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  • March 28, 2024, 10:53:50 AM

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Author Topic: cylinder head bolt clearance problem  (Read 1912 times)

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Offline AMC1

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cylinder head bolt clearance problem
« on: May 17, 2020, 12:15:55 PM »
I’m going to replace the 258 cylinder head gasket. There are 14 bolts & 12 seem to be ok in that I can fit a ½” drive - ¾” socket on them. The front & rear on the right side are a problem. I can only fit a 3/8“-¾” (slightly smaller circumference) on the front due to it being close to the casting. The rear one is impossible to get any socket on it at all, maybe 1/16” clearance. It also looks like the PO had the same problem. I can see smooth grinding marks inside the casting at the bolt but not on the bolt itself. He didn’t take off enough & I can understand that but I can’t figure how he got a socket on it unless he ground one down. I’m guessing that I’ll have to grind down a socket to fit. If I’m going to do that I would rather grind down a ½” drive rather than a 3/8”. I also use 12 point sockets but maybe I had better pick up a 6 pointer. Even then I may have to grind down one side to make it a five point socket, what chance do I have to break 85 lbs torque on a hex bolt with a five point socket. If I strip that bolt I’ll be up a creek. Am I the only one to see this problem?
1976 gremlin
pair of 1983 SX4's sports
1946 Cushman step-thru

Offline mudkicker715

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Re: cylinder head bolt clearance problem
« Reply #1 on: May 17, 2020, 04:56:48 PM »
I have rebuilt many 258s. This is a first. Never had a problem or remember anything unusual  about head bolts.



Manitowoc WI

Offline djm3452004

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Re: cylinder head bolt clearance problem
« Reply #2 on: May 17, 2020, 05:01:30 PM »
I’m going to replace the 258 cylinder head gasket. There are 14 bolts & 12 seem to be ok in that I can fit a ½” drive - ¾” socket on them. The front & rear on the right side are a problem. I can only fit a 3/8“-¾” (slightly smaller circumference) on the front due to it being close to the casting. The rear one is impossible to get any socket on it at all, maybe 1/16” clearance. It also looks like the PO had the same problem. I can see smooth grinding marks inside the casting at the bolt but not on the bolt itself. He didn’t take off enough & I can understand that but I can’t figure how he got a socket on it unless he ground one down. I’m guessing that I’ll have to grind down a socket to fit. If I’m going to do that I would rather grind down a ½” drive rather than a 3/8”. I also use 12 point sockets but maybe I had better pick up a 6 pointer. Even then I may have to grind down one side to make it a five point socket, what chance do I have to break 85 lbs torque on a hex bolt with a five point socket. If I strip that bolt I’ll be up a creek. Am I the only one to see this problem?



This is where a picture, if you could possibly post one please, would be worth the effort.  It's tough to diagnose or even comment on something like this without a visual...
Current Project: 1983 Eagle Wagon 258
Past AMC Project(s):  1979 Spirit Liftback 232
                                1968 Ambassador 287

Offline AMC1

  • Eagle Sport
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Re: cylinder head bolt clearance problem
« Reply #3 on: May 18, 2020, 11:28:04 AM »
The bolts on the right side I'm sure aren't stock. They are plated. I don't recognize the head markings but they show 12-13 dots that look like a clock with a triangle in the center. I assume these are for setting a torque angle but the TSM doesn't mention torque angles - only torque values. Left side looks stock. The thing is that both sides use a 3/4" socket. Would you happen to know if 5'8" head bolt size was possibly stock and not 3/4". It's going to be a problem. I'll have to pull or at least release the hood off the car now to get deeper in there. 
1976 gremlin
pair of 1983 SX4's sports
1946 Cushman step-thru

 

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