Piston ring fitting

[SquadX]

I am in the process of getting my engine rebuilt and my engine builder informed me Friday, the oil ring would not fit in the cylinders. So he called total seal (who is the ring manufact.) and they said the oil ring would be a tight fit, really tight fit but it will fit. So my enginer builder gets the oil ring on but is concerned because it is such a tight fit, and does not want to ruin my engine and all the engines he has built, he has never went with a fitting that tight. Does anyone know if this will be a problem? My builder said he's going to sleep on it and decide if to keep the oil ring in or get another were the fit is not so tight. Any input from the experienced engine builders out there?

This is an 01 motor with 96-99 forge pistons. block with honed and piston to wall clearance was .005-.006 or however many zeros are supplies to be in front of the 5 and 6.

 

[Solid Red 98]

If the oil ring fits so tight that there is no gap cold, upon heating and subsequent expansion, the ring could fail. Generally ring specs allow for some expansion which comes in the form of a specified gap. It is possible that the coefficient of expansion between the ring material and the cylinders is coordinated to maintain that zero gap through the expected range of heating, thus the manufacturer of the ring-set being confident that it is O.K. Your builder's caution is warranted in my book. More opinions?

 

[plumcrazy]

talk to DLM about total seal. he doesn't like them and i dont either...

 

[vp97]

You want at least .015 on your oil ring when checking end gaps. If they are tighter, you have the wrong ones. Do not grind on them to fit. Call your ring manufacter.

 

[SquadX]

You want at least .015 on your oil ring when checking end gaps. If they are tighter, you have the wrong ones. Do not grind on them to fit. Call your ring manufacter.

Ring manufacter (total seal) is saying they are suppose to fit tight but my engine builder says that is tighter then anything he has done before.

 

[SquadX]

talk to DLM about total seal. he doesn't like them and i dont either...

Whats your opinion on Total Seal? Why dont you like them?

 

[Joseph Dell]

Did you check all the specs on the pistons? there should be .005 piston to cyl wall clearance and it sounds like the pistons themselves may not be perfect. if they were run hot they could warp a touch. if they are new then nothing to worry about... but still worth checking. i've never had rings be _that_ tough to get on when buying a fresh pack...

 

[Black Mamba 47]

Total Seal will have a tech line you can call. From building many engines in the past you will want at least a .015 to a .018 end gap. I can see on their webb site that they want .015. Do not go any less than this or else during heat expansion and contraction you will lose the seal to the cylinder wall. You will be able to set the gap with a piston ring filer. Don't try it with a file because you will not get the correct angle on the ring. Hope this helps! PS I would call Total Seal to get the true spec from them.

 

[Greg Good Cylinder Heads]

Ring manufacter (total seal) is saying they are suppose to fit tight but my engine builder says that is tighter then anything he has done before.

When you say *tight* are you talking about the gap of the rails when installed in the bore, or the tension of the whole assembly? The minimum gap on the oil rails is .015" on any oil rail. Depending on who made the oil ring expander, Hastings or Sealed Power, and the tension it is rated for, it (the expander) could have a gap or not.

When dealing with 3mm oil rings (which is what your pistons should have), to get a decent amount of tension the expander will typically be larger than the bore, larger than the rails that go over them, and they are a b*tch to install, I can tell you that. You have to be VERY careful that the oil rails don't slip inside the lip on the back of the expander while putting the ring compressor over the piston. They are different than a 3/16 oil ring in that respect, and that is probably what is freaking out your engine builder.

What ultimately matters is the tension of the oil ring assembly in the bore, not the difficulty installing it. To check the oil ring tension you install only the oil ring assembly on a piston, install a pin in the piston, put the piston in the lubed bore, and hook a fish weighing gage to the pin. Slowly pull on the gage and watch what it reads as you pull the piston out of the bore. The *breakaway* reading will be high, but it will drop once the piston is moving. What the reading drops to after the piston starts moving is what you're looking for. 15 pounds is a good place to be with a 3mm oil ring in an aluminum block on the street.

HTH and PM if you need more help.


If your engine builder needs somone at Total Seal to talk to ask for Kevin Studaker. He is very sharp and will explain everything in detail. There's nothing wrong with Total Seal IMO. It's all I use.

 

[SquadX]

Did you check all the specs on the pistons? there should be .005 piston to cyl wall clearance and it sounds like the pistons themselves may not be perfect. if they were run hot they could warp a touch. if they are new then nothing to worry about... but still worth checking. i've never had rings be _that_ tough to get on when buying a fresh pack...

Hey JD,
the piston to cyl wall clearance is .005.

 

[SquadX]

Total Seal will have a tech line you can call. From building many engines in the past you will want at least a .015 to a .018 end gap. I can see on their webb site that they want .015. Do not go any less than this or else during heat expansion and contraction you will lose the seal to the cylinder wall. You will be able to set the gap with a piston ring filer. Don't try it with a file because you will not get the correct angle on the ring. Hope this helps! PS I would call Total Seal to get the true spec from them.

Hey Black Mamba,
My engine builder has been talking with the Total seal tech and thats who advised him the fit would be really tight.

 

[Greg Good Cylinder Heads]

Hey, did you guys get this figured out?