Reasonable price for a Penta AQ151C?

The B230F in my '85 is getting pretty tired. In the interest of having enough time to fiddle with the engine/not having to drive the motorcycle for a few weeks in the middle of winter, I'm tossing around picking up a second engine. I popped on to craigslist, and lo and behold, there's someone selling an AQ151C on there. Hmmmmm.....

He's a little hazy on the details, but he claims it is out of a freshwater only boat with a freshwater cooling system. It comes with all the accessories (alternator, starter, ignition, etc), although I expect a lot of it will be trash (boats and electronics don't get along well in my experience).

He's asking $900.

Does that seem reasonable, assuming it is in decent internal shape? I wouldn't pay that for a normal red block, but the C and D models are pretty sweet motors. You don't see them pop up for sale that often, so I honestly have no idea what they're going for. Forged 2.5L stroker crank, forged connecting rods, the larger bearings from the later model motors, pretty much direct bolt up AFAIK... pretty damn tempting. What do you think? Should I go balls deep?

Looking strictly at the fact that it's a 2.5l, I'd say yeah. I don't know much about penta motors, but I know a stroker crank shaft for our beloved red blocks floats around 1700, then pistons and rods.

Do it!

Hmm, that's kinda what I was thinking too...

FYI, the Penta AQ151C is a B230 block with a beefed up bottom end, a crap exhaust system, carbs and maaaaaaybe the 531 head (here's hoping). It was rated at something like 150hp NA, which ain't bad. I'll probably use this to finally do that supercharger project I've been masticating for forever.

Boat engines ALWAYS wear faster than car engines. Well, CAR engines that have been adapted to be BOAT engines that is....

For $900, you can find PLENTY in the PacNW. When I was there, I saw more RWD Volvo's on the road than I have seen anywhere else in America. Just opinion blended with possible facts!

Have you seen this particular engine model for sale though? I'm honestly expecting to rebuild it, so some wear and tear is fine (within reason). I know I can get red blocks all day long for a few hundred bucks, but the 2.5L is pretty rare as far as I know.

The crank alone is worth a good chunk of the $900 he's asking if you're trying to justify the cost, I think someone on here was selling rear thrust penta cranks for $650 a few months back.
You're correct, the c/d penta rods/pistons/crank is a direct swap to the later b230 blocks.

Maxdabreaker said:

Looking strictly at the fact that it's a 2.5l, I'd say yeah. I don't know much about penta motors, but I know a stroker crank shaft for our beloved red blocks floats around 1700, then pistons and rods.

Do it!

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And I know that in terms of dollars spent for returns in laughs, cc, performances whenever the price exceeds $50-60 for a Penta crank, its too much.

Excpt to lil chillins who know nothing who can then in vain hope to impress too-hip friends by saying
"Oh by the way, I got a stoker crank in my ratty ol Volvo. How ironic is that, brah?"
that's its main value

Penta cranks follow the cars for rear (and more importantly) 360? thrust..~1988+ for that. Not of great importance in an automatic car if you have one of those.

You'd have a lower static compression motor than the original.

I'd expect really not all that much difference from .2L of (likely) half worn out boat motor.

Kjets On a Plane said:

Penta cranks follow the cars for rear (and more importantly) 360? thrust..~1988+ for that. Not of great importance in an automatic car if you have one of those.

You'd have a lower static compression motor than the original.

I'd expect really not all that much difference from .2L of (likely) half worn out boat motor.

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Actually its about 151cc or less than a 7% increase of volume..Seems a increase in boost or compression--both which cost a lot less---would yield more than 151cc of mildness.

I've been eyeing that same motor now for a while, if it was in peetown I'd a bought it already. If he keeps dropping the price I might drive up near sleezattle and get it.

I like a nice steel stroker crankshaft that is already balanced by volvo to perfection myself, totally worth it. The extra stroking is nice when you need it.

<iframe width="420" height="315" src="https://www.youtube.com/embed/XCTSP1UQnzw" frameborder="0" allowfullscreen></iframe>

THis one in this video is in my 16v turbo motor. It came from a boat with 150 hours on it. It just needed some polishing on the journals and stock sized bearings.

Speed is just a question of money. How much money you wanna blow on your motor that blows? All of it I say, every last penny.

