LT1 SBC oder 454 BBC: Vor- und Nachteile?

[Grimmjar]

Moin!

Hab nebenan in der Werkstatt zwei Motoren gesehen.
Einmal BBC aus nem 77er Pickup. Der wird nächste Woche mal aufgemacht um zu sehen was damit los ist.
Dann ein LT1 mit Gußköpfen der auf jeden Fall gebohrt werden muß.

Was kann man von den Motoren erwarten,
was kann man noch an Hubraum schinden,
wo sind die Grenzen wenns auch ein paar Jahre halten soll,
wie sieht es mit dem Gewichtsunterschied aus
und wie macht sich das Tuning im Preis bemerkbar?

Hatte überlegt ob man da was mit Turbo bauen sollte aber ich hab auch noch ne feine Lachgasanlage die 600PS bereitsellen kann...


Im Gegensatz zu meinem V12 ist bei den V8 nunmal viel mehr Potential vorhanden und wenn mein Motor kaputt ist, kann der normalerweise in die Tonne und ein Gebrauchter müßte her. Denn aufbauen oder mal schnell 12 neue Kolben für nen BMW is sau teuer. Tunigteile allgemein sind teuer und sehr selten bzw. überhauptnicht vorhanden.
Das sieht bei den o.g. Kandidaten nunmal ganz anders aus. Und daher bin ich am grübeln.


Gruß Thomas

[Alex T.]

Hallo Thomas,
was´n nu??? Nicht mehr V12 mit Kompressor?

[Grimmjar]

Na mal sehen was nun mit den V8 geht und ob ich mir das leisten kann/will.

Ich fang mal anders an:
Was muß man berappen wenn man einen der beiden Motoren SB oder BB auf 600-700PS bringen und für ca. 1200PS haltbar haben will?
Bei SB würde ich den Hubraum so oder so etwas erweitern weil der eh gebohrt werden muß. Da brauche ich also nen haltbares Stroker Kit.
Sind Aluköpfe Plicht?

Beim BB sind Kolben und KW i.O. Könnte also ein 454er bleiben.
WENN denn KW, Pleul und Kolben das aushalten!!! Ansosnsten würde ich da auch etwas Stroken.
Wie sieht es hier mit Alköpfen aus? Die günstigen $800 Köpfe werde ich nicht nehmen. Hab bis jetzt 99 negative und 1 positive Meinung gelesen ;o)

Worauf ist noch zu achten? Dinge die unbeding zu tauschen oder umzubauen sind?

Gruß Thomas

[JYKing]

Hallo Thomas,

zur Inspiration hier ein schöner BBC Aufbaubericht: http://www.theturboforums.com/smf/in...topic=149824.0

Hier nochmal 454 Turbo, aber mit etwas günstigeren Komponenten: http://www.theturboforums.com/smf/in...topic=106790.0

Gruß,

Simon

[Grimmjar]

Hab da auch noch was gefunden. Eigentlich spricht erstmal alles für den BB....
Nächste Woche werde ich noch alle Gussnummer und Maße besorgen und mal genauer suchen.

Flow Test BB Heads:
http://www.airflowresearch.com/westech_figures.php



There are many ways to skin a cat; this is how we do it at Performance Motorsports:

Block:
Start with a tall deck Chevrolet 4 bolt-main truck block. This block has the following advantages:Truck block has thicker cylinder wallsAlmost always comes with a steel crankshaftBlock is fairly inexpensive
The first two items come in handy for this project.

Block Machine work:
Deck the block and bore it to .030 over size to make sure the bores are straight. Finish hone it to a smooth finish with 320 grit and plateau brush the bores this makes for a very even, clean bore.

Next o-ring the block and install the o-ring wire.

Wash everything with plenty of hot water and soap. When thoroughly dry, install Milodon main studs, and oil restrictors. We use the Donovan gear drive front cover (RCD makes a very fine piece too, very similar in design in all billet aluminum.

