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Eman
11-29-2005, 11:14 AM
My shop manual originally calls for Champion spark plug H-8 with a .035 gap. I found the cross reference to Champion stock#587, part#H8C. However, I think I may have gapped them at .030. I could swear I saw something for that plug and my V8 saying to gap them there instead of .035. Anyone know for sure which gap might be correct?



1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

Mike Van Veghten
11-29-2005, 12:23 PM
.035" has been a standard gap for almost all American (forign too ?) from the inseption of the modern spark plug up to the newer HEI style ignitions which then went to....from .045" to .065", depending on the manufacturer.

That said, I just read a short report from an Autolite Spark Plug engineer. Basically it said that with a "cut back ground strap, .025" is all that's needed".

I ran my Pro Gas Anglia (small block Chevy at 7800rpm) at .025". It had a Vertex magneto in it.

All this is to say....with a good/fresh ignition system, .035"/.040" is fine, no need to go further. If you system is a few years old, .025"/.030" will work just fine.

The bigger the gap, the harder the system has to work to fire the plug.

Hope that hasn't muddied up things more for you.

Roscomacaw
11-29-2005, 12:46 PM
.035 will do fine. So will .030.:D

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

wagone
11-29-2005, 03:40 PM
You guys are the EXPERTS (seriously). I'd just like to throw in my two cents on plug gaps set wider than .035" (above note by Mike says .035-.040"). Years (and years)ago I drove a '62 Lark with a 259 V8 and O. D. I'd set the gap at .038" and everything was fine UNLESS the car sat for ten hours or more without starting in a moderate climate (Virginia and the U. S. Navy). At which point it became virtually impossible to start. I stopped at a Stude dealership and asked what the problem might be--and the first question out of the mechanic's mouth was "where do you have the gap set?". He said change it to .035" and you'll have no more problems--and he was right. I bought this car from my parents and they purchased it new--I'm not sure what difference that makes though.:D
wagone and the mighty Avanti

N8N
11-29-2005, 06:05 PM
Eman,

I'm ASSuming from your sig that you're referring to a '51 Commander, i.e. an OHV V-8 engine, next time you change plugs instead of using a H-8 why not try a H-14Y, Autolite 437, or Bosch WR9FC which is a projected nose plug? That's what the later V-8s used (the H-14Y that is, a 437 is a direct cross while the Bosch is the equivalent of a RH-14YC, if such a thing exists - basically same plug w/internal resistance) they weren't recommended in the original shop manual simply because they weren't common yet.

BTW, H-8 sounds real cold for that engine, earliest listing I have is for a '56 which took a H-11. But I don't have your shop manual so you may very well be right, it just looks a little odd to me.

I feel obligated to add, projected nose plugs are for overhead valve engines ONLY - don't even think of trying to use one in a flathead (there's not enough room, bad things will happen)

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Roscomacaw
11-29-2005, 06:14 PM
The Champion H-14Y crosses to the new Champion #91

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

N8N
11-29-2005, 06:36 PM
There's a *NEW* numbering system? Dang, I just finally figured out the old one!

nate

(and the old one actually makes sense, too... what are the odds that the new one will?)

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

KevinSheen
11-29-2005, 07:17 PM
I just changed plugs this weekend from Champion H14Y's to the Autolite 437. They seem to be doing the job just fine. New spark plug wires too (from Stude Int'l). I'm leaving to go to sea thursday and am leaving the truck in the care of a trusted friend and excellent mechanic who will take care of the other jobs I have planned. Fixing the Wandermatic steering. New bushings for the leaf springs. Fixing that damned leak in the A/C so I don't lose all my freon in the hot Louisiana summers. When I get back in mid January I'm planning on heading to St. Pete, FL to see the folks. 800 miles each way. The adventure continues. In case I don't get around to it tomorrow, Merry Christmas, Happy Channukah, and Happy New Year to all. Drive safely. Kevin in the Stoogebaker

1963 Champ

Eman
11-30-2005, 12:35 AM
You have air conditioning?!:D


quote:Originally posted by KevinSheen

I just changed plugs this weekend from Champion H14Y's to the Autolite 437. They seem to be doing the job just fine. New spark plug wires too (from Stude Int'l). I'm leaving to go to sea thursday and am leaving the truck in the care of a trusted friend and excellent mechanic who will take care of the other jobs I have planned. Fixing the Wandermatic steering. New bushings for the leaf springs. Fixing that damned leak in the A/C so I don't lose all my freon in the hot Louisiana summers. When I get back in mid January I'm planning on heading to St. Pete, FL to see the folks. 800 miles each way. The adventure continues. In case I don't get around to it tomorrow, Merry Christmas, Happy Channukah, and Happy New Year to all. Drive safely. Kevin in the Stoogebaker

1963 Champ


1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

Eman
11-30-2005, 12:53 AM
Nate, I just looked again at my shop manual as well as my Chilton's manual, both say H-8 for the Champion spark plug. (You're correct on the OHV V8 btw.) What would be the benefit of going to either the H-14Y or Autolite 437?



1951 Commander Starlight Coupe (aka "Stella")
www.bulletshots.net

N8N
11-30-2005, 06:09 AM
The theory is that the projected nose plugs are more resistant to fouling as they run hotter but they don't cause detonation because they are cooled by the incoming fuel/air mix (because the electrodes actually project into the chamber) I'm not sure if it really works like this or not, but pretty much every OHV engine since the early 60s takes a projected nose type plug, Studebakers included. The H14Y was the recommended plug for the last Studebaker V-8s. I think a H18Y was recommended earlier, which might be the ticket for an oil burner that's not driven hard.

I wouldn't bother changing now if your car runs well, just stick it in the back of your mind for the next plug change to try one of the later style plugs.

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Dwain G.
11-30-2005, 03:56 PM
Not really a new system, it's just that parts houses like to use the stock # instead of the plug #.
BUT! The present H14Y is not the same plug it was originally. It is a colder plug, and for most people's driving it will foul easily.
The current Champion recommendation is RH18Y (stock # 857)which I have used with excellent results.

Dwain G.