12 initial and 36 total is a common number for our engines, when the vacuum is added we can get close to 50-52 which will be great for cruise and fuel economy. Maybe all you need is to do is use some lighter springs to get more advance sooner. That may give you some more acceleration while keeping the initial and total the same.
Thanks for your input. Not slowly getting worse, its just not as responsive as it was. Its the original untouched engine so with that compression ratio I'm thinking 34-36 total advance should be good. The kit came with 3 sets of springs, one busing and 1 set of weights. I rebuilt the dizzy 3 years ago and know the vac advance works and springs are good and lubed the weights, so nothing stuck and I took out the excessive play. I'll start from baseline and check timing next week, record initial, mechanical advance and total and go from there. Rocky Rotella wrote an article on Pontiac Engine timing and suggested to leave the original weights in place. Only use bushings and springs to get the timing right. I know I have the initial set at 12 believe I was able to get to 36, but don't remember the RPM. I'll record everything and post current settings on here. I think you're right that my curve is just not there cause once the car moves it goes with no problem. I can also hear a slight miss fire at idle and know its ignition related. More to come....
If your engine wasn't a dog on launch before and it is now it could be the advance, could be air fuel delivery as well. If it's not a case of slowly getting worse it may be the above or gearing. You'll want to check to see if the mechanical advance is even functioning, they can get gummed up and stop moving, springs can break, weights can jam. Same with the Vacuum advance, they can stick or the vacuum can can get a leak.
That curve kit you bought come with a selection of cams and weights as well as springs? Different shaped cams and different weight weights will give you a range of total mechanical advance as well as the speed it comes on. The springs will also vary when advance starts and stops in the rpm range. The idea is to find out what timing and advance curve is going to be best for your engine, An initial of 18 BTDC and a total of 30 at 2800 RPM may be great for one engine and crap for the next. Only way to tell is testing , by driving the car or on a chassis dyno. I set mine on an engine dyno, worked great with the engine on the dyno but I had to test and adjust the curve once the engine got in the car.
There are places one can send a distributor to along with info on the car, gearing, transmission, weight, engine specs, type of driving etc. and the company will set the advance curve using the supplied info. Even then I think further real life testing on the car on the road is the only way to get the timing and the advance correctly set.
how did you like the one piece headliner? I sent back 4 of them for my 68. the vinyl was falling off the substrate, hope you havd better luck than me . decided to go back to orig bow style I really wish I had a better experience with their quality.
Thanks Al, the car is kinda dogy from a dead stop, I'll recheck the timing and curve next WE and report back. HO did sell racing and street application aftermarket parts, I'm sure I got the street, need to verify that as well....
Don't know what the number of my bellhousing is but it's a stock 68 and my TKO bolts right up no problem. One thing you should check is bellhousing crankshaft run out. The TKO needs the center of the crank journals to be right in the center of the bellhousing register. Mine was out so I used offset dowel pins.
I also have a stump puller, you'll want to be able to flow some good air for that camshaft. My heads flow 310/220 at 55.
I also have the rpm intake, like Bob says some have hood clearance problems with it. I had to lose the one inch spacer and use a drop base filter housing to keep the hood from making contact.
That makes sense, the heavier the spring the more centrifugal force it's going to take to expand.
Well if you bought the kit from HO Racing it might be meant for a race engine with very high cylinder pressures. One may not want to get full mechanical until higher rpm unlike a street/highway car that would want it all in in the early 3000 range.
I have mine set at 28 total, I had to make a lot of adjustments to get 28 total at 3200 and still have the mechanical start to come in at higher than idle rpm and have a good initial for starting and keeping a smooth, cool idle. Lot of trial and error involved.
Most engines will run great with a close to stock timing and advance, but once it's modified it takes some screwing around to get optimum setting. Chassis dynos help for this but cost big $$$
You recurving due to problems with detonation or power?
Hi everyone I’m planning on putting a hood tach on my 69.... First I have to find a good 400 hood..... ( not sure if I want a aftermarket hood vs a original 400 hood ) Same for the hood tach...... What are the pro’s and con’s on original vs aftermarket hood tach......? Is it worth restoring an original.....? Maybe using an original housing with modern guts....?? Engine is a 70’s Pontiac 400 with HEI distributor ...... Also want the 69 Trans-Am gauges ( stack gauges ) ( but I don’t think anyone makes them anymore ) so not sure what in doing there yet..... Do know that I will have a tach,Speedo,and my four vitals.... in the dash without hacking up the dash bezel..... And then I’ll add the hood tach as well...... Thank you in advance This is just one of the many projects I have planned..... lol 😝
Had mine apart 12 years ago but having a hard time remembering how it made contact. The wire from one button connects with the wire of a second button the wire from there and the third button wire join together at the plunger. The plunger and the spring go into the tube in the canceling cam. The plunger is spring loaded to make contact when the wheel is turned. I think. Sorry no pics.
Thank you, Billy. Some oldtimers setting in. Only a year and a half ago I bought the #61 to #80 drill set and the #6-32 bottoming tap to drill emulsion ports and air bleeds for installation of jets in my 4150 style carburetor. Saw the logo laying on the shelf and couldn't remember where it came from and what it was for. I hope it doesn't get so bad I forget where my car is when/if it ever warms up enough to drive it.
Hello. I have complete interior set for sale for 69 firebird. Front seats COMPLETELY redone all new parts, and upholstery, even comes with slides and mounts, even has new curved headrest, headrest alone are around $300. Rear seats have new cushion and upholstery. All new door panels, with arm rests, ash tray inserts, etc. Headliner, carpet, firewall insulation pad, kick panels, dome light, pillar posts, sale panels, can even include some handles, water shields. Rear filler pieces for deluxe interior that is in rear. Sun visors with mounts. All interior is black. The only thing I don't have with this is dash pad. Complete kit for $1500. New emergency brake assembly, $50. New Right Stuff stainless steel emergency brake cable set. $90, all the way to rear. Wiper switch $75. Brand new cluster gauge dash panel, $250. All BRAND new steering linkage, linkage has been por-15, just like powder coated linkage, all for power steering, these pitman arms alone are around $300 same with V8 centerlink around $300 or more, . Selling all linkage for $500. Original wiper arms $40. Original rear view mirror, $30. I also have other items, to many to list. Let me know if you might need something not listed. Sure would like to sell everything as package deal. I would say everything valued minimum $4500-$5000 easily or more, Will sell all for $3000. Also have heater cables , all duct work, heater box with new heater core, astro vent knobs and ducting, original emergency brake assembly, 1 nice and working with keys non tilt steering wheel, and another just for core, will include all this with Total $3000 deal. Thanks Jerry. 314-605-6113