Engine Block 101
- Thread starter TurboTJT
- Start date
I'll answer the first two..... and some general info on the second two.....
"109" blocks refer to the casting number for the block. They came in mainly GM '86 and '87 RWD 3.8L cars.... i.e cutlass, regal... etc. The "turbo" blocks have an oil drain passage drilled and tapped into the lifter valley. The N/A 109's are identical except you must drill and tap that oil return into the lifter valley..... the boss is still cast into the block..... not a big issue.
"SG" blocks were (maybe exclusively) GM GoodWrench engines that were based off the 109's..... but also had "SG1" stamped into the block...... these were "crate" engines.... or replacement engines....... and pretty much had the "turbo" crank which had rolled fillets on both the rods and the mains. Pretty much these were made after regular '86 and '87 engines were depleted and GM needed to supply people with a replacement engine......N/A cranks had only rolled fillets on one of them..... not both...... and IMHO it is debateable if the N/A cranks were actually weaker or not.....(based on people that have actually broken a N/A crank)
"Stage" blocks in general are the equivalent to Chevy's "Bowtie" block. It was considerably stronger. They either had or had provisions to accept 4 bolt main caps.... at least on the middle two mains....... as well as much more meat in the main webbing. They also had provisions for or contained extra head bolt holes...... to allow better clamping of the heads. This is where you see some heads listed as "14-bolt" heads..... these are for use in blocks with the extra head bolts. Regular non-stage blocks merely had 8 head bolts per head.
As far as what to use..... it all depends on budget and overall horsepower goal.
Maximum effort 109's have now gone high 8's in the 1/4 mile...... but at that power level.... it is a ticking time bomb. They are also not at all cheap to build a 109 capable of such times.
Stage motors are now down in the 7's regularly.......
IMHO..... down to the low 11's or real high 10's...... a 109 can be built for reasonable $$ that will hold up if you stay away from detonation. Once you get much quicker than that $$ seems to approach infinity.... LOL
HTH
"109" blocks refer to the casting number for the block. They came in mainly GM '86 and '87 RWD 3.8L cars.... i.e cutlass, regal... etc. The "turbo" blocks have an oil drain passage drilled and tapped into the lifter valley. The N/A 109's are identical except you must drill and tap that oil return into the lifter valley..... the boss is still cast into the block..... not a big issue.
"SG" blocks were (maybe exclusively) GM GoodWrench engines that were based off the 109's..... but also had "SG1" stamped into the block...... these were "crate" engines.... or replacement engines....... and pretty much had the "turbo" crank which had rolled fillets on both the rods and the mains. Pretty much these were made after regular '86 and '87 engines were depleted and GM needed to supply people with a replacement engine......N/A cranks had only rolled fillets on one of them..... not both...... and IMHO it is debateable if the N/A cranks were actually weaker or not.....(based on people that have actually broken a N/A crank)
"Stage" blocks in general are the equivalent to Chevy's "Bowtie" block. It was considerably stronger. They either had or had provisions to accept 4 bolt main caps.... at least on the middle two mains....... as well as much more meat in the main webbing. They also had provisions for or contained extra head bolt holes...... to allow better clamping of the heads. This is where you see some heads listed as "14-bolt" heads..... these are for use in blocks with the extra head bolts. Regular non-stage blocks merely had 8 head bolts per head.
As far as what to use..... it all depends on budget and overall horsepower goal.
Maximum effort 109's have now gone high 8's in the 1/4 mile...... but at that power level.... it is a ticking time bomb. They are also not at all cheap to build a 109 capable of such times.
Stage motors are now down in the 7's regularly.......
IMHO..... down to the low 11's or real high 10's...... a 109 can be built for reasonable $$ that will hold up if you stay away from detonation. Once you get much quicker than that $$ seems to approach infinity.... LOL
HTH
CamoDeafie
New Member
- Joined
- Jan 7, 2010
so; 109 blocks are better than other stock blocks; how? (as a side note; I see on the GNTTYPE chart that the first years of the FWD 3.8s' block numbers end in 110......presumably because of the transmission layout; but shares crank numbers with the 1978s' and other rwd blocks)
probably stupid sounding question, but i'm curious
probably stupid sounding question, but i'm curious
so; 109 blocks are better than other stock blocks; how? (as a side note; I see on the GNTTYPE chart that the first years of the FWD 3.8s' block numbers end in 110......presumably because of the transmission layout; but shares crank numbers with the 1978s' and other rwd blocks)
probably stupid sounding question, but i'm curious
Of all the "stock" blocks.... the 109 is widely known to be the strongest. I don't know "how" much stonger it is...... just that it is accepted that it is the stongest.
Can't comment on the other stuff you inquired about... sorry.
CamoDeafie
New Member
- Joined
- Jan 7, 2010
hmm. generally accepted that 109s are strongest stock block, but no concrete "proof" that they are, other than the time slips and the fact they seem able to survive 8-10 second passes....I'd like photos of the bare 109 blocks out of the engine bays and compared to other castings other than the Stages/SG blocks. I've a friend who's got a '110 FWD 3.8 engine for me in storage for a project, depending on what i end up with (still looking for a Regal or G-body though)
I seem to recall that the '84 - '85 blocks...... some of them at least..... had thinner decks..... FWIW
BobbyBuick
Well-Known Member
- Joined
- May 24, 2001
the lifter valley is weaker in the 84-85 blocks although I have seen them go high 10s with no problems.
Also rumor has it that the SG blocks had more nickel dont know if it is true or not
Also rumor has it that the SG blocks had more nickel dont know if it is true or not
The major differences between the early blocks and the 109 are that they moved the the main gallery to the passenger side slightly to improve oiling and got rid of the open top design of the lifter valley. This may strengthen the block slightly but the biggest issue is the bottom end. It can walk around under boost so a girdle is really needed to make it stronger.
25-30lbs
