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lozinit 11-14-2002 06:37 AM

Installing rings w/o oil?
I wanted to see if anyone has attempted to start a new engine without first lubricating the piston rings. (A good case in point would be Scooters '33 over at project33)
I have talked to numerous builders in town and the general concensus seems to be split almost 50/50 in this matter.
I have always assembled the pistons/rings, and then dipped them in a coffee can full of fresh oil before installing them. (I get a little jittery thinking about dry metal to metal contact when starting up a new engine.)

Can you guys offer your opinions in this matter?

Does dry starting the rings lead to pre-mature failure in any way? (Or otherwise just bad to do?), or does coating them in oil first really lead to that bad of a carbon buildup from the get-go?
~Michael 11-14-2002 07:01 AM

I don't know the answer but reading your post is painful! I keep thinking of fingernails on a chalk board and dry rough hands on corduroy. Stop! Stop! I can't take any more!!!!

stonedchihuahua 11-14-2002 07:53 AM

yeah the thought of dry metal on metal doesn't sound too good... I am interested in the answer to this too..

engineczar 11-14-2002 08:49 AM

My usual process is to lightly oil the bores with 30wt. wiping away the excess so the bores are damp. Then oil the wrist pins and the piston skirts with 30wt. coat the bearings with assembly lube and slide them puppies in. The rings seat quickly, and the plugs don't foul. I've used this same process for years and I haven't had a problem yet.

tm454 11-14-2002 08:56 AM

I don't think I have ever heard of NOT oiling the rings, NEVER. What would be the idea, to make metal shavings? I don't think I would take the chance, if you have built engines using oil stay with it, it dons't take that long to break in an engine. Must make it very hard to install those pistons. :eek: :D

engineczar 11-14-2002 09:07 AM

Not hard at all, no shavings, no squeeking, no heat. Remember, I did say that I oil the bore prior to assembly so there is lubrication in all the cross hatches. Question, how much oil do you think is between the rings of the motor in your car sitting in the parking lot right now? If there's more than a thin film than it's probably time to rebuild it.

Quepas00 11-14-2002 09:49 AM

You should always lightly oil the rings and the skirt before installation.

engineczar 11-14-2002 10:04 AM

This might be one of those questions where there is more than one way to skin a cat. Whatever way you learnt or were taught it is ok so long as the end result is what you want. I build 15-20 racing engines a year and I'm very comfortable with my methods and the results.

engineguy 11-14-2002 10:23 AM

Add my name to the list. I have never heard of anyone installing pistons/ring with NO oil. My method is similar to czar's. First the engine is washed completely with HOT water and soap, then rinsed and blown dry using dry filtered air. Then the cylinders and all gasket sealing surfaces are wiped with clean lint-free cloth, using lacquer thinner or rubbing alcohol. Then, dried again this time with a fresh, dry, lint-free cloth. Cylinders are coated with 30# oil, then the rings, wrist pins and piston skirts are liberally oiled with 30#. Upper bearing shell is installed and lubed with ASSEMBLY lube (NOT moly lube or white (fishing reel) grease), then the piston/rod assembly is slid into the cylinder using a quality tapered ring installation tool, protection on the rod bolts. Crank is rotated so that the rod pin is at BDC before the piston is installed, that way you have room to work.
My engines are also built in a clean environment and always at a consistant temperature of 68 to 70 degrees.
Works for me.

Harlequin 11-14-2002 12:27 PM

I have always used a 50/50 mixture of 40# and stp…that has always worked fine for me…I am another addition to the club of hearing this for the first time…I think we need 4 JAW on this :D

lozinit 11-14-2002 12:46 PM

Ok, let me set the record straight before I get anymore PM's/emails about this.

I never said I do the dry start thing. In fact, I have always done quite the opposite.

I brought this question up because after re-reading an engine article at, Sehr performance built his engine for him and stated that he builds all his engines this way. (Along with something about "this is the way NASCAR builders do it too...")

