Engine blew up today.

[mikel1291979]

So my engine looks like it threw up a milkshake all over the bilge. I just got the boat and new a cracked block was a fairly good possibility. Such a good deal on a really nice boat I went for it anyways.
My question is this, and I know its been asked before but the answers are always confusing.
Straight out is there any reason I can't go to pep boys and buy a 4.3 from them? I have heard people ask are car engines and boat engines the same. The answer is generally yes, but then they list the differences.
The cheapest 4.3 I have found is $1450 shipped, and pep boys is almost half that with local pickup. This is for a long block.
Thanks.

 

[90stingray]

Re: Engine blew up today.

It needs brass freeze plugs. Camshaft is ground differently. I would reuse it if possible. As long as all the original accessories were marine rated... you're good to go. Make sure to get a similar casting. Not sure what year you are working on but I know they did some weird things to the 4.3's thru the years.

 

[Fireman431]

Re: Engine blew up today.

I know there are a lot of threads on here discussing what some of the differences are, but I don't know if there is a sticky that is a comprehensive list.

Aside from the freeze plugs and marinized bolt ons, I'm sure the wealth of knowledge on these boards will fill in the gaps.

 

[mikel1291979]

Re: Engine blew up today.

The boat in an 89. I think its the original engine although I am not 100% on that. I have no problem changing the freeze plugs out, but the cam will have to stay. I have the exhaust manifolds, risers, intake and carb that are still good.

 

[StevenT]

Re: Engine blew up today.

Have you verified the block is cracked? There are other problems that cause a milkshake in the bilge. Last year I had a upper seal go bad in my outdrive (Mercruiser Alpha One) This caused water and oil to mix and drain into my bilge. If the block is cracked I would highly recommend replacing with a Marine engine.

 

[Dieter]

Re: Engine blew up today.

When I thought my 4.3 was in need of replacement I asked my local boat mechanic and he said the cam is a must. Your power band is different in a marine motor and a car motor will not last a year or two depending on the use. He said the cam will go flat very quickly. IMHO good luck.

 

[mikel1291979]

Re: Engine blew up today.

Im nervous to use any internals from the current engine. If I do use the cam from the old engine won't I have to change the pushrods and lifters as well?

 

[jopes]

Re: Engine blew up today.

When I thought my 4.3 was in need of replacement I asked my local boat mechanic and he said the cam is a must. Your power band is different in a marine motor and a car motor will not last a year or two depending on the use. He said the cam will go flat very quickly. IMHO good luck.

Thats why you upgrade to a roller cam. they do not have the issues that a flat tappet cam does.

 

[Dieter]

Re: Engine blew up today.

Roller rockers are nice too. I would not use internal components from old engine it's just too risky. Get a marine short block and have your heads gone through then go from there.

 

[mikel1291979]

Re: Engine blew up today.

Scroll down to lines 25-27. They list roller tappets.
http://citymotorsupply.com/domestic.pdf

 

[mikel1291979]

Re: Engine blew up today.

Roller rockers are nice too. I would not use internal components from old engine it's just too risky. Get a marine short block and have your heads gone through then go from there.

The difference in long and short blocks is $200. If I go with the marine engine I will just get the long block.

 

[1ruralmailman]

Re: Engine blew up today.

i believe it was 86-87 that the 4.3 changed from two pice rear seal to one.also changed the flywheel.you need to keep all this the same so your coupler will work.i think you can tell wich you have by the casting numbers,if it has a 77 either ending,or starting it is a two piece rear main.good luck.

 

[jopes]

Re: Engine blew up today.

Roller rockers are nice too. I would not use internal components from old engine it's just too risky. Get a marine short block and have your heads gone through then go from there.

Don't full rollers have clearance issues with stock valve covers? Roller tips clear with out problems I beleive.

 

[elkhunter338]

Re: Engine blew up today.

