Repairing a 401 that’s already .060 iver
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=98992
Printed Date: Apr/18/2024 at 12:50am
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Topic: Repairing a 401 that’s already .060 iver
Posted By: Ramblage
Subject: Repairing a 401 that’s already .060 iver
Date Posted: Mar/14/2019 at 12:06pm
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I acquired a 401 just the other day for free that’s already been bored .060 over but there’s one cylinder that scared up deep but the cylinders are in really good shape. Would it be good to just sleeve that one cylinder and bore it .060 over or just put it on a catapult and launch it across a river or use it as lawn art or a boat anchor? Or sell it? ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Replies:
Posted By: shootist
Date Posted: Mar/14/2019 at 12:20pm
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.060 over is a bit extreme for a 401. If I were to do anything with it I would sleeve all of them back to factory spec. ------------- 
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Posted By: jpnjim
Date Posted: Mar/14/2019 at 12:25pm
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if otherwise good, not missing the main caps, badly rusted, etc then it's worth a shot to have it sonic tested before making up your mind on it. Some blocks are ok at .060, but you won't know till you check. Best case, there's plenty of meat left, and the other 7 .060 holes can get by with a hone. Then you're one sleeve away from a good block. Worst case, even the "good" .060" holes need a bore and core shift has them too thin even at .060". You never know till you check but if the "good" .060" bores need work you're more than likely out of luck for a street engine. ------------- 71 P-code 4spd Javelin/AMX some Jeeps and some Fords |
Posted By: jpnjim
Date Posted: Mar/14/2019 at 12:26pm
I agree but if the other .060 holes look good it's worth checking  ------------- 71 P-code 4spd Javelin/AMX some Jeeps and some Fords |
shootist wrote:Posted By: Ramblage
Date Posted: Mar/14/2019 at 12:45pm
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mmm ok! Ill have a shop look at it to see it’s good on the remaining cylinders and if they can sleeve it and go from there. ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Posted By: shootist
Date Posted: Mar/14/2019 at 1:25pm
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You have a point jpnjim and it really does depend on what you are doing with it. If it is a mild build it would might be ok at .060" but sonic testing will be the tell tale. -------------
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Posted By: FSJunkie
Date Posted: Mar/14/2019 at 1:35pm
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You will probably pay $100 per hole for sleeving plus the cost to bore and hone each to size. It's already had a "proof test" if it was running at .060" before, so I wouldn't worry about sleeving and boring the one bad cylinder to .060" to match the others so long as you are not stressing the engine more than it was before. Where you could get into trouble is if you plan to make more power with it now than it was before. That level of stress is untested on that block. That's when I would sleeve all eight. Plus, after sleeving all eight the engine can be rebored however many times you want. Just replace the sleeves when needed. ------------- 1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
Posted By: Ramblage
Date Posted: Mar/14/2019 at 1:48pm
It’s just gonna be a mild build nothing fancy. ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Posted By: dbltrbl
Date Posted: Mar/14/2019 at 2:13pm
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If you decide to sleeve that one cylinder, it doesnt have to be bored back to .060, as long as new piston has correct weight you will never know the difference. |
Posted By: Ramblage
Date Posted: Mar/14/2019 at 2:13pm
It has the main caps as well as not even rusted at all surprisingly to where I think it’s worth rebuilding. Just wanted to get opinions on it! ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Posted By: Trader
Date Posted: Mar/14/2019 at 4:25pm
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Year of the block seems to matter also. I have a 71 I'm working on now that is bored 0.030" over and though I did not get a sheet, the shop was surprised as the 73 block I did last year had average 0.100" less material.
