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Mercruiser 454/330 questions
Anyone know the specs on a '91-ish Mercruiser 454/330?
Compression ratio? Piston, crank, rod type? (Forged, cast, hypereutectic) Cylinder head intake runner volume (I assume they are oval port) Cylinder head chamber volume Thanks. |
Monty,
I'm not exactly sure on the comp ratio maybe 8.7:1 cast crank rods are 3/8'' rod bolts cast pistons GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so. 2.06" intake valves and 1.72" exhaust valves combustion chamber volume is between 119-121cc Perhaps someone else can jump in and help out on the specs---I'm just going by memory. I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330.... My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno! So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit. |
Compression Ratio 8:1
cast crank,rods,pistons Peanut port heads 120cc chambers 208cc intake runners 2.06/1.72 inch valves |
Thanks. In other words, only the blocks are usable ;).
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Cranks, rods are usable and reliable for around 500 horsepower and 5200-5500 rpms. There are a lot of people running upgraded 330 Mercs with great success. Don't let anyone tell you different.
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I'm sure they are fine, I was just kidding. I just prefer the 7/16" rods and forged pistons.
If I don't go with 502's, I'm going to rebuild the 454's with Crower billet rods and forged crank with JE forged pistons. |
Originally Posted by KAAMA
(Post 657955)
Monty,
I'm not exactly sure on the comp ratio maybe 8.7:1 cast crank rods are 3/8'' rod bolts cast pistons GM oval port "peanut port" heads not sure of the port runner volume---probably close to 235cc or so. 2.06" intake valves and 1.72" exhaust valves combustion chamber volume is between 119-121cc Perhaps someone else can jump in and help out on the specs---I'm just going by memory. I know you were only asking for engine specs on the Merc 330, but in case you were looking to upgrade here are some things that I have seen and experienced in relationship to the Merc 330.... My cousin had a pair of 330's that he upgraded by adding the 2.19" intake valves, 1.85" exhaust valves, pocket/bowl porting on the heads, bore notching on the cylinders, a flat tappet hydraulic cam of about 218*/226* on 110* lobes, 8.6:1 comp ratio, dual plane aluminum high rise intakes manifolds, Holley carb and with dyno headers they made 461hp @ 5100rpm and 510ftlbs of torque. He removed the stock Merc cast iron junk exhaust manifolds will be installing GIL exhausts manifolds. He didn't want to buzz the engines up much beyond 5000rpm because of all the cast components and he pretty much achieved his goal and made awesom power and torque from a Merc 330hp base engine without going too wild parts and maintaining the same head castings. Another friend of mine had a little bit larger of a flat tappet hydraulic cam with Merlin oval port heads with big valves, same intake manifold, same carb, same comp ratio and he made 505hp @5400rpm and 514ftlbs of torque on the SAME dyno! So unless you need 45 more HP, you can stay with the GM heads that you already have and still make make real good torque for cheaper $$$----and torque is really want you want in a good boat engine. Hope this has helped you a bit. "ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers... |
Originally Posted by Diego9040
(Post 4004650)
Bringing back this old thread to see if anybody can pitch in based on more recent experience , I was always told that 330's were not worth trying to upgrade into higher hp.
"ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers... Up to about 500hp the pistons are good, crank and rods as well, but rod bolts should be upgraded to arp as they always break before even the wussy 3/8 rods. That said, read "330 on roids" and you will see even 460hp is pricey with this engine. Guys here have done it and had differing outcomes. The nodular cranks and "cast" pistons in these motors are capable if approached from a reasonable perspective. As for my build, I decided to scrap everything and build a forged 496 with dart pro 1 heads and up my HP goal. If you are happy with around 460hp, which is no slouch, copy 330 on roids. The L-29 heads are very capable in the mid to upper 400hp range. I'm pretty sure members "whiteknuckle" and "crazyhorse" could give you some very helpful insight into this platform as they are some of the more experienced here with the 330. Also, the cam choice for 330 on roids wasn't in my opinion "optimal", that said consult an expert like Bob Madera from Marine kinetics. Good luck! |
Originally Posted by Diego9040
(Post 4004650)
Bringing back this old thread to see if anybody can pitch in based on more recent experience , I was always told that 330's were not worth trying to upgrade into higher hp.
"ICU looking" shared this with me and it got me interested since I already have SM exhaust with long risers... |
I am also interested as to the results of this thread as I am looking to upgrade my engine to make more power, as well as possibly significantly lighter and more efficient with aluminum heads, exhaust, and a hydraulic roller cam.
By the way, the Gen V marine 454 had a cast steel crank, cast aluminum pistons, and forged rods. It had peanut port heads and a non-adjustable flat tappet cam and valvetrain. My "Performance Tuned" version has the aluminum high-rise "Mag" dual-plane intake and 750 CFM Weber square-bore carb. |
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