got an 02 wrx recently. camaro has been sitting a while since i got a knock. still havent gotten to the bottom of it. well valve lash was reset and everything. may be a dead lifter but i have blown lots of header gaskets (3 sets in 6 mothes, 1 cause bolts came loose) well i got some percy's aluminum gaskets im going to put on to see if the noise is another blown header gasket.

but anyway the camaro seems slower then the wrx. i have a stick in the wrx and auto in the camaro do you think thats why it feels slower? camaro has the following in it maybe i have the carb setup wrong...

350 .030 over, Trickflow 195cc, 64cc chamber, 2.02/1.6 valves,
230 intake duration/234 exhaust duration @.050
Lift intake .528/ exhaust .539
LSA 110
Edelbrock RPM Air Gap Manifold
Holley 650 4150 series carb
blue cams #2 hole
jets are 2 sizes bigger the what comes in the carb, cant remember what size squirters right off hand.
3.73 gears
2800 stall B&M Holeshot

why does the camaro seem slower? do i just need more tuning or what?

 

fixed the headers gasket today. noise is gone. any ideas on how to get carb setup to not seem so "flat" like it doesnt seem like its really pulling hard or anything. what can i do?

 

how is your timing?
try bigger jets see what happens
do you have times or dyno numbers?

 

timing is at 8 btdc.

plugs came out brown/sand colored which is perfect from what i have heard. wont bigger jets throw that off?

no times no dyno numbers.

 

try more timing, mine is 12* base and 36* total

 

try more as in further away from tdc, or advance it? i dont know what my total is i only have a pointer that goes to 12. any closer to tdc and the car wants to die out.

 

advance it... i think, get the timing light out and set it to the 12* mark with no timing advance{vacum advance unhooked}

for all people i have head from 10 to 12* base and 34 to 36 total timing advance on a performance 350ci

 

It's more the total that's important (max mechanical advance with RPMs, without vacuum hooked up). The initial just keeps the starter from getting kicked back. If you have too much initial when you have it set for 34-36 total, you need to modify the mechanical advance to allow it to advance more.

 

Just the opposite. You need more initial timing at idle, less timing advance travel (in the distributor) and 34-36deg total advance.

if the starter is in good shape it will work fine up to about 22-24deg initial. A starter heat shield helps.

A motor like yours with a 230deg cam needs much more initial timing than 8-or 12. but still needs 34-36 total.
To see what I mean temperairily "lock out" the mechanical tming on your distributor by removing the rotor and advance weights and springs. Then tie wrap the mechanism fully advanced and reinstall the rotor. Orient the tie wrap tabs down to clear the rotor. No start it up and time it with a light at 34deg at idlle> it will not advance when reved. reset your carb idlemix and speed to 800rpm. Fill up with 92+ octane gas and go for a ride.
make sure you got it pointed where you want to go when ya stab the gas cause its going to go now.

now go back and tear down the distributor and recurve it by limiting the mechanical advance travel to allow 12deg travel from stock 20-24deg. this will results in 22-24 initial @idle and 34-36 total advacne. use a medium tension advance spring. then limit your vacuum advance to 10-15deg travel from stock 20-25deg ( too much now). (use ported vacuum.) Stock HEI weights are fine as long as they are not worn. You have to shorten (weld)the advance pin slot to limit the4 advance travel in a GM distributor.

The increased overlap of your cam requires different timing then typical stock motors. (more initial) The egr effect of the exhaust dilution at idle (rough idle) slows the burn rate of the fuel.
More initial timing corrects the timing and corrects the burn.
Now your car will idle rock steady at 750-800rpm and not overheat or foul plugs. The throttle response, low end grunt and fuel mileage will be much better. cause you have correct timing.
You can find and mark 36deg Before top dead center on your balancer by employing some math, a length of masking tape and some white/yellow paint.
Measure the diameter of your balancer (inches). Divide by 2. Square this result. Multiply by "PI" {pie}(3.14159). this is the circumfrence. Divide by 10. the result is the distance in inches from top dead center to locate 36degrees.

For and 8" balancer its 5.02" away from TDC. On a length of masking tape spread out on a flat surface, mark two points 5.02" apart for an 8" balancer. put the tape on the balancer and mark 36deg with the paint.
Measure your balancer. it may not be 8"
Your car may want 32-33-34-35-36-37-38deg for best results. But now you have a benchmark to start from.
usually its 34-36deg.

Here's another method of finding and marking 36degrees on your balancer.

 

ok here's the pic

 

Just a note: According to Sanderson Headers. Most headers leaks are caused by overheated exhaust headers tubes and flanges. The main cause is incorrect ( retarded) timing and incorrect AFR. Lean or over rich mixtures and late timing allow the fuel to burn in the exhaust ports and headers, instead of burning completely before the exhaust valve opens ( correct timing) .
This slow burn kills the gaskets. Once you get the tuneup in line your header gaskets will stop blowing out and leaking all the time.

