hey everyone, i have a problem that is driving me crazyyyy. i put a 229 chevy v-6 into my 37 hudson terraplane coupe, pulled it from a 82 malibu. dual jet 2 bbl carb, new/rebuilt unit. hooked all my va***es up and a new e.g.r. valve. plugs/wires cap and rotor new. 140 lbs compression all cylinders set timing at 0 degrees t.d.c.. starts/runs good choke pulls off to idle when warm {electric choke}. idles nice as can be, these are "shaker" motors appearantly because of firing order e.g. 1,2,3,4,5,6 . basic small block chevy missing 2 cylinders. now here is the problem, warmed up on idle and in park. i give it a quick shot of gas 1/2 throttle and she backfires thru the carb. boom, shoots flames up thru carb, same thing happens if driving and want to take off fast hit throttle and a backfire thru carb . not allways while in drive, just when i am trying to show off and give it a quick shot to the floor. spring is here and i am lost/pissed off. please, any ideas to what i am doing wrong? thanks ahead for all imput/ideas. i want to drive this and problem is still there, please i beg you to help, and again thanks. dermott. p.s. my lack of installing a t-stat would not affect this condition would it ????.
Production 200 and 229 cid engines have 2.10" rod journals, each pair of individual journals are offset 18 deg. to produce a semi even firing sequence of 132 deg./108 deg. throughout the order. Production 200 and 229 cid V6 engines have 1.84" intake and 1.50" exhaust valves. All production 90 deg. - V6 engines have 2.45" main bearings. Production 200 and 229 cid engines have 2.10" rod journals, each pair of individual journals are offset 18 deg. to produce a semi even firing sequence of 132 deg./108 deg. throughout the order. Production 200 and 229 cid V6 engines have 1.84" intake and 1.50" exhaust valves. All 90 deg. V6 engines have rod length of 5.70" (same as small block V8’s). (((Firing order on all 90 deg. - V6 engines is 1-6-5-4-3-2)))
ignition timing valve timing sticky intake valve burned intake valve broken intake valve spring faulty radio suppresent plug wires
Start with timing. Zero is awful low, GM didn't put much mechancial advance in anything during that era. You may have some kind of goofball vacuum advance can that's supposed to work in unison with a vacuum switch that alters timing thru thru extra wires on the module. You mention new EGR valve. That in itself is not a bad thing, but if the engine still has any of the other 15 vacuum switches it came with, ditch them all. Please use a thermostat, that's a wheel that doesn't need re-invented. What kind of vacuum does it make at idle, and is the gauge needle steady? I've known a few that had chronic intake gasket problems. Good luck!
Yea, I wasn't gonna say a thing about the firing order.............as I see it....there's a firin ' goin' on whilest thje intake valvator is open.....just my 2 Pecos...........
One thing that would cause the condition you have is running lean. If you have no thermostat, how warm is the motor when this happens? Less than 180 or so, you are lean. Is the gas old? Fill it with fresh and take a trip. Try some Marvel oil as an additive in the motor oil to loosen stuck valves.
thanks everyone, if it is a stuck valve will a qiuck shot with a hammer on the offending valve/valve spring help before i need to pull the heads? i am going to spend the week-end in the garage now that the brain is back to thinking again. may 10 is mothers day and i would like to take granny {80 yrs young} for a ride. she was 8 yrs old and remembers hudson cars when my coupe was new. thanks again, i do not think this motor was rebuilt as stated when it was installed. i work out of a small garage at my house, but pulling heads if needed is no problem, lack of welders/hoists is ! .dermott. 1 more note, if i find a valve sticks and bring that piston to t.d.c. pull plug and fill cylinder with air to prevent valve dropping. will removing valve spring allow me anything, e.g. spray/soak oil/additives into that giude? .
You'll probably never find a sticking valve with the naked eye and the springs in place. That's the kind of thing where the heads pretty much have to be on the bench, torn down, so you can feel the guide fit by hand. Think about putting a vacuum gauge on it before pulling the heads. Good luck! PS, Ole Don is deadly accurate about old gasoline
My first guess is your firing order those v-6s have different orders, check your motors book and look for the engine serial #. Also did you say if you took a simple compression check? It could be a valve too. Good Luck,Normal Norman
Since no one else mentioned it, I will..Does the distributor have a va*** advance can on it..? If not the distributor is from a computer controlled vehicle..Not sure about 1982 chevy.. If it does not have the va*** advance on it, then it will not have any machanical advance either.. You will need a new distributor for non ecm motor...
