What are the special features of a J block? I seem to remember something about oil injection, but I don't find anything about it on the brickboard. I spent about 20 minutes becasue I'm curious, not consumed with a need to know.
I've got a rebuilt 740 turbo (not by me, I was 15 when it happened) with a J block. The mechanic who rebuilt it couldn't find a used turbo block and so he reground the original. Driving 120 miles with no water will crack your block. It still drove to the mechanic's. Gotta love Volvos.

any help is appreciated.
-Will
--
1990 740 Turbo, on its way to stock specs, maybe beyond

"What are the special features of a J block?"

Personally, I've never heard of a "J" block, and I've never seen any mention in the Volvo manuals either. The original production run of the B230 was 1985 through 1987 (3 model years) and used lightweight piston rods and had a thrust bearing that could fall out of place (very rare occurances). The "K" block was used from 1988 through 1992 and had some stronger internal webbing to increase block strength, a new crankshaft with an improved thrust bearing (now at the end instead of the middle). Most of the K blocks made from 1988 through 1990 or 1991 have a one inch letter "K" cast into the iron just below the engine serial number (below the thermostat and intake runner #1). The "L" block was used from 1993 through 1995 and features thicker piston rods, rounded tooth cam/crank gears, and a piston oil cooling jets on the turbo models. I was recently told that the non-turbo "L" blocks did not receive the piston oil coolers, and have yet to confirm this for certian (I have yet to come across a non-turbo "L" block in a salvage yard that I can tear into).


A few side notes:

-Some or all of the "K" blocks may have received the thicker connecting rods that the "L" blocks had, as I don't know for certain what year the beefier rods were introduced. -it may have been a running production change.

-The 1992 and possibly the 1991 model year K blocks are missing the letter "K" cast into the iron just below the block serial number. However the "K" still remains on the paper engine ID tag on the front plastic timing belt cover. These engines are indeed K blocks, but are lacking the "K" designation that was cast into the side of the block. All K blocks will have a letter "A" cast into the iron next to the oil filter, not to far from the engine date code (which is hidden under the aluminum engine mount). A small handfull of the first production "K" blocks in 1988 also missed getting the "K" stamped into the iron, so the letter "A" by the oil filter is the only true way to know if you have a K block versus the original '85-'87 block (when viewed from the outside and missing the paper tag).

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 273k miles.
'88 Black 780, PRV-6, 149k miles.

Well, since the "K" block was the first upgrade to the B230, you'd think that the "J" would be the original small rod engine.
"L" got oil squirters and a relocated thrust bearing.