Thread: 350 spits fire when static timed

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Neebie here so greetings all,

Here's the problem: 1st lets start with a 350 out of a 1980 camaro. Strip all the cr*p down to just motor(no sensors and such) Add the Edelbrock performance kit, and no-one knows which one, other than it's supposed to have a "mild" rv cam. The kit came with cam , lifters, pushrods (maybe),and Roller rockers. The heads were reworked (I don't know by who or where). So sort of tuned (looking) headers , followed by dual full legnth (on a '50 Chevy Sedan Delivery) exhaust with cherry bomb mufflers. Back on top is a Pro-something (my friend/owners words not mine) aluminum intake topped off with a brand new Holley 600 carb and brand new Accel Distributor w/delco remy coil. Also has new timing chain.

Ok so HERES the problem. Timing this motor has been perplexing. To start with Im not sure the timing cover is correct as the mark plate sits way off the balancer. Secondly to bring the mark to 10 degrees at idle with vac. adv. removed and vac. gauge in place drops the idle drastically and will OCCASIONALLY spit fire through carb. The thing is when starting from this position on a luke warm motor, for the first minute or so it revs BEAUTIFULLY. The exhaust sounds good and the motor smoothes out. The trouble is that it drags on restart ( engine hot) and every third or so rev spits fire. Now I know this is timing issue as when the timing is advanced the rpms pick way up, the timing mark disappears from sight and while it still revs good it still lacks what it does with timing mark visible to 10 degrees on the plate w/tioming light.
We have done #1 piston tdc and checked rotor position and this is where timing mark shows on plate. I must be forgetting something so I will wait to here from you out there for any suggestions/Questions
Thanks for the chance,
Rick

Welcome Aboard Mechanic Rick, god to see you here.

How were you verifying that cylinder 1 was at top dead center and that you were on the compression stroke?

Thanks,
Finger over hole and coffee stir straw while going back and forth with crank bolt.

BTW when is god to see me...I wnat to be on my best behavior. :-)

Thank you Denny,
Plugs are new and correctly gapped. Wires are new and ohm checked good. Distributor is brand new as the sticking vac advance on old distributor seemed apparent after replacing vac module. Hence the new Accel Distibutor has (and I checked) new springs. Timing has been checked with vac. advance disconnected and plugged. No rpm gauge (yet) but would call it around 900 to 1000 rpms on idle.Valve adjustment hasn,t been checked nor compression at this point and there are no sounds or signs that would make me supicious of this problem. Also remember when static timed and motor cold it starts and revs like a stripped ape. Warmed up it begins to spit fire and start like timing is off. Time it by ear (best sound and rev response with out spitting) and with advance off and plugged I can't even see the timing mark on the balancer.
Thanks again,
Rick

Originally Posted by Mechanic Rick

I wnat to be on my best behavior. :-)

I hate auto spell!

Denny touches on it and I have the same inkling.. when cold, it runs well, when temp comes up it backfires.. I'd say check the valve adjustment. It "feels" like the valves are being kept open when the system gets hot.

Also, the Accel dizzy, I wouldn't trust any part of it. They've earned their reputation.. it ain't a good one.
Once upon a time, back in the 60's, you couldn't win without them.. but now?? Don't trust - verify!

Originally Posted by 34_40

Denny touches on it and I have the same inkling.. when cold, it runs well, when temp comes up it backfires.. I'd say check the valve adjustment. It "feels" like the valves are being kept open when the system gets hot.

Also, the Accel dizzy, I wouldn't trust any part of it. They've earned their reputation.. it ain't a good one.
Once upon a time, back in the 60's, you couldn't win without them.. but now?? Don't trust - verify!

I'd adjust the valves following proper guidelines, but you might also do a compression check cold, then warm it up and do another compression check. It might be telling.... And I agree on the Accel distributor - the line has become a poster child for problems.

Welcome to CHR too, BTW.

First Let me say thank you all for piping in ,for as you know Missouri loves company. Okay I admit to being lazy about dropping the headers and pulling valve covers for compression check and valve adjustments.So it shall be done but in the meantime,could we address the timing mark issue.The accel does exactly the same as the the one it replaced.I have a used HEI distributor I can try but still have to wonder why I can't time this with a light and have it run like it does statically.
Thanks for enlightenment on accel,as it is a 250.00 P.O.S.,lesson learned.I will get to the comp. and valve train soon and post findings.

Thank you all again,
Rick
P.S. 36 Sedan ,just wanted to be a grammar nut and response to "god to see you here" wnat was my contribution to misspelling ;-)

Has the harmonic balancer slipped on its hub? Remote chance, but possible. If it's OK, find the true TDC and put a timing tape on the hub.

