O.k. as some of you know I'm buying this '73:
http://www.picturejudge.com/memberpi...s/DSCF0010.JPG
http://forums.corvetteforum.com/zerothread?id=701668

I went to go start it on Sunday to run it before I bring it home, and we couldn't get it started. The timing was off and backfired into the carb. Smoke came out of the sides of the carb too, I hope this doesn't mean the carb is screwed.

Anyway, it wouldn't turn over. Is there another trick to use? Dry gas? starting fluid? We poured 87 octane gas into the carb directly. I thought I might have flooded it, but when I pulled the plug it was dry. I'm guessing 454's require a lot more gas than smallblocks, especially at 8.25:1 compression.

The timing may still be off, I'm going to try a timing light tonight while cranking the motor to make sure I'm near TDC.

The owner isn't mechanically inclined, I'm on my own unfortunetly, and I have more experience with ECM controlled FI motors. :rolleyes:

Thanks.


[Modified by vvv90, 11:44 AM 12/15/2003]


[Modified by vvv90, 11:45 AM 12/15/2003]

 

As long as it has been sitting it might be that the valves are slow to return with spring pressure. If that is the problem it will resolve itself with a couple of minutes of running.

 

I think more likely than not its your timing. I would even go as far as to check the firing order and the rotor position at TDC on the compression stroke (should point at cylinder 1 or 5 oclockish). It may be that it was all sorts of screwy even when the guy had it running and now that its been sitting it just isnt happy with a whacked out configuration.

Have you also check your cranking voltage... may not be strong enough. Shouldn't drop below, I think abouts 9 volts while cranking. If it is its alot harder to get poppin.

Good luck let us know how it goes.


[Modified by Spook, 1:54 PM 12/15/2003]

 

I think it may be timing too. Here's what I did.

1) I bumped the motor with my finger over the spark plug hole until I felt the air pressure push past my finger.

2.) Then, with a screw driver pushing against the piston through the spark plug hole, I bumped the motor until I could feel the piston start moving downward.

3.) Then I aligned the cap and rotor right on the cylinder 1 point.

4.) Then I cranked it and nothing would happen

--------Question: Do you think the piston was too far past top dead center for me to have had the cap and rotor dead on the cap contact point? I guess my real question is: Does the cylinder have to be pretty exact TDC? I thought by twisiting the distributor while cranking, it would catch and start turning over. :confused:

Also, since we were trying so long the battery in my truck which was being used to jump the car was going down to about 8 volts when cranking while trying the final steps that I just mentioned.




[Modified by vvv90, 2:45 PM 12/15/2003]

 

possibly you were on Top Dead Center of the exhaust stroke, you could try pulling the distributor and turn the rotor 180 degrees.
it should start even if the timing is off 10-20 degrees, might run like crap until you get the timing closer.
ALso, check the firing order, is there a chance the plug wires got mixed up?
Defintely make sure you have a hot battery and trickle a little gas down the carb, it should run for a couple seconds at least.

 

I could feel the air rush out of the spark plug hole when I had my finger on it with a lot of force. Isn't that a no brainer compression stroke? I'm not trying to be a smart a$z, but I'm truly confused as to why I couldn't get a little firing. :confused: :crazy:

 

Sounds like what Im experiencing right now with my 79. I have HEI. I have not been able to get the thing to start. So I defiitely feel your pain. It sounds like you are doing the right thing however, I cant be for sure becauses I cant get my Vette to start. I asked if anyone living in the Northern VA area who like to give me a hand to please do so. No takers so far.


[Modified by Oldguard 7, 9:09 PM 12/15/2003]

 

Did you check to see if your plugs are firing by pulling one and holding it to ground? What shape are the points in?

 

Leave your dist alone and roll the engine over until you reach another compression stroke on number 1. We think you had the exhaust stroke before. If you roll the engine over until your finger is forced out of the plug hole again, you should be on the compression stroke.

Brett :thumbs:

 

O.k. Now I"m really confused.

So what you're saying is that even on the exhaust stroke I should feel pressure.

But that I obviously can feel MORE pressure on the compression stroke and that by bumping the motor over twice I should feel the difference to know?

