Indexing Spark Plugs |
Post Reply |
Author | |
bjohnm
Member Joined: 28-July-2005 Status: Offline Points: 19 |
Post Options
Thanks(0)
Posted: 10-November-2005 at 12:59PM |
Can anyone give me the procedure for Indexing Spark Plugs? I an a bit confused about the positioning of the 'Gap'. Thanks. John M. http://photobucket.com/albums/c208/bjohnm/ Edited by bjohnm |
|
JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
Post Options
Thanks(0)
|
To my understanding you want the gap to face the intake valve, exposing all of the spark to the mixture, but upon further research, some engines like them indexed AWAY.. You'd need an engine dyno to get your optimal positioning. You can make a mark on the plug body and one on the head to determine when it's where you need it to be, and use washers (they make them just for this purpose) to get where you need to be. Also , it's only apparently good for 1-2% at best, so unless you're racing for money, you may want to save the $500-$1000 of dyno time needed to get optimal plug indexing and put it towards porting the heads or better induction/exhaust.. (or a roller cam, or nitrous) Jim |
|
1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
|
bjohnm
Member Joined: 28-July-2005 Status: Offline Points: 19 |
Post Options
Thanks(0)
|
Thanks for the info, Jim. I have a 72 GTS with a 400 engine that gives me 11-12 mpg. I'm just trying anything that might bump that up a bit, what with the price of gas. Any suggestions would be greatly appreciated. John Murray |
|
Nemtorino
Member Joined: 18-April-2004 Location: United States Status: Offline Points: 22 |
Post Options
Thanks(0)
|
gear change. I remember I was getting about 18 MPG with my 2.75 gears in my 4-door.
|
|
bjohnm
Member Joined: 28-July-2005 Status: Offline Points: 19 |
Post Options
Thanks(0)
|
Hi Mark, I guess you mean the rear end gears to change. I have the original rear end in, I believe it's a 2.75. The code is a 2. The car is all original except for 2 hood lock pins I installed. I had the hood open up on my 57 chevy going down the street and have used the pins ever since.
|
|
JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
Post Options
Thanks(0)
|
11-12 mpg where and under what usage? I got 13-14 on the highway with a warm 460 and 3.00 gears.. Check the carb and all vacuum lines, check the timing, check the air filter, and exhaust. A nice free flowing dual exhaust and a fresh and tuned carb go a long way towards economy, as does an easy throttle foot. When is the last time it had a thorough tune up? Get a set of fersh plugs, gap them and run it down the highway, pull into a rest area and check one. Also check one after running around town. Advance the timing a bit and see what that gets you as well. I got 4 mpg on the highway with the 545 and 4.33 gears, so it could always be worse..
:-)
Jim Edited by JimW |
|
1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
|
bjohnm
Member Joined: 28-July-2005 Status: Offline Points: 19 |
Post Options
Thanks(0)
|
Hi Jim, The car is a '72 GTS, 400cid, C6, dual exhaust, stock wheels, engine rebuilt about 3500 miles ago, Carb(2bbl) about the same time. Running 89 octane with timing set just before pinging. Tried 93 octane but hardly any difference noticed. Has 17" man vac, K&N air filter, Mobil 1 oil, AC 2 plugs(all plugs have a tan color), does not burn oil. 99% driving in local, in town. I might reach 60 before reaching city limits, then-35 mph. Only drive it to shows and displays. Have gotten this mileage since the rebuild. I tweak it and tune it weekly just to play with it. I just wanted to get the best mpg I could since the price of gas is so high. I'll bet you get some performance out of yours with 4 mpg! Thanks, John Murray http://photobucket.com/albums/c208/bjohnm/ Edited by bjohnm |
|
JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
Post Options
Thanks(0)
|
I get about 8mpg now I guess, the 3.56 gears really helped.... Tough to get mid 11's normally aspirated on pump 93 at 4000+ pounds and not drink fuel I guess What weight Mobil 1 oil? What cam? Have you tried just being extra gentle on the throttle? (I get 5 extra MPG out of my Daily driver if I try hard enough) What does it smell like? If you follow someone while they drive it, does it ever smoke? I'm not too good at MPG trick as I just drove mine less when it got too expensive.. Do you always check the air pressure in your tires and keep them at the high end of the range? Stop and go traffic will kill mileage in a 4200+ pound car for sure. Unless your 2bbl is tuned a bit rich somewhere and it covers up by being lean elsewhere I'm running out of ideas. I could give you 100 ideas on how to make it faster, and 50 to make it more efficient, but they all start to cost more than a few extra fill ups. Like rollerizing the C6, using lighter synthetic fluid in the rear, headers, TBI, different heads, etc.. I'll keep posting so this stays at the top, you can alos try the 335 series message board over on Network54, they might be able to help somewhat as well.. Jim |
|
1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
|
bjohnm
Member Joined: 28-July-2005 Status: Offline Points: 19 |
Post Options
Thanks(0)
|
Hi Jim, I am using Mobil 1, 5W-20, stock cam, stock engine, no smoke from engine, 35 psi in tires, drive like an egg is under gas pedal. Almost all of the driving is stop & go in city. Most people in town are retired so the police are really alert for speeders and any cars that look fast. I was just looking to cover all bases for fuel economy. I thought about checking the cam gear for valve timing. I believe the original was set for 4 deg. retarded for polution control back in 1972. Too much work and chance of screwing up something. It's running great now so I'll just keep making more trips to the gas station I guess. Thanks for the info. John
|
|
JimW
Senior Member Joined: 09-December-2003 Location: USA Status: Offline Points: 602 |
Post Options
Thanks(0)
|
That still seems low for a 400 2v combo.. Maybe try a trip where you dont vary the speed much and see if you get into the middle teens? I know they weren't rated much higher than 14 or 15 new, so you're close. Maybe try looking around for a set of the closed chamber 2v heads (Aussie). You might find more efficiency with those heads and at not too high of a cost. As for the cam, maybe there is a better design that could gain you some MPG? Lots of places to look.. Jim |
|
1976 S&H Gran Torino
460/C6/4.33 13.05@105.6 545/C6/3.56 11.52@117.8 More to come!!!! 463rwhp/495rwtq two tons of fun see it and hear it at: www.torinocobra.com www.st |
|
Post Reply | |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |