1G Valve contact - are these pistons salvageable?

[dwb]

Timing belt broke and I finally got the head off. All the pistons look about the same with valve marks. Are these pistons salvageable?

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[MindBlowin03]

I would say yes. Make sure to file down the rough edges to avoid hot spots.

 

[AWD-Tony]

+1. Real question is are the valves sealing/seated properly.

 

[dwb]

+1. Real question is are the valves sealing/seated properly.

Probably not. I'm putting a different head on.

 

[DSMPT]

If this happened at low/mid RPM, usually it's fine like already mentioned above, just smoothen the contact marks. But if it happened at high RPM, maybe it's better to inspect the pistons for damages, such as ring land and wrist pin boss, etc.

 

[dwb]

If this happened at low/mid RPM, usually it's fine like already mentioned above, just smoothen the contact marks. But if it happened at high RPM, maybe it's better to inspect the pistons for damages, such as ring land and wrist pin boss, etc.

Maybe 3k rpm with no load. I'll be going through the bottom end anyway, 270k and it was using a lot of oil.

 

[pauleyman]

If you're going through bottom end why wouldn't you replace the pistons? To your original question yes I've cleaned up something like that before but the above statements stand. I would inspect the wrist pin boss and the ring lands if you intend to use it. If I were doing a full bottom end, unless I already had nice forged pistons, I would buy new pistons. Further still you are going to have to go to the machinist anyway. If those bores don't check out you'll have to have new pistons anyway.

 

[dwb]

If you're going through bottom end why wouldn't you replace the pistons? To your original question yes I've cleaned up something like that before but the above statements stand. I would inspect the wrist pin boss and the ring lands if you intend to use it. If I were doing a full bottom end, unless I already had nice forged pistons, I would buy new pistons. Further still you are going to have to go to the machinist anyway. If those bores don't check out you'll have to have new pistons anyway.

Good point! I'm really just looking at my options for now. There's probably a lot more things I need than I realize.

 

[Adam]

If that's the only damage after a good inspection ... I'd run them. Just hit em with the Dremel. But like stated, if you're going through the bottom end anyways, might as well throw in some new ones. 270k they definitely have some wear on them.

 

[steve]

If the head you have hasn't been milled down to scrap consider having the machinist rebuild it too as a spare.

 

[dwb]

If the head you have hasn't been milled down to scrap consider having the machinist rebuild it too as a spare.

Is there a way to tell how much has already been milled? I'm pretty sure the one I plan to use has never been milled, but not so sure about the other one.

Speaking about machinists, Steve, since you're in Boulder do you know of anyone you can trust? I'm just down the turnpike from you. I'm going to give HiPro Engines in Denver a call, but if they don't work out I'm back to the drawing board.

 

[AWD-Tony]

Is there a way to tell how much has already been milled? I'm pretty sure the one I plan to use has never been milled, but not so sure about the other one.

Speaking about machinists, Steve, since you're in Boulder do you know of anyone you can trust? I'm just down the turnpike from you. I'm going to give HiPro Engines in Denver a call, but if they don't work out I'm back to the drawing board.

https://www.dsmtuners.com/threads/how-to-measure-a-4g63-for-cylinder-head-for-thickness.413757/

 

[steve]

Speaking about machinists, Steve, since you're in Boulder do you know of anyone you can trust? I'm just down the turnpike from you.

I'm a reverse snowbird that's been trapped by COVID the past few years. We bought this place for when my youngest was going to CU and started visiting for the winters once she graduated and got stuck here. My home base is back in Illinois until I figure out where we go next so I don't have any insight into Colorado machine shops.

@biglady112 is the Northern Colorado experienced insider that I know of.

 

[dwb]

I'm a reverse snowbird that's been trapped by COVID the past few years. We bought this place for when my youngest was going to CU and started visiting for the winters. My home base is back in Illinois until I figure out where we go next so I don't have any insight into Colorado machine shops.

@biglady112 is the Northern Colorado experienced insider that I know of.

Gotch, no worries at all. @biglady112 already recommended HiPro, so that's my plan for now.