olds 455

[chevyrat619]

hey everyone i have a few questions about my boat. Its 1970 something tri haul with a 455 olds and a berkeley pump. my first question is what should the timing be set at? Second queston is i have it set at 12 and it starts up fine when its cold but once it warms up it has a really hard start and and then the starter grinds anyone ever come across this? if i put the timing colser to 0 it starts better but then it back fires through the carb. just some added info i bought the boat from a guy that had no clue about anything and had the firing order all messed up. thanks corey

[rasorinc]

First of all it is a 30-40 year old boat. I would change out all engine wiring and replace with marine engine wiring. grounds, ignition, plug wires, etc. Also I would change plugs. Then you can tackle the problem with a fresh start.

[chevyrat619]

thats where i started and now im down to these problems

[rasorinc]

Can you find any names on the manifolds? Exhaust and carb? I'm thinking. These types of problems are elusive to say the least. Are all fuel components
clean and working good? Are you setting your timing by marks on the belt or pullys or electronically?

[chevyrat619]

it has a stock intake manifold and it has a holley carb on it that i just rebuilt not to sure the brand of the exhaust manifolds they dont have any writting on them but they have water running threw them and they are aluminum

[rasorinc]

How are you checking your timing? Does you engine have a standard distributer? One with points? Sorry to just ask questions but trying to help.

[chevyrat619]

no prob feel free to ask. ya it has points just replaced all that too. there is only a tdc mark on the pulley and the pointer on the front cover. not sure what its at but i moved the dist. till it stopped backfiring and ran good then would shut it off and then ill have the starting issue

[rasorinc]

I can really only offer you a guess on what is happening. I would say the distributer has been removed and when put back in changed the firing order.
I would bet that either this or the plug wires are placed in wrong and one or two cyclinders are mis firing. That is all I can think of and I have experienced
that and it sounds very similar to what you are telling me. Hope this helps. Really like your area--went through Boot there and have visited often. Boot was in 1961 so I'm old. Best of luck to you. Stan

[chevyrat619]

thanks for your help i think ill go threw it all again and try reseting the dist. if you come across anything else please let me know thanks again corey

[rasorinc]

Just remember the engine has no mind.................So it is electrical or fuel.
That does not make it any more simple though but it is easier than chips and sending devices. Good luck, Stan

[FAST FRED]

One flaw the 455 has in some years was plastic teeth on the timing chain.

At the 75.000 mile mark the chain would need replacement .

A solid dual chain is about $70 bucks with the gears , will tighten up the timing.

I would also look for fuel boil over from the carb when warm.

Same symptoms as you describe.

FF

[chevyrat619]

thanks you guys i will look into what you recomended this weekend and ill post the results

[Markster]

Be careful with the timing. I have a 74 jet with a 455 olds, and years ago when the timing was off it caused the engine to overheat. This eventually cracked a head. Took us forever to figure out the timing being off would overheat the engine. Can't remember the correct timing, does anybody know? 12 degrees at 1000 rpm sounds familiar, but not sure.

[chevyrat619]

So i spent the time re did everything with very little results, so i desided to pull the timing cover and check the timing chain come to find out the chain had over an inch of play and was causing a major timing issue. so after replacing the timing set the motor starts and runs 100% better. Thanks for all your help I will post on here bout how it does after i take it out

[Boston]

those things had hydrolic lifters as well so you might want to keep an eye on the oil level and switch it out often as it will make a big difference
there is a dwell setting that lots of people miss when making a tune up

glad you got it going better
B