1996 Four Winns Sundowner with 5.0 Cobra engine and drive

[Lpgc]

Hello everyone, I'm a new member and this is my first post. I did look to see if there was an introductions thread but didn't find one, hope it's OK to dive in with this post.

My username Lpgc is the same username I use on a few other car related forums, I convert vehicles to run on LPG (propane) and LPGC is the name of my company in the UK but I'm not here to talk about LPG...

I recently bought a 1996 Four Winns Sundowner with 5.0 Cobra engine (2bbl) and drive. There are stickers on the engine reading OMC Cobra and Cobra stickers on the drive. I don't know much about how boat engines (the main bits - block, heads, valves, cams, etc) differ from car engines other than the obvious differences to the cooling system... If this engine is broke, could I not just swap in the equivalent car engine and swap all the cooling system components (and possibly ignition and fuelling components) across? I've read 'boat engines are stronger' but if that's the case, why don't performance vehicle / hot rodders talk about fitting marine spec engines in vehicles?

I believe this Volvo Penta / OMC engine is actually a Ford 5.0 / 302, is that right? And if so, could I swap in another Ford 5.0 / 302 engine and just swap all the marinising parts across? And if so, could I swap a 5.8 Ford engine in and still use all the same marinising parts?

I suppose if the blocks are the same the bolt pattern on the rear of the crank could still be different, if the heads are slightly different the marine manifold won't fit, it's aspects like that that I'm really struggling to find any info on.

Since buying the boat a couple of weeks ago I've used it for 4 full days on the river.. there's a knock from the engine and I'm not sure if it's bottom end related like a rod bearing or valve train related. It's there at idle, goes away in gear at low speeds / engine loads and comes back at higher speeds / engine loads. I ran a test to try to help determine if it was rod knock.. I removed each plug lead in turn to see if the knock persisted after disabling each cylinder in turn, it did persist. I'm not sure how good a test that is but I'm thinking maybe it's not rod knock since it persisted? Does this engine have hydraulic cam followers of which one might be faulty? If it were a truck I could get underneath and on top of the engine to listen but I can't do that with the engine in the boat.

The boat needs a new prop (the previous owner really messed it up) which I'm also struggling to get hold of and I'm not sure what spec prop to buy, the current prop is a 14.5 x 21 3 blade, is that the right prop?

The boat is supposed to do 44mph but it's only doing around 30 with some vibration which I don't know whether is from the prop or from a misfire. The boat is now back in my yard, I've removed 7 x Champion RV15YC4 and 1 x NGK BR6FS plugs from it and have ordered a set of 8 RV15YC4 and a set of 8 NGK BPR4FS plugs to go in it (I'll fit whichever arrives sooner!). I expect the BR6FS that was fitted is incorrect for this engine (and expect it was fitted at the last plugs change when the fitter broke a plug during fitting and had to source another in a hurry) but I doubt it's that that's causing the misfire or vibration and it won't have been causing the knock.

Anyone any idea on what internal engine problem could be causing the knock?

My plans are to fit the new plugs and a new prop then take it to the river again and see if there's still vibration or a misfire then, also check top speed again. It's unlikely the knock will go away but if that's just a rocker issue etc it might not be much of a problem?

Can anyone point me to more info (engine diagram, parts compatibility, etc) for this engine and drive?

Sorry for the long first post!

Regards, Simon.

 

[Lpgc]

This is in addition to my recent thread about engine problems with the same boat... https://forums.iboats.com/threads/1996-four-winns-sundowner-with-5-0-cobra-engine-and-drive.766501/

I've only owned the boat a couple of weeks, at first the trim seemed to work properly but then seemed to stop being able to trim it up when under load (though I could still trim it up when in neutral). Then when I came to get the boat out of the water I trimmed it right up to lift the leg out of the water but by the time I'd pulled it out of the water and got to the top of the slipway the leg had gone back down.

I can't see a leak on the hydraulic rams, what is the likely problem?

 

[alldodge]

Welcome aboard

I merged your threads, don't post multiple threads on same subject

Truck and boat motors are mostly the same but next to none of the attached items are. Things like ignition, Alternator, Starter are all spark protected to keep the boat from blowing up, don't use auto parts on boats, but can use boat parts on autos

Can swap a 302 for a 351 so long as it's a carberated boat motor. If its fuel injected then need to use the 351 ECM because it needs more fuel

Doubtful if it's a rod knock because it goes away and if it was the motor would have locked up by now. Not knowing more it's very likely the outdrive and maybe the U joints. Pull the drive and inspect

Stop driving it with a vibration and messed up prop, it's just going to get worst.

