REGULAR ENGINE vs MARINE ENGINE

[bountyhunter]

Can anyone tell me the actual difference between a regular 455 Olds engine and a 455 Olds marine engine, and would a regular engine work and last in a boat? what do the letters on the heads (C,G,F, etc) stand for. Also, does anyone know how to tell what year an engine is?
Thank you

 

[fbpd227]

Most marine engines had 4bolt mains, forged cranks, rods, and pistons- but NOT ALL- SS head gaskets, marine approved alt, carb,flame arrestor, and higher power band cams. I tried to put an auto engine into a boat- made the safety upgrades but it performed horribly! Camed all wrong! I have also put a marine engine into a 4X4 mud bogger truck and actually had good success...lol! Similar power bands/ camed the same. For what it costs to convert an auto engine- your much farther ahead to start with a MARINE ENGINE. There are also other differences, but those are some of the basics. I have "tulip'd" valves in an I/O from over heating and not having the right timming- so I/O engines are very oeticular since they run in a MUCH harsher enviroment than ANY automotive engine! My $.02 anyway- others with ALOT more input im sure!

 

[fbpd227]

Mor-tec.com has ALOT of casting number info- but I'm not sure about BPO engines? I'm sure there are other sites similar to mor-tech for the info you seek.

 

[Big Red]

Can anyone tell me the actual difference between a regular 455 Olds engine and a 455 Olds marine engine, and would a regular engine work and last in a boat? what do the letters on the heads (C,G,F, etc) stand for. Also, does anyone know how to tell what year an engine is?
Thank you

The 455 used in Checkmates and probably most boats were the 68-69 model engines. These were better blocks and heads and components. Find a old Oldsmobile sled from 68-69 factory 4-barrel engine they had the same blocks and heads used on the boats.

But then again any Olds 455 will work if you are going to rebuild it.

 

[robwkamm]

all 455 blocks are the same. 1968-76. no differences. ( some say there are not proven) most boats had steel cranks. all were 2 bolt blocks. the heads are as follows. c heads are the best port shape and flow from the factory. used in 68-9 only. e are 1970. good heads, some big valve not all. F are the holy grail, 1970 w-30 only head. worth nore than the boat! LOL. sell them off if you find them. 2k. g-ga heads are good also. 1971-2. k heads are marine or dealer replacement for the e-f heads. good also. j heads are junk. so go find a car motor and get a good crank and a set of edelbrock heads and your done. easy.

 

[robwkamm]

also dont be tempted with the 403. its a small block design with windowed main webs. junk in the boat and its lower deck height. 400 and 425 are the same externally and would work.

 

[bountyhunter]

all 455 blocks are the same. 1968-76. no differences. ( some say there are not proven) most boats had steel cranks. all were 2 bolt blocks. the heads are as follows. c heads are the best port shape and flow from the factory. used in 68-9 only. e are 1970. good heads, some big valve not all. F are the holy grail, 1970 w-30 only head. worth nore than the boat! LOL. sell them off if you find them. 2k. g-ga heads are good also. 1971-2. k heads are marine or dealer replacement for the e-f heads. good also. j heads are junk. so go find a car motor and get a good crank and a set of edelbrock heads and your done. easy.

The heads on mine have a large "G" then a smaller "A" about a 1/2" from the "G". I finally got it to run this past weekend and did 3 great runs (for not being used for about a year). Then the oil pressure went down to 0 (lost oil pressure last weekend, but came back up a little while idling) and it started knocking. This time the oil pressure didn't come back and it finally locked up. I guess I'm going to try and rebuild this one. I found a couple of rebuild kits already, but one of them says you have to know the piston size and something else I forgot,lol. If all 455's are the same why would you need to know the size of the piston I think they said 4.25?
Thanks for the help

 

[bountyhunter]

The 455 used in Checkmates and probably most boats were the 68-69 model engines. These were better blocks and heads and components. Find a old Oldsmobile sled from 68-69 factory 4-barrel engine they had the same blocks and heads used on the boats.

But then again any Olds 455 will work if you are going to rebuild it.

