muscle cars (my dad was a Chrysler engineer) but now am dealing with these weird Quadrajets that seem to do everything on vacuum. There is definitely a learning curve here.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
True about the slippage with the trans and no low end torque. The lack of spring pressure will also cause the lack of low end torque, detonation and lack of power. Overall poor performance. Poor fuel quality, octane and pressure will cause as well.
3 years is a long time for fuel to sit in a carb, lines and tank. The fuel in the carb likely gummed up internals and or just evaporated completely leaving sediments on the free floating needle and seat and float causing it to stick. Clean lines internally with carb cleaner and blow lines out with compressed air. Replace all fuel filters and would replace fuel pump as well as the diaphragm has likely deteriorated. Free up all internal carb parts.
My revised suggestion is to run 102-110 octane in it and see if there is any performance improvement. If pinging subsides, but performance is still poor, clean the entire fuel system as it seems the first likely source of problem. Replace filters, pump, clean out gas tank. Run car again.
I have an inline filter and a carb filter..One is metal, cadmuim color, GF 98 is the part number. Carb is a paper element with cad colored ends.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
more detail...vacuum gauge reading is rock solid, no wiggle in the needle, at any steady throttle setting. With engine off and choke disengaged, secondary throttle plates open fully. I presume air valve opens with vacuum, as I have to manually operate it with engine off. There appears to be a little discoloration around accelerator pump plunger. There is no fuel odor or liquid fuel other than inside the bores. Carb throat and plates are immaculately clean.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
A clarification...pinging is not a problem, unless for some reason I need to advance initial timing in excess of 15 degrees. At 12 degrees initial and below there is no apparent spontaneous detonation. I think I'm fighting a fuel delivery or timing issue, just don't know which end to start on.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
Harmonic damper/timing tab should not be an issue. I checked by locating TDC and marks on tab and damper agreed. Cam may or may not have been disturbed, or chain and gears may have worn. Accel SuperStock coil measures proper primary and secondary resistance and primary voltage. Induction timing light shows steady firing on all cylinders, so ignition system should be okay. How do I check for trans slippage in TH400?
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
Is vacuum stady through the rpm range? does if fall or rise when you accelerate under load?
With 62's You are at 9.95 to 1 std. and 10.1 .030.
It should not be pinging terribly bad at either CR. But I would increase octane and see where it gets you.
I would shoot for the Turbo Blue and set initial at 12-14 and total of 34 all in by 2500 (just a base setting) If you cant get the distributor to advance due to it being hung up or too stiff spring tension, the engine can't advance with crank/cam rotation. I would start with the middle tension spring on both counterweights.
If it still persists, fuel lines, filters and pump next.
Someone else have any suggestions?
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
I'm not sure how you would check to see if your tranny is slipping without going to a repair shop. It's more of a "feel" thing. If engine RPM is increasing steadily and your car isn't moving in relation to the RPM's then this would lead to transmission slippage (based on everything with the engine looking like it checks out). Chances are your transmission fluid will be a brown color and smell burnt. You could have bad bands or your torque converter could be shot.
Since you wrote that you have good acceleration when you get the RPM's up try shifting manually. Put it in low 1 and don't shift until you get to the end of your best acceleration in that gear. Do the same from second to third. You have that high gear that keeps your engine from running the RPM that gets it in it's power band. Jim
Found a minor misalignment in the choke linkage that prevented air valve lockout from releasing. Shortened choke linkage a little and air valve now opens easily manually with engine off. In the garage, the air valve doesn't open but maybe I'm not revving the engine hard enough to open the secondaries. I will try to road test tomorrow. I tested for vacuum leaks but didn't find any.
Acceleration does not improve with engine rpm, but comments about possible first gear slipping are interesting. My Dodge truck has an engineering problem that causes a very dangerous lack of acceleration problem when cold. Pulling out of my driveway onto the major road, especially in cold weather, is dangerous as the engine revs and the torque converter slips. The 'bird doesn't have that feeling, and trans fluid is clear and bright and fresh smelling. Instead, the engine just doesn't have any real acceleration from a standstill or low speed start. It doesn't overrev, it just doesn't open up quickly.
I will change the springs on the distributor tomorrow after work if I have a chance.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
Quote: "Off the line, the first-second shift comes late on full throttle acceleration but fine under normal acceleration. There is no bog, but rather a slow buildup of speed until about 40 miles per hour, at which time the car begins to accelerate very well and will hit 65 quickly. Second-third shift is fine. Any acceleration from a steady cruise to full-throttle has the same gradual buildup of speed, then a rapid transition to real acceleration." This quote from you is what lead me to believe you have a low RPM/high gear problem. Jim
Cam chain might need attention. As it stretches and the gears wear, the cam goes retarded, cutting low-end torque. It's an easy thing to check and change. Retarded cam will also retard timind without appearing to. 12 will be true 8 (and so on) with 4 degrees retard. It's not hard to get 4 degrees with a loose chain.
