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tahitijet
12-26-2001, 08:49 PM
Ok i'm finally gonna start building my 454 it's gonna be my first boat motor and there is very little in the way of informative shops in this area, so I need to know what i want before i go for machine work.. Could someone help me with a few questions and recomendations.
the motor will start as a stock bore 454 4 bolt main and will end up a 468 in a jet boat. I would like to build somewhere in the area of 550-600hp but this may change once i get budget figures together.
1. what is the highest compression i can safely run on pump gas.
2. will the stock crank and rods be ok with this power?
3. now there seems to be a ton of differn't answers on this one but should i use aluminum aftermarket or beefed up stock cast iron heads?
4. should i have the machine shop make any modifications to the block as far as oiling? or altering for anything else, i have heard talk of machining the block for o-rings?
5. I would like to run a tunnel ram with 2 4's any good combo's you guys are running on a similar hp motor?
and last where do you recomend i buy parts from? I want to gather all my parts take the motor/ heads/ pistons and rods to the machinist have everything machined then assemble it myslef but i prefer to buy the parts myself so they don't try and put some junk in.
thanks for the any info

HUFFPOWER
12-26-2001, 09:18 PM
first off you need to know how much cash you have and can spend on your motor,don't try to build your motor by buying item by item,it will cost you more !your profile says your in calif,thats good because some of the best engine guru's are in calif.you might call,greg shoemaker,wilkes marine,pfaff racing,teague marine,these guys will get you in the ballpark for cost.parts are not the biggest cost,prepping,machining,setup do cost to have it done right.and most important marine engines are set up different than car engines!!!!!good luck.

DOHARA
12-27-2001, 04:44 AM
TAHITIJET, I would order your parts from JEGS. Go online and compair prices to a local shops prices, JEGS doesn't charge sales tax. The compression #'s have been discussed in forums many times. If your going to be running on pump 91-93 octane, I would try to stay at 10:1 or 10:5.1 . As for heads, I would run a good set of aluminum but, a good set of cast like MERLIN would work great also. Everything depends on how much money you want to spend. I would build a good bottom end with good set of rods and crank for a long lasting motor. Just to give you a idea of price I had my 454 completely redone by a local machine shop that I know the owner and he has alot of years boating behind his belt. For block to be comp. gone thru,balanced,crank and rods redone,new pistons to bump up comp. heads redone w/valve job, I bought new cam and ARP hardware from jegs and I already had MERLIN heads, It cost around 2k. for machine work pistons,head work,and assembly, so depends on what you already have for parts, most of these marine engine shops will charge you around 4-6k to do your complete engine, you may save alittle doing assembly yourself. I called all these shops HUFFPOWER said and I wasn't going to spend that kind of money on engine, and yes marine and auto engine's are set up different so make sure you take that into consideration when assembly comes. I would call DNE in costa mesa, this guy knows his stuff and works next to the world famous jet builder, Jack at MPD. Hope this helps and sorry for rambling, its early in a.m.
DANO

69 Elim
12-28-2001, 08:04 AM
You guys mentioned that marine engines are set up differently than cars. What is defferent & why? Just trying to learn. Thanks for your help and knowledge.

rivercrazy
12-28-2001, 09:16 AM
Brass freeze plugs, starter, distributors, & alternators that are sparkless, specially designed carbs that dump excess fuel down the barrels, cams with no overlap, high capacity oil pans, special waterpumps with stainless parts, etc, etc.....

69 Elim
12-28-2001, 09:40 AM
Thanks for the reply, but I realize those differences. Is there any differences when assembling a long block? i.e. bearing clearences for different oil/water temp?

Havasu Hangin'
12-28-2001, 09:42 AM
Everything Rivercrazy said, plus, I believe the (forged) piston to cylinder wall clearances are set for the cooler running enviroment.
In general, marine engines need to build alot of torque, faster than a car engine. Also, since they are constantly under load, detonation is always a concern.
Try a search (http://free.***boat.net/cgi-bin/search.cgi?action=intro) on the board. There's some good information somewhere around here...
http://www.goldenplasma.f2s.com/forum/smilies/happy25.gif

wsm9808
12-28-2001, 07:17 PM
The marine engine will need more piston to cylinder wall clearance than a car. J&E recomends .002 to .003 extra wall clearance for a boat motor and even more if your running NOS or a blower. Merlin says to ad an extra .001 to the lifter bores on one of their new blocks, but shouldnt be nesacery on a well used stock factory block. The valve guides will also need an extra .001 or so clearance. The bearing clearances should be ok at the loose side of stock.
The oil temp on your boat motor tends to run a little higher than in a car and the internal temp of the engine is as high or higher than in a car, but the the cold raw water running through your block and heads wont allow them to expand as much, so you need the extra clearance "built in" to keep everything from seizing up.
Ask your machinist about marine clearances, if he doesnt seem to know or care about them then find another shop fast. Stock car clearances will cause problems and are not for your boat.