If I bought it, I'd probably ditch the 531 head and go with a turbo 530 head. I could sell the 531 with the V cam for 400-500 possibly if it was in good shape. No way to tell until you take it off. If I wanted a 531 on my car, I'd get one from Europe that was in a car without that steel sleeve they put in the boat 531's in number 4.

I paid 1500 for the AQ171c boat motor that I'm putting in my 242. Got it on ebay out of san fran and it came with the SP290 outdrive, sold that and all the boat carbs and stuff. Also it had zero hours on it, brand new. Only broke in by volvo before they put it in the boat.

Paid 600 locally for aq171c with 150 total hours on it.

sbabbs said:

The extra stroking is nice when you need it.

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For what "need"?
What happens if you don't have the extra 151cc when you "need" it?

Do they come and re-po the house?

Drag the kids off to Gulag camp in Kolyma?

Hmm. I went and looked at it. It started right up, surprisingly with no audible piston slap, and the compression was a solid 160 psi in all 4 cylinders. Overall it looks like it's in pretty good shape. That's the good part.

What concerns me is that it has a 530 head. I'm not positive, but I was under the impression these all had 531 heads from the factory. If that's true, someone has replaced the head, probably with one out of a car. It does have a freshwater coolant system, but the coolant was pretty rusty and nasty looking. My concern is that someone blew up the original had and replaced it with a cheapo car head.

I'm torn. On the one hand, it runs great even with a set of no doubt very poorly adjusted carbs, it has no slap and it has excellent compression. On the other hand, it doesn't have the more desirable 531 head (which may or may not be original), it has a grimy coolant jacket and I don't know how many hours are on it (the instrument cluster is missing on the boat). So, what would you guys do in my situation? And by "you guys," I of course mean everyone other than John.

I told him I'd sleep on it, and I honestly don't see it moving anytime soon. There soonest I'd be able to get down there is next weekend anyway, so I have a little bit of time to make up my mind.

Fjergus said:

Hmm. I went and looked at it. It started right up, surprisingly with no audible piston slap, and the compression was a solid 160 psi in all 4 cylinders. Overall it looks like it's in pretty good shape. That's the good part.

What concerns me is that it has a 530 head. I'm not positive, but I was under the impression these all had 531 heads from the factory. If that's true, someone has replaced the head, probably with one out of a car. It does have a freshwater coolant system, but the coolant was pretty rusty and nasty looking. My concern is that someone blew up the original had and replaced it with a cheapo car head.

I'm torn. On the one hand, it runs great even with a set of no doubt very poorly adjusted carbs, it has no slap and it has excellent compression. On the other hand, it doesn't have the more desirable 531 head (which may or may not be original), it has a grimy coolant jacket and I don't know how many hours are on it (the instrument cluster is missing on the boat). So, what would you guys do in my situation? And by "you guys," I of course mean everyone other than John.

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Don't like honest no bullsh!t advice, eh?
530 vs 531..
Gonna win the big race?
Gonna impress the ladies?

Why do you pretend it makes a whit of difference to you or anybody else?

You have a worn out tired motor--you need a fresh motor..and you ask these silly pointless questions about crap that is not 1% or 2% difference to you one way or another..
Fantasy fapping...

Are you going to pair this $900 crank with a "warm" cam?

160psi compression, especially if it has a car head on it with the car total emissions cam, is fairly lousy. *assuming fairly accurate compression gauge (not much to go wrong with even cheapo ones) and fairly healthy battery/starter combo. Should knock up to ~200something to high 180s withing 5-10psi of max in like 2-3 hits on a tight motor give or take a little on a B230F. If it has an automotive head and emissions cam, I'd expect something like that.

Was pretty common practice to stick a car head on them on the average nasty corroded out boats that sit sagging stern end down in the water for years on end. We did that all the time. Most boat guys just wanted them to run *at all.* If they had any money I'd shim the boat cam back in it. Otherwise, they were lucky they were getting fresh fluids and a basic "check" (slightly more than the sharpie on the air cleaner, but not much...just want to address it coming back to bite you as much as possible on a thin dime).

If I really wanted a 531 I'd probably get one from Europe as Sbabbs says to avoid some nasty iron ring corroded out junk that you will find in 9+/10 boats.

Really, boats are great if you get a nasty rusty mess but inside usually the crank is still good if you just have to have it.

