Is it true that the plugs are pre-gapped from the factory Why?
Nearly all companies that mass-produce spark plugs pre-gap the spark plugs before they ship them out. Shipping and handling, however, may cause the plugs to move around, resulting in changes in the gap size.
What’s the difference between Hei spark plug gaps?
Well, we simply reduced the spark plug gaps back down to the original .045 sizing, and, MAGIC, LIGHT OF LIGHTS, NIRVANA, THE WARRANTEE COIL/HEI MODULE FILURES/PROBLEMS AND FAILURES STOPPED, and failure rates went back to the levels pre-giant gap.
Why are there gaps in the spark plugs?
Opening up the spark plug gaps was done by a few brand name engineers, mostly at Olds, that dimply did not understand that the HEI will not tolerate giant spark plug gaps, it was an easy “fix” for a more sensitive fuel/air mixture developing situation, and their “fix” was totally WRONG..
What kind of spark plugs do you use on a 1969 Chevy?
Engine is a 1969 350 horse 396, all stock so far. BTW, I will not use Champion plugs. Maybe their quality has improved but not willing to give them a fourth chance. Kids will be kids, but parents should be parents. Edited by 69 SS396 on 04-23-11 06:42 AM. Reason for edit: No reason given.
Are there any gaps in Autolite spark plugs?
Autolite spark plugs because they are cheap – gapped at .038 to .042 depending on driving conditions but haven’t found that any gaps from .035 to .045 make any noticeable difference. I did install a D.U.I. module in the 55 gasser and may send my distributor to D.U.I. for a custom curve – but why?
When did GM start using Hei plug gaps?
Back in 1975 when GM started using HEI, they wanted plug gaps set at .060 till they found out it was hard on caps and rotors, as mentioned. They then changed their specs to .045. So as mentioned, .040-.045 is right on the money. They went to .060 – that was still an issue, so they dropped to .045.
Where are the spark plugs on a HEI distributor?
Tip: Label or mark the location of your spark plug wires on the distributor cap for fast, easy reference. Tip: When you have installed your HEI distributor, its best to widen the plug gap as well. Tip: You should run a new power wire that is getting a full 12 volts.
When did GM change spark plug gap to.045?
Back in 1975 when GM started using HEI, they wanted plug gaps set at .060 till they found out it was hard on caps and rotors, as mentioned. They then changed their specs to .045. So as mentioned, .040-.045 is right on the money.
How much gap does a HEI ignition need?
Many ignition scopes overread the high end firing voltages because the clamp on pickup is non-linear. They also vary in accuracy by what type of wire they are clampled on. Dynoloading a 3.8 SFI regal would require about 20KV with .060 gap plugs at full boost. We used a High Speed Tetronix DSO with a 100KV lead to measure voltages at the plug.