Mercruiser engine I.D.

[marada1]

Hoping someone can help me identify a merc engine. I am considering buying a 350 mercruiser engine to replace my current 4.3L and I'm trying to confirm that it is a roller cam engine. The serial number is OK281645. It has a two barrel carb. All online parts lists I can find indicate that it could be a roller or flat tappet engine. Is there a way to confirm? The seller is telling me it's a roller because he says "all Vortecs are rollers." This may be true but I was thinking all Vortec engines were fuel injected. Like I said this is a carb engine.
Thanks in advance for any input.

 

[Don S]

Re: Mercruiser engine I.D.

It's a 97 model engine. It should have roller lifters, but you can verify by checking the GM code numbers against this service bulletin.

http://www-alt.mercurymarine.com/mnetdata/Service/Cruiser/Bullet/02/02_08.pdf

 

[John_S]

Re: Mercruiser engine I.D.

MERCRUISER (TB5, W/PS, TWOPCEX, WORO)
Serial Number: 0K281645 Model Number: 457B110KT

I'd verify that it does have vortec heads. A quick look-up (see above) does not indicate it is gen+. Ususually, but not always, it comes up in the description. According to a 1997 Merc manual, the gen+ (vortec) was not offered w/2brl. It was in '98, though. Now, you might have an early '98, or someone installed vortec heads. I think you will find the block id that Don provided will indicate it has a roller cam, but having vortec heads or not, makes a much bigger difference.

PS; Confirm what heads it has by counting the intake manifold mounting bolts. 8 (4 per side) = vortec, 12 (6 per side) = non-vortec.

 

[marada1]

Re: Mercruiser engine I.D.

Thanks Don and John!! Great help!
John, please decode all of this-MERCRUISER (TB5, W/PS, TWOPCEX, WORO)
Serial Number: 0K281645 Model Number: 457B110KT.
I guess you have a source for serial number info.

Also are the codes in the bulletin Don sent Merc specific? Here's why I ask. I checked the code on my OMC 4.3 and found that its "KC". It is a roller cam engine but didn't seem to match the bulletin. Just curious.

Thanks again

 

[Don S]

Re: Mercruiser engine I.D.

If you go to Mercs parts express http://www.mercurypartsexpress.com/PartsExpress/ProductSelection/ServiceParts/sphome.asp?CID=
and type in your SN, you will get all that info. Some of it I understand, the TB5 is the Tunderbolt V ignition, and you have Power Steering. Not sure about the rest

I can only assume the GM codes are for Mercruiser engines only, since Merc orders specific engine setups different from when OMC existed and they are different from the Volvo engines.

 

[John_S]

Re: Mercruiser engine I.D.

The info was from: http://www.mercurypartsexpress.com/PartsExpress/ProductSelection/ServiceParts/sphome.asp?CID=

Count the bolts. Its the easiest, sure fire way to know if they are vortec.

The reason I think it is a roller, is because my Sept '96 built 5.7L 2brl non-vortec has a serial number of 0K017089, which is quite aways from yours. All '97 5.7Ls were suppose to have roller cams.

According to the above website, the cylinder head part number is 938-9718. That is the merc part number for a non-vortec head. Vortec number should be 938-803860T.

The heads are more important than which cam it has. The difference is 210HP vs 250HP.

 

[GiMLit]

Re: Mercruiser engine I.D.

Thanks Don and John!! Great help!
John, please decode all of this-MERCRUISER (TB5, W/PS, TWOPCEX, WORO)
Serial Number: 0K281645 Model Number: 457B110KT.
I guess you have a source for serial number info.

Also are the codes in the bulletin Don sent Merc specific? Here's why I ask. I checked the code on my OMC 4.3 and found that its "KC". It is a roller cam engine but didn't seem to match the bulletin. Just curious.

Thanks again

marada you have a PM

 

[marada1]

Re: Mercruiser engine I.D.

Okay

 

[marada1]

Re: Mercruiser engine I.D.

So John, are you saying your 5.7 is a roller?
I've asked the seller for the code. I'll let you guys know

 

[John_S]

Re: Mercruiser engine I.D.

I am saying it is "highly likely" it is a roller cam.

According to the serial number, it is not a vortec head engine. That is more important to you than the cam, IMO. And easier to verify.

 

[marada1]

Re: Mercruiser engine I.D.

Yeah John I agree that there is more bang for the buck with the Vortecs. I'm just trying nail down the specifics of this engine before I make an offer on it. I do prefer a roller engine and it would be worth a little more to me than a non-roller. The motor is out of state so it's not where I can look at these things myself. I've requested the info from the seller and waiting on his reply.
My question to you was whether or not your engine is a roller. You never really said when you compared the model numbers although that is what I think you were implying.
Thanks

 

[John_S]

Re: Mercruiser engine I.D.

My Sept '96 mfg 5.7L 2brl, did not have a roller cam. I installed the merc roller cam, this spring, when I upgraded to vortec heads. From a Merc '97 brochure, they advertise that all their SBs have roller cams (that year). BTW, I only went roller, because an iBoats member made me a very good offer on a lightly used complete set (cam, lifters, pushrods, spyder, timing set, cam retainer). It does not provide a hp improvement over the flat based. It does, provide less cam lobe wear.

The least obtrusive method to confirm a roller cam, outside of relying on block numbers, would be remove a valve cover, and loosen one rocker arm, and remove/measure the pushrod. The roller cam engine has shorter pushrods (you would have to look-up what the lengths are). With the valve cover off, I'd also get the casting number on the heads, to confirm that they are 350 heads.

What size boat do you have?

 

[marada1]

Re: Mercruiser engine I.D.

The boat is a 1991 18ft Marada.

 

[John_S]

Re: Mercruiser engine I.D.

A 4.3L vortec w/4brl, will get you about the same prop shaft hp as the 5.7L 2brl non-vortec. ie your wot top speed will be very close. The 5.7L would put you on plane quicker, but the 4.3 vortec is not a slouch in an 18' boat. The 5.7L will weigh the stern down more, and would probably be a more costly conversion. Just something to consider, if you haven't. Good luck on your project.

 

[marada1]

Re: Mercruiser engine I.D.

Yeah I am considering that too. I actually have a set of 4.3 Vortec heads. They are automotive. I've read some debates on auto / vs marine heads. What do you know about that. Are they different?

 

[John_S]

Re: Mercruiser engine I.D.

I have done very little research on 4.3L engines. If there isn't a difference between vortec car and truck heads, I'd say they are ok for marine. At least thats how it is with the sbc.