Penta 2.5L B21ft?

swedishK · 07-11-2018, 12:26 PM

I might have a line on a cheap aq151 possibly two, and was wondering if I’d run into any issues swapping the 2.5 block into my turbo kjet wagon. I’ve seen b230 heads on 2.1 blocks, so I’m assuming they’d go the other way as well? Will a mildly modified turbo kjet fuel system be adequate to keep up with 400 extra CCs? The motors have been sitting outside on a pallet for a bit, and will probably need a full rebuild. Is the extra displacement worth the effort?

Now I’m unsure if they’re actually 2.5 blocks. One has a 531 head and the other has what appears to be a 405. Both single carb. I did not see any AQ designation on the ID tag by the starter, however both tags start with the prefix 250A.

dl242gt · 07-11-2018, 05:24 PM

Single carb penta will have the A cam. The AQ151 is the 16V penta. You are looking at two types probably a pre B230 block one with the 405 head and a B230 based one with the 531 head. I think they may have also called them AQ130 or AQ131.

You may have to drill some holes for a sensor or two. But the block and head would work for a buildup. Or you could use the heads if they aren't engines with the longer crank throw. Make sure you check that number four exhaust port. My penta sourced 531 needed a good bit of welding to repair it from corrosion.

77volvo245 · 07-11-2018, 05:52 PM

aq250 are b230 blocks and are 8v 2.5l
aq251 are b230 blocks with 16v heads

they started numbering aq250 after 92 i think

swedishK · 07-11-2018, 09:02 PM

so if i can get one for $100 i should go for it eh?

dl242gt · 07-11-2018, 11:52 PM

That's a very fair price just for parts. Have fun with it.

apachechef · 07-12-2018, 12:42 AM

Quote:

Originally Posted by dl242gt

The AQ151 is the 16V penta.

AQ171?

mark244turbo · 07-12-2018, 12:57 AM

Buy it before someone else does!

Jack · 07-12-2018, 01:41 AM

Quote:

Originally Posted by mark244turbo

Buy it before someone else does!

You buy that **** when you see it

122power · 07-12-2018, 02:21 AM

Quote:

Originally Posted by dl242gt

That's a very fair price just for parts. Have fun with it.

Fair? Thats a steal at that price.

swedishK · 07-12-2018, 02:36 AM

picking up two 250a motors on friday. $100 a piece. will update on condition when i can dig into them.

John242Ti · 07-12-2018, 03:26 AM

Quote:

Originally Posted by dl242gt

Single carb penta will have the A cam. The AQ151 is the 16V penta. You are looking at two types probably a pre B230 block one with the 405 head and a B230 based one with the 531 head. I think they may have also called them AQ130 or AQ131.

You may have to drill some holes for a sensor or two. But the block and head would work for a buildup. Or you could use the heads if they aren't engines with the longer crank throw. Make sure you check that number four exhaust port. My penta sourced 531 needed a good bit of welding to repair it from corrosion.

AQ151 is the 8 valve 2.5 liter stroker engine, essentially an early 250A. The AQ171 is the 16 valve 2.5 liter stroker, which became the 251A. In the early years, the number was the horsepower the engine provided. Case in point, the AQ255 V8 engine was not a 4.2 liter V8, but a Chevy 350 smallblock.

swedishK · 07-13-2018, 06:41 PM

Any helpful tips for working with a probably saltwater motor that’s been sitting outside on a pallet for a while?

sbabbs · 07-13-2018, 08:48 PM

Drop it in a big cattle watering tank that is full of oil and let it soak for a week. Or just spray WD all over and in it every day for a few weeks.

Harry Tuttle · 07-13-2018, 10:02 PM

Quote:

Originally Posted by sbabbs

Drop it in a big cattle watering tank that is full of oil

Marvel Mystery Oil! You might be able to get 10 or 20 gal of it without maxing out your credit card...

sbabbs · 07-14-2018, 01:09 PM

Probably the most valuable part on those is the crankshaft, they would both be rear thrust and forged steel and stroking on the shaft rods are stock, pistons have shorter crown for longer stroke. Should be able to get the crank out easily enough. Hard parts can be the boat exhaust manifold, but even if you break the bolts, still will come off. Basically you need to get the head off if you wanna put the short block in your car. All the boat motors I've ever had where like new inside, real clean. I've never seen a volvo penta redblock boat motor that had salt water running through it. They use a closed coolant system with a heat exchanger. The salt water would run through the exhaust manifold. That is the hardest part to take off, but if you don't need head, you can take off the head with the manifold still attached and just toss it. Cam should be a V cam, but all 250's I've seen had dual carbs and you said these only had single carbs, might be A cam then.

