V6 Chevy 90 degree engines
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**4.3L V6 VIN CODE Z** | **4.3L V6 VIN CODE Z** | ||
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1993 T15 (GMC Typhoon) | 1993 T15 (GMC Typhoon) | ||
3LD | 3LD | ||
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==Blocks== | ==Blocks== | ||
The Chevy 90º V6 is formed by the removal of the #3 and #6 cylinders of a SBC. All three V6 engines share the same 4.4" bore spacing and 9.025" deck height of the SBC engine. | The Chevy 90º V6 is formed by the removal of the #3 and #6 cylinders of a SBC. All three V6 engines share the same 4.4" bore spacing and 9.025" deck height of the SBC engine. | ||
| − | Production 1992 4.3L engines with RPO L35 had modified cylinder blocks where a balance shaft | + | Production 1992 4.3L engines with RPO L35 had modified cylinder blocks where a balance shaft is used. The balance shaft is gear-driven off the front camshaft gear; camshafts for use with balance shaft motors have a longer dowel pin, which cannot be interchanged with non-balance shaft engines. The current engine block in production since 1995 eliminated the front and rear freeze plugs with extra strengthening ribs. The oil pan used was changed from stamped steel to an aluminum alloy casting. The engine block has 10 oil pan bolts, making the early and late oil pans incompatible. |
==Cylinder Heads== | ==Cylinder Heads== | ||
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==Displacements== | ==Displacements== | ||
There were three displacements of the Chevy V6: | There were three displacements of the Chevy V6: | ||
| − | + | #200 cid (3.4L), it is basically 3/4 of the 267 cid SBC V8. Made 1978–'79. | |
| − | + | #229 cid (3.8L)- not to be confused with the Buick-derived 3.8L 231 cid V6). It is 3/4 of the 305 SBC V8. Made 1980-'84. | |
| − | + | #4.3L (262 cid) is 3/4 of the SBC 350 and as such, shares some of the parts and dimensions with the 350. Made 1985-2014. The 1992 model year saw the first use of a balance shaft; all 1995-present 4.3L V6 engines are equipped with a balance shaft. The 4.3L V6 got a revised cylinder head in 1996 with specs much like the SBC V8 [[Vortec L31 cylinder head]]. Passenger car usage was limited to B and G-bodies; after 1990 (with the exception of some 1991-'92 fleet Caprice) the 4.3L V6 was used exclusively in truck/van/SUV and marine/industrial use. | |
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| + | The 4.3L V6 has the advantages of far better availability, a larger displacement and larger bore diameter than the 200 cid or 229 cid V6. It also enjoys better aftermarket support. For these reasons, the 4.3L is the preferred Chevrolet V6-90 engine for performance use. | ||
==Bore and stroke== | ==Bore and stroke== | ||
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All the Chevy V6 cranks are 3.48" stroke. There are major differences between the 200/229 engines and the 4.3L engine, though. | All the Chevy V6 cranks are 3.48" stroke. There are major differences between the 200/229 engines and the 4.3L engine, though. | ||
| − | Scat | + | Scat used to make a cast crank for the 4.3L engine, p/n 9-4.3L-3480-5700. It was for the 1-piece rear main seal engines. |
[[File:Even fire chevv6.jpg|thumb|350px|right|Production 4.3L even fire crank, arrows show split rod journals]][[File:Odd fire Chev v6crank.JPG|thumb|400px|left|Odd fire crank showing common rod journals]]<br style="clear:both"/> | [[File:Even fire chevv6.jpg|thumb|350px|right|Production 4.3L even fire crank, arrows show split rod journals]][[File:Odd fire Chev v6crank.JPG|thumb|400px|left|Odd fire crank showing common rod journals]]<br style="clear:both"/> | ||
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All the Chevy V6 90 degree engines share the same firing order of 1-6-5-4-3-2. The two smaller engines, the 200 cid and 229 cid, have what is called a "semi-even fire" sequence which alternates between 132º and 108º. This comes about due to the "slipped disc" crank pins; each pair of rods are offset by 18º. The design of the crank required the connecting rods to have 0.050" narrower ends to fit onto the available rod journal space due to the material added to the cranks for strength. | All the Chevy V6 90 degree engines share the same firing order of 1-6-5-4-3-2. The two smaller engines, the 200 cid and 229 cid, have what is called a "semi-even fire" sequence which alternates between 132º and 108º. This comes about due to the "slipped disc" crank pins; each pair of rods are offset by 18º. The design of the crank required the connecting rods to have 0.050" narrower ends to fit onto the available rod journal space due to the material added to the cranks for strength. | ||
