Buick V 6 Delimma

[h34gunner]

I think my 3.8 Buick has a knock... at times it's muffled, some times not even noticeable and at times rather loud.. I was convinced it was simply spark knock or dirty gasoline.. I rebuilt the carb, rebuilt the distributor, set the timing every way possible.... the knock almost disappears when I retard the spark to almost 0 degrees, but alas, it's still some noise...
QUESTION: Rebuild this Buick 3.8 or go back original with 4 cylinder flathead? Are engines available? is the transmission and transfer case the same as Willys jeeps? Any help or advice would be very much appreciated. This is a 1951 Pickup in otherwise very good shape. :cheers:

 

[BrokeJeepNut]

There are some questions that may need answered before making that decision. Is the rest of the vehicle and drive train original? No sense trying to go back to original if nothing else is. Is it a daily driver? The additional power, reliability and parts availability of a more modern v-6 may be advantageous. Not totally following the transmission question. Is what transmission and transfer case same as Willys Jeeps? Me personally I would probably not go to the flat head 4-cylinder unless you really like flat heads. They can be found but not too common and you have fewer parts sources. Since your vehicle is already adapted to a six cylinder I would replace it with a more modern of the Buick you have. Just my two bits. Good luck!

BrokeJeepNut

 

[willys way]

Is your oil pressure good? Also make sure the drivetrain is not contacting the body or frame. That can make a sound at times similar to a knock, especially in an odd fire. I just got the complete drivetrain from a 71 Jeepster commando with the dauntless V6 yesterday. Idk anything about it till I get it in the shop and investigate and learn because I never had one before. I don't know if I'm gonna keep it or sell it because its been sitting for years.

 

[h34gunner]

Thanks, Eric
The pickup is totally stock except for the 1976 Buick Odd Fire 3.8. She shifts easily and smoothly and everything works. Very worth keeping. Not a daily driver at all.... cruise nights and landscape hauling short distances.... I just bought it for a work truck around the house but will be fixed up for cruise nights, etc. I enjoy driving her except for the knock.
The question about the Transmission and Transfer case was to determine if engines from other Willys could be easily adapted to my pick up. Still welcome advice and suggestions.

 

[silicond17]

The Buick V6 should have a different bellhousing than the original engine. Does it look like there's an adaptor on the bellhousing? Do you have the factory T-90 3 speed and Dana 18 transfer case? It may be easiest just to find another Buick V6 or have yours rebuilt. It could be an easy fix. Drop the oil pan, grab a hold of the rods and shake them and see if you've got a bad rod bearing. You could possibly replace those without pulling the motor and without machine work (if that's the knock).

The Buick V6 is a great motor. Not too large as to cause overheating problems in our small engine bay, but still generates plenty of power, and very reliable. I don't know about your area, but those flathead and F-head 134 4 cylinders are a dime a dozen around me, but chances are if you find one it'll probably need a rebuild itself.

 

[h34gunner]

ing and the The truck is very original except the engine... Yes, it has a small adapter between the bell housing and the T-90... I'm not really familiar with the conversion, but it looks like a very neat installation. Everything else is original and seems to work correctly. I'll pull the pan and change out the oil pump first and see if that helps any... and check for obvious rod wear while I'm in there. Thanks.

Does anyone at all recommend going back to the original Engine? Is that a bad idea?

 

[mikes47jeep]

ing and the The truck is very original except the engine... Yes, it has a small adapter between the bell housing and the T-90... I'm not really familiar with the conversion, but it looks like a very neat installation. Everything else is original and seems to work correctly. I'll pull the pan and change out the oil pump first and see if that helps any... and check for obvious rod wear while I'm in there. Thanks.

Does anyone at all recommend going back to the original Engine? Is that a bad idea?

well it all depends on what YOU want, if you love the truck as it is except for the knock, then i say rebuild the 6 and be done with it

if you want it more original you could go back to the 4 but you'll have less get up and go. also how have the motor mounts been changed?

as far as parts, for both engines there is nothing i haven't been able to get from NAPA within a day or 2 (cheat sheets for part numbers help alot)

my 59 pickup, had the buick v6 when i got it but it was very tired. i put a rebuilt original 226 flathead 6 in it didnt see much difference in power, a little lower top speed because the flatty redlines at a lower RPM but i like it

 

[dlj]

I would go back to stock! No real reason ,I just like them stock.

 

[martisan]

I think that engine has the oil pump on the timing cover, outside of the pan. They were somewhat noted for failing pumps, and maybe the timing cover had some of the wearing parts that went with it. Do some Google research as this MAY be correct information I am giving but I am no Buick expert.

 

[silicond17]

Does the knock go away after it warms up? Or always?

I'd go for getting that current motor fixed. I love the factory motors, but you're going to be looking at $$$ to get one rebuilt unless you can find a good running one. Your bellhousing adaptor was somewhat common, but being that it is the older Buick/Oldsmobile/Pontiac bolt pattern, it leaves your engine swap opportunities limited if you want to keep the same bellhousing/transmission/transfer case intact. The only thing that would really make sense to me would be the Buick V6.

Although, your bellhousing adaptor would also bolt up to an Oldsmobile Rocket 455 V8. Then you could drive around listening to that 90s country song "455 Rocket" and be the coolest kid on the street. Seriously though, I don't think our poor little T-90 would appreciate all that additional horsepower from the Rocket 455.