 

Yep, on the exhaust stroke you'll still feel pressure, because there is airflow resistance through the exhaust valve and exhaust system. The open spark plug hole is the path of least resistance.

 

You guys need to re read what he wrote. The way he described it it sounds like the compression stroke. He said air was forced by his finger. I guess you could use a compression gauge or pull the valve cover to observe the valves to confirm.

Further, why in the world would his distributor be off 180 deg if the engine had been running and the distributor hadn't been removed. You guys need to think a bit more before implying such things.

I'm afraid your cam timing chain may have jumped a link. But first you need to verify you still have a spark and check the timing with a light. If you didn't pull the distributor originally, there is absolutely no reason to believe you're out 180 deg on your distributor.

Anyway, charge the battery or bring one of those portable jumper contraptions. Then check the timing with a timing light. You WERE NOT on the exhaust stroke if you had the rotor pointing to #1 and you hadn't removed the distributor.

IF it continues to backfire thru the carb with the timing properly set you probably have a bad timing chain. You might also check the compression with a gauge. I'm not sure of the exact effect of the chain being off but I'm sure there will be some effect.

If you have difficulty setting the timing, this is another indication of a bad chain that has skipped a link or two.

On the positive side, if the chain is bad it's a darned good excuse to put a decent cam in that smog sucker.

 

PS - I could still use the pics of the drive belt layout on your engine. It would be very much appreciated. email to blunsford2@comcast.net

 

I started it up today. I took the plugs and distributor out and I bumped the engine to TDC, #1 cyl. I reinstalled the distributor so the rotor was pointing toward the #1 terminal on the cap. I then secured the distributor, but when I put on the cap, the coil was slightly cocked. I attempted to start the engine and it did not start. I loosened the distributor a little I could rotate it. When I attempted to start it again it sounded like it wanted to start so I rotated it a little more and it fired up. (coil is cocked) It startled me. That is the good news. Look out for the uupcoming thread that will explain the bad.

 

I started it up today. I took the plugs and distributor out and I bumped the engine to TDC, #1 cyl. I reinstalled the distributor so the rotor was pointing toward the #1 terminal on the cap. I then secured the distributor, but when I put on the cap, the coil was slightly cocked. I attempted to start the engine and it did not start. I loosened the distributor a little I could rotate it. When I attempted to start it again it sounded like it wanted to start so I rotated it a little more and it fired up. (coil is cocked) It startled me. That is the good news. Look out for the upcoming thread that will explain the bad.

 

I read that the first time (how bout you?). We dont know when the last time the engine was running or what if anything may have changed since then. This has been in his cousins sisters stepfathers brothers garage for like 10 years or something.

I think the timing chain jumping is not a likely scenario. I think your timing is still if not more FUBAR. You need to get on the setup a little better and go through the works like many have suggested.

Heres my quick list;

Check the battery with a decent multimeter [even go for the acid check if you so feel] and start it charging while you do other things. It should be running the 12 with no draw and when you go to crank make sure it doesnt drop below 9...Take a look at your gas gauge... Ask about the gas thats been in it (when? and how was it stored?)... you may need to change it out or atleast add some good stuff ontop of some old gnarly stuff. I'd give that all a try as starters and just for kiks (because you should look at this easy stuff on your new ride anyways)...

Then

Find TDC on the compression stroke and then make sure of your rotor position. All thats been talked about, you can do a search, or go to http://www.corvettefaq.com and get Lars tuning guide he describes it there.

Organize your wires and make sure your firing order is good [I would just take em all off and put em back on].
867-5309!!!! Jenny Jenny!!! you'll figure it out...
If your battery was really dead and you have some time you could even go through and check thier resistance... check your spark somewhere in there too... WHOOT WHOOT FUN TIMES!!!

Now crank and play with distrib action (easy with 2 guys)... you can if everythings lined up relatively decently rotate the distrib all over the place until you find something that gets some sort of poppin. So dont be afraid.

