Home » Public Forums » GMCnet » Tune Up Requirements
| Tune Up Requirements [message #348711] |
Sun, 29 September 2019 22:07  |
Mike_H
Messages: 16
Registered: September 2019
Location: Grand Rapids, MI
Karma: 0
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Junior Member |
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So...now that I know what engine I have (see threadhttp://gmc.backyardwildlife.com/GMCforum/index.php?t=msg&th=42989&start=0&rid=5830) I'm making a list of AC Delco part numbers for a tune up. I want to replace the PCV valve. They are cheap and I don't know when it was last done. However, I cannot find the PCV valve listed in my parts manual. Everything listed is for the 455 not the 403. I looked up a 78 Toranado and found one, but I'm not sure yet which engine parts cross over and which do not.
Also on the breather side, I have a breather in good shape, but the two rubber elbows that connect it to the air horn are shot. Are those available?
Mike and Jessica
West Michigan (Just north of Grand Rapids)
1978 Royale Twin bed, Dry Bath
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| Re: [GMCnet] Tune Up Requirements [message #348713 is a reply to message #348711] |
Sun, 29 September 2019 22:34  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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78 toro was 403.
Do not gap the plug any more than .40 , prefer .37.
On Sun, Sep 29, 2019 at 8:08 PM Mike via Gmclist
wrote:
> So...now that I know what engine I have (see threadhttp://
> gmc.backyardwildlife.com/GMCforum/index.php?t=msg&th=42989&start=0&rid=5830)
> I'm making a
> list of AC Delco part numbers for a tune up. I want to replace the PCV
> valve. They are cheap and I don't know when it was last done. However, I
> cannot find the PCV valve listed in my parts manual. Everything listed is
> for the 455 not the 403. I looked up a 78 Toranado and found one, but I'm
> not sure yet which engine parts cross over and which do not.
>
> Also on the breather side, I have a breather in good shape, but the two
> rubber elbows that connect it to the air horn are shot. Are those
> available?
>
> --
> Mike and Jessica
> West Michigan (Just north of Grand Rapids)
> 1978 Royale Twin bed, Dry Bath
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Tune Up Requirements [message #348714 is a reply to message #348713] |
Sun, 29 September 2019 22:41 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Part # in parts book are not very good
On Sun, Sep 29, 2019 at 8:34 PM Jim Kanomata wrote:
> 78 toro was 403.
> Do not gap the plug any more than .40 , prefer .37.
>
>
> On Sun, Sep 29, 2019 at 8:08 PM Mike via Gmclist
> wrote:
>
>> So...now that I know what engine I have (see threadhttp://
>> gmc.backyardwildlife.com/GMCforum/index.php?t=msg&th=42989&start=0&rid=5830)
>> I'm making a
>> list of AC Delco part numbers for a tune up. I want to replace the PCV
>> valve. They are cheap and I don't know when it was last done. However, I
>> cannot find the PCV valve listed in my parts manual. Everything listed
>> is for the 455 not the 403. I looked up a 78 Toranado and found one, but
>> I'm
>> not sure yet which engine parts cross over and which do not.
>>
>> Also on the breather side, I have a breather in good shape, but the two
>> rubber elbows that connect it to the air horn are shot. Are those
>> available?
>>
>> --
>> Mike and Jessica
>> West Michigan (Just north of Grand Rapids)
>> 1978 Royale Twin bed, Dry Bath
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Tune Up Requirements [message #348716 is a reply to message #348711] |
Sun, 29 September 2019 23:24 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Mike, Do not get hung up on the NB? RPO code When I saw it I guessed it had something to do with emissions, fuel tank, or something like that. It was a guess on my part that it was a California thing but since I did not look it up I did not post a response.
So just go to what ever auto parts store and get the parts for a 78 Toronado with a 403 engine. Those parts you listed were common across many, many, GM vehicles.
As an example that PCV valve is: AC Delco 19310783, or Standard Motor products PCV112, Microguard PCV112, or Autozone PCV1118DL. The rubber grommet if fits in is either Dorman 42314 or 42061.
When looking up these products on line, none of the asked about the RPO code and they fit various Oldsmobiles from 1963 through 1979.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Tune Up Requirements [message #348717 is a reply to message #348711] |
Sun, 29 September 2019 23:24 |
Dave Stragand
Messages: 307
Registered: October 2017
Karma: 0
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Senior Member |
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The Toronado elbows are the same. I got them both at Advance Auto for under $10 but they are more fragile than the originals. Our vendors may have more durable replacements. The valve cover grommets on each side are the same as well. PCV should be the same too.
-Dave
1978 Transmode near Pittsburgh.
> On Sep 29, 2019, at 11:08 PM, Mike via Gmclist wrote:
>
> So...now that I know what engine I have (see threadhttp://gmc.backyardwildlife.com/GMCforum/index.php?t=msg&th=42989&start=0&rid=5830) I'm making a
> list of AC Delco part numbers for a tune up. I want to replace the PCV valve. They are cheap and I don't know when it was last done. However, I
> cannot find the PCV valve listed in my parts manual. Everything listed is for the 455 not the 403. I looked up a 78 Toranado and found one, but I'm
> not sure yet which engine parts cross over and which do not.
