Knock in the '77

Ok so I have a knock in my 77 Trans Am - 400 4-barrell, and there is an knock internally. I know that a common problem with the 400 is the main bearings have a tendency to go bad, but before I pull the block and rip at all apart, any suggestions about what else it could be?

NOTE: If I replace the mains, I'm going to replace the crank and all of the other crank kit parts, not just the mains.

sweet car! welcome to af.. i dont know much (anything) about the 2nd gens..but theres a bunch of people who pretty much tore it down and built it back up..hope they catch this one.. good luck!

Ok so I have a knock in my 77 Trans Am - 400 4-barrell, and there is an knock internally. I know that a common problem with the 400 is the main bearings have a tendency to go bad, but before I pull the block and rip at all apart, any suggestions about what else it could be?

NOTE: If I replace the mains, I'm going to replace the crank and all of the other crank kit parts, not just the mains.


Welcome.

How many miles are on it?

How bad is it knocking?

ive seen many things other than mains causing a knock.Check the balancer and pully first. Then listen back at the flywheel and torque converter, as these can disguise themselvs as a internal engine noise. Of course you will need to put it up on a lift to do this very well. If you cant find the culprit, it very well could be the bottom end of the block. It also could be a piston wrist pin. If you go to all the trouble of replacing the bottom end, it would probably be a good idea to replace the pistons as well. Good luck and again, welcome to the forum.

Hotrod's got a alot of good ideas. My input is to pull the oil filter and drain the contents through a paper towel for any signs of metal debris.

There are 135,000 miles on it. The knock is not that bad, noticeable, but not bad. I didn't think to check the flywheel/converter. I'll have to listen for that. Thanks!

Also, I have a hardtop. Does anyone know of any company who can install t-tops? I know that i'll have to reenforce the roof to keep from blowing the back window out, but I have yet to find a company in MI that does them. Any ideas?

There are 135,000 miles on it. The knock is not that bad, noticeable, but not bad. I didn't think to check the flywheel/converter. I'll have to listen for that. Thanks!

Its a long shot, but its best to explore every option before going through a total rebuild.

Also, I have a hardtop. Does anyone know of any company who can install t-tops? I know that i'll have to reenforce the roof to keep from blowing the back window out, but I have yet to find a company in MI that does them. Any ideas?

If you had a parts car that would make it easier. A LOT easier. Doing the work yourself can save a bunch of cash IF you can use a welder and grinder. Its easier to put a top on a car than it is to build a block.

All you have to do is come up with a welder, a grinder, reciprocating saw and a sharpie. If your good you can make your cuts, weld your welds, and not have to paint anything major. Oh yeah a tool to cut the glass out too.. or a set of guitar strings.

There are 135,000 miles on it. The knock is not that bad, noticeable, but not bad. I didn't think to check the flywheel/converter. I'll have to listen for that. Thanks!

Its a long shot, but its best to explore every option before going through a total rebuild.

Also, I have a hardtop. Does anyone know of any company who can install t-tops? I know that i'll have to reenforce the roof to keep from blowing the back window out, but I have yet to find a company in MI that does them. Any ideas?

If you had a parts car that would make it easier. A LOT easier. Doing the work yourself can save a bunch of cash IF you can use a welder and grinder. Its easier to put a top on a car than it is to build a block.

All you have to do is come up with a welder, a grinder, reciprocating saw and a sharpie. If your good you can make your cuts, weld your welds, and not have to paint anything major. Oh yeah a tool to cut the glass out too.. or a set of guitar strings.