How do you raise block height efficiently?

[NME308]

Rod length theory's are a rather hotly debated waste of time! There is no hard evidence that there is ANY power difference to be made with differing rod lengths in the same engine...

There are mega HP small block naturally aspirated chevy V8's using anywhere from 5.5 to 6.4 inch rods and each engine builder will argue as to why the rod length makes a difference. Long or short the piston still ends up at top dead centre and even if a fraction of timing adjustment either way is required they will still make similar power if the rest of the combo is the same. Some evidence certainly exists however as to the problems associated with mega long rods and short pin height pistons suffering reduced engine life from piston rock and subsequent bore scuff etc.

By raising the deck height on a 3TC simply to fit a longer rod in I can guarantee it would be nothing more than a pointless excercise in expense. If it were to go about fitting in a longer throw crank then the loss of ability to fill the cylinders properly through a 3TC pushrod head with a naturally aspirated engine of a few hundred cc's increased capacity would also in my opinion render it a pointless excercise! If the twin cam 2TG head could be ported efficiently enough to allow such a stretcher stroker bottom end to breathe properly then a rich man may gain a couple of 'because I can' points.

The most avid bunch of 3tc guys in the america's all seem to agree that N/A there is not too much potential for the pushrod 1.8 engine. The old pushrod 1.8 cannot compete with hypo N/A honda engines and other more modern 4 valve examples. Turbocharging however changes all the rules allowing the strong old dinosaur to be artificially filled up with copius quantities of combustible fuel and air!

Cheers,
Jason

[BLK_20v]

1" sounds huge.... Normally clearance issues can be overcome using shorter pistons

[Radar]

As J-M said it'd be nicer to have longer rods with the 4Y crank, and the only way I saw around this is a longer block. If you use the 4Y crank and 5" rods your still only getting 1.48R/S (crap imo) and that involves using a piston with a compression height of only .789". From what I understand mass sidewall loading and stupidly small pistons will cause piston rock which is not ideal. So by raising the block height 1" the use of longer rods say 5.6" and pistons with a compression height over 1" is doable. Which should mean less sidewall loading and a piston with less chance of rock. In other words a more reliable 2.1L stroker motor.

[Radar]

Turbocharging however changes all the rules allowing the strong old dinosaur to be artificially filled up with copius quantities of combustible fuel and air!

In a true blue NA performance car you can do just that with manifold tuning, get more air and fuel in the cylinder. Inertia tuning.

[Hurricane]

its late and i may have missed it but what are u trying to do if u can make the block height taller?

my brother had a datsun L18 2.1 litre x rally motor that was built by some place in melb (cant remember, i think he builds the best L4 series in vic or aus?) anyways the motor was some secret build (it f**kin went well) it has a steel spacer plate between the bllock and the head, it used to leak oil but apart from that never had an issue, i think it was o rings around the bores not sure about the water jackets. it was maybe upto 3 or 4mm tall and was used for running a longer rod with its pistion combo. the motor is now sold so i cant check it but my bro minght know more info on it.

[J-M kujala]

As J-M said it'd be nicer to have longer rods with the 4Y crank, and the only way I saw around this is a longer block. If you use the 4Y crank and 5" rods your still only getting 1.48R/S (crap imo) and that involves using a piston with a compression height of only .789". From what I understand mass sidewall loading and stupidly small pistons will cause piston rock which is not ideal. So by raising the block height 1" the use of longer rods say 5.6" and pistons with a compression height over 1" is doable. Which should mean less sidewall loading and a piston with less chance of rock. In other words a more reliable 2.1L stroker motor.

if ´789 is correct calculated, pin height to 5" rod, its ok to use a 1" height piston .2" can come over the block with "block spacer" or thick gasket.

mine +4mm 127mm long rods what i have at spare some sets. push 3T piston 8mm over the block with 4Y Crank so the correct pin height without spacer with 1mm HG is ~27mm.
with ~5mm spacer can use Wiseco K557M87 pistons, but had to confirm that these got enough material to make valve pockets.

usually 1" is most short piston and with wiseco desing, can usually come max 5-7mm over the block.

135mm Rod is minimum lenght what can used with 4Y crank without modify the crank, piston will hit the counterweights !!

but mine engine runs nice with 123mm rods =) rod angle is horrible.