REBUILDING THE 454 AGAIN

[man-of-war]

hi Gui's, i got the engine out the boat . the mechanic is allowing me to do the rebuild in his shop, with some supervision .i could work on the engine on Saturday's, something for me to do over the winter months. the engine is a 454 bb 7.4 L four bolt main . <br />he is going to fix the leaking rings problem. <br />i want to start working on the heads,and i will like to put the marine items in this engine. <br />could you boys help me with the correct valve springs,valves ,VALVE GUIDES,valve seals , and what ever you think that ill need to help make my 2006 summer a trouble free year <br />ill take some pic of my progress at the mechanic shop <br /><br /><br />this is what the heads look like.i don't know what size any of these springs are or the valves. the rockers are 1.7 ratio. <br /><br /> <br /><br />i would like to order these parts from comp cams or what ever company that you guys would recommend .i need help picking the correct parts along with the part #.<br />

<br /><br />

 

[rodbolt]

Re: REBUILDING THE 454 AGAIN

once you decide on the type of exhaust and the type of induction as well as the mechanical compression ratio your going to use call comp cams tech line. explain what your trying to do and a realistic RPM range your trying to run and they can select the proper cam and springs.<br /> myself I like forged pistons on a big block if its going to see continuos duty above 4800 rpm.<br /> compression ratios about 8.5-9 works well in most marine applications but will still most likly require premium fuel on a carbed model.<br /> eliminate any engine vacum crankcase evacuation systems and go back to the flame arrestor mounted system. pay very close attention to all bearing cleartences, pay very close attention to ring end gaps and piston to wall specs. insure everything is ABSOLUTLY clean on reassy. have the connecting rod big ends checked or rebuilt.<br /> keep your goal realistic. your not building a 1/4 mile 8000 RPM motor. your engine operating speed will be 4500 to 5000 RPM. anymore and you will be playing with gear ratio's and props. sub surface proips start losing it after a shaft speed of around 2500. much more and it gets expensive to keep pushing water. no need for gear drives and such. a good tru-roller timing chain will do anything ya wnt. I do reccomend checking the cam timing with a dail indicator. the specs will come with your cam.<br /> use good quality gaskets such as felpro marine and throw the silly cone in the trash. well maybe a drop at each corner of the pan and the intake end seal corners. for the rest of the gaskets I use perfect seal or 3M super weather strip adhesive. I usually dont use any sealer around the intake ports or exhaust crossover ports. you can gain some HP by eliminating the ex crossover but may have problems with carb icing during certain operating conditions that will require a hot water carb spacer. myself on your rig I would leave the cross over alone. carefully check all valve springs for free hieght and compressed pressure. the specs will be with your springs. carefully check installed spring height and valve stem tip height. check all push rods for warpage.<br /> its all about the details. anyone can assemble a chevy but without the details it wont work right.

 

[ron7000]

Re: REBUILDING THE 454 AGAIN

spend a few bucks at amazon.com and buy some engine building books that would be relevant. It doesn't have to be "how to rebuild a 454 marine motor". Just needs to detail bottom end repair, valvetrain and cam setup, and whatever else you're looking to do. Having solid reference material rather than soliciting internet opinions will be most helpful, and read and research before buying and installing parts. Fail to plan and you plan to fail.<br /><br />Few months ago amazon had a deal- open up an amazon visa credit card and get $35 off an order, I ended up getting 3 or 4 books shipped for $8.

 

[Zamboni]

Re: REBUILDING THE 454 AGAIN

I was impressed with books carried in our local library-you should start there.<br /><br />Did you buy this boat on ebay...saw it somewhere.

 

[man-of-war]

Re: REBUILDING THE 454 AGAIN

went to do the tear down today.but got nothing done,because the mechanic is moving all his scrap/junk engines to another part of the building.<br />got to talking to him for a while about the engine.he mentioned the exhaust system, he said for all the modifications that he did to the engine it has to pump out close to 400hp. he said that i have to get an exhaust manifold system with bigger exhaust ports.to get the full potential of this engine.<br />IS THIS TRUE...? <br /><br />

<br /><br /><br />My next question is, he said that he's going to hone or/horn the block and replace the rings with new one's .<br />rember my problem after the breakin 10 hours of use.oil on plugs,120 TO 140 PSI leak-down test 5 ,8 ,9 % LEAKAGE. or should he be reboring the block and using new pistons and rings? thanks