>
> Also on the breather side, I have a breather in good shape, but the two rubber elbows that connect it to the air horn are shot. Are those available?
>
> --
> Mike and Jessica
> West Michigan (Just north of Grand Rapids)
> 1978 Royale Twin bed, Dry Bath
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
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Unsubscribe or Change List Options:
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1978 Transmode (403)
Pittsburgh, PA
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| Re: [GMCnet] Tune Up Requirements [message #348724 is a reply to message #348711] |
Mon, 30 September 2019 09:37 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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Mike and Jessica,
GMCMI has a really good chart for plugs online that I created, but I have added a text version today. If you need to have questions please call Jim K or you can call me at nine8nine eight5nine-zero 7one5. The GMC community is large and very knowledgeable. The 78Z parts book is a 1970’s snapshot in time as Ken has said. The part interchange list on GMCMI is probably the most current listing of part number for the GMC coach.
As for you request on PCV valves you can use any of the following:
Fram FV-112
Motorcraft EV-10
AcDelco CV-679-C
NAPA CBR-29281
Typically if you have a 455 motor then use the 1975 Toronado as a base and a 77 Toronado for the 403 and chances of you have a California version are very slim. Anything other that the engine use the 1975 Toronado as a search item.
J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan Midland
Spark Plug Application Guide (09/28/13)Reviewed 5/8/17
Brand Type 455 403 Gap
ACDelco Platinum 41818 41818 .038
ACDelco Standard R46SZ R46SZ .060
ACDelco Platinum AC41833 (Napa) AC41833 (Napa) .038
Autolite Standard 847 847 .060
Autolite Platinum AP847 AP847 .038
Bosch Standard 7921(WR10FCZ) 7920(WR10FCY) .060
Bosch Platinum 4023(WR9FPZ) 4022(WR9FPY) .038
Champion Standard 66(RJ18YC6) 66(RJ18YC6) .060
E3 Premium E3.52 E3.52 As from Box
NGK Standard 4536 4536 .038
NGK Iridium XR45IX (7293) XR45IX (7293) .038
NGK Iridium XR5IX (7355) XR5IX ( 7355) .038
Plug Gap Settings: Gap setting is gap out of the box; plug gaps out of the box vary by manufacture and application and should always be checked before installation. Dick Paterson several years ago conducted Dyno testing on several different plug gaps and found that there was little difference between the large and small gap settings for power output. My personal setup was a Paterson HEI, running original ACDelco #7 Rapidfire gapped @ .038 as per DP, yours may vary. The smaller gap reduces the load on the HEI coil. Factory specified gaps have varied over the years for the coach. The 73/74 point distributor called for a .040 gap. The 455 with the HEI distributor (75 thru 77) called for a .080 gap. The 403 with HEI distributor (77 thru 78) had 2 gaps listed. The gap for the Federal motor was .060 and the California motor was .080. It has been seen that the .080 gap was hard on the coil and module and had seen a higher failure rate. An article in GMCMHI newsletter V 4, I 3, P 3 stated that GM dealers both in California and east were recommending a .045 for the 403 HEI giving the best performance.
Now a personal comment and again yours may vary. I had run our 77 403 with the .060 gap (R46SZ) (98 thru 03) and saw that the plug gap was pounded out to better than .075 in less than 4K miles. I was changing plugs every year. I also had several modules failures during that time. I switched to the DP HEI and #7 plug in 2004 I did not had any failures. Same #7 plugs, 32K miles, Cleaned and regapped in 2008, still looked good, ACDelco listed these as a 100K-mile plug. Another personal comment, is I would run one of the platinum or Iridium plugs and close the gap down to the .036 to .040 range or the
E3 plug as it comes out of he box.
NOTE: The original ACDelco #7 is no longer available in original plug tip. New ACDelco #7 is not the same construction and should be avoided. In 2010 Dick Paterson recommended the NGK XR5IX plug as a replacement. I now run the E3 Brand E3.52 plug and have about 10000 miles.
Onan Spark Plugs: Both the 4K & 6K use the same heat range spark plug. Plug gap for both is .020”
Cummins Onan spark plugs are part# 167-0262-99 On Sep 29, 2019, at 11:07 PM, Mike via Gmclist wrote:[/color]
>
> So...now that I know what engine I have (see threadhttp://gmc.backyardwildlife.com/GMCforum/index.php?t=msg&th=42989&start=0&rid=5830) I'm making a
> list of AC Delco part numbers for a tune up. I want to replace the PCV valve. They are cheap and I don't know when it was last done. However, I
> cannot find the PCV valve listed in my parts manual. Everything listed is for the 455 not the 403. I looked up a 78 Toranado and found one, but I'm
> not sure yet which engine parts cross over and which do not.
>
> Also on the breather side, I have a breather in good shape, but the two rubber elbows that connect it to the air horn are shot. Are those available?
>
> --
> Mike and Jessica
> West Michigan (Just north of Grand Rapids)
> 1978 Royale Twin bed, Dry Bath
_______________________________________________
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