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Help with Ignition timing!!

S

sscam69

Guest
Ok guys heres the deal

I have got my car back on the road but there is a dilema. I let the car idle at startup and I decided to rev it a little. I started to hear an abnormal popping. I decided to rev it and hold it at those revolutions. I kept it at 2500 and I started hearing a lot of abnormal popping. It sounded like someone set off a firecracker in the exhaust. Like a pop in a hollow tube. At first I thought since I had the car sitting for a while the octane might of have gone down, i use medium grade, and it was preigniting (detonation). I have never heard detonation or pinging before so I assumed thats what it was. In either case it didn't sound right. I added octane booster and was not as bad but still there. I took her for a spin and just wasn't to her full potential.

I decided to check the timing BUT the mechanic didn't line up the mark with the position of the piston. Therefore I have no reference point to indicate how many degrees BTDC the ignition is setting off. I think he just set it by ear.

What I did was have my brother rev and hold the rpm's at 2500 and you could clearly hear the pinging. I loosened the bolt that pins down the distributor and I retarded the timing until the sound ceased and sounded "normal". I told my brother to let off the gas and she idled fine.

Was what I did correct?
How can I figure what the actual timing is without tearing apart the engine?
Should I have done it at 3k rpm? Thats when the advance reaches its max right?

Thanks in advance

Frank
 
R

rpounds

Guest
Hiya Frank. I don't know whether I would say that what you did was right or wrong. I'll tell you this . . . my old man, an ex-circle track racer, never was a fan of using a timing light for performance tuning. Although, back when he was racing, adjustable timing lights were unheard of.

You can pull #1 spark plug and stick something in the hole and turn the engine by hand to determine TDC and then mark the damper so you'll know where it is. Take the distributor cap off so that you know that you are not 180 degrees out and then either mark the balancer or apply a timing tape to the perimeter. Some people will stick a screwdriver in the spark plug hole, but I was never comfortable with that. A drinking straw is better in my humble opinion.

It's not uncommon for the outside ring on a damper to break loose from it's rubber mount and rotate. This may have happened to yours, in which case you could replace the damper and then the marks should line up.

Ron
 
S

sscam69

Guest
One of many other problems

Hey Ron

Yeah I wouldn't feel to comfortable with a screwdriver also, to rigid. Thanks for the tip.

And another one. Some how after my freeway run with a "ricer" the relay on my temp switch for the electric fans went out. I bought another one from "haynes" and according to the instructions the fan switch turns on at 185 and shuts off at 165. According to BOTH temp gauges I have she goes up to 220 and shuts off at 180. The funny thing is both relays are the exact same and both work on this new one at the same temp. I followed the instructions to the letter and this is what I get. I think its the temp switch but I have to call up on that one, and double check the lines. Just to make sure

I figured out that something went wrong with the little black box on the old one and it was not the relay. On the old one the temp would go up to 180 and the fans would turn on. I tried to crack the little black box open to see what went wrong but was to tired to do it.

AAARRRGGGHHH!!! Such frustration sometimes.

Frank
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
You may have an air pocket trapped in there that is giving you false temp readings. Make sure you have purged the system. Otherwise, the fans may do some strange things. That is your temp sensor is in a different location in the block than the fan temp sensor.

On the timing. Are you saying that you don't have a timer marker on the front of the timing chain cover?

Normally, you can rotate the engine and line that up. If you have the number one spark plug out, and line that up when it pushes your finger out the hole you have TDC. If there is nothing going on when the marker lines up, you are 180 degrees out.

You need an adjustable timing light. That way you can get a better feel for what is zero degrees timing, etc. Try to get it to max out around 2,500 RPM at about 36 to 38 degrees.

The great news is you can get adjustable lights now for $100 or less at the local store.

Now, after all that, you still have to drive the car and feel it out for yourself, then adjust up and down to what seems to give you the best overall performance based upon the fuel you are running, temps, and driving habits.

Good luck!
 

mmvette80

Well-known member
Joined
May 12, 2002
Messages
273
Location
Central NY
You need an adjustable timing light. That way you can get a better feel for what is zero degrees timing, etc. Try to get it to max out around 2,500 RPM at about 36 to 38 degrees.


I have a timing question. On the damper there are degree marks. They go so far. How do I get the total timing at 36- 38 degrees if the marks dont go so far?
 
S

sscam69

Guest
Well I am seriously considering buying a Firbird Forumula.

