Help-carb back fireing

[T-P Auto]

Hello:

I have a 350 V8.
I just replaced the hi proformance intake with a stock intake.
The hi profo n carb caught fire is the reason that I replaced the intake.
Burnt n meltted the vac lines,dist n wires.
I have replaced the intake carb Dist wires plugs n vac lines.
When I try to start the engine it spits the fuel back thur the carb.
With no responce.
No timing advance when moving dist,no idle responce either.
Have 110 to 120 comp per cyl.
Pulled carb down ck the float n clean inside.
Have ck the #1 to TDC n installed dis.
FO 1-8-4-3-6-5-7-2
Have not had this problem ever before.
It has me stumped ! ! !

All Help Appreciated

T-P Auto
Tim

[69chevytrucker]

your 180 out if gas out the carb your not tdc on compression stroke your tdc on exhaust stroke

[T-P Auto]

69chevytrucker;

I will ck that on Wed.
I have a dr(eyes)appt tomorrow.
I'm going to start over from the start.
Ck the TDC first
Then ck the dist pointer
Reset dist so that #1 will point to #2 cyl .
That give the vac adv room to set the advance.
This eng come out of a corvette that caught fire.
I don't know what caused the fire under the hood.
So this as been a very big headache so far.
Been on it for a couple of days.
Going to take a brake tomorrow.

Thanks
T-P Auto
Tim

[mud.man.rj]

Even if you pull #1 plug, turn it over till it blows your finger off which is compression stroke then pull cap and see where the rotor points, plus don't set timing to TDC, set #1 to approx 10atdc which is where the engine would approx fire and run, in other words set the rotor to match #1 plug on cap at factory rated timing, prob 10 or 12 degrees. if that doesn't solve the problem pull both valve covers and check all the pushrods, may have one bent or broken rocker arm which would cause a backfire also. Still sounds more like distrib is 180 or 1/2 turn out and trying to fire on #6 cyl instead of #1 as already mentioned. Good luck keep us posted.

[rich weyand]

This may help. On every Chevy V8, the crankshaft pulley key lines up with the #1 crank throw. That is, TDC is when the key is aligned with the #1 cylinder, 45* CW from straight up (as seen from the front). Ignition stroke is when no valves are open, so the cylinder will hold air; exhaust stroke both valves will be open a bit (exhaust is still closing, intake is already opening), so the cylinder won't hold air.

[KQQL IT]

The rotor should point almost straight ahead as it blows your finger off the plug hole.

[gchemist]

If the distributor was dropped correctly as taken out, the problem was prior to intake installation. Is the timing chain stock? What year? If the nylon gears are breaking, it's only a matter of time before the chain strips the sprockets.

[T-P Auto]

Mud,man,rick, koolit;

Thanks:

I'll give it all atry later today.(6am) here.
Have to drive 90 miles to the eye dr today(one way)
I'm a vet so go to the VA dr's in Alb,NM
Again thanks for the info,will try it later today or first thing tomorrow.

T-P Auto
Tim

[geezer#99]

Here's a nice wiki on finding tdc #1.
Shows pics of what Rich Weyand is describing.
http://www.crankshaftcoalition.com/w...op_dead_center

[T-P Auto]

Hello again;

Got back on ter 350v8 carb back firing.
Reset the TDC
Reset wires 1-8-4-3-6-5-7-2
First spin runs for about 30sec
Then starts pushing fuel back thur carb.
Pulled the front off the eng, cked the timming marks.
Set cam dot to crank dot
try to start
now belching flame out of carb not just fuel spray.
going to pull v/c off and ck the rocker arm n push rod tomorrow.
going to back off the valve adjer nuts also.
going to try to run with out the cover on the can n crank.
still can not get any info from the person who burnt up the corvette engine.
did find out that several people saw him rodding the vette on the back streets before it caught fire under the hood.
that as one thing about a small town,someone will notice things.

Till tomorrow;

T-P Auto
Tim

[T-P Auto]

Hi all;

Question?

What is floating the valves?
I have heard this term;
Just do not know what it means?
What are the reffect of this?
I have never had this much trouble with a small block 350 v8.

All Help Is Appreciated

T-P Auto
Tim

[Dead Parrot]

Any chance the distributor cap is cracked or carbon streaked?

[T-P Auto]

Have changed out Dist cap n wires n plugs n intake.
took off the EGR intake,replaced w nonEGR intake.
have try 2 different carbs.
still same problem as stated in the first post.

T-P Auto
Tim

[mud.man.rj]

Originally Posted by T-P Auto

Hello again;

Got back on ter 350v8 carb back firing.
Reset the TDC
Reset wires 1-8-4-3-6-5-7-2
First spin runs for about 30sec
Then starts pushing fuel back thur carb.
Pulled the front off the eng, cked the timming marks.
Set cam dot to crank dot
try to start
now belching flame out of carb not just fuel spray.
going to pull v/c off and ck the rocker arm n push rod tomorrow.
going to back off the valve adjer nuts also.
going to try to run with out the cover on the can n crank.
still can not get any info from the person who burnt up the corvette engine.
did find out that several people saw him rodding the vette on the back streets before it caught fire under the hood.
that as one thing about a small town,someone will notice things.

Till tomorrow;

T-P Auto
Tim

Ok, setting cam dot to crank dot is distrib firing 1/2 turn out, that is "not" tdc, 100%. that is how to install a timing chain set but then turn engine over 1 full turn "then" drop in distrib on timing mark of approx 1.degrees and distrib and #1 plug term lined up and "done my friend. I have made that mistake many times when I first started out. Go get it done right now. So line distrib up on #6 firing now, pull distrib and drop in to #1 as mentioned. Will be right, good luck.
Mudman.