Hi Big Red,
Yea, I'm going to have to rebuild it. I finally got it out again, after greasing the u-joint and thrust bearing. The really bad vibration it had quit this time and the engine and pump responded immediately, did that about 3 times, then lost oil pressure and then locked up. Did great on those runs for not being run for about a year. Put out a good rooster tail for having a bad engine.
Thanks for all your help

 

[bountyhunter]

O.K., Now then lets look at what I have. I have a 1976 Checkmate Jetmate with a 455 Olds engine (supposedly 1976) with "G" heads, an Edelbrock "Torker" intake with a 600 Holley, a Hardin Marine exhaust and valve covers. I beleive it's got a Mallory Distributor and a Motorala alternator. It ran fine for a couple of times then went to knocking and then locked up.
My question is; When it locked up, if it locked up on the lower end, couldn't I rebuild this same engine and just put new bearings/connecting rods/crank (or have the crank turned) or whatever it needs and still use the old camshaft and put in new camshaft bearing. I have found a few rebuild kits on eBay, but none say for Marine.
Thanks

 

[robwkamm]

ga heads are 1972. you can use a non marine rebuild kit. when you pull the heads put your finger in the exhaust port. youll feel a small bump. grind it out. its the AIR bump. worth a few cheap hp. you can cut the crank. its probably best to pull it all apart before you buy anything. they want to know piston size incase it was ever rebuilt before. i would think the gaskets may different for a non marine aplication but not sure. i would toss the cam out. not worth wiping a lobe and going back into replace it.these are low rpm motors. long rods, big torque # check out this site. realoldspower.com they have a boating section. good info there and stuff for sale.

 

[bountyhunter]

ga heads are 1972. you can use a non marine rebuild kit. when you pull the heads put your finger in the exhaust port. youll feel a small bump. grind it out. its the AIR bump. worth a few cheap hp. you can cut the crank. its probably best to pull it all apart before you buy anything. they want to know piston size incase it was ever rebuilt before. i would think the gaskets may different for a non marine aplication but not sure. i would toss the cam out. not worth wiping a lobe and going back into replace it.these are low rpm motors. long rods, big torque # check out this site. realoldspower.com they have a boating section. good info there and stuff for sale.

On the heads, the bump is it visible and how much do I grind off ? Yea I was going to pull the engine first, just needed to get some heads up on what type of kit(s) to buy and how much they run. Thanks for the realoldspower.com site, I have been there before and forgot all about it.
As for the cam, I agree with you, but what size should I look for (stock or bigger), If this engine hasn't been re-built before I thought about having it bored a little. I found some rods that are 5 5/8" don't know what mine are yet.
Thanks for the info and help I really appreciate it.

 

[Big Red]

You really need to replace everything and do it right. A boat engine is under extreme load unlike a car. For example its like driving around in your car with the E-brake on all day or climbing a mountain all day long. Or in my terms is like pulling plows threw the dirt with a tractor. And to really put icing on your cake it takes more power to push a jetboat than a I/O or O/B.

You really need to pull your engine out and bring the bottom end and heads to a good machine shop and have it inspected and go from their.
95% of the time you can never buy a set of new pistons and use the same bore. I also feel the cam needs to be tossed in the trash. I feel if you had a oil problem the rods will need to be re-sized, crank turned, block bored, new valves, springs, and hardware.

You can patch it up and get by maybe a season or 2 or do it correctly and get years of good service.

I patched, cut corners, reused old junk for years untill one day I got sick of pulling engines out. From now on I do it right the first time

 

[Jetmate]

Can anyone tell me the actual difference between a regular 455 Olds engine and a 455 Olds marine engine, and would a regular engine work and last in a boat? what do the letters on the heads (C,G,F, etc) stand for. Also, does anyone know how to tell what year an engine is?
Thank you

Check this price out. They can do a marine version. Never used them, Maybe someone out there has. http://www.dougherbert.com/454chevybb565hp-p-25796.html?cPath=614_615_749 Chevy is the way to go.

 

[Big Red]

Check this price out. They can do a marine version. Never used them, Maybe someone out there has. http://www.dougherbert.com/454chevybb565hp-p-25796.html?cPath=614_615_749 Chevy is the way to go.