Thanks, everyone, for the advice. Rather than a single possibility, it looks as if I need to start at the bottom and check everything. I no longer have the gauge and fitting to check cylinder compression, but I can get one. Pulling plugs on the even bank is tough with the A/C; would checking the odd bank be enough for these purposes? Spec on cylinder pressures with the 72cc heads is supposed to be 185-210 psi; is this realistic on a 35 year old engine?
Raining this afternoon, no road test today
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
It's probably not realistic if the motor's never been apart.
You don't need to check all the cylinders unless it sounds like you've got a miss. Getting to the even bank is usually done through the wheel well or from below the car with a universal joint (or two).
Since the car and motor matches, may be wise to rebuild the motor and trans for insurance. Very hard to find a numbers matching 67-9 Firebird and the difference in value between numbers matching and non is approximately $4-5000, higher for convertables.
Before you start to really enjoy the car, I would consider thoroughly scrutinizing the operative concerns before possibly causing irreperable damage.
I do not want to be a kill joy, but if you just can't nail the problem, tear it down.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
I agree with Banshee ... but I would go further to tell you to put together an extra (read: thrasher) motor that you don't mind putting some hard miles on, and rebuild the 400 to stock specs, saving it for later.
I agree with Tom and Quenton. Although I would leave the numbers matching engine "as is". Leave it as a "blank slate" until you decide what you want to do with it and it's a plus for resale if you have the original engine that has never rebuilt. Jim
If the motor is still strong,I would consider a carb kit and changing rear end gears.Convertibles were meant to be cruisers. The "highway gears" that are in there will never give good performance off the line but will give economy and high speed. Consider a change to 3.55 and maybe a shift kit if you want to get there a little quicker and sacrifice some economy and high speed. Changing from a 2.94 to a 3.21 in my Barracuda woke it up pretty good. A rear gear change could be done quite a bit cheaper than an engine and would help get you to your power band sooner as well.
Wow, now there's a great idea. It would never have occurred to me to build a spare engine that I don't have to be afraid of breaking. How complex is an engine swap with the A/C components in the way? Looking under the hood it looks rather crowded.
I do treat the car fairly gently. Most of the driving is local, and we did the Woodward Dream Cruise last year along with the Gratiot Cruise and Utica Cruise and the Carnival of Cars show. The rest of the time it's just top down driving to A & W Drive-In and around town just for fun. I do miss having my rough looking, tough old 'Cudas that I could beat the snot out of without doing any damage, including an original 440-6 body that had a beater 400-4 engine. I didn't have to worry about the paint, or rough roads, and even a big block had tons of room in the engine compartment. Having a very nice classic car is like having a new baby...
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
Tom will show you how to build a 'Cuda eating 400 that you can beat the snot out of and still make it to the A&W in time for the blue lite special. You owe it to yourself, and your car.
The engine swap is pretty easy. You can hang the A/C compressor off over the fender and pull the motor forward with the radiator out.
As long as you're thinking "spare" motor, think 455. Same block dimensions, but a whole lotta torque. Or a 428...
The components I would worry about are the heads and block. You can swap out everything else without fear of damage. Swap out your intake/carb, exhaust, dist, pulleys, PS, AC..etc. Essentially, all you need is a rotating assembly (short block) and heads.
Find a 67-71 block and heads and you are in the game. As far as complexity with swapping out..not bad at all. 2 hours to remove, 4 hours swapping out from a to b and another 2 hours install.
Not only do I have a perfect replacement, I can rebuilt your original engine.
Tom
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
The 'bird is due for a new exhaust system anyhow...the ancient pipes are getting more than a little thin in spots. It looks like the resonators bit the dust years ago and straight pipes were used to replace them. The over-the-axle muffler, tailpipes, hangers and the rest look factory and are ugly. I was thinking stainless from the manifolds back, 'cause I don't want to change them again...
What kind of $$ are we talking about for a short block swap? I've spent a lot of my budget already on replacing the original way past dead ball joints, hoses, belts, blower motor, relays, ignition, etc.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
The shortblock..basic stock rebuild plus cost of block $1000-1200.
Rebuild kit $459 machining and misc and assembly. $3-400 cost of shortblock $2-500
Or take your chances with someones recently rebuilt shortblock.
There are a few that I know of..68-70 vintage ready to drop in.
If you want it installed, will be a case of beer extra.
