79transam Posted October 12, 2004 Share Posted October 12, 2004 hi guys, i was wondering if any of you could help me in my delima. i'll start off by naming my components. i have a 70 model F4 W-30 marine 455. on the internals i've got stock crank, stock connecting rods, std. bore pistons (block is standard bore), federal mogul bearings, new melling oil pump, the cam is a factory W-30 i just bought, its a melling as well. rings are speed pro. up top i have a set of ported and polished J heads, stock valves, edelbrock magnum roller rockers, hardened pushrods, guide plates, comp cams hydraulic lifters, edelbrock performer intake, edelbrock 750 carb, accel H.E.I. distributor, dynomax headers,and stock water pump. planting the power from the engine to the tires is a BOP turbo 400, i had a b&m shift kit put in it and had it totally rebuilt with all new parts. ok now for the dilema. a friend and i were tryin to start the engine for the first time. we turned the starter over and all we got were backfires from the carb, and im talkin harsh. so after retarding it and advancing it and only gettin backfires i figured we must have been 180 degrees out. well, i took the distributor out and turned the rotor 180. same results. well i figured we might as well try the other way again. so i pulled the distributor and we were going to put piston #1 on tdc (by hand) and the engine would'nt budge. you may be able to turn it one way or the other slightly but then it will just stop. i even took the spark plugs out and tried to turn it over by hand but no luck. so i pulled the valve covers and none of the valves have dropped and none of the pushrods look bent. so after all the money and time i put in this motor for this just to happen, i just walked out, im sure someone feels my frustration. so any help you guys can lend me will be much appreciated. thanks for your time. Link to comment Share on other sites More sharing options...
Pontiac59 Posted October 12, 2004 Share Posted October 12, 2004 We'll assume you prelubed everything and I'll ask - is there any chance the pistons don't clear the valves? I'm going to also assume you rotated the crank assembly before putting the heads on and checked everything out.Some marine engines are built to rotate in the opposite direction as your normal auto engine for applications in boats with multiple motors using a direct drive. This is just a wild theory, but you didn't mix a reverse-rotation marine block with a normal rotation camshaft and have the pistons going one way, the valves the other, so they're hitting a piston that should be going down instead of up at that point in the rotation and thus keeping your motor from turning....? That's even assuming you have it built so they can interfere with one another.The only motor I had that wouldn't turn over was a 301 that threw one rod completely (another was on the way) and it slid down and blocked the crank. One buddy had a 305 Chevy throw a rod out the pan and they were still able to drive the car for a while. Maybe it's something goofy - there is a wrench in one of the cylinder bores, or stuck up into the bottom of a piston, for instance. About all you can do is start taking it back apart. Link to comment Share on other sites More sharing options...
seasand77 Posted October 12, 2004 Share Posted October 12, 2004 My 455 marine engine rotated backwards from the car engine. Link to comment Share on other sites More sharing options...
79transam Posted October 12, 2004 Author Share Posted October 12, 2004 well i did have 30 thousandths taken off the heads, but i dont think that would make a difference because im using the factory dished pistons from 1970. talk about a deep dish and i believe the piston at TDC was somewhere between 10 - 25 thousandths. yes, i did prelube the engine. this engine hasnt even cranked so hence, it has run unough RPM to ruin anything. or at least i think nothing should be. i was thinking it may be the transmission, but highly doubtful. or maybe the harsh backfires did the old pistons in. ill just take it apart and see. thanks for all the help you guys. Link to comment Share on other sites More sharing options...
Sgt Art Posted October 13, 2004 Share Posted October 13, 2004 Let us know what you come up with. This one has me scratching my head. Link to comment Share on other sites More sharing options...
Guest Albert Posted October 13, 2004 Share Posted October 13, 2004 maybe check that all the rods are still connected, by removing all the plugs and placing a long screwdriver down each hole while turning the motor a little each way. recheck the distributer as well, remove the valve cover over #1 piston and with both valves closed for #1 and the timing mark on tdc, re insert the distributer so the rotor points to the #1 cyl. Another thing to check is now the rotor is turning in the oppsite direction so all the wires are in the wrong spot. Link to comment Share on other sites More sharing options...
Sgt Art Posted October 14, 2004 Share Posted October 14, 2004 The tests you suggest are good, but he's stated the engine is siezed. I think he needs to tear it down, if it's stuck to the point he can't rotate it. Link to comment Share on other sites More sharing options...
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