The head gaskets need to be marine and brass soft plugs. Unless you have fresh water cooling then you do not need that marine stuff. Yes cams are different and such, but I know of those in the old days rebuilt a chevy in-line 6 with I am sure car parts stuffed it in a boat and it ran fine. This was fresh water cooled.
Also I know of guys who used cylinderhead right off a car/truck engine and bolted it on the engine in their boat. I would bet a car engine would run a long time if you kept the rpms under 3,500 most of the time.
I would verify where the water has come from, if it came from the engine your oil in the engine should be milky. Maybe blown head gasket or something easier to fix.

 

[infideltarget]

Re: Engine blew up today.

If you get an automotive long or short block, get a cam grind that is similar to a high performance grind. For example: when ford wanted to make the 302 from the '83 and older Mustangs into the 5.0 H.O. engine, they used the cam grind from a 351w marine engine to get the performance they wanted. I have also been told that a truck or RV cam grind is very similar to a marine grind. Just something for you to check on. I am sure you can get the advertised cam specs from each engine you are looking at, and compare them to see the differences in cam grinds. Use the marine grind as a baseline, and find an automotive grind that is close.

 

[mikel1291979]

Re: Engine blew up today.

The head gaskets need to be marine and brass soft plugs. Unless you have fresh water cooling then you do not need that marine stuff. Yes cams are different and such, but I know of those in the old days rebuilt a chevy in-line 6 with I am sure car parts stuffed it in a boat and it ran fine. This was fresh water cooled.
Also I know of guys who used cylinderhead right off a car/truck engine and bolted it on the engine in their boat. I would bet a car engine would run a long time if you kept the rpms under 3,500 most of the time.
I would verify where the water has come from, if it came from the engine your oil in the engine should be milky. Maybe blown head gasket or something easier to fix.

I only run in fresh water lakes. I am in east texas and have no plans to ever put in salt water. Would the dead gaskets be ok as it?

 

[kewlkatdady]

Re: Engine blew up today.

IMHO opinion...I wouldn't buy much from pep boys.

Much less a car motor for a boat.

I just did the same replacement and I went with Rapido Marine.

Motor seems stronger than the original, plus there is a warranty.
Just my $.02

 

[zbnutcase]

Re: Engine blew up today.

Pep boys, Autozone, O'reillys, are all to be avoided at ALL costs...mass market garbage

 

[Don S]

Re: Engine blew up today.

I would suggest you avoid "High Performance" cams. The 4.3's are real bad about reversion (sucking water in through the exhaust when running). Auto mechanics seldom know about this little tidbit that can destroy your newly rebuilt engine.
You also need to get a long block of the proper vintage as a replacement, or you will have problems with all your accessories not fitting on the engine. Brass core plugs, marine cam, and composite head gaskets is all you have to worry about. Getting a marine long block of the proper year vintage will make your job go very smooth.

 

[stackz]

Re: Engine blew up today.

For example: when ford wanted to make the 302 from the '83 and older Mustangs into the 5.0 H.O. engine, they used the cam grind from a 351w marine engine to get the performance they wanted.

they used the windsor firing order. lift/duration was different from any factory 351w grind. they also changed the heads and went to a speed density FI setup.


from what I've seen with the specs on marine 350's versus automotive 350's is that most stock marine cams are very very similar to automotive "towing" cams. generally the marine cams will have a little less lobe separation as they can since there's no torque converter to worry about.

I dont know where people are coming up with the whole "wiping the lobes" on the cam from running it flat tappet. pretty much all engine whether marine/auto were flat tappet before 1982. how do you explain those boat engines lasting? much less automotive racing engines from the same vintage. sure most had solid lifters but thats a mute point.

I agree that pepboys/vatozone reman'd engines probably arent the best in the world as they are contracted out to the cheapest rebuilder and you get what you pay for...but they have a warranty. though, I'd just buy a used 4.3 from an s-10 or such...

fresh water = just toss it in and go, change the cam if you want.
salt water = brass plugs/marine headgasket swap, change cam if you want, then toss it in and go.

yes, you'll want new lifters if you swap the cam. 4.3 lifters are dirt cheap though. cam swap is super simple. pull the timing cover, pull the valve covers, remove pushrods/lifters, unhook the timing chain/gear. slide the cam out, slide old marine cam in. line up the timing gear dots, install new lifters and old pushrods. button up, set distributor to #1, crank up and set the base timing. not rocket science.