You can find ready to hang exhaust systems, manifold back with or without x or h pipes for $250-350. Correct exhaust runs $1-200 more. Add $200 for splitters. check Dr. Gas, Edelbrock Pypes, etc.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
I'll confirm what Banshee said earlier: it's a timing problem, or rather a lack of timing advance. Your engine gives all the signs of being in good shape. Steady vacuum readings mean no burnt or bent valves, 450 rpm in drive with no missing says the same. If you want to make sure, get a leakdown test done. One thing to check that Quenton mentioned is the timing chain. Easy way is to remove the distributor cap and watch the rotor as you manually turn the crank back and forth. How much you can turn the crank without turning the rotor tells you how worn the timing chain is. If you have the timing mark on the harmonic balancer at TDC, you can read the number of degrees of slop you have. You'll be able to feel when the chain tightens in either direction as you turn the crank. At 72,000 miles if it hasn't been replaced yet, it will be loose. Change it to a timing set that has multiple keyways in the crank gear and set it at 4 degrees advanced, as Quenton also stated. Next, do as Banshee has stated several times, get your distributor sorted out properly. The fact that your engine pulls fine once the rpm is up says that your mechanical advance curve is slow, meaning that you're not giving the engine the advance it wants soon enough. If you have a tach and an adjustable timing light, you have a distributor machine. And it always takes several tries to get the curve right, whether in the car or on a proper distributor machine. Try the combo that Banshee suggested. If you don't feel that you want to recurve your distributor, get someone to put the distributor on their machine and tell you what you have now, and get them to recurve it to the specs that Banshee gave, all in around 2500 rpm. Get them to set your vacuum advance to start at 6" and end at about 12" vacuum. Have them set the end clearance in the distributor at .010" to .015". This next bit is for the guys that do their own recurving. I do the recurving at our shop, and I have yet to put a kit into a distributor and have it produce a decent curve without having to reprofile the cam (center piece) by grinding. I have a template that I grind every one of these to before installing it in the distributor. This gives me a smooth, linear curve, instead of one that goes in steps. The other modification that I do is to weld the slots that the upper piece moves in, to limit the total amount of advance to about 22-24 degrees. This is so you can run about 12 degrees initial timing and end up with about 36 degrees total timing once the curve is all in. I weld the "slow" end of the slots so that the springs have some preload on them. Makes the springs a bit easier to select and the curve more tunable. Yes, the weights seem to stop the curve without the welding but at high rpm the timing starts moving again. The torque converter in your Dodge is draining back into the tranny, and the pump needs a bit of time to refill it after starting before it will work correctly. If the torque converter on your 'Bird isn't working right, it won't be "converting" or multiplying the torque from the engine, and will act as a fluid coupling only. Could be but I don't think so. Take care of the timing chain and the distributor first.
From your varied experiences, what is the optimal combination of stock and Accel distributor weights and springs to achieve the street performance curve described above? Factory weights and medium Accel springs? All Accel parts? Distributor number is 1111946, if that's important. Car is heavily optioned convertible with highway gears and a lot of weight, 400 YT 4bbl 10.75:1.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
Every distributor is different. Depends on counterweight weight, condition, bushing condition, gear condition (play and free movement)
The spring selection will be trial and error based on the above factors. My distributor in my 69 convertable will react differently (maybe minute, maybe extreme) if placed in your car. Just depends on overall condition of the parts in question.
Set your initial, then advance until 32-36 degrees total is achieved by 2500 rpm. You will have to change springs a few times to get her close. If your initial is 12, you need roughly 22-24 advance all in by 2500 for a total of 34-36 degrees.
Si Vis Pacem Parabellum
1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
Can you tell me what the correct diameter or circumference is for the '69 YT 400 harmonic damper? My measurement came out to 21.5" circumference, which should be 6.84" diameter, which seems an odd size. If correct, 30 degree timing mark should be about 1 13/16" from zero mark?
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
After rotating engine clockwise to the timing mark, I can rotate 10 degrees CCW until I feel tension and the rotor begins to move. Same thing if I then rotate CW.
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
That has the effect of retarding the cam by 10 degrees, which - by most accounts - is a lot.
I would guess that your cylinder cranking pressure will be near or below 150 PSI.
I'm sticking to my guns. TOHCan and Banshee are smarter than I am about setting up a distributor, but I still think your performance issue is caused by a stretched timing chain.
I will both replace the timing chain and gearset AND tweak the distributor to the new curve. Any recommendations on brand of timing set for good strength and performance? Is there anything I need to look at in the water pump or fuel pump eccentric while things are apart?
Vikki
1969 Goldenrod Yellow / black 400 convertible numbers matching
I would recommend a Cloyes double roller timing chain set with a multiple key way lower gear. You can order it from Summit if you have trouble finding it locally.
I went with a Cloyes Double Roller with straight up and 4° +/- keyways. I don't know if yours has the seperator plates in the water pump housing but if it does I would make sure they aren't rusted away (like mine were). Also look for weak spots/pitting in the timing cover where the water passages are. Felpro makes a nice timing cover gasket kit with everything you need to replace the old gaskets on the front of the engine. It would be a good time to replace the water pump if it's old.
Holy Cow! Wait, that's India: Mad Cow! No, that doesn't cut it either. Yes, 10 degrees movement is a lot (five degrees of retard - half the slop in each direction)! Change it before it skips a tooth! Good call, Quenton. Banshee is again correct, it's hard to just pick the parts and expect results, but I'll check my notes at work and see if there are any tips I can share. One thing to watch for, make sure your mechanical advance doesn't start until 1200 rpm, or you can get an unstable idle (surging when really bad). If you write down the number of degrees advance at every 500 rpm as you're playing with the springs and weights, you should be able to zero in on the right combination pretty quick. Don't be surprised if it takes 4 or 5 tries on the first one.