Chevrolet used 3 different timing arrangements on the Gen I motor, 12:00 O'Clock Noon, 2:00 O'Clock and 2:30 O'Clock as you look at the motor from the front. If you have not been in possession of the motor since it was new, you have no idea of the mixing and matching of parts that has taken place over time. Also, you have no idea if the outer inertia ring on the damper has slipped on the elastometic material that separates the ring from the hub, rendering the damper invalid for ignition-timing the motor.

My best advice is to purchase this rebuilt 2:00 O'Clock 6.75" harmonic damper from Damper Doctors and match it up with a 2:00 O'Clock timing cover or bolt-on timing tab from a '69 to '91 350. Damper Doctor uses new elastomeric material, clocks the hub to the eccentric ring and presses the whole mess together under tremendous hydraulic pressure. I prefer buying a rebuilt damper rather than a new one because you know that the damper hub originally matched up with a 350 crank snout diameter at the factory. Aftermarket dampers may or may not provide the correct press fit. A correct press fit is necessary because if the hub if too tight on the crank snout, you may never get the hub seated in its correct position and your belts will not line up. If the hub is too loose on the crank snout, harmonics will not be transferred from the crank to the damper hub and onto the inertia ring to be cancelled out and you could crack the crank.
CHE3501 69-91 #6272222 12551538 10066046 2:00 TAB
Then buy this genuine Chevrolet bolt-on 2:00 O'Clock timing tab.....
Genuine GM Chevy Small Block V8 Timing Pointer 6 75" 7" Balancer GM 3991435 | eBay

Here's a tutorial that I wrote some time back that may help you....
http://www.crankshaftcoalition.com/w...op_dead_center

I guess I really want to say - Don't trust - But Verify!
Finding top dead center with a straw? I guess it'll get you close, but not dead nuts TDC!

When doing any kind of troubleshooting, you must verify each of the basics. And you must know without any doubt.

Wow and thanks to all who have answered,
and a special thanks to techinspector 1 for the extensive evaluation and information. It's exactly as you said about the hodge-podge mixture of parts and assembly. I will pass along the info and most likely order the balance assembly as prescribed, as it sounds like the best, total fix.I think we will go ahead with checking valve adjustments, as this was done the same time as the rest of the mistakes, found in this partial build. Although mechanically speaking, I would think, loose valves should be noisey and less likely to flame the carb, too tight valves would allow flames no matter the timing, generally speaking. Any thoughts on ear timing the motor and just observe temperatures and plug burn for trouble?This is after all a street rod show car and not subjected to any harsh endurances or regular use. Also there has been some talk of replacing the motor with a crate/turn key motor.Any suggestions?
Thank Again Everyone
Rick
P.S. Techinspector 1, I 100% agree with you about this planet's function in the universe. I'm koo-koo for cocoa puff's......

To find exact TDC after seeing where the rotor is close to firing #1 cylinder, I always used a cheap ol' piston stop (oreillys uner $3) in the spark plug hole, turn it over by hand clockwise (never with the starter), mark it where it stops, turn it back counterclockwise make a mark where it stops, exactly between the two marks is your TDC. This should also tell you if your balancer ring has slipped. Not to take away from everybodys expert advice, but I had this happen once with the SBC hodgepodge of different timing pointers vs different dampers, nothing being wrong with my new parts but I was using the wrong timing pointer.

Originally Posted by Mechanic Rick

Any thoughts on ear timing the motor and just observe temperatures and plug burn for trouble?

If you replace the damper and timing tab, you shouldn't have any further trouble with timing the motor with a light. Production cast iron heads, 12 at the crank and 24 in the weights for a total of 36. Aluminum heads or cast iron heads with good chambers, such as L31 Vortec heads, 12 at the crank and 22 in the weights for a total of 34. More cam will want more initial at the crank. Of course, all of us on this board have ear-timed motors in the past. If you want to keep track of what the motor is doing, purchase a lighted Longacre plug loupe and bone up on reading plugs.
Longacre Racing 50884, Longacre Tools and Pit Accessories | Longacre Racing

https://www.google.com/search?q=read...e9Mh-0-mH2k%3D

Originally Posted by Mechanic Rick

Also there has been some talk of replacing the motor with a crate/turn key motor. Any suggestions?

We were just discussing that subject on another thread.....
What does a Scratch Built 383 cost?

Originally Posted by Mechanic Rick

P.S. Techinspector 1, I 100% agree with you about this planet's function in the universe. I'm koo-koo for cocoa puff's......

Rick, you and I are going to get along just fine.

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