[T-P Auto]

mud man;

Thanks;

Will try this out tomorrow n let you know what happens

T-P Auto
Tim

[mud.man.rj]

No problem, it will work for sure, it happens a lot, makes no sense the way Gm set the timing marks, a lot of engine guys laugh about it.

[T-P Auto]

mud man;

Did not work on the 350v8 problem.
I was going to try to work the rat rod.
Instead I cleaned up the shop.
I put up peg board n shelfs.
Got the shelfs full.
Hung a lot of tools up on peg board.

Tomorrow I'll get on the rat rod.
Plum in the fuel pump n lines,
Drop in the Dist
Refresh the Q-jet carb
Plum in the heater hose n rad
Trans lines
Install oil press gauage (manuel) Temp gauge (manuel)
Then try to get the valves adj
Going to leave the trans un hooked till I get the engine running.

Hope I can get most of the above done tomorrow.

Still have to wire in the elect system to steering colume.
Just going to use jumper n starter buttom to set the valves.

T-P Auto
Tim

[mud.man.rj]

So ..what do you have for a Ratrod Tim, car, truck, sounds interesting.

[T-P Auto]

mud man;

I have a 52 chevy pu cab
with a 51 bed
setting on a 86 s-10 frame
305v8 just what I had laying around
86 pontiac 200r4
sets n steering wheel out of 1992 conversion van
15" smoothies on rear
14" cragers on front
92 olds 4x4 rear end
1.5" drop in rear end
I have a post on this sitein the 47 to59 chevy
I call it the "Frankenstine"
due to all the different parts (All GM)

Not working on the 350v8 till tuesday.
Have another dr appt in Alb ( leg replaced)

T-P Auto
Tim

[mud.man.rj]

I kind of like frankenstine, cool project. Must be hard to find the time, especially if you have other stuff like Dr. appointments going on too. Still want to hear about the back fire engine.

[T-P Auto]

Mud man;
Got the heads pulled on the 350v8
Pulled the cam out n found 8 out of 16 lobes wore down.
Also cked the exhaust valves, looks like new valves.
cked the intake valves also
looks like the exhaust valves were never setted in.
could not find a wear ring on the valve thats looks like it was setted
The intake valves show the wear ring
Was told that the engine was a fresh rebuilt ! ! ! ! !
I just had to pull it down to see what was going on.
I also think that who ever built the engine had the valves turned down to tight.

Thats it for how.

So did you ck out the build project I"m working on?

I have a lower left artifical leg, a couple of month ago the leg fell apart. I was just lucky that I have an extra leg here. It has my tennies in it but it has gotten me thur.
I had to have the VA order me a new set up with a liter spring setting.
I get to see if it will be the right one on Monday.
If it is then I will get them to order me another set up for the other leg.
I have a work boot leg
A dress boot leg
n a tennie leg
It was the work boot leg that broke.
The dress boot spring is to hard to walk on, that is why I have not used it before.



T-P Auto
Tim

[mud.man.rj]

Hey Tim, wow with all those legs would be hard to fund a project, what are they like for cost, prob not to cheap for anything specialized like that I bet. Very cool you found the problem, figured so. Most try the 3/4 turn preload, I always go 5/8's of a turn..max from 0 turn on the pushrod or just tight drag. I always use a breakin additive and double it, way cheaper than a cam again. Have always for around 20 years used GM cam and lifter lube, always use 2 and Rotella T diesel oil for my 20 min @ around 1,800 rpm breakin then dump the oil and filter, use 10w30 and another Gm additive for about 300 kms, change it out and what ever oil usually still 10w30 so for less leaks in the summer and always run an additive w every oil change on all our cars and trucks, even the newer cars we have for our kids, oil today is crappy so cheap insurance. That is why I preset my timing to 10/12 degrees to fire it up for my breakin so I can get to my 1,800 with the timing close. If you have to play around trying to set the timing you can wipe out a lobe with low Rpm in as little as 1 minute. Good your getting it figured out, and yep I do like the other project, man that can be a nice one when your done, well even before. don't need great paint these days, the patina thing helps a lot to be able to get a project running and use it without the pretty factor.

[T-P Auto]

mud man;

The legs don"t cost me.
I"m a vet so all goes thur the VA.

The engine problem was a hard problem to get to the bottom of.
Glad that I will have tomorrow,just going to the VA most of the day.

As for the rat rod;
Guess I need to post on the project site for the build.

T-P Auto
Tim

Will keep you posted on the engine problem as we go back together.

[mud.man.rj]

Didn't know how old you were Tim, I am just turning 53 on tuesday, cool on the price of the legs for sure. As for the cam problem, have run the same before a few times and that is why I mentioned to pull the covers and run at idle or turn it over and watch how much each rocker arm moves, as for yours...they couldn't have moved very many arms hey. Just pulled apart an original 327 in a 68 Gmc, which ran pretty good but made a bit of valve train noise and found that due to having only 27,000 miles on it that the oil had never been changed and was run every year in storage for 20 years now so the oil was gunk and the cam had about half the lobes wore down about 1/2 way, just sad but spare engine now in my back shop for something, can rering and rebearing it but the valve seats also pounded into the heads so need heads, easy stuff at least.
Talk to you soon Tim, just heading out to a friends 46th birthday, young guy.

[T-P Auto]

mud man;

I have had several sbc with cam problems,
just not one like this.

I have b-day next month - will be 65 years young - I want to try to get the rat rod running by then.
I want to try to drive it to coffee one morning.
Even if it has no windows in the front ! ! !
Will wear glass for protection.
No law states that I need a ft window to drive.

T-P Auto
Tim