I bought this Rover mower with a quantum engine on it. The Magneto was kaput so I replaced it and now it starts and seems to run fine but I noticed one of the head bolts had been snapped off and all the others were not tight enough. Still started fine though. The threaded portion remains in the engine block. The lower RHS corner bolt one is the broken one.
What do you think? Should I leave well enough alone or should I try and drill the remains out? The latter option is fraught with danger as the drill bit would rather drill the soft aluminium of the block than the hard steel of the bolt and all I have is a hand drill. So my preferred option is to leave it in and just tell the buyer that there is a potential problem.
Those bolts are pretty tough to drill out and I have found "Easy outs" a waste of money. There is about 20mm of threaded section left in the block.
Sparker, what can I say, you have answered your own question, you don't have many options, it is a difficult job even with good workshop equipment. Left hand cobalt drill in a drill press will get it out somehow, still has the potential to damage the existing thread and this is cost prohibitive if you take it to a workshop. Put it back together with a new gasket with maybe a smear of JB Weld on both sides of the gasket around the area where the bolt is missing. Who cares if you can't get it apart in the future, it is a Briggs and they don't last forever.
So I not the only that found the easy outs got a tendency to break off. The reason is the head bolt and other steels bolts can be galled to the aluminum and become as one piece.
Okay here a tip if you plan to try drilling the broken portion. First using a center punch make an indention dead center of the bolt to drilled out. Now don't try drilling completely in one step; instead, use step drilling process. This involves using a fairly small sharp split point bit at first as to not drift off center and drill as straight as you can through the bolt. Then using gradually increasing sizes of bits work your way out drilling. Once you reach the tapping size you want stop and tap. Hopefully you have enough area around the through hole in head as to allow you to enlarge it if you need to oversize to the next bolt size as some taps can't cut the head steel without breaking.
Just last week I had to drill out a steel bolt in a Kohler head to accept a new bolt so I could bolt down the valve cover. I manage to go from 6mm to 7mm so I was lucky.
Thanks for the tip about the split point drill bits. "Walking" of the drill was my biggest fear and I will get a couple of those split points for future jobs (like those pestilential Rover blade bosses).
I think I'll do what Norm says. I hadn't thought of the JB weld and that's a good option. Off to SupaCheap.
Sparker, another option you could try, not sure if it will work, but worth a try, forget the gasket and just JB Weld the head on. One thing you would need to do is put a washer under each of the head bolts to compensate for the gasket thickness unless you can be sure there is enough thread depth in the barrel housing.
I left the gasket in place but filled the part where the bolt goes through the gasket, the 2mm of the block where the bolt remains and the bolt hole in the head with some JB weld type epoxy. They didn't have the JB weld only some permatek "cold weld" stuff that they recommended. I'll test it out tomorrow and let you know how it goes or blows.
I was going to suggest you JB Weld the bolt head back in place and nobody would know it was even missing, that is until they tried to pull the head off LOL
Sparker, I tried one this afternoon to see how it goes, I removed the gasket and ran a bead of JB Weld all around the head and bolted it up. Will see how it holds up in the morning
I had one of those recently..... I waited to find another block . Might need all the bolts..... But have a go....................... what can you loose.... If it doesn't work, then you'll have a few spare parts.
good luck speedy
........................Keep your blades sharp......................
Boy someone got a lot more faith in JB Weld or any of the other epoxies when it come to true holding power. I have yet them to work under any stress loads. I tried recently the Prematex Steel Weld epoxy and it didn't even hold the threads once cured. They pulled right out before I even the spindle half torqued.
But they use high bond glues for some sports cars don't they? I agree though, there is no match for actual welding of metal.
I actually use some Permatex plastic weld epoxy to fuse ABS hoods back to together after customer smacks a tree. Kinda wish they came in John Deere green instead of just cream and black colors. It actually melts the plastic back together.
I try JB Weld and was highly disappointed as it didn't even hold at all.
Thanks for the update Norm. Mine runs fine but, of course, it was doing that before the Permatek. If I had a compression tester I would have done a "before and after" test but I don't, so I didn't. I wonder if the other bolts together with the repair will be enough. Others here don't have much faith in the epoxy. I'll mow my lawn with it in the next day or so and I'll report back here. It will be interesting to see how much effort is needed to get the head off your mower now.
Well I got 80% of the back yard done and then the mower began to stutter. However, I don't think it is a compression problem; it felt more like a fuel issue. It would start to stall then pick up again and repeated this until it stopped. I didn't hear any hissing from a leaky head gasket either. It's too hot to work on so I've hosed it off and I'll check it out Thursday. Anzac Day tomorrow so mowers can bugger off.
Norm, I know your low opinion of Briggs' engines but that's what is fitted to most of the mowers I get. If the engine is any good then try another head gasket. A used one off one of your wrecks, lol.
