Bbc 454 build.
10-16-2020 | 01:32 AM
#221
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From: Finland
janiH.the clamping load differs from different bolts,keep in mind that the big end of the rod gets honed to size with the bolt torqued to spec,if you remove the L19 bolt and install an 8740 or a arp 2000 bolt the big end bore will no longer be round.you don,t want that do you?
10-16-2020 | 04:37 PM
#222
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From: taxachusetts
you'd have been better off w/ this cam than that abomination of a cam your getting. just saying.
https://www.lunatipower.com/efi-retr...k-289-299.html
https://www.lunatipower.com/efi-retr...k-289-299.html
10-16-2020 | 07:34 PM
#223
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Joined: Jul 2004
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From: chicago
Not sure how youre getting 9.5:1, using a 13cc dome piston, with quench of .037. Assuming the chambers measure out to 119-121cc, that makes it around 10:1.
i do believe with the cam you have, its gonna make some torque down low. Which sounds like what you asked for. One thing id be careful with, is detonation. Thats alot of conpression for a marine engine, esp with a small cam thats gonna get lugged around at 2500rpm like you want to. Id be very careful with my tuneup, and try to keep the engines water temp as cool as possible. I wouldnt even think of locking the timing out on it.
L19 rod bolts are silly in an engine that wont see north of 5200-5400rpm. Esp with a 4" stroke crank. Youll never be near the piston speed, or breaking point of even the standard 8740 bolts. Rpm is what kills rods. But you have them, so run them. Like Mike T said, dont change bolts unless you plan to have the rods resized.
Im not a fan of peanut ports. However, I think they do have their place in trucks and what not. The reality of it is though, you pay a price with them. For what they do down low, they give up on the big end. Today, a modern oval port, say like an AFR 265 or similar, wont give up anything to the peanuts down low, and blow them away up top. Can and have guys made them flow decent, yea. But no way would i ever spend that much time and money, putting big valves in them, tons of port work, then worry about hitting water ,etc. They just arent the heads you want if going fast is the goal. But speed doesnt seem like is what youre after, so, they should be fine. Most offshore guys here are looking for speed gains. And you dont gain speed in boat by adding low end torque. You gain speed by adding upper end torque (which is horsepower).
i do believe with the cam you have, its gonna make some torque down low. Which sounds like what you asked for. One thing id be careful with, is detonation. Thats alot of conpression for a marine engine, esp with a small cam thats gonna get lugged around at 2500rpm like you want to. Id be very careful with my tuneup, and try to keep the engines water temp as cool as possible. I wouldnt even think of locking the timing out on it.
L19 rod bolts are silly in an engine that wont see north of 5200-5400rpm. Esp with a 4" stroke crank. Youll never be near the piston speed, or breaking point of even the standard 8740 bolts. Rpm is what kills rods. But you have them, so run them. Like Mike T said, dont change bolts unless you plan to have the rods resized.
Im not a fan of peanut ports. However, I think they do have their place in trucks and what not. The reality of it is though, you pay a price with them. For what they do down low, they give up on the big end. Today, a modern oval port, say like an AFR 265 or similar, wont give up anything to the peanuts down low, and blow them away up top. Can and have guys made them flow decent, yea. But no way would i ever spend that much time and money, putting big valves in them, tons of port work, then worry about hitting water ,etc. They just arent the heads you want if going fast is the goal. But speed doesnt seem like is what youre after, so, they should be fine. Most offshore guys here are looking for speed gains. And you dont gain speed in boat by adding low end torque. You gain speed by adding upper end torque (which is horsepower).
Last edited by MILD THUNDER; 10-16-2020 at 07:43 PM.
10-17-2020 | 03:23 AM
#224
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From: Finland
Not sure how youre getting 9.5:1, using a 13cc dome piston, with quench of .037. Assuming the chambers measure out to 119-121cc, that makes it around 10:1.
i do believe with the cam you have, its gonna make some torque down low. Which sounds like what you asked for. One thing id be careful with, is detonation. Thats alot of conpression for a marine engine, esp with a small cam thats gonna get lugged around at 2500rpm like you want to. Id be very careful with my tuneup, and try to keep the engines water temp as cool as possible. I wouldnt even think of locking the timing out on it.
L19 rod bolts are silly in an engine that wont see north of 5200-5400rpm. Esp with a 4" stroke crank. Youll never be near the piston speed, or breaking point of even the standard 8740 bolts. Rpm is what kills rods. But you have them, so run them. Like Mike T said, dont change bolts unless you plan to have the rods resized.
Im not a fan of peanut ports. However, I think they do have their place in trucks and what not. The reality of it is though, you pay a price with them. For what they do down low, they give up on the big end. Today, a modern oval port, say like an AFR 265 or similar, wont give up anything to the peanuts down low, and blow them away up top. Can and have guys made them flow decent, yea. But no way would i ever spend that much time and money, putting big valves in them, tons of port work, then worry about hitting water ,etc. They just arent the heads you want if going fast is the goal. But speed doesnt seem like is what youre after, so, they should be fine. Most offshore guys here are looking for speed gains. And you dont gain speed in boat by adding low end torque. You gain speed by adding upper end torque (which is horsepower).
i do believe with the cam you have, its gonna make some torque down low. Which sounds like what you asked for. One thing id be careful with, is detonation. Thats alot of conpression for a marine engine, esp with a small cam thats gonna get lugged around at 2500rpm like you want to. Id be very careful with my tuneup, and try to keep the engines water temp as cool as possible. I wouldnt even think of locking the timing out on it.
L19 rod bolts are silly in an engine that wont see north of 5200-5400rpm. Esp with a 4" stroke crank. Youll never be near the piston speed, or breaking point of even the standard 8740 bolts. Rpm is what kills rods. But you have them, so run them. Like Mike T said, dont change bolts unless you plan to have the rods resized.
Im not a fan of peanut ports. However, I think they do have their place in trucks and what not. The reality of it is though, you pay a price with them. For what they do down low, they give up on the big end. Today, a modern oval port, say like an AFR 265 or similar, wont give up anything to the peanuts down low, and blow them away up top. Can and have guys made them flow decent, yea. But no way would i ever spend that much time and money, putting big valves in them, tons of port work, then worry about hitting water ,etc. They just arent the heads you want if going fast is the goal. But speed doesnt seem like is what youre after, so, they should be fine. Most offshore guys here are looking for speed gains. And you dont gain speed in boat by adding low end torque. You gain speed by adding upper end torque (which is horsepower).
Last edited by JaniH; 10-17-2020 at 03:42 AM.
10-17-2020 | 03:51 AM
#225
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From: Finland
Dont know if anyone is interested but i have build thread in restorations and upgrades section, 1988 chris craft stinger 260. Too many hours of blueprinting the bottom, new transom, stringers, paint.
11-10-2020 | 02:13 PM
#226
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From: Finland
Crank is In. Main bearing clearances 1-4=0.0031". 5=0.0039". Rods seems to be around 0.0030". Have been wondering my oil pump spring set up, should I shim the stock spring to 60psi Or use the 70psi spring? Melling select 10778 Hi-volume pump.