Double check what you have before you tear it apart. Just because you pulled it from something doesnt mean thats what it is. Gm monkeyeed around with lots of things in that era. I'm not certain but I dont think the 123456 firing order showed up till much later than 1982. [edit] Odd and even firing Many older V6 engines were based on V8 engine designs, in which a pair of cylinders was cut off the front of V8 without altering the V angle or using a more sophisticated crankshaft to even out the firing interval. Most V8 engines share a common crankpin between opposite cylinders in each bank, and a 90° V8 crankshaft has just four pins shared by eight cylinders, with two pistons per crankpin, allowing a cylinder to fire every 90° to achieve smooth operation. Early 90° V6 engines derived from V8 engines had three shared crankpins arranged at 120° from each other, similar to an inline 3-cylinder. Since the cylinder banks were arranged at 90° to each other, this resulted in a firing pattern with groups of two cylinders separated by 90° of rotation, and groups separated by 150° of rotation, causing a notorious odd-firing behavior, with cylinders firing at alternating 90° and 150° intervals. The uneven firing intervals resulting in rough-running engines with unpleasant harmonic vibrations at certain engine speeds. An example is the Buick 231 odd-fire, which has a firing order 1-6-5-4-3-2. As the crankshaft is rotated through the 720° required for all cylinders to fire, the following events occur on 30° boundaries: <TABLE width="90%"><TBODY><TR align=left><TD width="12%">Angle</TD><TD width="11%" colSpan=9>0°</TD><TD width="11%" colSpan=9>90°</TD><TD width="11%" colSpan=9>180°</TD><TD width="11%" colSpan=9>270°</TD><TD width="11%" colSpan=9>360°</TD><TD width="11%" colSpan=9>450°</TD><TD width="11%" colSpan=9>540°</TD><TD width="11%" colSpan=9>630°</TD></TR><TR align=left><TD>Odd firing</TD><TD width="11%" colSpan=15>1</TD><TD width="11%" colSpan=9>6</TD><TD width="11%" colSpan=15>5</TD><TD width="11%" colSpan=9>4</TD><TD width="11%" colSpan=15>3</TD><TD width="11%" colSpan=9>2</TD></TR><TR align=left><TD>Even firing</TD><TD width="11%" colSpan=12>1</TD><TD width="11%" colSpan=12>6</TD><TD width="11%" colSpan=12>5</TD><TD width="11%" colSpan=12>4</TD><TD width="11%" colSpan=12>3</TD><TD width="11%" colSpan=12>2</TD></TR></TBODY></TABLE>More modern 90° V6 engines avoid this problem by using split crankpins, with adjacent crankpins offset by 15° in opposite directions to achieve an even 120° ignition pattern. Such a 'split' crankpin is weaker than a straight one, but modern metallurgical techniques can produce a crankshaft that is adequately strong. In 1977, Buick introduced the new "split-pin crankshaft" in the 231. Using a crankpin that is 'split' and offset by 30° of rotation resulted in smooth, even firing every 120°. However, in 1978 Chevrolet introduced a 90° 200/229 V6, which had a compromise 'semi-even firing' design using a crankpin that was offset by only 18°. This resulted in cylinders firing at 108° and 132°, which had the advantage of reducing vibrations to a more acceptable level and did not require strengthening the crankshaft. In 1985 Chevrolet's 4.3 (later the Vortec 4300) changed it to a true even-firing V6 with a 30° offset, requiring larger crank journals to make them adequately strong. In 1986 the similarly-designed 90° PRV engine adopted the same 30° crankshaft offset design to even out its firing. In 1998, Mercedes-Benz introduced a V6 engine that not only had split crankpins, but had a counter-rotating balancing shaft between the cylinder banks to eliminate almost all primary and secondary vibrations, resulting in a very smooth-running engine.
bump timing up to 6-8 intial and PUT a thermostat in it . If it is running below 160 that is a real good sign of a lean backfire just like a inop choke.
thank you to everybody, and shifty. that site you forwarded to me is mint, t-stat &va***e and 6 degrees b.t.d.c. i was getting down but you folks brightened up my outlook sometimes we all need a boost. thank you, now i am ready to hit it hard with my bud on sun/monday. the cruise,s starting up here may 1 st. dermott.
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