Hello guys: I bought a 1966 Riviera recently that had spent the last 15 years sitting in the New Mexico desert. The body is super clean, rust-wise, but the cranberry paint was scorched and the white bucket seat interior was covered by about an 1/2 inch of dust. Anyway I got it started and it doesn't smoke but it does knock; what sounds to me like a rod knock. After I returned to Houston I got to thinking and have some questions for those of you more familiar with these big beauties. Is it possible to remove the oil pan and change out the rod bearings without having to remove the engine? Did all 66 Rivieras come with a 425? Is the transmission a turbo 400? Did the transmission come from the factory with a switch pitch converter? Given that the '67 Rivs changed over to a 430, how difficult is it to put a 455 in the '66? Does anyone have a running 425 that I can buy? Any thoughts are appreciated. Thanks.
Hello ! Welcome to V8Buick.com:TU: Sorry I don't have the answers for you. I barely know where to put the gasoline. The is the place for your answers, though. The experts will be along shortly.
I am only going to offer my opinion on the engine. I say no to pulling the pan and swapping bearings. I have seen guys do it and get away with it but not very often. If a bearing has spun out of its seat then you obviously have a lubrication issue to start with. You will also find the rod/rod cap will be egg shaped and the journals will be damaged. The scoring alone will destroy the bearing surface upon start up and thats if it doesnt spin in its seat again. Same if its a main bearing. I have seen people drive them much longer with a main bearing problem but again it is a lubrication issue that is not going to fix itself and will in fact get worse quickly. To do it right you will have to reman the crank, replace the bad rod with cap, have it line bored and proceed from there. This will depend on availability of parts, your budget and the final outcome of what you want from the engine. I am sure guys on here will offer much better and more professional opinions and idea's than what i just did.
I would also look very closely at the pistons - all of them. If they're original, it's likely that one or more are cracked along the skirt. that could also be a cause of your noise.
Welcome to the board! Where around Houston are you? There are a few of us Buick folks around town and a few of us happen to be Nailhead owners. Im sure we can help get things diagnosed or point you in the right direction. But I would certainly advise against trying to shortcut the problem. The Nailheads are pretty bulletproof when done right, but they arent like a small block chevy that can be thrown together by just anyone and bandaided regularly. Do it once and do it right and it will last you a long time.
Thanks to all of you who responded to my posting. I live on the northwest side of Houston and was a member of the Houston Buick Club until it disbanded. My Riviera is in El Paso where I go frequently because my wife's family lives there. If anyone can point me to a thread where someone has converted a nailhead to a 455 set up in a '66 Riviera that would be appreciated because I have a complete running 455 with a turbo 400 sitting in my warehouse. From what little I know changing the radiator and getting or fabricating an oil pan are part of the roadblocks to converting them. The point is that I was hoping to not spend 4 or 5k rebuilding a nailhead which is why I was asking my cheese whiz questions on possible quick and dirty solutions.
Well unfortunately I don't anyone in El Paso that works on Nailheads. I know a couple shops in Houston that are supposed to be familiar, but they probably still need to be spoon fed a small amount just to be reminded they are not Chevy's. And I can't help in the conversion over to a 455. However, if you decide to pull the 425 out of the Riv and want to part with it let me know. Cause I or the Uncle could very likely take it off your hands. Good luck and let us know what you decide to do.
There was a fellow who used to frequent this site some years ago that removed the 430 from his '67 Riv. & installed a "Nail" into it just because he had it. I would imagine that it can't be that difficult as the '66 & '67 are somewhat the same. Just my thoughts.
Swap to a 430 or 455 is not as easy as it looks. For starters the motor mounts are completely different. Then you will need the brackets for the frame that the motor mount bolts go through. I believe they are welded on. A 67 driver side motor mount is a one year only part. Might be able to work around that when welding motor mount brackets onto frame. As you stated the radiators are different. Starter and fuel pump are on opposite sides when compared to the nailhead. A 67 to 70 Riviera oil pan and pickup tube will save you time and fabrication. Not impossible, but a lot of work. If I remember correctly the gentleman on this forum who swapped a 430 out and put a nailhead in had a complete car he was taking the nailhead and running gear out of. Good luck to you whatever you choose to do. Ken
Sounds like a lot less that 5k worth of easy fab work for that swap! I say go ahead with your 455 swap!
My first suggestion.... make sure the knock you hear is caused by a bad bearing and not loose converter bolts or cracked flexplate! They can sound very similar and one is much easier to repair than the other! Drain the oil and see if it looks like metallic paint.... a good sign the bearings are shot. The guy with the Nailhead in a '67 Riv went by the user name 'Nailhead in a '67" , name was Joe. Wonder what happened to him, hasn't posted in years.
Another good way to tell if your motor is failing is to tear the oil filter apart and check the folds of the filter for bearing material. I rear mine apart after every oil change.
You mentioned fabricating an oil pan. Easier to get the steering linkage from a 67-70 Riv then use a stock 430 pan or a 455 pan may be same. Also get a wiring harness from a 67-70. That will make it easier. You'll need little stuff like new head pipes for the exhaust, speedometer gear in the trans. There are many more small requirements as well as bigger ones mentioned above. Assuming you can do all the work yourself and have access to a 67-70 Riv parts car you can do it and it will be a cheaper. By the time you ad the nickels and dimes putting together all the needed components and then a factor that hasn't been mentioned is "if" you have to pay a shop to do some of the work I am skeptical that you'd be any further ahead doing this swap. If this was a simple swap we'd see many more nailhead to 430/455 swaps. In 35 years of playing with 66-67 Rivs and looking at thousands of cars on ebay as well as attending Riviera meets, 66s that had been converted are few and far between. I've seen maybe 4-5. On projects like this costs can swing low or high depending on ones mechanical skills, knowledge, access to parts, and time & place to perform the work. As mentioned, you need to fully access the source of knock problem before doing anything else especially if your goal is to get through this with as little cost as possible.
how long did you run the engine?a lifter can sound like a bearing knock,alot of ties they stick from sitting,sunds like you have given up to soon
with the engine running pull a plug wire off one at a time and see if the noise goes away on any one cylinder,if it does you have lower eng problems,if not its somthing not as serious
Thanks to all for the excellent information and advice. I will be back in El Paso in a few weeks and intend to thoroughly research the source of the knock which I found to be loose converter bolts in a 1987 WE4 I bought a few years ago. I'm still on the fence as to what direction to go because I like the looks of the nailhead and it is the original motor. I will make up my mind when I get the car started again on my next trip. I also intend to put the Riviera in gear the next time to see if the tranny is still good which for some reason I think it is. And I will take some photos of this desert survivor and post them as it is a virtually rust free body.
You beat me to it. If it's a high-mileage engine, I'd put more dough on it being a piston then I would a bearing. As to the engine, my CONSUMER GUIDE book on GM (1908-1986) lists the 340 hp 401 as the only engine available in the '66 Riv. I can't imagine GM hooking anything except a THM 400 to that torque monster. As to the converter being a switch pitch I honestly don't know. Update on the above - I don't believe that there ever was a factory 340 hp 401. I rechecked the book and I didn't misread it - I think the book is in error and it's a 425. The engine code should be MW stamped upside down right in front of the valley cover and easily visible. That's the engine that you see in my avatar being installed in my Chevy pickup.
All good stuff guys. I am really torn as to what to do. On my next trip to El Paso which will likely be in a couple of weeks, I am going to do a bunch more checking on this motor before I go any further.