| − | The cam and distributors are specific to the 200/229 cid engines and they cannot be interchanged with the 4.3L V6 engine. Distributor bodies used on the V6-90 are identical to the one used for the Chevrolet small-block V8 except for the pickup coil and pole piece assembly. The main difference between the semi-even fire series (200/229) and 4.3L distributors is the 4.3L distributor pickup coil and reluctor wheel has six equal points, one every 60 degrees (6 x 60 degrees = 360 degrees). Also, a majority of the distributors used on the 4.3L has a small distributor cap, same as used on the 2.8L V6 60 degree engine. The small cap/external coil ignition system is commonly used with the TBI and CPI motors. The 1985-'86 4.3L engine used in Chevrolet trucks, vans (including the Astro/Safari) used the traditional large-cap HEI on the RPO LB1 motor. Marine applications used a unique small-capped distributor not interchangeable with those used in automobiles. | + | The cam and distributors are specific to the 200/229 cid engines and they cannot be interchanged with the 4.3L V6 engine. Distributor bodies used on the V6-90 are identical to the one used for the Chevrolet small-block V8 except for the pickup coil and pole piece assembly. The main difference between the semi-even fire series (200/229) and 4.3L distributors is the 4.3L distributor pickup coil and reluctor wheel has six equal points, one every 60 degrees (6 x 60 degrees = 360 degrees). Also, a majority of the distributors used on the 4.3L has a small distributor cap, same as used on the 2.8L V6 60 degree engine. The small cap/external coil ignition system is commonly used with the TBI and CPI motors (the distributor is also used with the Delco Voyager ignition kit for marine and industrial applications). The 1985-'86 4.3L engine used in Chevrolet trucks, vans (including the Astro/Safari) used the traditional large-cap HEI on the RPO LB1 motor. The LB1 distributor (with a 5 pin module for electronic spark control) is a rare find in salvage yards where the pole piece and pickup coil from a 1974-88 Chevrolet 250 or 292 inline six (some 250s manufactured between 1981-85 may have a 5 or 7 pin HEI module - usually for California applications which is similar in design to the ESC distributor used with the LB1 or 81-86 Chevrolet 305s with ESC) are usually swapped in place of the Chevrolet V8 pole piece and pickup coil. Marine applications used a unique small-capped distributor not interchangeable with those used in automobiles (with the exception of the GM small cap distributor similar in design to the passenger car/light truck small cap variant commonly supplied with the Delco Voyager ignition kit). |
| − | + | From the 2007 model year until production ended, the traditional distributor was eliminated where coil packs were phased in. | |
==Intake manifolds== | ==Intake manifolds== | ||
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[[File:OEM 4.3 L V6 Q-jet intake 1986-back.jpg|thumb|left|OEM 4.3 L V6 Q-jet intake 1986-back]] | [[File:OEM 4.3 L V6 Q-jet intake 1986-back.jpg|thumb|left|OEM 4.3 L V6 Q-jet intake 1986-back]] | ||
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| − | The 1985 Astro van had this intake; passenger cars came standard with TBI fuel injection | + | The 1985 Astro van had this intake; passenger cars came standard with TBI fuel injection. Passenger cars (B- and G-body) as well as trucks/vans manufactured after the 1986 model year (including 1988-'94 S-series trucks) came with TBI intakes. A central port injection intake manifold (with an upper and lower casting) was introduced in 1992 which has a central fuel injector with six poppet valves (used with the Astro/Safari and S-series SUVs (Blazer, Jimmy, Bravada), later revised in 1996 with sequential fuel injection. Central port injector used with 1996-'01 were known to have fuel leakage where GM redesigned the fuel spider which converts the CSFI system to a multipoint injection system. |
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| + | The limited production Syclone/Typhoon has an intake manifold which uses a multipoint injection setup (with a throttle body similar to the one used with the tune port injected Corvettes and IROC-Z Camaro/Trans Am). Parts for such a conversion do not exist from the aftermarket. | ||
===Marine intakes=== | ===Marine intakes=== | ||
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*[http://www.brodix.com/heads/v6heads.php Brodix heads] | *[http://www.brodix.com/heads/v6heads.php Brodix heads] | ||
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[[Category:Engine]] | [[Category:Engine]] | ||
[[Category:GM]] | [[Category:GM]] | ||
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