3b overheat damage results and question?

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Dec 7, 2019
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North Carolina, USA
After overheating my bj70 the engine was missing and ran rough on startup. At one point there was a clanking noise. I feared a cracked head and possibly a dropped pre-cup. I pulled the head and all the precups look okay but on once on cylinders 2 and 3 it has obviously swallowed something and I have evidence of metal smashing into the piston and cylinder head. this is damaged one of the valves and valve seats on one cylinder. Cylinder walls look okay. I have no clue what this engine could have swallowed. anyone have any ideas what the engine may have swallowed and why it would have happened on overheating?
This vehicle is new to me I only drove it about a hundred fifty miles before this happened. There is evidence of poor mechanic work prior. Maybe a pre-cup had dropped before or pieces of one and smashed into the head and piston and had been left there on a previous repair and those bits of metal broke Free and started rattling around on this overheat instance. It overheated due to previous J-B weld freeze plug repair blowing out and all of the water blowing out of the engine the temperature gauge never went up. She started losing power and shut off as soon as I pushed in the clutch.

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mongoose2231

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Holy chit, have you found the culprit pieces of metal to try and do some detective work and see if you can piece together what broke off from where?
 
Joined
Dec 7, 2019
Messages
50
Location
North Carolina, USA
Holy chit, have you found the culprit pieces of metal to try and do some detective work and see if you can piece together what broke off from where?
Exhaust seat cracked and fell down inside the engine. ......... I was expecting to have to buy a new head but I think this may not be so bad. I'll disassemble to head the rest of the way take it into a machine shop have them inspect it for cracks and see if it's warped. If it's not cracked, I'll have them put a new valve seats to replace the bad ones, I'll smooth out scars on the head with a dremel to try to not to have too many hot spots. And I'll do the same on the piston. . .... That may be a bit shade tree but I think it's a tough little engine and will run on with a few scars on the inside.

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Joined
Dec 7, 2019
Messages
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Location
North Carolina, USA
Exhaust seat cracked and fell down inside the engine. ......... I was expecting to have to buy a new head but I think this may not be so bad. I'll disassemble to head the rest of the way take it into a machine shop have them inspect it for cracks and see if it's warped. If it's not cracked, I'll have them put a new valve seats to replace the bad ones, I'll smooth out scars on the head with a dremel to try to not to have too many hot spots. And I'll do the same on the piston. . .... That may be a bit shade tree but I think it's a tough little engine and will run on with a few scars on the inside.

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You might have some cracks.

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You are right I do. She's cracked between the valves on every cylinder. I guess it's new head time.
 
Joined
Dec 7, 2019
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I want to know if you are joking or not. Are you suggesting that it will be OK to run with those cracks? I don't know . I assume that pressure will blow through and blow water out of my coolant system. Are you suggesting I get 2 new exhaust valve seats for the ones that dropped and bolt the head back on and run it to see what happens? Not sure how much it would cost to get 2X new valve seats installed, but I'm not sure if I want to spend $200 to patch a head with cracks when I can get a new head for around $650.
 

lowenbrau

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I want to know if you are joking or not. Are you suggesting that it will be OK to run with those cracks? I don't know . I assume that pressure will blow through and blow water out of my coolant system. Are you suggesting I get 2 new exhaust valve seats for the ones that dropped and bolt the head back on and run it to see what happens? Not sure how much it would cost to get 2X new valve seats installed, but I'm not sure if I want to spend $200 to patch a head with cracks when I can get a new head for around $650.
I seriously believe that 75 percent of 3Bs have similar or worse cracks between the valves. I’ve owned dozens of them and pulled heads from engines that failed for other reasons. Those cracks are quite normal. That being said, a high nickle head is a small investment for years more service from an engine that can easily go 30000 hours.
 
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Dec 7, 2019
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I seriously believe that 75 percent of 3Bs have similar or worse cracks between the valves. I’ve owned dozens of them and pulled heads from engines that failed for other reasons. Those cracks are quite normal. That being said, a high nickle head is a small investment for years more service from an engine that can easily go 30000 hours.
This vehicle is relatively easy to work on and it isn't that bad to bolt it together and take apart again. Based on what you are saying above I will check into getting a couple of new valve seats and 2 new valves and bolt it back together and see how it does before I order another head.
 
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Dec 7, 2019
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Coolant that blew out of the engine is black color. Soot? oil? I'm going to have a machine shop take a look at it. Maybe pressure test it before I pay for any machine work. My wife has been using Alibaba for some time and from what I am seeing I can get a new head for less than $550 out of china DHL to me in less than 3 weeks............I may do a Alibaba learning adventure fixing the cruiser.
 