69 Elim
12-29-2001, 06:16 PM
Wow, thanks for the reply. I am glad to hear about the differences. Also got a question on the new Vortec heads for small block chevys. They say they are not for marine use. Why? I was thinking they would be a good replacement for my old stock heads. I know about 64cc and different bolt pattern.

wsm9808
12-29-2001, 10:17 PM
I'v never heard of any reason, nor can see, why you could not use Vortec heads for marine use. I dont really follow what the new boat builders are installing, but I thought they had been using Vortec engines in several of the new marine packages for a few years now.

waterbum
12-30-2001, 08:36 PM
Since you plan on assembling the engine yourself,make sure to pay strict attention to the manufacturers specs for piston to wall and ring end gap.Not enough piston to wall in a marine engine and sieze will result,not enough ring end gap and the ends will butte,seize and tear the top's off your piston's!!!An information sheet should be supply'd with your pistons.I'm runnin aluminum heads with 10.3 to 1 comp. on 91 octain. You can get away with more compression with alum. head's because they dissapate the heat faster=no detonation. Make sure you have a good torque wrench,cover underside of headbolt heads and threads with a good assembly lube,O.M.C.gasket sealing compound or equivilent on any threads that enter a water jacket this will give you true torque readings.Hope this was a help. The Bum

Infomaniac
12-30-2001, 08:49 PM
I would not use the Vortec heads unless they are free. They are very thin and light weight. Crack very easily.

tahitijet
12-30-2001, 11:51 PM
Thanks,
So can i get away with 10.5:1 with cast iron heads? Also on the piston spec sheet will it have a spec for clearances for marine applications? or do i need to ad 3 thousandths myself?
thanks

waterbum
12-31-2001, 10:18 AM
10.5 to 1 with iron heads will probley result in detonation cause they won't dissapate the heat. Iron heads maybe 9.5 or 9.7 at most. Aluminum heads,10.3 to 1 no problem. I used Keith Black hyperutectic pistons and they did come with all pertnant info for marine applications.Have a blast,there's no better feeling than being able to say I created this beast you had to buy yours.Ha Ha Didn't mean to offend anyone. The Bum http://free.***boat.net/ubb/biggrin.gif

DOHARA
12-31-2001, 10:43 AM
I WILL HAVE TO DISAGREE W/WATERBUM. THE PROBLEM WTIH JET BOATS IS GETTING ENGINE TO
RUN WARM ENOUGH, JETS RUN TO COOL. I RUN CAST
IRON HEADS W/ 10:1 COMP. AT 36 DEG ADVANCE AND NEVER HAD A DETONATION PROBLEM ON 91 OCT.
I'M ALWAYS HAVING TO CLOSE WATER VALVE LITTLE BY LITTLE TILL I GET IT TO RUN AT 160-175 DEG.. JETS ALWAYS HAVE FRESH COLD WATER RUNNING THRU THEM. ANY ENGINE BUILDER WILL TELL YOU A ENGINE THAT RUNS TOO COLD WILL NOT PERFORM PROPERLY AND WEAR OUT JUST AS IF IT RAN TOO HOT.

Tinkerboater
12-31-2001, 10:00 PM
Why don't you jetboat guys run a thermostat housing and piping like the i/o boats. I dont see any reason why it wouldn't work.

waterbum
01-01-2002, 03:35 PM
You know something DOHARA,it's ok to dissagree with me but you didn't have to DISS me by CAPPIN me out!!!As long as your engine is running warm enough to burn off moisture(a byproduct of combustion)it is fine.Furthermore it's been proven on the dyno that a cool running marine engine will make more horsepower(also read this fact in a past issue of Hot Boat)although it may produce a little more carbon.Also on the compression thing,how do you know your not detonating?Is it mabe because you think you can hear it?How do you know that that 91 octain your buying is really 91 octain?What makes you think your jetboats run cooler than my I.O.?My 500h.p. and my 383 stroker both run around 140 degree's with no problems !! The man asked about runnin 10.5 to 1 iron heads your runnin 10 to 1=lots of piston heat,HARD on your oil.Remember this ain't 1965 fuel were runnin.Yo man,you gave me the thum too and I'm still tryin to be nice,mabe you should try that!! The Bum http://free.***boat.net/ubb/biggrin.gif http://free.***boat.net/ubb/biggrin.gif
[This message has been edited by waterbum (edited January 01, 2002).]
[This message has been edited by waterbum (edited January 01, 2002).]

