454 initial timing questons
02-23-2022, 01:44 PM
#51
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So it ran ok at first but started getting hot, and on shut down, dieseled and popped back through the intake. Then it wouldn’t idle down. I still got money on gasket blown out especially with mix matched ports. Is it leaking vac into the crank case?
02-23-2022, 04:28 PM
#52
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Location: Murrayville Georgia
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so as I understand it this has a rectangle port intake and peanut port heads which is way different from each other so when it idles for a while there is probably a pint of fuel sitting at the port of the head. also is this still the net zero lash rockers? if so and the head and block have been cut was that factored in or are the lifters now bottomed out? sorry but this motor seems to be very mismatched in parts for it to perform properly in a cruiser.
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02-23-2022, 06:40 PM
#54
so as I understand it this has a rectangle port intake and peanut port heads which is way different from each other so when it idles for a while there is probably a pint of fuel sitting at the port of the head. also is this still the net zero lash rockers? if so and the head and block have been cut was that factored in or are the lifters now bottomed out? sorry but this motor seems to be very mismatched in parts for it to perform properly in a cruiser.
02-23-2022, 06:41 PM
#55
Busy couple days but we haven't seen much indication of vaccum leak when running motor and spraying carb cleaner all around.
02-23-2022, 06:44 PM
#56
My understanding IF im reading the information posted correctly: motor was overheated then repaired again
18 cc domed 4.280 bore pistons
113 cc peanut ports, IF motor was overheated they had to have been milled/surfaced at least once
block, again, if bored, rebuilt and overheated at one time deck clearance went closer to zero from its original .022-.028 in hole
I ran thru compression calculator, over 10-1 with iron heads, with a small cam thats design is to build torque by spiking cylinder pressure
we run over 10-1 on aluminum headed motors with 20, 30 dgrees more cam duration , strictly on premium
no knock sensor so no way to hear /tell if its knocking
only way it will live is jetted fat to mask the detonation with good premium
buy a 02 bung, put it in a riser, see what you cruisng afrs are and wot, id jet the hard cruising into mid 12's and the wot in mid to maybe upper 11s with that compression with iron heads
18 cc domed 4.280 bore pistons
113 cc peanut ports, IF motor was overheated they had to have been milled/surfaced at least once
block, again, if bored, rebuilt and overheated at one time deck clearance went closer to zero from its original .022-.028 in hole
I ran thru compression calculator, over 10-1 with iron heads, with a small cam thats design is to build torque by spiking cylinder pressure
we run over 10-1 on aluminum headed motors with 20, 30 dgrees more cam duration , strictly on premium
no knock sensor so no way to hear /tell if its knocking
only way it will live is jetted fat to mask the detonation with good premium
buy a 02 bung, put it in a riser, see what you cruisng afrs are and wot, id jet the hard cruising into mid 12's and the wot in mid to maybe upper 11s with that compression with iron heads
Big blocks are built like this all the time, I'm not sure why so many think it's some radical build???
02-23-2022, 06:46 PM
#57
You act as if the motor can see what kind of boat it's in. Why does it matter if it's a cruiser or a race boat. Air, fuel, spark still applies.
02-23-2022, 07:15 PM
#58
Air- you have a vacuum leak and mismatched head port styles. Fuel = yours is old and low Octane. Spark = -10 degrees
Engines do not know what type of boat/vehicle it is going to be installed into, BUT, they do know what operating parameters/they perform well/reliably in.
The boat dictated the type of build the engine requires. That is why they make so many cam variations, head runner length, intake manifold designs, carb variations, exhaust manifold styles, etc. etc. etc.
Not being sarcastic just trying to get you to take a objective view of the situation. Some of the most knowledgeable engine builders on the forum are trying to help you.
My suggestion is find a new mechanic so far seems like yours is not making good decisions on your behalf.
Just my .02
Good Luck.
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02-23-2022, 07:34 PM
#59
Charter Member # 55
Charter Member
so as I understand it this has a rectangle port intake and peanut port heads which is way different from each other so when it idles for a while there is probably a pint of fuel sitting at the port of the head. also is this still the net zero lash rockers? if so and the head and block have been cut was that factored in or are the lifters now bottomed out? sorry but this motor seems to be very mismatched in parts for it to perform properly in a cruiser.
Also, the rocker shoulder bolts are the same part number for the both the 7.4 and 454mag.
My thought was the valves were possibly too tight and not fully closing, which could still be the case.
02-23-2022, 07:40 PM
#60
Charter Member # 55
Charter Member
No, it was not. Same engine went in all kinds of boats. The Bravo3 part is for heavier boats.
Heavier boats will place more load on the engine and cause detonation more easily.
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