 

 

ok thats what i thought cause it runs better the farther back from tdc just like the diagram. i will have to measure the balance and mark it as suggested. than get back with you on that.

only thing i dont understand yet is the vaccum, weights and spring thing. you want me to take the weights and springs out and ziptie what part? i didnt take it apart when i built the motor but i know what it basicly looks like. how to i adjust the vaccum advance?

thanks for all the help

 

No, I said it correctly. There's no reason to tax a starter with excessive initial advance. If you need more advance to get it to idle correctly, then use manifold vacuum for the vacuum advance.

Adjustable vacuum advance cans are available. You can also tweek the system with mechanical stops on the vacuum advance, but that's probably getting into details that aren't necessary.

If you don't understand weights and springs, you need to bone up on mechanical advance theory. That's been covered in other posts here (and on the Tech forum). I'm sure there are websites available with the basics, a net search should be beneficial there as well.

 

crane makes an adjustable vacuum advance can, ~$30. The tech article on the main page of TGO (written by Damon I think?) is VERY good, i'd highly recommend it.

Basically the weights are ok, leave them. Changing the springs gives your mechanical advance sooner (earlier RPM).

 

I understand mechanical advance and how to modify it just fine. Been tuning hi performance cars ( with large rough idle low vacuum cams for just about 35years.
If it can be tried I've tried it.

If you try to set up mechanical for low initial say at cranking speeds then very quick travel from idle to 2500 it becomes very unstable. light springs jump around at idle, weights stick open sometimes because of the weak spring tension. Timing jumps all over the place.
Just not stable. Then trying to employ full vacuum advance at idle to get the increased initial needed (15-20+deg at idle) with a weak vacuum canister setting. ( remember you only have about 4-5" vacuum at idle in gear. To get say 20deg additional vac adv at idle all with 5" vacuum requires a weak spring setting . U end up with a unstable hunting idle. The engine flairs up as soon as you go from "in gear" to neutral because of the sudden vacuum rise and mechanical instability.

Further because you've used up all of the vacuum travel (20deg at 5") you have no way of modulating needed vacuum advance travel for what it is intended for . that is light load hi speed cruising driving mod when the throttle is near closed but rpm is relitively high. Cruising down the road at hyway speed. No modulation because now you have 12-15" vacuum so the vac advance can is just pegged at any thng over about 7".

I have tried this way. it's unstable at idle and does not allow proper timing while hwy cruising.

Theory is all fine and good... except in the practical world it often does not pan out like you'd want.

This method works: give you a stable, clean idle, good throttle response. Aceptable starting when hot. ( remember the heat shield). Proper ignition advance in *all mods* of driving. Stable timing in all mods. Good gas mileage. Now you can drive your race car to the track

 

You cannot do this while sitting in front of the computer.
You have to go out and take the distributor apart.

you'll get all confused if you treat mehanical advance and vacuum advance together.

Don't make it hard(er) on yourself... Treat them as separate issues. cause they are.
Vacuum advance is not used at idle. (ported vacuum)

Set up the mechanical advance first. Disconnect vacuum advance. You cannot achieve the right mechanical curve just by changing weights and springs. You must limit the travel of the mechanical mechanism. Take the distributor apart and look how it works. You'll see how the pin slides in a slot on the underside of the mechanism. The slot must be shortened. (weldedup and ground out) Now the pin's movement will be limited.
This will shorten the travel from about 20-22 deg *stock* to about 12degrees travel. Now if initial is set at 22 deg at idle the distributor will advance to 34 at full advance at high rpm ( 3500+) 22 +12= 34.
Your car will now idle correctly with the carb throttle blades in the correct "sweet spot" position. And will advance smoothly as the engine speeds up till about 3500rpm when it will peak out at full mechanical advance(34)
Usually this involves a stock GM weight and a medium tension springs or 1 medium and 1 light from an advance curve kit. ( the lightest ones are unstable at idle)

To get your car running right ( carb adjustment) you can *temerairly* lock out the mechanical advance by removing the weights and springs from the mechanical advance mechanism. Work it with your hands. you'll see how it works. Now: bind/lock the mechanism fully advanced with two medium sized electrical tie wraps. Point the tie wrap tabs down so you can reinstall the rotor.
Now start up your car with vacuum advance disconnected and reset the distributor timing to 34deg at idle. With a timing light. Not by ear. Reset the carb idle speed and mixture now after it warms up. You want idle at 750-800rpm with best idle quality. Adjust the idle mix screws slowly and evenly.
now with the distributor set locked at 34deg and vacuum disconnected, go for a ride. Drives much better now I'll bet.