With the leg not staying up it's probably a internal leak in the cylinders or the pump, need to investigate

 

[Lpgc]

Thanks for the reply and for merging my threads, sorry I thought it would be better to split up the engine and leg issues to different threads but I understand your point.

It's a carb engine, Holley 2 barrel. I'm not sure if I could post pictures or if they would help?

I find the Volvo Penta / OMC / Ford relationship difficult to understand but I believe it's a Ford engine, do you know if that's right?

So if it's a Ford 5.0 302 I could swap in a Ford 5.8 351 from a car and swap the marinising bits over and it would all fit/work properly? Would that be the 351W engine?

I understand about the ignition, alternator, starter etc and spark protection.

Thanks for the insight about the knock noise - You think this could be outdrive (leg)? I've tried to listen around the engine and it seems to me to be coming from the middle of the engine so I was thinking rod knock or valvetrain but I'm here for advice and trust your judgement more than my own on this.

I know it's good advice to investigate by pulling parts and inspecting, kind of seemed to need to run the boat a while just to see what symptoms it had before pulling anything.

I've been looking around the pump, can't see where I'd refill the hydraulic fluid. Can pumps / cylinders be repaired?

Again thanks for the reply.

Simon

 

[alldodge]

So if it's a Ford 5.0 302 I could swap in a Ford 5.8 351 from a car and swap

No,
I said it has to come from a Truck not a car. A truck has a different cam then a car.

A boat also has brass of stainless freeze plugs, and auto can have aluminum. The head gasket is also stainless so not to rust. Now if this is a closed cool motor then not having a marine head gasket or freeze plugs is not an issue. Meaning it has antifreeze going thru the block and not raw water

Thanks for the insight about the knock noise - You think this could be outdrive (leg)? I've tried to listen around the engine and it seems to me to be coming from the middle of the engine so I was thinking rod knock or valvetrain but I'm here for advice and trust your judgement more than my own on this.

The first thing that should be done when getting a new to you boat is pull leg, inspect gimbal bearing and leg. Change drive lube. Can run the motor with leg off by putting hose connected to thermostat housing



If all you wat to do is go out

 

[Lpgc]

Thanks.

I knew about having to change headgaskets to marine spec but I didn't know about the different cam. The main things I wanted to check were that a different engine would mate up to the marinising bits, which you've answered thanks.

Would a 351 also match up with the marinising components? Same situation with the cam?

Will any 302 or 351 match or do I need an engine from a particular range of years?

I'm in the UK and US engines from the 1990's can be difficult to obtain, there are a few specialists who might be able to supply a 302 or 351 but I might have to settle for an engine from a car and then fit it with a cam suited for a truck / boat... Would it be OK to do that or is there something else I've overlooked that could be a problem?

My dad was boating mad when I was growing up but he had mostly outboard engines, always checked the gear oil before even buying a boat.. I intended on checking the oil in the leg on this boat but haven't checked the leg yet, I'll take your advice and pull the leg to check the gimbal bearing and change the drive lube.

Thanks again.

 

[dubs283]

If the long.block you source is from a truck the cam (if oem) ought to be of proper spec to suit your needs

I love ford products, I tell random strangers on the street how great ford products are without provocation.

Unfortunately ford has never had as significant a presence in the sterndrive/inboard engine supply as gm. The market is limited for marinized ford engines so automotive is an obvious avenue for replacement. Just make sure you properly marinize the long block

Ford v-8 engines even when improperly tuned run smoother than any gm product tuned to spec or otherwise. Ford long blocks can withstand much harsher environmental treatment from an operator/surroundings. They just keep going, and going, and going

I will say the same for subaru engines, amazing durability. But that's another conversation

 

[ScottinAZ]

biggest issue with swapping from a 302 to a 351 is going to be the intake manifold. The 351 has a taller deck height, and correspondingly larger valley between the heads. The intakes are NOT interchangeable between the two. That said, proper marine manifolds should be relatively easy to source with the advent of the internet, and international shipping. the other marine components should swap over without too much issue. Being as you are in the UK, I would just get a car engine, and swap out the cam and timing chain. Chances of you finding an F150 over there are about nil, thankfully the cam is a relatively easy swap, since you need the heads off anyways to change the head gaskets. Freeze plugs are another relatively easy thing to change, at least before the engine goes in. clearance gets a bit tight when installed in the hull.....

as for matching the engines, I would try to get one about the same year, as that will make the addition of the accessories a bit easier. Manufacturers have a bad habit of adding/deleting bolt holes when they are not needed, and you dont really want this to bite you in the middle of a project.

 

[Lpgc]

Thanks Dubs283 and InvaderScott.

