Engine Pull at 7PM

Need to make a deck wherein you bolt the head down to a thick metal plate to keep it from warping during the heat treat.
Epoxy won’t work?

If the head heats and cools evenly, it shouldn’t warp. If the temperature is kept below 250, it shouldn’t warp under any conditions. I’d hesitate to take it much above 300 even stripped down. Additionally, heating to 250 or higher while bolted to a deckplate will almost certainly cause it to warp.

All that said, I’m still not 100% convinced heating the head will be necessary to fill the void. Ferman raises an interesting point regarding epoxy. I’ve used JB weld in the past to fill voids and secure bolts in aluminum engine blocks. I wouldn’t do it for a structural repair, but it should bond well enough to clean aluminum and be strong enough to hold a timing belt tensioner or idler in place.

So would you JB Weld and tap or JB weld the bolt in place permanently? We made a piece last night that’s looks like a idler pulley spacer, but also goes into the gaping hole of the engine block, I guess we could JB weld that in? I’d be worried about proper centering and right angling

I would fill with JB Weld, grind flush, drill, and tap. I’m assuming there’s still some metal there to drill into while remaining within the bolt’s length, but also without intruding on a water jacket. The tensioner will take up some error in idler positioning, so I’m not super super worried about putting it into the exact spot. That said, being 90 degrees to the head surface is more critical, but within 5 degrees of 90 would probably work, since it’s just rolling along the back of the belt, and should be a bit wider than the belt so the edges won’t interfere.

That said, a drill press should do pretty well as far as keeping the bolt hole square with the head surface.

This is what I was talking about using his video for a guide. If I were to weld it.

+1 :blankspace::blankspace:

Could you drill it out and JB weld / braise / weld a nut in the opening?
Or change the bolt to match the larger hole and tap that?

This is what happens when I’m let to my own thoughts.

The bolt hole can’t be expanded, since it mounts an idler pulley. There’s no material to hog out on the pulley. You can tap JB weld, though, and if the 5/8" depth is enough to keep the pulley stable in aluminum, then it should do with a JB weld repair in part of it. Tapping the epoxy will be stronger than trying to set a nut in place in it, not to mention the difficulty with getting the nut perpendicular to the head surface. Drilling directly can be done with a drill press, which makes squaring it up easier.

That’s how I’d go about this anyway. I mean apart from the aforementioned spare cylinder head. I mean, apart from lighting the ZX2 on fire and calling it a day.

How about a stepped stud? Thread the existing hole, then machine a stud/bolt such that the protruding end is proper for the idler and flush when threaded into the head…

Based on pictures and Luke’s description, the original hole has been hogged out too far (~15mm) for that to be a viable option. I’d also be concerned that the existing hole isn’t square to the head. Moreover, a water jacket is likely only a few millimeters from the stock hole depth, so drilling further isn’t an option. The only way to recover this head is to fill in the hole the previous owner made, and start over. All that’s really up for debate is, what material is best suited to filling that hole.

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I don’t disagree, but I thought I’d throw the idea on the pile…