I just saw it today for 14k. I think its what I have been looking for.

BUT to be able to pay for it I have to sell my vette:cry

I am asking for 6K firm for my vette, I have put over 5k~6K (documented) plus what the car cost me 3k. I am at a loss but it comes with the territory.

I will get another shark later,80-82:) and use that as my project.
 
R

rpounds

Guest
Frank,

Good to hear from you again. My sentiments are as always . . . you're a young man and have a lot of time to fulfill a number of dreams. If the Firebird is your dream of the moment, I say go for it. If you sell your vette, please make sure that you keep in touch. Gonna miss you around here.

So, what year Firebird are you looking at? I have a lady friend who has an absolutely pristene '68, with documentation showing that it once belonged to Steve McQueen. It's a 400 and screams like a banshee when you step on the loud pedal!!

Please let us know what you end up doing.

Ron
 
S

sscam69

Guest
Thanks for the support Ron

Yeah I really hate to let go of her and even my girlfriend was telling me "don't sell it, even I am attached to it" LOL

BUT I really don't have the money to do anything for awhile and she is just sitting collecting dust. Actuallly I run her just to keep the juices flowing. I am also getting married around next August and paying insurance for two cars as well as maintenance is putting a real dent in the wallet. So this car will simplify things. I got to test drive it and man THEIR QUICK!! There were three people in the car and she was still pulling hard!

The one I am looking at is a 98 with ~63k miles on it. Keep in miind that I will be getting a 4yr/60Kmi warranty on it and I am going to use it as a hardcore racer later. Looking to make over 600rwhp:s but for now she will just be a daily driver. I really like these cars.

Don't worry Ron I will be sticking around for a very long while. I actually haven't been surfing here lately but I am planning on getting another shark 80-82 and a ZO6!!!

Even if I don't get this particular car I will sell both of my cars (vette and 96 cougar) to look for something that is doable.

Frank
 
R

rpounds

Guest
Ah man . . . you struck another chord . . . Cougar . . .

I know, I know . . . Ford and related products are probably taboo around here, but many years ago (about 27 years), I had a '68 Cougar XR7 . . . man what a sweet ride . . . wish I had that one back . . .

Some day, you will say . . . "oh man . . . my first Vette . . . wish I had that one back". Hey!! That's what makes the automotive world go 'round!! Of course, if I still had every car that I wished I had never sold, I would need a MUCH LARGER GARAGE!!

I know this is a vette forum, but if you end up with the 'bird, post or email some pics. Sure would love to see it . . .
 
S

sscam69

Guest
ROFLMAO!!!!!

Yeah its a nice car to have actually. She has a 4.6L engine and is torquy as heck. You can really feel her pull between 2.5k-4k. Leather interior power everything. Shes actually a "pimpin" ride. I'll take some snapshots of her so you can see. My girlfriend tells me "if you take that car to Mexico everybody is going to think you are some kind of drug dealer or something, your not taking it over there!!!" LOL My dad started to laugh when she told me that. The XR7 was given to me for my as a graduation gift. You know I feel pretty fortunate, I have two cars and I never asked for one of them or any for that matter. I took my girlfriend on our first date in a dirty beat up GMC cargo van, boy that was embarrasing :eyerole I am rambling ain't I.


Anyways I have been aching for one of these firebirds for awhile and now that I have graduated and went through absolute hell, at least thats what it felt like, to graduate in 4 years I feel I owe my self this car. I still want that first gen camaro but I don't have the money for my vette let alone another project

This is an opportunity I don't think I want to pass up. I hope I don't regret selling my vette.
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
/mmvette80 ... I have a timing question. On the damper there are degree marks. They go so far. How do I get the total timing at 36- 38 degrees if the marks dont go so far?

With an adjustable timing light ... and a damper & tab with a known zero timing mark --- then you set the adjustable timing light dial to 36-38 degrees --- then run & hold the engine at desired rpm --- slowly turn distributor until timing marks align at ZERO --- double check that light's dial is set on 36-38 --- tighten distributor clamp --- again, check that damper & tab's marks are on ZERO and check that light's dial is set on 36-38 --- you're done.