I realise I'd need a different intake manifold if swapping from the 302 to a 351 but I appreciate all replies and info. I only realised because I read about the different deck heights... If I hadn't read about the different deck heights I might have assumed they were the same blocks with the 351 using different pistons and shorter rods than the 302 (hehe!)... Even if something may seem obvious to others more familiar with the subject than myself it might still be something I'd otherwise overlook which could cause me problems and/or money... Please keep the advise coming! I'd rather be told something I already know than not be told and not know.

So far with everyone's help I've found out / confirmed that it is a Ford engine even though it's labelled as a Volvo Penta / OMC setup, that I can swap in a truck engine (or car engine if I swap the cam) and the marinising bits (cooling system, sealed dizzy, sealed starter) will fit / mate up. That info really opens up my options.

So if it's a 302 engine in my boat, is it the 302 Windsor engine?

I did read somewhere that the 302 boat engine uses the same cam as the 351.. I wonder if they meant the 351 truck engine cam?

Would my 302 heads fit (and be suitable for the boat application) on a 351 bottom end?

Would my 302 dizzy have the correct rpm advance curve for the 351? (I'd expect a minor issue that I could correct if not?).

Truck versus car cams has been brought up - Some boat owners increase the bhp of their existing engine by changing cams. Every cam is a compromise... I'd guess the truck cam is more of a torquer cam than the car cam and the torque would help get the boat on the plane but a performance car cam could give better top end speed (torque cam probably won't give as much top end bhp)?

My boat is a 1996 model year, meaning the engine was built at latest in 1996 and could be earlier. Will it have hydraulic lifters? Maybe the knock I've heard is just a broken hydraulic lifter, in which case I might just fix that instead of fitting a different engine. I've read the 351 uses a lot more fuel than the 302 (more that the size increase would suggest) but I think if I were to change it I'd rather have the 351 anyway.

 

[dubs283]

Advance would probably be okay, ford's are pretty forgiving in that regard and can handle over advanced timing to a point. Think gm 454, which can handle gobs of advance, like high 30's to low 40's no issues. Aside from the 3.0/2.5 gm the 454 is my favorite marine engine

Selecting the right cam is important as there is a fine line between top performance and reversion with a naturally aspirated marine engine. Wet exhaust reversion will destroy a long block right quick with little indication to the operator as to a fault

 

[ScottinAZ]

Small block Fords, the 260, 289, 302 and 351w are all “Windsor” engines, you see the distinction with the 351 due to Ford using no less than 3 different 351 engines…… (Cleveland, Windsor and the “Modified”). Cleveland and Windsor were named for their respective assembly plants, whereas the modified is essentially a “Cleveland” with a big block bell housing pattern. A bit long winded to say, yes your 302 and 351w are the same family, but a little knowledge goes a long way. The 351’s are NOT interchangeable easily as they share no common parts.

 

[dubs283]

The only compatible components between a 351 windsor/cleveland are the pistons, crank and associated hardware. All other components, block, heads, cam, lifters, intake, water pump, etc are specific to the respective engine

 

[ScottinAZ]

The only compatible components between a 351 windsor/cleveland are the pistons, crank and associated hardware. All other components, block, heads, cam, lifters, intake, water pump, etc are specific to the respective engine

cranks are NOT the same. Windsor has 3 inch mains, Cleveland uses 2.74" mains...... Pistons may fit, but the canted valves on the Cleveland family are different than the paralell valves on the Windsors..... valve cutouts will likely not match between the two..... Deck heights and therefore compression height in the pistons is also different (.300 shorter on the Cleveland). very different engines to be sure

while you can get parts modified to fit, they are not drop in replacements for one another.

What’s the Difference Between a Ford 351 Windsor, Cleveland, or Modified Engine?

Get a breakdown of the differences between Ford's 351 cubic-inch Windsor, Cleveland, and Modified engines, including how to visually identify them.

www.onallcylinders.com

 

[dubs283]

See?!

Iboats has a wealth of useful information provided by its users

Here I've thought the cranks were the same, they are not

Find yourself a decent 302. It's a solid v8 that should provide years of good use

 

[Lpgc]

Seems that I can fit any 302Windsor in my boat then? Just make sure bracket holes are in the right places?

And any 351Windsor will fit? Same concerns about bracket holes and I'd need a suitable intake manifold. I don't know if 351's were always fitted with 4 barrel carbs / manifolds or were available with 2 barrel setups? My existing carb is 2 barrel, I suppose I'd want a 4 barrel setup to maximise the power increase from fitting the bigger engine so would need to change the manifold and carb..

I only have to make sure I haven't mixed up a Windsor with a Cleveland? I don't think I'd make that mistake if I compare engines side by side (even just by carefully looking at pictures?), or if I buy from a specialist supplier (or even just a clued-up private seller) they shouldn't make that mistake.

