Rings won’t fit in grooves on pistons.. HELP!

[67charger383]

I’m partway through building the bottom end of my 383. I was just about to gap the piston rings but when I test fit them they won’t go in the grooves on the pistons…

Do I need special rings or something? 30 over TRW L2293 dome pistons and Hastings 30 over moly rings.

 

[pnora]

If they wont fit they obviously are wrong. What are the piston ring lands measuring? What do the rings measure.

 

[67charger383]

These rings came in a bottom end rebuild kit that I bought and specd 30 over rings.

the new rings and the old factory rings are the same height and both fit Fine in the groove on the factory pistons but neither will on the TRW domes… I guess these pistons require special rings that are different than factory spec? Someone on this forum that has run a set of L2293s has to know

 

[pnora]

Your rings are most likely 5/64 and you need 1/16. So you most likely ordered the wrong rings for the pistons you intend to use.

 

[67charger383]

How would I measure that? I just ordered factory replacement rings for 30 over pistons not knowing that they could be different

 

[pnora]

What is your bore size? 4.280? These might be close but double check the oil ring fitment. Calling Hastings they might know on that obsolete piston.
Hastings Piston Rings 2M5519030 Hastings Premium Ductile Ring Sets | Summit Racing

 

[Fran Blacker]

TRW piston aren't factory pistons, my TRW's 1/16, 1/16 and 3/16 think that is what TRW's use.

 

[Master Gunner]

You order rings to fit the pistons you're using, not what came from the factory.

Mark

 

[MoparRobTX]

Here is a piston from ebay. Looks like it has a 1/16,1/16,3/16 ring pack. Looked your Hastings rings up on summit and they are 5/64, 5/64, 3/16

 

[67charger383]

Here is a piston from ebay. Looks like it has a 1/16,1/16,3/16 ring pack. Looked your Hastings rings up on summit and they are 5/64, 5/64, 3/16

View attachment 1395726

Thanks I ordered the 1/16 ring pack

 

[toolmanmike]

The world is a scarry place sometimes.

 

[33 IMP]

Late to the party. TRW dome pistons are 1/16.
(Clicked on to see if he was using used pistons with pinched ring grooves. Guess the answer is much simpler).

 

[Cranky]

Is this your first engine build? My first 'overhaul' was done without any measuring tools and well, imo I lucked out that everything worked well. Over the years I became a machinist and learned that you CANNOT trust others to make sure things are right. If you plan on building more in the future it would be a good idea to get some tools to measure things. They will pay for themselves over time....and the first time an engine expires during a cam break in, you will spend a lot more fixing it than what the tools cost.

 

[toolmanmike]

Is this your first engine build? My first 'overhaul' was done without any measuring tools and well, imo I lucked out that everything worked well. Over the years I became a machinist and learned that you CANNOT trust others to make sure things are right. If you plan on building more in the future it would be a good idea to get some tools to measure things. They will pay for themselves over time....and the first time an engine expires during a cam break in, you will spend a lot more fixing it than what the tools cost.

The whole thing went south when a "kit" was bought and the rings were for stock pistone and the OP had TRW"s. That will happen. Like a gasket kit for your 318 and you have Edelbrock heads and intake. Of course the gasket's aren't going to be right.

 

[Cranky]

The whole thing went south when a "kit" was bought and the rings were for stock pistone and the OP had TRW"s. That will happen. Like a gasket kit for your 318 and you have Edelbrock heads and intake. Of course the gasket's aren't going to be right.

Still not a bad idea to measure the parts. It doesn't happen very often but there have been times when the parts in the kit weren't right. And if the machine work on the block etc isn't right, the parts in the kit ain't gonna fit even if they are the right parts lol

 

[Nxcoupe]

Is this your first engine build? My first 'overhaul' was done without any measuring tools and well, imo I lucked out that everything worked well. Over the years I became a machinist and learned that you CANNOT trust others to make sure things are right. If you plan on building more in the future it would be a good idea to get some tools to measure things. They will pay for themselves over time....and the first time an engine expires during a cam break in, you will spend a lot more fixing it than what the tools cost.

As a former engine builder as a proffesional, I can say most hobbyists don't see it this way. It's just a bunch of parts you take out of the box and bolt together. I still do assembly as a hobby/side gig, as I still have all my tools, and it can take several days to get all the clearances right, pistons assigned to bores, rods assigned to journals, etc. Most guys are just lucky. I'm not.

 

[BSB67]

The world is a scarry place sometimes.

And it appears to be getting worse, quickly