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MG MGB GT V8 Factory Originals Technical - Need help indentifying block
|After reading in the arcives and consulting How To Give Your MGB V-8 Power, I still can't figure out what year or compression this Buick 215 is. It came with a four barrel intake. Can anyone help? Stamped on block : I114467 Thanks, Dana|
|The first thing you need to find out is if you have a Buick or Oldsmobile block. The Buick block has what looks like a cast boss for the cylinder head bolts, but is undrilled and tapped. Buick and Rover heads will fit on either block, but Olds heads only fit the Olds block. I believe these blocks are the same for both years with the exception that the Olds has one more bolt hole.|
The Buick takes a dished piston that gives you a 9:1 compression on the standard engine, which usually is a 2 barrel carb. The Olds engine has flat top pistons, and the compression is higher, about 12;1 I think) you can put the Olds piston into the Buick block and get an 11:1 compression. The Buick engine also came in some Pontiac Tempests. The Buick has a semi-hemispherical combustion chamber, while the Olds is more of a wedge design. Intake and exhaust manifolds will fit either one. There are at least two castings for the Buick head, and I believe that the chamber volume is what controls compression. The higher compression ia around 12:1.
The Olds four barrel engine has a compression ratio of about 12;1 (Which I think would be a little too much these days unless you were very careful about the grade of gas you used) . There are slight differences in the intake manifolds between the Buick and Olds, but they are interchangable and both take the Rochester carb. (predecesor to the Quadrajet) I'm not certain, but I think the bolt pattern on this manifold is the same as the Weber-Edelbrock carb.
If you have a four barrel manifold, I would guess you have the higher compression ratio, if you indeed have a Buick. Look at your heads. If the area over the cylinder is cast such that the chamber depression covers the entire area, they are probably the lower compression heads. The higher compression head usually show just the pocket where the valve are located as part of the casting.
If this is all too confusing, let me know and I'll pull some of the shelf in the shop and email you some pictures.
|Phil, Thanks for all the info. The top of the pistons are flat except for 4 little cresent shaped areas. Looking at the heads, the area over the cylinder is not intirely depressed, maybe about 70%. There is some flat area there but not much. While I don't expect to use this block, I am most interested in the pistons. If they are high compression, I might try to use them in another engine.|
|The 200 hp four-barrel Buick was available only in ’63 in the Skylark whereas, the two-barrel Buick with about 155 hp was available for all three years of production in the Special.|
Where was your number stamped at on the block, that is the first indication on a complete motor as to buick or
olds or pontiac or rover. Case and point; the I indicates a 1962 Buick if the number is stamped on the left hand of the engine block in front of the valve cover. The book you referred to says that a original 4 barrel buick made 190hp with 11.0:1 compression.
|Can anyone tell me what this V-8 motor is and it's year please? I haven't found a casting reference table yet. |
Stamped on the right hand deck-face of the block, just in front of the cylinder head are 2 numbers:
the first reads "HI4289I" in a neat and tidy looking script and the second number, upside down and adjacent to the first number reads reads "OH250718" in a rougher looking and slightly larger script.
The induction manifold is a 4 barrel.
|Anthony, Phil, and Dana:|
This is what my experience has left me with the engine I.D. between the Buick and the Olds. The easiest way of 'eyeballing' the difference is looking at the rocker covers, the Buick has flatter covers on top, with only 4 bolts to fix them to the head (same as Rover). The Olds uses 5 bolts, and the tops of the rocker covers are parallel to the head mounting surface, or at an angle sloped towards the exhaust side. If you want to unbutton the engine, Phil is dead on, the Olds uses 6 bolts per cylinder (one of which holds the rockers assembly down) Buick uses only 5. Buick 300 heads and later Rover 4.0L + use only 4.
On the Olds engine it is the head that determines the compression ratio, not the piston, so there are two different head castings (worth noting) Buick used different pistons. Phil is again correct with compression ratings. The '63 Jetfire Olds turbo engine actually had 11 to 1+ compression ratio, and only ran about 4-6 psi of boost with a special 50/50
"turbo jet fluid" mix of alcohol and water.
I hated the Rochester carb on my '62 Skylark, replaced it with a Carter AFB. Count the air horns on the Rochester....
Prefixes: (Buick only sorry)
1961: H (155 hp)
1962: I (155 hp) 2 barrel
HI (185 hp) 4 barrel
1963: JM (155hp) 2 barrel
JN (200 hp) 4 barrel
I deal in Buick stuff, not Olds so hope this info helps
C in Sacto.
**NBA: see Webber stay, see Weber go to Orlando..**
|O.K. More info on my block. The numbers, I114467, are stamped on the right (passenger side, U.S.) front of the block. The rocker covers are not slanted, they have 5 bolt holes and the cylinders have 6 bolt holes around them. I guess this means I have a Pontiac engine or, pieces of one. Assuming the 4 barrel intake that can with it is the correct one for this engine, will it bolt up to a 1980 SD1 block?|
|When I stated that the rocker covers are not slanted, I mean off the heads, sitting on a bench they are not slanted but would be slanted mounted on the engine.|
This thread was discussed between 24/06/2001 and 01/07/2001
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