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425 repair


Rhentsch55
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I have a 1966 Wildcat with a 425 which unfortunately was diagnosed with a cracked cylinder and oil journal.  The shop is advising that the cylinder can be sleeved to fix the crack.  Wondering if this is a recommended and reliable repair?  I understand it is fairly common but will it hold up in a high compression engine like the 425?

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Thanks, Bill.  I found a lot of online chatter about repairing a cylinder with a sleeve but for scored or pitted cylinder walls to deep to fix by boring.  I didn't find any discussions about using a sleeve to repair a crack.   Seems it should work but wondering about long term.  Is the crack likely to continue to grow even with the sleeve in place?

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 Need more detail on size of crack and location. You also mentioned an oil journal crack. That's odd. Where is that located. 

Any idea what caused the cracks?

Successful sleeving is highly dependent on the skill of the machinist.  

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I'm waiting for more details from the machine shop on Monday.  It appears that the engine was not maintained well by a previous owner and probably driven very hard.  There was at least one bent pushrod and there's a lot of sludge throughout.  It was swapped out for a 401 so I'm trying to decide whether or not to sink $ into the 425 since it's the original engine, or stick with the 401.

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2 hours ago, Rhentsch55 said:

I'm waiting for more details from the machine shop on Monday.  It appears that the engine was not maintained well by a previous owner and probably driven very hard.  There was at least one bent pushrod and there's a lot of sludge throughout.  It was swapped out for a 401 so I'm trying to decide whether or not to sink $ into the 425 since it's the original engine, or stick with the 401.

Rather rare to find a `66 Wildcat with a factory 425, especially if the car in question is not a GS model which came standard with the 425. 

  Tom Mooney

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Tom-you'd be the one to know best, but I recall that for the '66 the 425 was a $59 option from the 401. My 225 has it and my dad was one who always ordered cars to his wants and would check the largest engine option!     I've not seen a crack involving the oiling system either.        Dan   Mpls. Mn.

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6 hours ago, Lapham3 said:

Tom-you'd be the one to know best, but I recall that for the '66 the 425 was a $59 option from the 401. My 225 has it and my dad was one who always ordered cars to his wants and would check the largest engine option!     I've not seen a crack involving the oiling system either.        Dan   Mpls. Mn.

Hi Dan,

  I have the production totals and based on memory I recall the 425 being rarely ordered without the GS option. This is very similar to the `65 Riv Super Wildcat equipped cars WITHOUT the GS package. Very unusual compared to the # of GS cars built. I suspect back in the day it was a better value to order the package instead of just the single engine option, especially considering the increased utilization of the extra cubes thru a better rear gear, etc...

  Usually the middle cast oil passage gets clipped by a rod with piston pin attached when the pin gets ripped out of the piston skirt. I was burned by this once....

  Tom

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If the 401 is running well keep it an make other repairs. You won't notice a difference in normal driving. My '64 had a 401 out of an Electra when I bought it, but the internet didn't come along until after I had owned it for 15 years. Prior to that it didn't make much difference.

Bernie

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The car is a Wildcat GS convertible.  That's mainly why I'm interested in saving the 425.  It's the original engine.  If all the cracks can be reliably repaired I hope it would be worth saving.  The shop where it's sitting seems experienced with these repairs but I'm trying to understand what I can expect from such a repair.  

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Go back and read Tim's post #6.  He has one of, if not, the earliest documented 425 '63 Rivieras.  He was faced with the same sort of predicament as you are.  

 

Ask your machinist for some referrals.  You'd be much better off talking directly with some of his previous customers rather than polling a bunch of us who've never had direct dealings with him.

 

Ed

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6 hours ago, Rhentsch55 said:

The car is a Wildcat GS convertible.  That's mainly why I'm interested in saving the 425.  It's the original engine.  If all the cracks can be reliably repaired I hope it would be worth saving.  The shop where it's sitting seems experienced with these repairs but I'm trying to understand what I can expect from such a repair.  

I also have several `66 Wildcat GS converts. I have much info related to the `66 models. Sent you a PM,

  Tom

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I just got back from the machine shop and had a chance to see the block.  #4 cylinder is cracked where the broken connecting rod tried to escape.  #6 cylinder has pieces broken off the bottom of the cylinder.  The machinist says the cracked cylinder can be easily sleeved.  The one with the chips at the bottom may not need a sleeve since the pistons are full skirted so won't wobble at the bottom of the stroke.  If it does need a sleeve that can be done.  Also, the main oil galley has one section bent and cracked where the broken rod made contact.  They say the galley can be drilled oversize and a tube inserted and ported to match the galley.  There are no other issues with the block.  The heads are in good shape, just needs push rods and valves.  The shop has done a number of 401s but this would be there first 425.   

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No difference other than a 1/8" larger bore on the 425.  So the diameter of the piston is the only difference in the two cubic inch displacements.  That along with some casting lugs that help align the block for the original boring machine which, once the engine left the machining process,  were no longer of any use.

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