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Nova Scotia, Canada
There are some threads on here about the alibaba heads not fitting properly, i think most 3b's in BJ70's are the large valve versions - but i am not sure of this. Last i checked Engines Australia high nickel heads were no longer available. CruiserParts sells large valve chinese heads for $1300usd so someone still makes them.
 

mano002

 
 
 
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Mar 24, 2002
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Calgary AB Canada
I know someone that bought a small valve head (possibly from china) from 4wheel auto recently. He could not find a high-nickel head.
 
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Dec 7, 2019
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North Carolina, USA
Took the head to a local machine shop that specializes in head repair and rebuild. They said they could fix my head. it's going to set me back about the same as the cheapest head with shipping on Alibaba. I told them to fix it. We'll see how this turns out.... There are several variations for 3B heads. I would think that if you got one that match the part number needed for your vehicle it would be correct. There are several variations for sale on Alibaba. Most of them these days list part numbers. Service is getting better as well as descriptions in detail probably less risk on an Alibaba purchase today than 5 years ago. It would be easy to buy an incompatible head if you didn't exercise due diligence in the deal.
 
Joined
Dec 7, 2019
Messages
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Location
North Carolina, USA
Update-Head repair shop told me: "I think we can fix it. Shouldn't be more than $375. It's a minimum of $70 to magnaflux and test it." ....they tested and went to work fixing it, but more and more leaks kept coming up. They called me and said It's not worth fixing. So I gave them $70 for the effort and ordered a head off of Ali express. Interestingly the old head was not a typical "new"3B head and the valves were not seating on the seats. Yes it appears the head was replaced before and the original valves reused and were a bigger size than the valve seats in the head. Spring pressure however closed them and valve lash adjustment took care of mis-sizing and it ran on that way. I chose to do a made in China Ali baba adventure......Since then the Corona virus has happened. My head still has not shipped. When I get the head if it works out without additional machining I will posts contacts etc.. As of late I have put in manual hubs, new radiator, and am working on putting in a complete replacement of the broken cable/rotten core/stuck valve factory heat and vent system with a new system from Vintage Air with the addition of AC(voltage converter and 12V auxillary fuse panel to feed this as well). Have new rear diff bearings/crush wasther/seals in a box with a spartan locker arriving this week.
I will put pictures when complete, but I have to say that the control panel for the climate control system from vintage air is a thing of beauty. It is their cheapest horizontal sliding unit and is $79, but it is not plastic. It is heavy duty machined aluminum and quality switches. The best way I can describe it is early 1960's weight and quality of material with modern quality and precision. It is absolutely better than it has to be. My wife is from overseas. When I pulled the control out of the box I called my wife and told her: "This is what made in America quality looks like when you can find it. Heavier and more durable than necessary. Simpler than a European design."
 
Joined
Mar 30, 2011
Messages
4,909
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Huntsville AL or Yuma AZ
Update-Head repair shop told me: "I think we can fix it. Shouldn't be more than $375. It's a minimum of $70 to magnaflux and test it." ....they tested and went to work fixing it, but more and more leaks kept coming up. They called me and said It's not worth fixing. So I gave them $70 for the effort and ordered a head off of Ali express. Interestingly the old head was not a typical "new"3B head and the valves were not seating on the seats. Yes it appears the head was replaced before and the original valves reused and were a bigger size than the valve seats in the head. Spring pressure however closed them and valve lash adjustment took care of mis-sizing and it ran on that way. I chose to do a made in China Ali baba adventure......Since then the Corona virus has happened. My head still has not shipped. When I get the head if it works out without additional machining I will posts contacts etc.. As of late I have put in manual hubs, new radiator, and am working on putting in a complete replacement of the broken cable/rotten core/stuck valve factory heat and vent system with a new system from Vintage Air with the addition of AC(voltage converter and 12V auxillary fuse panel to feed this as well). Have new rear diff bearings/crush wasther/seals in a box with a spartan locker arriving this week.
I will put pictures when complete, but I have to say that the control panel for the climate control system from vintage air is a thing of beauty. It is their cheapest horizontal sliding unit and is $79, but it is not plastic. It is heavy duty machined aluminum and quality switches. The best way I can describe it is early 1960's weight and quality of material with modern quality and precision. It is absolutely better than it has to be. My wife is from overseas. When I pulled the control out of the box I called my wife and told her: "This is what made in America quality looks like when you can find it. Heavier and more durable than necessary. Simpler than a European design."
Geeze man feel like reading a Lamour book, how about some pictures?
 
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