AMC machining, special needs?

[skid2964]

I have pulled the engine(401), will take everything to machine shop this week. What "special needs" does an AMC engine require from a machinist point of view? concerning block and rotating assembly, heads, etc.

[FSJ Thing]

Nothing special for an AMC. Same as all the others. So far on my 401, I had it baked and jetwashed, had all the connecting rods matched, I had the crank turned .010 on main and connrod journals, bored cylinders over .060, and had new cam bearings pressed in. This week he'll be balancing the rotating mass. The only unique thing I did was have him mill down 390 pistons for higher compression. My heads arn't in need of a rebuild be I figure that if I'm rebuilding the rest of the motor, I aught to have those baked and have new valve guides put in it and if I'm doing all that, I might as well have him grind the valves and seats too. As far as machine shop work, that's all I can think of right now. The rest is stuff you'd do yourself.

[Elliott]

Do the vally pan oil line mod, balance the internals and you'll be happy.

[TexasJ10]

I think I would be careful boring .060. I have heard of a lot of over heating problems on the 401 when it is bored that much. I know you can get pistons for that much over bore, but I thought the factory recomendation was to stay under .040.

[skid2964]

Originally posted by TexasJ10:
I think I would be careful boring .060. I have heard of a lot of over heating problems on the 401 when it is bored that much. I know you can get pistons for that much over bore, but I thought the factory recomendation was to stay under .040.Well, My engine has been bored .040 already, so I guess I will have to find another block. Not sure I want to spend $600 to have it sleeved.

[Al Johnson]

I've heard of those problems with large overbores on 401s also. I've heard as many stories of successful .040 and .060 overbores. Maybe your machine shop can sonic check the cylinder wall thickness to determine whether it can go that big.

[ March 09, 2004, 07:40 AM: Message edited by: Al Johnson ]

[FSJ Thing]

Yes, I originally wanted to go 40 over, until I measured and found out that I was 40 over already. That's why I went 60. I'm comfortable with that because I'll be running propane with burns cooler, and I'll be using a higher flowing water pump, maybe even with a smaller pully on it so it pushes more water and using a water wetter like product from BG that I recently learned about. I'm also painting the heads black, because dark colors convect heat better than lighter colors (despite that they absorb radiant heat better too) and use headers to get the hot exhaust gasses away from the engine faster. I beleive that going 60 over does make heat a bigger problem, but I also think that it's a problem we can overcome if you really want a 419 ci engine. :D

EDIT>>>I forgot to mention that the man I bought my engine from, a member named slewfoot, has a 401 bored out to take 454 pistons, which is like a .200 over bore. He says he doesn't have heat problems, but of course, I didn't make him take the heads off so I could measure or anything...

[ March 09, 2004, 07:52 AM: Message edited by: Wago Thing ]

[Rande]

The 401 block has a high nickel content. The machinist should be made aware of that. The nickel makes the block tougher to machine. Whether that will change any procedures or not, I don't know.

[skid2964]

Originally posted by Wago Thing:

EDIT>>>I forgot to mention that the man I bought my engine from, a member named slewfoot, has a 401 bored out to take 454 pistons, which is like a .200 over bore. He says he doesn't have heat problems, but of course, I didn't make him take the heads off so I could measure or anything....200 over without sleeves! :eek:

[FSJ Thing]

That's what the man said. I wouldn't do it, but it does give me the confidence to go .060 and know that I can deal with it. For those who want more details, he says he milled down the crank to take GM connecting rods to get the 454 pistons down into the hole, since the deck hight would be too high to mill down the pistons. That would put too much angle on the connecting rods for my tastes, but it worked for him.

[jode]

Kong (a forum member) is currently having overheating issues with his 401. I dunno if he has solved them or not yet (he rarely posts anymore), but you might try digging up his info to see if he has got it figured out yet.

[skid2964]

Actually, as I was telling Wago in another post. I found two std bore 401 blocks! Im getting two bare std blocks and a set of rods for $700. And he is within driving distance!

[ March 09, 2004, 09:14 AM: Message edited by: skid2964 ]

[JERSEY JOE]

Make sure if the heads have been milled a few times that your machine shop cuts the intake manifold or you may not be able to start the bolts.
As the block gets decked and redecked, and the heads get cut a few times, the heads move closer to the bottom of the block, and the intake is then "too wide."

[Elliott]

Originally posted by skid2964:
</font><blockquote>quote:</font><hr />Originally posted by Wago Thing:

EDIT&gt;&gt;&gt;I forgot to mention that the man I bought my engine from, a member named slewfoot, has a 401 bored out to take 454 pistons, which is like a .200 over bore. He says he doesn't have heat problems, but of course, I didn't make him take the heads off so I could measure or anything....200 over without sleeves! :eek: </font>[/QUOTE]454 = 4.250" bore
401 = 4.165" bore
requires 0.085 overbore std to std ;)

[FSJ Thing]

Yeah, that sounds right. I couldn't remember the bore of a 454, I though it was a little less than 4.5 but couldn't remember the actual dimensions. thanks for the correction! ;)