My 1980 HJ45 suffers from overheating at highway speeds only, around town it runs fine, starts easily, runs smooth, no smoke. But at 55-60MPH it gets compression into the coolant jacket resulting in the expected overpressurization. Eventually I was able to find a headgasket leak towards the fire wall. I decided to replace the headgasket and check the head for trueness and cracking. So into the shop it went.:Mechanic:
All the parts came off happily with ease and the project was running smoothly. As I removed the headbolts I checked the torque on them. (before you all chastise me I have already been lectured by a mechanic telling me not to use a torque wrench for removal), that being said all bolt were in the 90-115 ft/lbs range to break them free with the exception of a cluster of three towards the firewall that were down around 60ft/lbs. It seemed to me that I had found the source of my leaking compression. Unfortunately the final step in removing the head was not as smooth as I would have desired. Once all bolts were removed the head was attached to the lift and tension placed on it.
..nothing budged...I gave it another crank on the lift and I could see the head begin to break free from the block. Telltale coolant beads forming all around the outer edge. I took a break leaving tension on the hoist and started up the usaul BS'ing conversation with a friend in the shop. A minute or so into the conversaion the head popped off the block with more force than desired. As it came up it hit the overhang at the fire wall scaring the life out of us, but otherwise did not seem to do any damage.
After a few moments of looking things over I realised that as the head lifted off and hit the overhang on the firewall it shifted a link on the chain hoist resulting in a downward angle and made contact with the fire ring on the number 4 cylinder sleave.
The head was found to be true, but has cracks between the intake and exhaust valve in each cylinder. The cracks are only visible under magnafluxing. I am not a mechanic, but it does not seem to me that these cracks were the source of my overheating.
Though at this point it seems like the head issues are the least of my problems. Anyone on the list care to give me some guidance on next steps? I assume I need to remove the sleave and replace it.
All the parts came off happily with ease and the project was running smoothly. As I removed the headbolts I checked the torque on them. (before you all chastise me I have already been lectured by a mechanic telling me not to use a torque wrench for removal), that being said all bolt were in the 90-115 ft/lbs range to break them free with the exception of a cluster of three towards the firewall that were down around 60ft/lbs. It seemed to me that I had found the source of my leaking compression. Unfortunately the final step in removing the head was not as smooth as I would have desired. Once all bolts were removed the head was attached to the lift and tension placed on it.
..nothing budged...I gave it another crank on the lift and I could see the head begin to break free from the block. Telltale coolant beads forming all around the outer edge. I took a break leaving tension on the hoist and started up the usaul BS'ing conversation with a friend in the shop. A minute or so into the conversaion the head popped off the block with more force than desired. As it came up it hit the overhang at the fire wall scaring the life out of us, but otherwise did not seem to do any damage.
After a few moments of looking things over I realised that as the head lifted off and hit the overhang on the firewall it shifted a link on the chain hoist resulting in a downward angle and made contact with the fire ring on the number 4 cylinder sleave.
The head was found to be true, but has cracks between the intake and exhaust valve in each cylinder. The cracks are only visible under magnafluxing. I am not a mechanic, but it does not seem to me that these cracks were the source of my overheating.
Though at this point it seems like the head issues are the least of my problems. Anyone on the list care to give me some guidance on next steps? I assume I need to remove the sleave and replace it.