With only a NON-adjustable timing light ... and damper /timing tab has limited markings --- then purchase a "timing tape" that adheres to damper. Timing tape has degree marks out to about 50-60 degrees. Make sure you get the proper tape ... tt's length is sized according to damper's outside diameter. TT's can be had at Summit, Jeg's, local auto parts house for about $5. Your GM dealer offers one for an 8" damper/balancer... GM pn 12367601
JACK:gap
 

mmvette80

Well-known member
Joined
May 12, 2002
Messages
273
Location
Central NY
Thanks for clearing that up. What RPM should the timing be set at? Is 36-38 for daily drivers or high output engines?
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
/mmvette80 ... What RPM should the timing be set at? Is 36-38 for daily drivers or high output engines?

Total timing is set at the rpm that YOUR (varies from car-to-car) mechanical advance is fully advanced ... PROBABLY somewhere between 2500 -3000. To find out ... hook up a tach and a timing light .... raise rpm as you watch tach & marks ... when the timing marks stop drifting that is rpm at which the mech advance is maxed out ... that rpm is where you set total timing.

Start with 36-38 will work for most ... you can experiment later & vary as much as plus/minus 3 degrees to see how mileage/performance improves or degrades.

Once you have the timing procedures down pat ... Your 80 may benefit from a distributor timing recurve kit. Widely available for $5 - $10 ... easily & quickly installed. By swapping springs contained in kit, the kit will allow you to adjust the rpm points at which the timing advance both begins and ends. Our cars often benefit by having the advance curve both begin & end somewhat earlier in the motors rpm range ... earlier than what GM had to use to meet emissions/gas mileage constraints. Remove your distributor's rotor ... if you see two small springs about an inch long at very top ... a recurve kit will fit.
JACK:gap
 
B

Bullitt

Guest
Hey Frank, how's it going? I know you asked about my progress in another thread, but I'll answer it here instead. Slow! That's the operative word, but I'm not plannning on dying tomorrow, so at least I got till then. :L

XR7s! There's a sweet one running around my part of town, painted green with a black vinyl top. It's jacked up a bit in the rear with sidepipes to boot! It really looks sweet. I saw another Cougar in a junkyard awhile back, but that baby is too far gone. Looks like it spent the last decade or so rotting under a tree. :(

Hey Ron, did your friend score that Firebird from McQueen's estate auction after his death? I'd desperately by interested in some pics and any other information you could provide. I'm not in the market for another car, but how much is she asking?

--Bullitt
 

mmvette80

Well-known member
Joined
May 12, 2002
Messages
273
Location
Central NY
Thanks Jack. Where can I get the recurve kit? The engine isnt stock I have the GM Goodwrench engine with a step up in the cam. Its supposed to have 250 hp but doesnt feel like it.
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
/mmvette80 ... Where can I get the recurve kit?
Kit recommendation below are kits for NON-computer GM HEI distributor that came originally equipped with non-adjustable vac advance can.

Kit with springs, hardware AND adjustable vac can = Crane pn 99600-1 ... about $25.

Kits without adjustable vac can = Mr Gasket pn 929G ... also Summit pn SUM-G5212 ... either one about $5.

Check Summit, Jeg's ... first check w/ local auto parts house.
JACK:gap
 
S

sscam69

Guest
OOPS, I gues not

Well after driving the firebird she had a few things that didin't make me to comfortable.

1. Squeaking noise coming from crank area somewhere
2. Gears kinda grinded a bit when I shifted, this would lead me to conclude the synchros are worn because of speedshifting. If this thing was run hard the differential could be in bad shape, they don't hold for long when run hard on these cars
3. Service light was on, could be "reset" but doesn't solve the problem

and last but not least an out pour from friends, family, and fiance NOT to sell the vette. My fiance told me that if I could wait another year we could work on the vette and get the Trans-Am.

she gave me "an offer you can't refuse" LOL

gawd I wish I was more patient!

Frank

next on the list is a new temp relay, pics of the finished heli-coil kit install, and hi-amp alternator...Here we go again LOL
 
S

sscam69

Guest
And another thing, more on the original subject of this post

I think the balancer spun. I was thinking for awhile and if I was remembering correctly I watched the mechanic setting the timing and seeing the yellow mark line up with the timing marks.
 

mmvette80

Well-known member
Joined
May 12, 2002
Messages
273
Location
Central NY
I should get the recurve kit first and then play with the timing? I also get a adjustable light.
 
R

rpounds

Guest
Hee hee . . . hey Frank, got ya wrapped around that little finger, huh?:L

Well, I guess we're all in that boat right along with you! Corvettes are in the blood . . .
 

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