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Discussion Starter #1
though I'm probably saying too much (cuz me and pat still need to race) I need opinions on this most angering situation.

I have a gm goodwrench 350 with RV cam, edelbrock 600 cfm carb, flowtech headers, msd ignition, 2 1/2 in dual exhaust and flowtech terminator mufflers. the car is a 67 camaro, with a 4 spd and 3.55 posi.

the thing has always run like crap (the cam and a new 3.55 rear make is run a little less like crap, but still bad all the same) and now I'm just beginning to get the time to work on it. My problems are

it bogs real bad and falls on it's face during a launch (and I rev the hell out of it, usually have to slip the clutch pretty bad to keep the revs up for power) after it comes out it pulls alright, then at about 3-4300 rpms the engine just go kapoot and doesn't make anymore power till about 4300 rpm. It backfires through the carb sometimes and I sometimes hear a popping noise under load through the muffler that isn't loud enough to be a real backfire and it doesn't really sound like pinging either. I checked the timing, and it's pretty close to perfect, and the advance curve is right where it should be, so I'm pretty sure it's not timing.

If ya'll could do me a favor and just throw me every possible problem you think it could be, I'll be happy to check everything and maybe we can get this thing running like it should. Thanks in advance for your replies.
 

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Over tuning? First verify you don't have any vacuum leaks then take a day (the whole day) and start over at the begining. It sounds like carb issues to me but start by pulling the plugs check and re-gap (are you running rich, lean or just right?) and look over the insulators to make sure you didn't crack a plug or two when you installed them. Next go over fuel delivery, clean filter good flow to carb? Unless your carb is brand new I would put it on the workbench and rebuild it. Find the spec's on things like acelerator pump and anything else that can be adjusted on that carb and make the adjustments to factory specs. Then go over the ignition wiring, grounds etc look for anything loose even new plug wires could be causing some of this if the connectors are not crimped well.

Once you have gone over everything and have it back together get out your timing light and a vacuum gauge and warm the mill up. Set the lean idle screws first (shoot for highest vacuum) then adjust the idle and reset the timing. The engine should be warm and the choke shouldn't be getting in the way. If it's coming on at all it may be part of the problem.

I'm not saying this will solve 100% of the problem but it will level the playing field before you start replacing jets or other parts.



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...Dennis
"The '69, the '96 & the club"
 

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Discussion Starter #3
It's running a tad rich at idle but I think it leans out in the higher revs since the carb is only a 600cfm. I installed a new fuel filter last night, I think I might have clogged jets or something because I didn't put my engine together, i had some friends do it, and they forgot to put a filter in (and I can't believe I didn't notice till I went to replace it). there is supposed to be a filter in the carb, but all I found was a crumbled metal screen. there hasn't been a change in performance with that, but I would assume without filters, the jets are probably pretty screwed up. the carb is only about a year and a half old, but I will probably rebuild it to see if that's what did it. After all, the original lines were used and I'm almost certain there was a lot of crap in them. I will get back with the results of the carb check, but if that's not it, anyone other ideas. And thanks dennis for your speedy reply.

[This message has been edited by lil_beast_67 (edited 01-20-2002).]
 

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ok Curt, i bet your right about the crap in the carb thing. if you want ive got a friend whos selling one of those new holley street avenger carbs I think its a 670cfm. its brand new but i think he probrably wants allmost full price for it. Ill try and talk him down if ya want. cause i want to hurry up and smoke you already.....heh heh

-pat

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Discussion Starter #5
you? smoke me? you must be smoking something if you think your one legged wonder can keep up... i could PUSH my car faster than you can drive
and thanks for the offer, but I'm pretty near dead broke right now, I finally broke down and bought a car alarm (after someone opened their door into the side of my car and left a nice big scratch). I'm gonna take the edelbrock apart and see if I can't figure this sucker out. I might be out in san jose next weekend so I'll call you and see if you're out.
 

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Have you tried doing a compression check just to see where each cylinder stands? Before you go tearing into your carb or other things make sure your motor is mechanicaly sound. Ive replaced many parts that werent needed trying solve driveabilty problems when it turned out being a week cylinder or something. Just a thought I had because you said someone else put your engine together and you never know what they did or didnt do.

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70 Camaro 307cid(350soon) /350th ex. dark purple (dark blue soon) in. black
74 Trans Am 400cid/th400 ex. red in. red power windows
 

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One more small thing but it might help with what seemed to be backfiring. Pull the valve covers and make sure you don't have a broken valve spring or some other problem like a bad rocker arm.
 