Trouble is, with the distributor llocked out with 34deg at idle there starter strains when trying to start it hot.
Opening the throttle while cranking, helps.

8-12deg at idl is not enough. 34 is nice, but then the car is hard to start when hot. 22 is just right.

Now that you've got it running the way it should, you can now remove the distributor and set up the mechanical advance curve as discribed above. (limit the mechanical travel)

Vacuum advance is a totally separate issue. vacuum advance is not employed at idle. When the car is idling and the carb is set up correctly there is no vacuum available at the ported vacuum source.

As you drive down the road with the throttle partially open there is a good strong vacuum at the ported vacuum port.
This strong souce of vacuum moduates the vacuum advance to give increaded advance in addition to the mechanical advance. A motor wants more advance while cruising at hwy speeds. ( high rpm, high manifold vacuum light engine load) It wants a total of 51deg while crusing on the hiyway.

*Vacuum advance* use ported vacuum

*Stock vacuum advance canisters* are set up with too much travel capability for your modified car, now. (20-25deg)
You need to limit the travel of the vacuum advance canisters linkage rod to about 10-15deg. The easy way to do this is to buy a new Crane adjustable vacuum canister. There is a limit stop tab that is to be installed on the linkage arm. this limits the total travel available. Limit it to 10-15deg.

Then: the vacuum diaphram spring adjusts the rate of advance. Adjust this by trial and error to find the right spring tension for you car. Too fast ( lighter spring tension) and the engine will ping as your roll into the throttle from cruise. Not enough and you'll waste fuel on the hwy.

 

another little tip I got from "Lars" was that you can cruise around with a vacuum gauge hooked up, to get an idea as to how much vacuum you're getting in different conditions. Then adjust your spring tension while watching your vacuum gauge and timing, and get the correct timing. (probably want to disengage the mechanical timing to not add confusion here..)

Here's the articles by Lars, if you're interested in the reading on timing.
link

 

All good advice for relatively mild motors with moderate cam duration up to about 222@.050"

But.... when you get beyond that into the 230-240+ deg @.050" range radical street rough idle the engine just needs much more advance at idle.

That's where my method comes in.

 

I guess if you're planning on using MSD/Mallory/Accel or some aftermarket ignition setup, a starter timing retard starts to pay off in spades eh?

I always wanted to get one of those timing controllers, just a **** in your car to retard/advance timing up to 15* in either direction... Mostly because having extra ***** and buttons is cool, but i'm sure it'd have a purpose as well...

 

Yes it's a nice addition when using my method of setting up the distributor for max performacne with more radical camshaft.

The timing controller ***** are nice if you have a very high compression motor like 12:1 and want to have the flexability to cruise on the street without damageing the motor while useing affordable pump gas. ( 110-114 octane race gas is expensive) You can just, knock back the timing to around 27 total mechanical with the dial control from optimum (36) and get *acceptable cruise and performance* without damageing the motor.
Then when you go race at the track, switch fuels and go back to full max power timing.

Nice thing to have. Mine is a Accel programable digitial multi channel Shift/switchable/ NOS retard that includes the crank/start retard feature. (no *****) Its adjustable too. conveniently installed inside the center console. Can be adjusted "on the fly also"

 

...

 

Sorry, my comment was directed at Kevs87Z28, who said he didn't understand it. I should have made that clear.

 

Header Gaskets - I also found that the Felpro SBC gaskets with metal inside didn't work for me (hedmann headers) - the holes don't align well with the headers tubes and I had a leak I couldn't fix. I looked at all gaskets I could get to see whose had closer matching cutouts to stop my leaks.

And my 350 has 12-13* initial timing - I had to increase timing and decrease idle adj. to get enough vacuum for brake booster.

 

thanks f-bird for the help. im getting ready to go fix the timing. im marking 5 inches from TDC toward the pass side if the notch in the balancer is at 0 degrees. i hope thats right. going to see what happens. going to attempt 20-24 initial. then i will do the springs when i get a recurve kit and an adjustable Vac advance.

i dont drive it right now since the snow and salt have arrived but i still want to start getting it setup right. appreciate the time and effort your putting in.

Kevin

 

Not all 350's have an 8" balancer. 5.02" is only right for a 8" balancer. You can buy a MR. Gasket balancer timing tape that is marked off in each deg to about 50 deg.

 

MAN, you are just an insane source of information there Fbird! I am still trying to grasp how all of this works, I too have a very large cam (480" valve lift 230 duration @ .050") and have the same problems. The car runs like garbage, I know its not timed right, and I know my rear gears aren't right for it yet either, but do you think timing can make that much of a difference? On the engine dyno, it got 360HP and about 375 torque, but it just feels like a dog in my car....

Anyway, thanks for the info, I hope to put it to use myself as well!