• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

What have I got

Share this page

Spriteman65

Spriteman65

Senior Member
Offline
I recently picked up (for free) a 1275 shortblock and 3 heads from a guy who was moving and needed to get rid of them. I'm thinking about rebuilding this engine and putting it in my car. I was hoping one of you could tell me what I have and if is ok to go in my 65 Sprite.

The engine tag is
12CD-DA-H 17743

One head which is rebuilt and has hardened exhaust seats in place has a casting number of
12G 940

The other two heads need rebuilding and both have casting number
12G 1316

Is either of these heads better than the other?

Thanks
Jeff
 
I am not positive but I think that a Cd is '68/'69 or so.
In reality a 1275 is a 1275, they are all good for what the majority of us use them for.
Bill
 
Bill
After reading the other thread you referred to, I went out and checked, the 12G940 head has the raised area at the thermostat housing that Hap said to avoid. It did not appear to have any cracking at the intake valve so maybe it is ok for a mild street engine.

Jeff
 
Most of the 12CD's I've come across originated in 68-69 Spridgets. Note that Sprites disappeared from the US landscape in 1969. These were the higher compression model engines (8.8-1) and like Bill states are good a base for virtually all performance mods or reliable street type builds.

Previous discussions on the head cracking by myself may have incorrectly given the impression that it is a fairly common and catastrophic occurence. I'm sorry if this was the impression, but it is just not so. Most of the time with standard valve diameters, it is a rare occurence. These "Metro" style heads can be good candidates for modifications and many years of reliable service. With lead free seats in the exhaust already, it sounds like a very fortunate find.

If the Two (2) 12G1316 emmissions heads are the early type (good exhaust port), then they are good candidates for any of your local racer types who compete in SCCA type racing. A quick glass bead or abrasive type blasting of the area between the valves will ID whether there are any cracks or not. BLMC cylinder heads did not fair too well in the exhaust seat area with chronic use of no-lead fuel and lack of valve adjustment. Seats are often needed to correct excessive recession and pitting.

With the added displacement of the 1275, you will need to check carb needles, maybe make a slight jet adjustment and/or maybe an adjustment to the 1275 "AN" needles or the slightly richer H6 or M's would be needed. Just depends on you state of tune.

Mike Miller
 
Last night I was at the shop and walked by the 1275 engine I picked up from a NC salvage yard a week or so ago. It was partially disassembled and I have been taking it down to core components. The engine lost a few bearings, but has some good pieces in it. Needs a line bore too, but the point of this additional post is just to pass on the engine tag ID number. It is 12CD-Da-H-16360. My hunch is that this originally came in a 1968 vehicle. Head was not a 68, but more like after 1971 due to the "X" over the center exhaust. It was a previous build with +20 pistons and a steel billet cam. Quite an eclectic mix of pieces. Some good, some junk and some recoverable. A good project for the coming year.

Take care, Mike
 
Mike,
I am only planning a mild upgrade from stock in the power department for this engine. Sounds like I am good to go using what I have.

Thank you
Jeff
 
Jeff;

You're welcome. Yep, sounds like you have a good starting point with the "found" pieces. I always find it challenging, satisfying and fun to create performance engine builds from these types of pieces.

Have a great Holiday season,
Mike
 
Back
Top