DOHARA
01-02-2002, 02:37 PM
HEY WATERBUM, I'm not dissing anyone, I just think your a little off thats all. I don't think a half point in comp. will determine detonation or not. It depends on fuel. If you run high comp., you need to run higher octane fuel. Every engine is different so if he runs 10,10.5,11.1 etc. it may detonate at 10.1 or may not. also depends on how you tune your engine. I know what your saying about engine temps, I am simply saying that too cold of engine temps can cause loss of performance, so can a engine that runs too hot. What do you think a thermostat is for? A thermostat is to control temp. and assure a quick warm up, and to keep it operating at the most efficient and safe temp. for performance and engine life. If your engine runs too cold, fuel can condense and rob the combustion chamber of fuel required for performance, also causing a lean condition that will also causes detonation. Also, yes I know my engine isn't detonating cause I can't hear it. The definition of detonaton is: the explosion of the mixture in the engine cylinder, becomes audible through the combustion chamber walls, usually caused by fuel with too low octane rating FOR THE ENGINE,ignition timing too advanced,high engine operating temp., or excessive carbon buildup in the combustion chamber. So, the man asked if he can run 10.5.1 comp. I personally think he can. Ya aluminum dissapates heat faster but marine engines run pretty cool water thru the heads all the time so why would it make that much of a difference on a mild engine. I also know that I can run my engine colder than your 140 If I choose to. I have run it so cold that the temp gauge didn't budge off 120 deg., until I adjusted the water pressure going into the engine. What's with all the "HOW DO YOU KNOW" BS? SO let me ask you how do you know? I know enough, I have grown up in a family that has had plenty of high performance toys we have built, all my friends either race cars or build and dyno engines, I myself am a ASE certified mechanic that has been wrenching for many years. I don't know everything but, I know when someone doesn't know what they are talking about. All I stated was that a half a half point will not be a reason to buy aluminum heads when you can run a little better gas and get away with it. You think someone needs to buy aluminum heads if they jump out of your 9.7.1 comp. range that you stated before? I say your wrong thats all....ENOUGH SAID http://free.***boat.net/ubb/smile.gif

77charger
01-02-2002, 04:45 PM
If you run a bigger cam you can get away with 10-1 comp with cast iron heads using 92 octane.I my self run a 11-1 motor and it gets by well on av gas timing is at 38 also.if i back it to 32 i can get by on 92 with octane booster if i had to.but it wouldnt survive at 38 this i already know.the theory you have on aluminum heads holds true for cars as they are under load but i have gotten away with a 10-1 small block that was well built on 87.nainly because it ran cool 160 degrees.But a jet boat is not really under load.If you tied it to a dock you will still get max rpm you just wouldnt go anywhere.but they do take torque to get past a certain point (your max rpm)I pretty much agree with dohara on the comp issue i've been there myself and know from experience.

waterbum
01-02-2002, 06:15 PM
Well maybe I took you wrong.I too have been doing all my own wrenching for many,many years.I have never owned a squirt boat so I didn't understand that they aren't under the same load as an I.O. I am man enough to admit when I may have been wrong.The load factor would play a big role when deciding what comp. to run.Also my h.p. has a crossover(no circ pump)and no thermostat,lake water blows straight through,takes a while to heat the oil but never any sign of moisture in the oil.Guess maybe I learned somthing about squirt boats.Got kinda pissed at the thum and CAPS though.By the way,the cooler the fuel,the dencer the charge=horsepower! The Bum

DEL51
01-03-2002, 12:41 AM
Tinkerboater,there is a thermostat kit for jet boats, some call it a recirculator and it works good. some setups control the temp with valves only.I think an important part of preventing detonation is polishing the combustion chambers and the correct spark plug.Hot spots can occur where little casting "peaks"appear and polishing removes them and makes it more difficult for carbon to stick.I coated all my pistons with a thermal barrier coating and will do the chambers as well.

tahitijet
01-04-2002, 06:21 PM
thanks guys didn't mean to start a fight here.. still a little confused on cr ratio though. 77 i have been told to look for a roller cam in the 610-.680 lift, .315-330 dur. 108-110 lobe centers range. i planned to run the world merlin heads with probably no extra work to them. I'm sorta gathering the 10.5:1 is gonna be to much would i have any problems wtih 10:1 or could i go higher?
thanks

77charger
01-04-2002, 10:14 PM
tahiti jet with that kind of cam and 10-1 in a jet should be no problem on 92 pump gas you can bump the timing down a little if it is a problem or add a can of octane booster (still cheaper than race gas too).but in a boat or a car 10-1 is about the max you can get away with on pum gas.