Stripped Allen head bolts
Posted: Tue Jul 07, 2015 10:55 pm
Hi everyone,
My name is Dexter and I'm new here and hoping someone can help me with some issues I have with my L300. Particularly 1 issue for now.
I rebuilt my 4d56 engine October 2014. 9 months later my timing belt snapped and broke 2 rockers. I have no idea if the valves are bent and I got all but 2 head bolts slackened out. Those 2 are now rounded on the inside and so I have no clue how to get them out (including without having to take the entire engine out as its the 2 rear bolts).
I have a theory but I have no practical way of testing as I dont have any old heads and valves to work with. This theory is to check for damaged valves. By removing the rocker arm assembly, all valves are supposed to be in properly closed positions which would mean all are supposed to be at one level at the top end. By using a straight edge, placing it at the top of the 1st tappet touching all the way across the top of the others down to the last one, wouldnt a damaged valve be unable to make contact with the straight edge?
Same principle used in checking for a warped head. Can anyone help with this please?
Is there any other way to know if the valves are damaged if i cant get those bolts out? My next idea is to use an old injector (housing) rig up a connection to my air compressor and pressurize the piston chambers one at a time and see if its holding pressure. If it isnt, then certainly a valve/valves are damaged. Again, any help with this is appreciated.
Im not a mechanic, just a guy who enjoys using his hands after spending alot of money at garages and not being satisfied. Now i do it myself once time allows me.
What could possibly have caused a relatively new timing belt to snap considering also the mileage for 9 months is pretty low as well and the vehicle is not used for commercial purposes.
I will give details and answers to whatever questions you may have.
Your help is greatly appreciated.
Thanks guys.
My name is Dexter and I'm new here and hoping someone can help me with some issues I have with my L300. Particularly 1 issue for now.
I rebuilt my 4d56 engine October 2014. 9 months later my timing belt snapped and broke 2 rockers. I have no idea if the valves are bent and I got all but 2 head bolts slackened out. Those 2 are now rounded on the inside and so I have no clue how to get them out (including without having to take the entire engine out as its the 2 rear bolts).
I have a theory but I have no practical way of testing as I dont have any old heads and valves to work with. This theory is to check for damaged valves. By removing the rocker arm assembly, all valves are supposed to be in properly closed positions which would mean all are supposed to be at one level at the top end. By using a straight edge, placing it at the top of the 1st tappet touching all the way across the top of the others down to the last one, wouldnt a damaged valve be unable to make contact with the straight edge?
Same principle used in checking for a warped head. Can anyone help with this please?
Is there any other way to know if the valves are damaged if i cant get those bolts out? My next idea is to use an old injector (housing) rig up a connection to my air compressor and pressurize the piston chambers one at a time and see if its holding pressure. If it isnt, then certainly a valve/valves are damaged. Again, any help with this is appreciated.
Im not a mechanic, just a guy who enjoys using his hands after spending alot of money at garages and not being satisfied. Now i do it myself once time allows me.
What could possibly have caused a relatively new timing belt to snap considering also the mileage for 9 months is pretty low as well and the vehicle is not used for commercial purposes.
I will give details and answers to whatever questions you may have.
Your help is greatly appreciated.
Thanks guys.