Sounds to me like you just need a plug n play viable B230F? It's 1000 dollars time/trouble/effort to change a motor and another 2-300 in gaskets/seals/fluids whatever blah. Whether your motor comes in a smashed low mile parts car or best you can find on half off roll of the dice PNP special, I think on your budget, that's more realistic. Or take another pull at the slot machine and try another car to roach down factoring in the above? IDK.

In stock form, the 8V boat motor, other than having a slightly better cam (I think I've seen V, K and H in the higher HP boat motors as the "marine cam"), doesn't really seem like it'd make any more power with the stroker crank, but less compression. I wouldn't worry about it or fixate on it.

Kinda same with the 16V version...more cam, little lower static compression (carbed and runs basically wide upen or 1/2 throttle + constant higher RPMs). I suspect the additional power in the 16V version (171 or whatever instead of 153 quoted B234F) is basically entirely cams/no emissions junk.

If you are building one and insist on the stroker crank and setting up any rod piston combo you want, I guess go ahead?

Or you somehow found a boat in amazing shape/no hours sbabbs style with the 16V head and everything...

Why want a 2.5 anyway... It'll fall apart anyway

No John, the reason I don't want your opinion is that you invariably answer a question no one asked. Frankly, I just don't feel like getting into a pissing match with you again. I asked what a reasonable price for a AQ151C engine was. You responded with "AQ151 engines are stupid and so are you," and I suspect you were moments away from launching into a barely coherent sales pitch about drop forged dilithium crystal moon-rock composite cranks from an Indo-Chinese domestic market Volvo tuk-tuk that are WAAAAAY better than a stupid Penta. If you want to answer the question, feel free to stick around. If you're just going to be abusive and obnoxious, feel free to go piss up a rope instead.

@Fly-Half, it's $800 for an entire running engine (including marine intake, carbs, exhaust, water coolant system, and electrical system, which I would resell), not just the crank. To answer your question, possibly. It depends on which cam it has (the owner won't let me pull the valve cover, understandably), but I would probably swap my K cam over if it has an M. So yes, I would probably put a "warm" cam in it. That said, the engine was rated at ~150hp with carbs and an extremely restrictive marine exhaust system, so I imagine a properly functioning fuel injection system and even a stock automotive exhaust manifold would bump that into the 160 range without too much dicking around.

Bear in mind the reason I am interested in the AQ151 engine isn't the power it puts out stock, but the potential for expansion it offers. The C model has the later style large main bearings and a forged crank, rods and pistons. It might not make that much power right off the bat (although it's a roughly 35% increase over a stock B230F), but it is arguably the most durable redblock bottom end available.

My question isn't "will this make me the coolest kid around" or "will I be able to finally beat that kid in the Evo IX who lives down the block." All I'm asking is whether this is a reasonable price or not.

That sounds lovely but going through the trouble of getting the "arguably the most durable redblock ever made". Are you going to build a top end to live up to the "arguably the most durable redblock ever made"?

Considering the "potential for expansion it offers" a "warm" cam doesn't come off as a good start but again I'm sure there is a method to your madness. If you get this thing then I'll get my popcorn ready. I'm curious to see what you will do with it.

Fjergus said:

The B230F in my '85 is getting pretty tired. In the interest of having enough time to fiddle with the engine/not having to drive the motorcycle for a few weeks in the middle of winter, I'm tossing around picking up a second engine. I popped on to craigslist, and lo and behold, there's someone selling an AQ151C on there. Hmmmmm.....

He's a little hazy on the details, but he claims it is out of a freshwater only boat with a freshwater cooling system. It comes with all the accessories (alternator, starter, ignition, etc), although I expect a lot of it will be trash (boats and electronics don't get along well in my experience).

He's asking $900.

Does that seem reasonable, assuming it is in decent internal shape? I wouldn't pay that for a normal red block, but the C and D models are pretty sweet motors. You don't see them pop up for sale that often, so I honestly have no idea what they're going for. Forged 2.5L stroker crank, forged connecting rods, the larger bearings from the later model motors, pretty much direct bolt up AFAIK... pretty damn tempting. What do you think? Should I go balls deep?

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does seem a bit high considering it as is where is. It he has had it for a while you might offer texas tens and get it a little cheaper. If not take a few tools and inspect it before paying. that way you know what you are getting. 10-15 minutes to pull the pan and look at the inside.