Hi, I’m new to Buick and the forum. We had to change the leaking fuel pump on the 1962 Wildcat. The new one is New Old Stock. The new one has a terrible sound, clank clank clank on start up. It seems to work ok just sounds awful on start up, for about 30 seconds. Then it is ok, sound wise. However, with the old fuel pump the engine ran fine, smooth, etc. With the new pump it runs terrible, shaking and stumbles. Is there a connection? Thoughts please. Thanks Chuck
Have you checked the fuel pressure? NOS parts, especially those with rubber parts, can fail right after installation. Seals can leak or diaphragms harden and tear.
Thanks, the fuel pump pressure and a compression check is on the agenda when we visit the Wildcat next. Chuck
What Mark said. I like original parts, but would not install a fuel pump that might be 40 (or more) years old on an engine that I was expecting to run. It would be perfect for a display engine, but unless it has been stored in a Nitrogen filled container in total darkness, I wouldn't consider it for a driver.
We did a compression test today. One bank is low, 120PSI and the other is 180PSI. However, #6 and #5 had no compression at all. After squirting oil in those cylinders it came up to 30# and 60# respectively. The NOS fuel pump failed also. What is the cost to overhaul a 401 Nailhead if someone else does it? I have done Small Block Chevy's and Corvairs, but don't think I'm up for this beast. Thanks, Chuck
Hi Chuck, by #5 and #6 are you talking about two cylinders side by side on the same bank? If so it could be a blown head gasket between the two cylinders. Nailhead cylinders are numbered on the passenger side 1,3,5,7 and on the driver side 2,4,6,8, starting from the front, opposite of a SBC.
Thanks. No they are on the opposite banks. #5 on the Passenger side, and #6 on the drivers side. These are the zero PSI. Chuck
How many miles are on the engine? The zero compression sounds like pistons or rings. If the engine is at or near 100,000 miles I'd be thinking a pair of cracked pistons. If you are prepared to pay a bit more then replacement cast pistons I would recommend a set of Tom Telesco's (telriv on this forum) forged aluminum pistons.
The odometer shows 24,000. I presume that is 124,000. The owner passed away and his wife doesn’t know. I always put forged pistons and Total Seal rings. Don’t think I’m up for this beast of an engine. Looking for someone who knows Buick Nailheads to do the rebuild. Any suggestions would be appreciated
Chuck, Tom did the 425 that you see being lowered into the Buchev in my avatar. It runs great and does have Tom's pistons in it. Tom said that these pistons raise the theoretical compression ratio to the actual compression ratio (10.25 or 10.5:1) The improvement in this engine's performance was amazing. It's not a street racer (4,300 lbs) but has the torque to rip the door off of a bank vault.
There are rebuild kits for the the oem acdelco fuel pumps. All the rubber components are replaced. Once you do that oem cant be beat in my opinion. Was going through one of the newer type about every 9000 miles. Got old real quick.