So the 71 block can go 0.090" over and still have more meat then the 73 at 0.060" over. The 73 through 75 blocks I have worked on seem the same. I have not had a 72 block yet. My opinion is that at the studs you need 0.300" minimum and everywhere else 0.250". If I had the block, I would test and sleeve if possible. It really does not matter after the test to go standard bore on one cylinder or not. If 0.060" is the limit of the block, then make all the same. If you could do another bore to 0.090", then sleeve for the 0.090" bore and bore this time to 0.060". |
Posted By: WesternRed
Date Posted: Mar/14/2019 at 4:32pm
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Would anybody consider sleeving it back to 360 bore size, or possibly some intermediate size to facilitate a stroker combo with off the shelf parts, and building a stout 360 or other combo with provision for 4 bolt mains? ------------- I've finally given up drinking for good...........now I only drink for evil. |
Posted By: jpnjim
Date Posted: Mar/14/2019 at 5:02pm
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https://www.tapatalk.com/groups/amcdragracing/sonic-checking-amc-blocks-t1611.html" rel="nofollow - https://www.tapatalk.com/groups/amcdragracing/sonic-checking-amc-blocks-t1611.html ^pretty good thread on sonic testing ------------- 71 P-code 4spd Javelin/AMX some Jeeps and some Fords |
Posted By: Ramblage
Date Posted: Mar/14/2019 at 7:35pm
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dang pretty interesting jpnjim. If shops charge 100 to sonic check I’m probably better off just buying my own which I just looked up there around 100 bucks and do build a lot of engines myself not just amc. Would definitely come in handy! ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Posted By: AMoCoLite
Date Posted: Mar/14/2019 at 8:43pm
I don’t know if it’s practical...but it seems like a pretty cool thought.
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Posted By: Trader
Date Posted: Mar/14/2019 at 9:27pm
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Cool, but also scary. 0.100" wall thickness - if the shop had told me that it would be scrap metal. 0.200" is what I was taught minimum for a cast block so i like the conservative 0.250". They typically measure at piston ring top, mid and bottom of the stroke, not 5/8" down. Have to do some math now, but if peak cylinder pressure is 22 to 27 degrees ATDC then 5/8" down must be close to middle from TDC to the top of the piston and seeing maximum cylinder pressure??? But have never seen a cylinder fail in that area??? Cracks at the head cap screws or near the bottom of the stroke from piston skirt wear seems common - other then throwing a rod. |
Posted By: PROSTOCKTOM
Date Posted: Mar/14/2019 at 9:54pm
Tom  |
Posted By: Ramblage
Date Posted: Mar/14/2019 at 10:32pm
Not to sure on the year which I did look up the casting number on it (3198951) ranges from 71-78 and it’s just a bare block ------------- 1960 Customized Land Barge Rambler Super with Dodge 360 & 5spd 1971 Silver Bullet Javelin w/232 Engyne! 1972 Crappy Green Javelin w/401 and AW4, still in the works |
Posted By: farna
Date Posted: Mar/15/2019 at 5:54am
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$800 or so to sleeve it all back to original (or some other) bore. At that point figure out what pistons you want and go with whatever bore is most cost effective. Chevy pistons and rods? If you really want a 401 and can't find a closer to standard bore block (getting hard to do!) then sleeving all would be a good option. You'd probably pay $800+ for a good standard bore block, and sleeving done right is as good or better. Often the sleeves are stronger than the block. Or just build a stout 360. The problem with the 0.060" overbore is that the engine will likely have heat related issues, especially if building for the street. You might get by with that on a drag car, but extended running will likely have issues. I wouldn't use it for a street build, would just get a 360 block and maybe use the 401 crank and rods for a stroker build. Four bolt mains aren't necessary, nor the thicker webs if you aren't going to be running it really hard all the time. ------------- Frank Swygert |
Posted By: SC397
Date Posted: Mar/15/2019 at 9:31am
Thanks!
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Posted By: jpnjim
Date Posted: Mar/15/2019 at 1:05pm
Thank you for making a wealth of information available to us Rick! I hope you don't mind me cross posting it, I should have probably asked, or mentioned it to you first. ------------- 71 P-code 4spd Javelin/AMX some Jeeps and some Fords |
Posted By: SC397
Date Posted: Mar/15/2019 at 4:15pm
No problem at all.. Once it is on the interweb, it is free use for everyone! |