Crankshaft:
The crankshaft is sent to the crankshaft shop, to be turned .010/.010 under sized on the main and rod journals. We usually run our motors on the loose side, .004 rod and main clearance.

This is a good time to cut the crankshaft for two keyways on the snout to better hold the blower pulley. While it is at the crankshaft shop be sure to have it checked for straightness.

Have all the oil holes chamfered and the crankshaft polished.

Installing the Crankshaft:
We install the crankshaft seal (the gray one) and use our special mixture of 50 weight Kendall and assembly lube on the bearing surfaces of the CHILDS and ALBERT bearings. Carefully lay the crankshaft in place after installing the crankshaft gear.

You can check the clearance with plastic gauge, this should be done dry before final assembly (plastic gauge is an easy way to check clearances and very easy to use even at the track).

Torque the mains to 110 Lbs. and back off 3 times, this will pre-stress the hardware.

Next, install the camshaft and the camshaft thrust plate.

Install one ARIAS 11.1 piston and rings combo and a .500 long Brooks aluminum rod in #1 cylinder. (Long rods makes less stress on the cylinder wall ------less stress =longer life).

We will find TDC and install a RCD crank hub, mark top dead center and proceed to degree the camshaft.

Camshaft:
We usually run 2-4 degrees advance with a 701/320/114 Howard's cam and Crower roller lifters.

701/320/114 Cam means:
701 = Valve lift
320 = duration
114 = lobe centers

Connecting Rods & Pistons:
Install the other 7 piston-rod combos with the ring end clearance set. The rule is looser is better than tighter. We add .005 to whatever the manufacturer recommends.

Torque the rod bolts to 75# loosen and re-torque three separate times, this will help in the long run. Check the rod clearance for .030-050 side clearance.

Button up the cam cover and the fuel pump drive extension.

Oil system:
Install the TITAN sportsman oil pump and shaft and install the MILODON 8 quart dragster style oil pan. We run KENDALL 50-weight oil and with the TITAN sportsman oil pump we run with 85 lbs. of oil pressure.

Cylinder Heads & Valve Train:
Install Milodon head studs hand tight in the block. As for cylinder heads, there are many ways to go. I prefer the Chevrolet iron 990 casting. We do a little port matching and bowl blending with our Standard Abrasives porting kit.

We use the iron heads because:
We are shooting for 1000-1200 horsepowerThey are readily availableThey flow wellThe iron is especially durable and holds heat well
They run $200-$450.00 and since you don't run water sometimes finding a crack can be a bargaining tool.

We install Milodon stainless exhaust valves and intake valves and add .002 to your valve guide clearance. Install K-Motion kr1000 valve springs and titanium retainers and keepers set. Use 235-lb. spring pressure @1.950- and a good 3-angle valve job.

We bolt on the heads and torque to 80 lb. with a SCE .060 head gaskets. 060 gives you a softer hit and something to tune with at altitude where you can change this to .043 gaskets for more compression.

We install Crower push rods and rockers. Norris stainless rockers are very durable, but are a little heavy. Next, install your favorite brand of stud girdle. Mine is the Moroso's I've had since 83'. We use the B&B valve covers or the Billet Fabrication valve covers. I install the quick release breather 1" tube to a puke tank.

Blower & Fuel system:
For an intake manifold I prefer the Littlefield tall deck manifold and a 6-71 Littlefield alcohol Teflon lined blower turning 25% over drive. We use an Enderle bug catcher and the Nitro barrel valve at .009 (69 % Leak on the barrel valve).

An Enderle 110 pump and a high speed set at 65 lbs. with an 85 jet. Use a 140 -170 main jet and 52 jet for the injectors.

Ignition:
We use the Mallory Super Mag III with Mallory wires and NGK #9 spark plugs.

Overview:
This combo is a proven setup, not real fancy with trick of the week gizmos, but a reliable setup with which we have won six world championships. You can update or change this recipe to suit your tastes, but it should give you a baseline with a minimum of headaches.

Brendan Murry