If my 302 engine didn't have the knock and ran normally I probably wouldn't seriously be considering fitting a 351, not worth the work or money... But if it seems a better idea to replace rather than fix this engine then I might as well fit a 351 because I'd prefer the higher power.

I still need to diagnose the knock on this engine. Alldodge has been very helpful and answered many of my questions, also suggested the knock might not be from the engine at all, could be from leg/coupling. Come to think of it I think there is some UJ type noise from the leg when cornering or trimming and I know it's good advice to check the leg anyway but I still expect this knock to be from the engine. What components can I easily check that could be causing the knock without removing the engine?

 

[alldodge]

As said before

Can run the motor with leg off by putting hose connected to thermostat housing

 

[Scott Danforth]

Seems that I can fit any 302Windsor in my boat then?

kind of.

most marine 5.0 fords used the 5.8 heads and cam. so you have to verify firing order BEFORE you buy parts, and you most likely have to build a motor.

any truck motor you start with will need to be stripped down to just the longblock and built back up as a marine motor with brass core plugs, marine head gaskets, marine circulation pump, all the marine front accessories, all the marine electrical and all the marine induction system.

If my 302 engine didn't have the knock and ran normally I probably wouldn't seriously be considering fitting a 351, not worth the work or money... But if it seems a better idea to replace rather than fix this engine then I might as well fit a 351 because I'd prefer the higher power.

If you want more power and you have to swap the motor, I would seriously suggest swapping everything pulley to prop for a GM 5.7 and a mercruiser drive, or even a volvo drive (not the OMC drive you have).

I'm in the UK and US engines from the 1990's can be difficult to obtain, there are a few specialists who might be able to supply a 302 or 351 ........... I intended on checking the oil in the leg on this boat but haven't checked the leg yet, I'll take your advice and pull the leg to check the gimbal bearing and change the drive lube.

since you are in the UK, find a wrecked boat with a better motor and drive and pull the whole thing and swap pulley to prop

also, I know that Summit Racing and rockauto can ship to Scotland faster than shipping to florida. So they will also ship to the UK..... so you have choices.

 

[ScottinAZ]

Seems that I can fit any 302Windsor in my boat then? Just make sure bracket holes are in the right places?

And any 351Windsor will fit? Same concerns about bracket holes and I'd need a suitable intake manifold. I don't know if 351's were always fitted with 4 barrel carbs / manifolds or were available with 2 barrel setups? My existing carb is 2 barrel, I suppose I'd want a 4 barrel setup to maximise the power increase from fitting the bigger engine so would need to change the manifold and carb..

I only have to make sure I haven't mixed up a Windsor with a Cleveland? I don't think I'd make that mistake if I compare engines side by side (even just by carefully looking at pictures?), or if I buy from a specialist supplier (or even just a clued-up private seller) they shouldn't make that mistake.

If my 302 engine didn't have the knock and ran normally I probably wouldn't seriously be considering fitting a 351, not worth the work or money... But if it seems a better idea to replace rather than fix this engine then I might as well fit a 351 because I'd prefer the higher power.

I still need to diagnose the knock on this engine. Alldodge has been very helpful and answered many of my questions, also suggested the knock might not be from the engine at all, could be from leg/coupling. Come to think of it I think there is some UJ type noise from the leg when cornering or trimming and I know it's good advice to check the leg anyway but I still expect this knock to be from the engine. What components can I easily check that could be causing the knock without removing the engine?

yes, any 302 should work fine with the caveats Danforth posted above. I would gravitate towards a carbed engine for your application. 351W engines typically came with a 2bbl carb, but there are plenty of aftermarket 4bbl options out there that will work just as good for your application.

Chances of mistaking a Windsor for a Cleveland are slim in your location. The Clevelands only lived for a few years in North America, and I dont know if any made it to Britain, however the Aussies got them up until the mid 80's or 90's IIRC, so unless your supplier gets one from Down Under, you should be safe.

 

[Lpgc]

Thanks everyone for all the replies, I think that answers all my questions for now, much appreciated.

I have some other work to do over the next few days, when I get around to working on the boat again I'll post updates and probably ask a few more questions then.

A few pics...

Took the plugs out and belts off.



On the river Ouse just South of York



Just got the boat out of the water



Simon

 

[Horigan]

If you want more power and you have to swap the motor, I would seriously suggest swapping everything pulley to prop for a GM 5.7 and a mercruiser drive, or even a volvo drive (not the OMC drive you have).

Being a '96, a joint venture year, it's basically a Volvo SX-M drive.
When my EFI Ford 302 needs replacement, I'll have to investigate the GM route you suggest.