Still not running? Make sure your getting fuel in the carb...
Also if you desire: There is a little copper [I think its copper??? no no brass] filter in the Qjets that needs to be changed from time to time that may be FUBAR'ing you up and may have crusted over [you won't be able to tell by looking at it]... its cheap [$5] and easy to change if you have a 1 inch [again I think] open end.

I am just trying to help. Maybe somethings I said were stoopid... maybe I shouldnt be recommending any of this. But all and all you should be able to do this in an hour and should not cost any more than optional 5 bucks and I can't stress enough that effort is so minimal.

But if you wanna remove your timing chain cover... be my guest... I dont think it will get you anywhere atleast not anywhere you want to be heading right this moment. :crazy:

Again.. Good luck... if you can give us any more info we will do our best.
Thanks to everyone else for thier input... *I dont need to be putting anyone down... :reddevil

btw: I like to spray some liberal carb cleaner in there instead of pouring gas down the carb... my .02 on that.


[Modified by Spook, 11:18 PM 12/15/2003]


[Modified by Spook, 1:31 AM 12/16/2003]

 

Spook I'm not sure WTF your problem is but I wasn't referring to your post so get it right. If the engine was previously running as he had previously indicated and he hadn't removed the distributor there is no reason the distributor could be 180 deg out. That's simple 101 engine knowledge. I agree that the timing could be off as you indicated in your first post.

If you think the timing chain being one link off couldn't cause that then you have no business giving advice. Backfiring thru the carb is a DEFINATE sign of a possible timing chain slip. READ ANY TROUBLE SHOOTING GUIDE FROM ANY CAM MANUFACTURER!!! I have personally had on slip in an old Ford van I had. That was the EXACT symptom so get it right.

Before you go slamming someone I suggest you be more careful and get it straight.

Sorry everyone but I have no patience when I'm on flu meds.


[Modified by blunsford, 4:20 AM 12/16/2003]

 

What eva ... What eva eva :confused:

Like I said its not a bad thought but not the greatest one you want on your plate right now. Maybe the block is cracked and the engine is toast... maybe you should drop the oil pan and check the bottom end... That would be awesome fun in someone elses driveway/garage... looked like a storage facility (getting better)... Gotta lug tools over ... YES, OH YES!!! SUPER DOOPER!!! :thumbs:

I didnt like that your making out like everyone else was being stoopid and not reading the post... I cut and paste that out for you nice and simple. Personally I think you should lose a few points for that previous post.

Oh and just for you maybe I will go break out a manual or two so I can come up with some of the poopietiest possible problems he may be having.:thumbs:

Before you go slamming everyone who's responded I suggest you pop some extra meds and take a nap. :thumbs:


:thumbs: :thumbs: :thumbs: :thumbs: :thumbs: :thumbs: :thumbs:
:reddevil

Also, I am sorry I am coming off as an ars... Like I said everyones just trying to help... Don't think that the help should include the WHAT ARE ALL YOU CRAZY PEOPLE THINKING LINES.


[Modified by Spook, 11:38 PM 12/15/2003]

 

just to repeat what others have said... check your rotor position... I just screwed around with my 71 350 for days, until somebody in the know pulled my distributor out and pointed the rotor at #1 and BOOM ...started like a champ.

Tim

 

Damn, this got out of hand :lol:

O.k. guys, I got it started. First of all Thanks to all, especially Spook and also Blunsford for the cam advice, :grouphug: but the only thing I did change was the dist. so I didn't think it was anything as crazy as the cam, but the crazy stuff is what you have to look out for sometimes :yesnod:. Although you were right about the "air rushing past my finger being the compression stroke" Blunsford, I didn't think I should feel such pressure on any exhaust stroke like was suggested. :skep:

I bumped the engine 360 degrees and only felt pressue on the comp stroke.

Got it to TDC, put the dist. in the right position, checked my firing order, and it started right up.

Oh BTW: Congratulate me, I'm the proud new owner of a numbers mathching, show car condition, '73 454 with 44 total miles on the frame off restore, and all for the low price of $15k

WOOOOOOOOOOOOOHOOOOOOOOOOOOOOOOO!!!!!!!! !!

:party: :party: :party: :party: :party: :party: :party: :party: