1987 Buick Somerset 3.0L Engine - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Blu Ray · 04-05-2021, 09:38 AM

**Question** I just scored this low mileage(63K) 1987 Somerset with the GM 3.0L LN7 - 181 cu in - It has a NASTY knock - Would you Rebuild or Replace?
IF I do replace - Can I drop in a LG7 GM 3.0L V6 which was the replacement for the LN7 in 1989
Any sites or yards that would have either of the motors from that time

95 imp · 04-05-2021, 12:23 PM

Just guessing, probably not.

The biggest thing to check is if the TA is the same. They might of beefed up the newer TA to match the TQ output of the new motor.

Boost Creep · 04-10-2021, 09:49 AM

Wow!

Rebuild might prove difficult if parts like a crankshaft or connecting rods are needed due to spun bearings. This engine was not as common as say the 3.8 where support would be more robust.
Not sure if swapping in the newer engine would be possible without enough research. Things like crank reluctor tooth count, cam sensor design change, other things GM may have updated or modernized/changed might put some hurdles in the way.

Finding a used engine might also be an issue as cars like this aren't that common in this part of the country anymore due to rust. Might have to look down south or out west where cars last longer.

Good luck, I started out working on these cars when they were new, surprised the fluorescent display still works as good as it does.

BuddyLee · 04-10-2021, 10:02 AM

I don't know about the engine but I see that they used the same steering wheel as they did in the GN. Also the dash appears to be the same. This is a front wheel drive configuration? Also, does the odometer tap out at 100K and then reset to zero as they do with the Regals? Which is why there are so many under 100K GNs for sale being offered. Most,I would suspect, are above 100K or even in the 200K range with no way to prove it other wise.

Blu Ray · 10-11-2021, 12:16 PM

Sorry for the delayed reply - here she is with a few updates and a new Engine

Blu Ray · 10-11-2021, 01:18 PM

Sorry for the delayed reply - here she is with a few updates and a new Engine

04-05-2021, 09:38 AM	#1
Blu Ray ALWAYS-N-BOOST Drives: 2021 ZLE A10 Join Date: Dec 2011 Location: Alpine, NJ Posts: 2,376	1987 Buick Somerset 3.0L Engine Question I just scored this low mileage(63K) 1987 Somerset with the GM 3.0L LN7 - 181 cu in - It has a NASTY knock - Would you Rebuild or Replace? IF I do replace - Can I drop in a LG7 GM 3.0L V6 which was the replacement for the LN7 in 1989 Any sites or yards that would have either of the motors from that time Attached Images __________________ 2012 1LS M6 Black-Sold 2013 2LT M6 BluRay- Sold 2015 1SS 1LE M6 Black-Sold 2021 ZLE A10 Riverside Blue - Awaiting Arrival 01/10

04-05-2021, 12:23 PM	#2
95 imp Dumb Ass Deluxe Drives: A Tricked Out Mountain Bike Join Date: Jun 2019 Location: Arizona Posts: 1,959	Just guessing, probably not. The biggest thing to check is if the TA is the same. They might of beefed up the newer TA to match the TQ output of the new motor. __________________

04-10-2021, 09:49 AM	#3
Boost Creep Drives: '18 1SS 1LE Join Date: Sep 2017 Location: Pennsyltucky Posts: 2,571	Wow! Rebuild might prove difficult if parts like a crankshaft or connecting rods are needed due to spun bearings. This engine was not as common as say the 3.8 where support would be more robust. Not sure if swapping in the newer engine would be possible without enough research. Things like crank reluctor tooth count, cam sensor design change, other things GM may have updated or modernized/changed might put some hurdles in the way. Finding a used engine might also be an issue as cars like this aren't that common in this part of the country anymore due to rust. Might have to look down south or out west where cars last longer. Good luck, I started out working on these cars when they were new, surprised the fluorescent display still works as good as it does. __________________ '18 1SS *1LE* Black, PDR

10-11-2021, 12:16 PM	#5
Blu Ray ALWAYS-N-BOOST Drives: 2021 ZLE A10 Join Date: Dec 2011 Location: Alpine, NJ Posts: 2,376	Sorry for the delayed reply - here she is with a few updates and a new Engine Attached Images __________________ 2012 1LS M6 Black-Sold 2013 2LT M6 BluRay- Sold 2015 1SS 1LE M6 Black-Sold 2021 ZLE A10 Riverside Blue - Awaiting Arrival 01/10

10-11-2021, 01:18 PM	#6
Blu Ray ALWAYS-N-BOOST Drives: 2021 ZLE A10 Join Date: Dec 2011 Location: Alpine, NJ Posts: 2,376	Sorry for the delayed reply - here she is with a few updates and a new Engine __________________ 2012 1LS M6 Black-Sold 2013 2LT M6 BluRay- Sold 2015 1SS 1LE M6 Black-Sold 2021 ZLE A10 Riverside Blue - Awaiting Arrival 01/10

04-10-2021, 10:02 AM	#4
BuddyLee Drives: 2013 Camaro 2SS/RS Join Date: Aug 2020 Location: Pacific Northwest Posts: 802	I don't know about the engine but I see that they used the same steering wheel as they did in the GN. Also the dash appears to be the same. This is a front wheel drive configuration? Also, does the odometer tap out at 100K and then reset to zero as they do with the Regals? Which is why there are so many under 100K GNs for sale being offered. Most,I would suspect, are above 100K or even in the 200K range with no way to prove it other wise.