• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Smog head 1275 question

Share this page

drooartz

drooartz

Moderator
Staff member
Gold
Country flag
Online
The 1275 I have is a late one for the States, with the smog head. What are the 4 bolts for in the side? I'm assuming they are filling holes used for some purpose. Do they have to be long, or could the bolt heads be flush with the block?

https://www.drooartz.com/documents/sagas/project_midget/pages/page_4.html

Just curious... Patrick has me thinking about head differences.
 
Mine stick out also, never noticed before, and have no idea what they're for. Mine are studs however, not bolts which leads me to believe they are just plugs of some kind.
Hope you don't mind, but I snagged 2 pics from your site there as your bay is what I'm trying to accomplish sans emissions junk and heater so my 'before' photos don't suprise me too much when all back together.
 
it is part of the air manifold which fastened into those holes then ran through a check valve and into the air pump. I have studs in mine that I cut a 2 flats on and just screwed them in tight and painted the same colour as the head. A lot of people just put bolts in and paint them. I think I have some nice brass dome head bolts that I may put in. As Bob says they were used to plug the holes left from removing the emission system.
 
As everyone has already said these are the smog pump air rail holes. The long bolts were probably all the PO could get his hands on, I used allen head set screws, looks so much better. I'm working on a 12G1316 1275 head right now (that's what you have as well) and they had just pinched the tubes off and folded them over, I'll install the set screws in this head as well. I use black oxide plated steel set screws, they won't strip like the brass ones will.
 
[ QUOTE ]
The allen head plugs are always on ebay

[/ QUOTE ]

Yep, that exactly what I use, I buy them in bulk because I use them so often. I'm lucky that I have a really nice fastner shop near my shop and can easily soucre that kind of stuff. If you have a good fastner store in town these can be sourced for about a buck. I want to spit out the size, but my memory seem a bit off this morning, I report back with size and length I use. It's just a common fine thread set screw.
 
i got mine off of ebay. nice set of four brass plugs with hex heads. the PO had the original fittings with the tube ends crimped and bent over.
 
I wuz tryin ' to remember as well... done a bunch. Hate that "cut tube, fold and squeeze" solution I've seen so many of. I've an "assortment" of 'em in a drawer here: All different sizes & threads, so not sure of the Dia./TPI for the Brit heads.
 
i believe they are the same thread size as the brake line connections. def. one of those "weird" sizes. As mentioned, they are all over ebay.
 
My question, to expand on Drews, is..What WAS there? Horlers doesn't go into it.
My 1275 has the studs in situ at that location and all the emissions junk was there when I bought it.
These studs appear to have been in for quite some time also.
Could it be that the A-series head had the threads milled for something that just was never installed?
 
Nope. They were as stated above, a "rail" of tubing to inject fresh air into the exhaust ports apres combustion to "thin out" the noxious gasses at the tailpipe.
 
[ QUOTE ]
My question, to expand on Drews, is..What WAS there? Horlers doesn't go into it.
My 1275 has the studs in situ at that location and all the emissions junk was there when I bought it.
These studs appear to have been in for quite some time also.
Could it be that the A-series head had the threads milled for something that just was never installed?

[/ QUOTE ]

What year is yours Barry
 
there were some changes to the emission system, my '72 does not have a pipe coming off the valve cover but my '73 parts car did.
 

Attachments

  • 269233-emm1.jpg
    269233-emm1.jpg
    85.3 KB · Views: 121
oops only got 1 attached
 

Attachments

  • 269235-emm1.jpg
    269235-emm1.jpg
    85.3 KB · Views: 131
they probably used the same head, plugged the holes and brought a pipe off the valve cover instead ,oops attached the wrong pic
 

Attachments

  • 269240-emm.jpg
    269240-emm.jpg
    131.4 KB · Views: 152
I got my blue anodized allen head plugs off the shelf at the (good) local parts house. For anyone out there, don't kill your air rail... I don't believe they are being made anymore and anyone in a hardcore smog state like CA is going to need one. I sold mine on ebay for a pretty penny.
JACK
 
Ok, I'll quit after this. I used about all the combinations you can use for rail plugs, Brass plugs strips out on the heads or allen in a socket head. Aluminum plugs weld themselves to the cast iron head and it is a real pain to get back out ( forget anti sieze they are getting pretty well cooked by the exhaust heat, so that won't last for long). Steel set screws won't strip out the socket head or weld themself to the cast iron. I always put something together as if I'm going to be the next person to have to take it back apart.
All lessons learned from past experiences. /ubbthreads/images/graemlins/wink.gif
 
Back
Top