77volvo245 · 07-18-2018, 09:02 PM

Quote:

Originally Posted by John242Ti

AQ151 is the 8 valve 2.5 liter stroker engine, essentially an early 250A. The AQ171 is the 16 valve 2.5 liter stroker, which became the 251A. In the early years, the number was the horsepower the engine provided. Case in point, the AQ255 V8 engine was not a 4.2 liter V8, but a Chevy 350 smallblock.

250c and 251c are all late rear thrust engines

Lord_Athlon · 07-19-2018, 12:14 PM

Just send it

07-11-2018, 05:52 PM	#3
77volvo245 Board Member Join Date: Apr 2007 Location: Portland Oregon	aq250 are b230 blocks and are 8v 2.5l aq251 are b230 blocks with 16v heads they started numbering aq250 after 92 i think __________________ STSmachining

07-12-2018, 12:57 AM	#7
mark244turbo Board Member Join Date: Sep 2010 Location: Netherlands	Buy it before someone else does! __________________ 1994 960 B204FT, full options, leather interior. 1991 745 B204GT (Swede Sixteen VT) M90 conversion. 1986 745 B230FT, 302mm V70 brakes, camber mod. (sold) 1983 244 turbo B21FT/AW71 - leather /airconditioning 1987 244 GLT - Polaris, Strutbar, viking motorsport lower chassis brace, k-cam, gaz strut/shocks, pu-bushings

07-13-2018, 08:48 PM	#13
sbabbs Board Member Join Date: Dec 2006 Location: Rushing Lane, Scappoose, OR	Drop it in a big cattle watering tank that is full of oil and let it soak for a week. Or just spray WD all over and in it every day for a few weeks. __________________ 1988 245 White slicktop M47 Wagon! 2.5L NA 8v going in. 1990 745 B230FT Getrag JohnV flywheel 240mm clutch 13c A-cam 3.54 G80 548K MILES 1991 740SE B230FT NPR Strut braces IPD bar A cam 550cc EV14's. 3.73 G80 M90 to put in.

07-19-2018, 12:14 PM	#17
Lord_Athlon Just damn Join Date: May 2003 Location: Real world	Just send it __________________ 84 242 turbo msII My build https://forums.tbforums.com/showthread.php?t=8675309

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07-11-2018, 05:24 PM	#2
dl242gt Can play the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	Single carb penta will have the A cam. The AQ151 is the 16V penta. You are looking at two types probably a pre B230 block one with the 405 head and a B230 based one with the 531 head. I think they may have also called them AQ130 or AQ131. You may have to drill some holes for a sensor or two. But the block and head would work for a buildup. Or you could use the heads if they aren't engines with the longer crank throw. Make sure you check that number four exhaust port. My penta sourced 531 needed a good bit of welding to repair it from corrosion.

07-11-2018, 09:02 PM	#4
swedishK Design by Beefsma Join Date: Sep 2008 Location: Soldotna, Alaska	so if i can get one for $100 i should go for it eh?

07-11-2018, 11:52 PM	#5
dl242gt Can play the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	That's a very fair price just for parts. Have fun with it.

07-12-2018, 02:36 AM	#10
swedishK Design by Beefsma Join Date: Sep 2008 Location: Soldotna, Alaska	picking up two 250a motors on friday. $100 a piece. will update on condition when i can dig into them.

07-13-2018, 06:41 PM	#12
swedishK Design by Beefsma Join Date: Sep 2008 Location: Soldotna, Alaska	Any helpful tips for working with a probably saltwater motor that’s been sitting outside on a pallet for a while?

07-14-2018, 01:09 PM	#15
sbabbs Board Member Join Date: Dec 2006 Location: Rushing Lane, Scappoose, OR	Probably the most valuable part on those is the crankshaft, they would both be rear thrust and forged steel and stroking on the shaft rods are stock, pistons have shorter crown for longer stroke. Should be able to get the crank out easily enough. Hard parts can be the boat exhaust manifold, but even if you break the bolts, still will come off. Basically you need to get the head off if you wanna put the short block in your car. All the boat motors I've ever had where like new inside, real clean. I've never seen a volvo penta redblock boat motor that had salt water running through it. They use a closed coolant system with a heat exchanger. The salt water would run through the exhaust manifold. That is the hardest part to take off, but if you don't need head, you can take off the head with the manifold still attached and just toss it. Cam should be a V cam, but all 250's I've seen had dual carbs and you said these only had single carbs, might be A cam then.