I never and will never try this method, like I said in my original post- I just fear the thought of dry metal to metal contact.
I suppose if people are doing it, it can be done, but I'm not willing to find out on my own.

I can see from the general response I recieved though, I am not the only one who thought this idea didn't sound too great. Call it old school, common sense, whatever you want - I just prefer there to be some kind of lubrication on moving parts.
Who knows, maybe we've been doing it all wrong for all these years. (Makes me wonder about priming the oil system before startup now... maybe thats not needed either. hehehe) ;)

bullheimer 11-14-2002 01:17 PM

i think the light coating of oil would be okay if your so good you know the motor will start soon. i never am. with an old fashioned oil can i squirted a couple of shots into the plug hole and turned it by hand before i put the plugs in. you low/no oilers who are afraid of plug fouling might be interested to know it started on the first turn. but if you build mass amt's of engines you've built more in a week than i have in my life. since the rings dont move against the piston groove, it doesnt need lube right? if it aint broke, dont fix it. i sure as hell would not even think about putting them in dry as a bone, that sounds like insanity. but i'll bet the rings break in quicker that way!! :D

Airport Towing 11-14-2002 01:37 PM

Wow....Dry installing rings. Now I HAVE heard everything. Well I guess whatever turns you on is OK, but it sure sounds like a great way to ruin good parts to me. I personally have to scrub the block, just like engineguy said, but I'm kinda meticulous, so I do it at least twice. :-). I then follow engineczar's method almost to the letter, except I lubricate enough to make things slide just enough. I think the idea is to use just enough oil, but not too much. Yeah, engineczar is correct again, if there is more than a thin film of oil, it IS time for a rebuild. A thin film is all that's required for seal and lubrication. Sorry, but I actually know some NASCAR Engine builders (yeah I know, but it is TRUE) in North Carolina shops who would NEVER install piston rings dry. I know this because I have been present during assembly, so I would say whoever saiid that is WAY wrong. What exactly would be the point of dry installing rings anyways? Does anyone actually think or believe this would promote rapid break in or is it for some other reason? MY 2 cents. :-)

drewhelm 11-14-2002 01:38 PM

I've heard of people coating the cylinders with ATF. Actually, that's what I used on teh clyinder walls when I assembled the 455. Lightly oiled the rings, pins, and skirts, but the cylinder bores were prepped with ATF....Dexron III to be exact!!!

4 Jaw Chuck 11-14-2002 02:25 PM

You can assemble the rings on the pistons dry and then install them on a dry bore but...this should only be done on engines that have been bored and honed with a superfine finish like 600 or finer.

Why you ask.

The theory is this, on an engine the first few strokes up and down the bore before the engine starts is the break-in and compression in the cylinder will condense water in the air and form a lubricating film, actually this is how most oiless air compressors operate although they use carbon rings in this application. After the engine starts 90% of the break-in is already accomplished and oil slung off the crank will immediately lubricate the bore.

Should I do it?

Not unless you are intimate and confident that the engine was assembled perfectly and the bores are perfectly round (honed with torque plates) and the finish on the bores is very fine and absolutely clean.

Does 4 Jaw do it?

What are you nuts? Not on your life although I did this regularly on two stroke racing snowmobile and dirt bike engines (the oil is in the fuel!). I have seen instances where dry bores and dry rings have picked up and galled the bores after only a few minutes of running using this procedure especially with cast iron rings. Chrome-moly and straight chrome rings/bores are much more forgiving in this regard.

Why do people do it?

You got me, I think it is because they like to roll the dice and tempt the engine Gods because they think they are such great engine builders. Me, I like to appease them whenever I can and I say a little prayer whenever I start an engine for the first time. The engine can break-in slowly for all I care, it's a lot safer.

I use STP on every piston/ring because of the high pressure additives, it's good enough for an air cooled aircraft engine it's good enough for me. I do wipe off the excess mind you. Just because some guy says he does it how do you know he didn't at least give the rings a shot of WD-40 before he installed them. The BS can get thick at times.

Be careful out there.

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