Doug Herbert is to exspensive on anything. I do not live far from their and have been their a few times when I wanted a part ASAP.

I would just buy the parts from Summit. I agree a BB Chevy would be the better way to go if you are starting from scratch. But it will cost him a crap load of money to change over. He will need to buy exhaust, distributar, intake, flywheel, motor mounts, bell housing, starter, pullys, front plate for the water hook up and everthing else that goes with it., And their will be other items but this is a quick list.

 

[Jetmate]

Doug Herbert is to exspensive on anything. I do not live far from their and have been their a few times when I wanted a part ASAP.

I would just buy the parts from Summit. I agree a BB Chevy would be the better way to go if you are starting from scratch. But it will cost him a crap load of money to change over. He will need to buy exhaust, distributar, intake, flywheel, motor mounts, bell housing, starter, pullys, front plate for the water hook up and everthing else that goes with it., And their will be other items but this is a quick list.

How do his engines hold up? He advevtises marine versions, but I've never priced them.

 

[Big Red]

How do his engines hold up? He advevtises marine versions, but I've never priced them.

I dont have a clue I never herd of anybody buying one from him around here local, or any boat site.

 

[robwkamm]

i used his cams over the years. all good stuff. i built a blower motor with his parts. no issues to talk about. i thought the $ for the parts was fair. dont know if he assembles his complete motors. if they do im sure there good. he does race top fuel. they hold up there most of the time LOL

 

[Jetmate]

i used his cams over the years. all good stuff. i built a blower motor with his parts. no issues to talk about. i thought the $ for the parts was fair. dont know if he assembles his complete motors. if they do im sure there good. he does race top fuel. they hold up there most of the time LOL

Thats good to know, Thanks

 

[wca_tim]

If you're looking for a top notch marine builder, you probably wouldn't be disappointed if you call "Joey" Griffin in Washington, North Carolina. He and his guys make a living mainly building engines for the offshore racing and circle track crowds. He knows his **** and his guys do some of the best machine work I've ever seen. I know they've built some winning offshore engines and that they have a solid reputation for building bullet proof high performing engines. I was never out to the shop that there weren't big power blown big blocks going together or being run on the dyno. Note that I'm far from a deep-pocketed high end customer - I've only had occassion to have them set up a moderate but real solid little 383 at this point. Yet they took the time and attention to detail to do top notch work on my stuff just like they do for someone spending $25k or way more. I was trained as a machinist in a past life and stopped out a time or two while my mess was going together - impressive work, good people.

If you decide to call, don't be put off if he doesn't have a bunch to say. He is economical with words... but a straight shooter and a nice fellow. I'd be comfortable doing business with him over the phone after the first experience with he and his guys.

They're listed under Griffin Automotive, I think the listing is in Grimesland, North Carolina if you decide to give them a call... If you can't find the number drop a pm and I'll dig it up.

Oh, and I gaurantee you won't get a hard sell or anything, I never got the sense he has to go looking for business... at all.

Hope that's helpful and good luck with whatever you decide to do.

 

[bountyhunter]

Thanks guys,
I appreciate all the help and info. I have the engine out now and apart. Found the number 6 piston had thrown it's rod. Have freind that is coming by to look at it for me, he works at a machine shop and rebores/rebuilds engines and is part owner of the local dragstrip here. I know the crank is going to have to be turned and bearings replaced. The problem is all of the mechanics here work on car engines not marine engines. As for the Camshaft, how can you tell what size/RPMs it is, I was told that I needed a cam with rpms up to 5800 (I think). If it hasn't been bored, I'm going to have it bored and I would like to have a little bit of a lope in it, when it goes back together. A little more HP would be nice. It does have a Holley 600 and a Edelbrock Torker 455 intake, but as for the HP now I have no idea, because I don't know if it has been previously rebuilt. What about a gasket set, can I use a regular type gasket set or does ot have to be a special type set? Friend is suppose to come by and look at it tomorrow or Tuesday.
Again, Thanks for everybodys help, I appreciate it.