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I had a very similar problem on my 67 Chevy pickup with a 283. I had replaced EVERYTHING (carb, heads, distributor, wires, etc.) with brand new stuff except the spark plugs (champions SUCK). The porcelain had broke loose from the metal outer shell on 6 of the plugs and it ran like $h!t. It would sometimes backfire through the carb and sometimes it would make that popping sound through the exhaust and sometimes wouldn't do anything. It only had half the power it should have and it sucked.
 

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Kind of sounds like a broken valve spring to my. Pull the covers and check or do a vacume check and see if the gage is jumping all over.
 

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Discussion Starter #11
charlie, the other day we took it out and ran it at just about every possible initial timing there is. we ran it at 10 degrees retard all the way up to 15 degrees advance, and at no point did the car run well. currently it's at 8 degrees retard which is the best that it does, and it still sucks. I will check the heads today, I'm also going to order a carb rebuild kit and go through and clean mine out, since there was no fuel filter for a while. Thanks for all the replies so far, now I got some things to check.
 

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Curtis,

You shouldn't be running better retarted... Just to clarify if the setting is Before Top Dead Center (btdc) then it's advanced and if it's atdc (After) it's retarded. (not an insult, just want to make sure you know)

I'm starting to suspect you have a spun dampner or wrong timing marker tab added to and compounding the problem. If you know how to find #1 TDC you need to do so and verify ypur dampner and tab before going any further. Once you find TDC you can make refrence marks to TDC if yours don't line up and then use a dial back timing light to adjust...

I just realized you have an MSD ignition and if you're using aa dial back it may not be reading correctly!! Check out their web site for more on the timong light!!

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...Dennis
"The '69, the '96 & the club"
 

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Discussion Starter #13
thanks for the claification dennis, so maybe the engine isn't the one that's retarded


I'm not so sure it's a timing problem, just because we ran it up and down to everything we could think of and at no point did it run right. maybe the cam is degreed wrong... but still, the timing made very little difference as to the performance of the engine. Today I'm going to rebuild the carb, and check the heads for any broken stuff, I'll probably also check my spark plugs but I did a power check and the revs dropped for every plug I pulled. We'll see what turns up I guess.
 

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Just an Idea but you said that you didn't assemble the motor. It sounds valve train related but if you pull the covers off and everything looks ok why don't you pull the timing chain cover and see if they installed it right. It might be a tooth off. just my .02
 

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Don't know if it's the difference in temps here but AC spark plugs (Rapid Fire) never worked fine on my 350. I had backfires thru the carb at around 4k RPMs. Installed a set of Bosch platinum plugs and the mill is willing to throw out the fan belts out of the pulleys. You have MSD, ignition or box? I also upgraded the HEI with better coil, module, cap and springs and were able to notice a performance increase.
-------------Oh, Good luck to both of ya, if thats possible.
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Our affair with Camaros is a live sentence without the possibility of parole. www.geocities.com/c68ss http://home.coqui.net/borench
 

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Discussion Starter #16
UPDATE:

Just pulled the valve cover, I'm only working on the driver's side at this point because the popping was coming from the driver's side exhaust pipe. The spark plugs are pretty evenly tannish brown (I knew it was running rich) but the #5 spark plug is wet (gas). There also seems to be some sediment or something on the tip, which isn't too good of a sign. There doesn't seem to be any damage on the pushrods, valve springs or anything else I can see in the valve train. Maybe the spark plug just sucks. I got some extra ones in my garage so I'll replace it and see if it makes a difference. A friend of mine has a holley 750 DP that I can get for pretty close to nothing, do you think I should rebuild the edelbrock and see what I can do about it's tuning, or just put it on the shelf and use the holley?
 

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I had simular problems an thinking back my
exaust made popping sounds before it just
stopped running .Thinking maybe a worn cam lobe or stuck valve was causing it but it
turned out to be the pickup coil.
 

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sounds like the camshaft is the wrong duration for a 4 speed car. your cam could be for an automatic check this i think this could be your problem
 

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Discussion Starter #20
check it tonight, one of the spark plugs was fouled, replaced it. ran alright then started running like crap again. Here's the new twist. The carb is an electric choke. Some guys put the thing together for me a while back and used a wire tie to hold the choke open. Shouldn't this make the car run a little lean? The car runs really rich, regardless of the adjustment screws. At this point I'm relatively certain that the problem, although made worse by the fouled plug, is in the carb. Would the wire tie holding the choke open be it, maybe dirt? I bought the rebuild kit but don't know when I'll have enough time to actually do it. After all this stuff with the carb and everything, the car won't even run right. And my girlfriend (of two years) and I broke up tonight.. what a day.
 
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