Guest Karm13 Posted June 3, 2017 Share Posted June 3, 2017 Hello all I am new to the forum! I have a 53 nash ambassador custom 252 iron head 2 x 1 bbr carbs It's leaking coolant from multiple places Around the head gasket. But runs! I wanted to replace rod bearings And piston rings for it. While cylinder head is off. The engine has been rebuilt at least ounce before. My question is when I measured the cylinder bores they were all 3.55 the standard bore size for this application is 3.50 and oversize rings come 0.2 0.3 0.60 the oil control rings are worn as well So they warrant replacement also, with little or no lip at the top Has any one seen this before. Is it ever permissible to install 3.60 rings into a 3.55 cylinder bore? Or is it necessary to rebate the block? Link to comment Share on other sites More sharing options...
Frantz Posted June 3, 2017 Share Posted June 3, 2017 Welcome to the forum! I love Rambers, Nashes, and Hudsons! Is it possible additional ring sizes were available at an earlier time too? I've assembled motors, but never gone through a whole rebuild so hopefully someone else can lend a hand. But I would think the ends of the ring would be too close together and the ring would also be at risk for cracking since it will always be compressed. Also, you'd likely get additional wear on the cylinder walls too. Again, I'm not an expert and sometimes the wrong way works better than no way, but I'd think something else is being misseed. Did you calibrate your bore gauge lately? Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 4, 2017 Share Posted June 4, 2017 (edited) It is quite possible to install oversize rings. This used to be a common trick to fix an engine with tapered cylinders without boring or buying new pistons. The secret is to file the rings to size. To do this you need to push the ring into the unworn part of the cylinder using a piston. Measure the ring gap with a feeler gauge. Take the ring and file the ends until you have the correct clearance. To file the rings clamp the file in the vice and hold the ring in your hands. Clamp the ends of the ring over the file and file away. Now that I have showed off my lore of old time mechanical hacking I have a question. Are you sure of your measurements? I never heard of .050 pistons, usually pistons and rings come in matching oversizes. Edited June 4, 2017 by Rusty_OToole (see edit history) 1 Link to comment Share on other sites More sharing options...
Willie Wurke Posted June 4, 2017 Share Posted June 4, 2017 I bought a new Nash Ambassador in 1953 with that same engine except mine had the aluminum head that was prone to corrosion big time! They later went to the cast iron heads. As for piston rings you should try standard . The manufacturers used to label them as standard to .010 oversize. That was a great engine: it first appeared in Nashes in 1917 and was used thru 1955 . REMEMBER: When fitting engine parts it is best to go for a loose fit instead of too tight! Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 4, 2017 Share Posted June 4, 2017 Hello 1st I would like to thank you guys For your responses. I will be considering which route to take soon, I measured each cylinder with a electronic caliper at the top of cylinder lip and with a bore gauge and micrometer! and the reading Is 3.55 in several places in each cylinder bore, I'm at a loss also. Im Wondering how to proceed... parts for big 6s are scarce online. Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 4, 2017 Share Posted June 4, 2017 Willie thank you for replying! you guys Have given me good information. What is the ring gap I'm looking for if tailoring rings to ea cylinder? I'm used to just plug in play! Link to comment Share on other sites More sharing options...
Bloo Posted June 4, 2017 Share Posted June 4, 2017 File fit rings are checked way down in the un-worn part of the cylinder. They need to be pushed straight before measuring. An upside down piston can do this if they're flattop pistons, if not find something the same diameter. You want them as tight as possible at the bottom, because no matter what you do, when they are at the top, where it matters, and where the cylinder is worn, they will be too loose. You want them tight up there too, but its impossible because of the taper. You are only making it less bad. If you get them too tight, the ends will touch when they get hot, and the ring will break and destroy the piston and cylinder. In theory you would set them to the tight end of the acceptable range of gaps in the manual. In real life, leave them slightly looser than the minimum acceptable gap. You cant afford to have them touch. Link to comment Share on other sites More sharing options...
Willie Wurke Posted June 4, 2017 Share Posted June 4, 2017 The ring gap should be .003 inches per inch of cylinder bore; in your case .011" Also check the top ring groove of your pistons for wear. The fix for this is the installation of K-wall spacers. This involves cutting the top of the groove and putting a spring steel spacer above the ring. For some unexplained reason this makes the top groove outlast the original. I used to do this in my shop on all engine overhauls. It involved a manual lathe which rode in the second groove and cut the worn top of the top groove and was operated by hand Link to comment Share on other sites More sharing options...
JWLawrence Posted June 4, 2017 Share Posted June 4, 2017 You should also check for cylinder wall taper. I forget the amount of taper would require a reboring, but someone here will have that info. Too much taper will not allow the rings to seal and piston clearance will be too much. JWL Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 4, 2017 Share Posted June 4, 2017 Over .007 taper is considered due for a rebore. However, in the old days there were special brands of rings like "10 Up" and "Cord" rings that were made for cylinders worn more than that. There is no harm in having an over large ring gap but could be a lot of harm in having too little. Be sure to stagger the gaps when you install the pistons, do not let them all line up. Have been told to put the ring gaps in line with the piston pins because they will work their way around there anyway. Link to comment Share on other sites More sharing options...
cahartley Posted June 4, 2017 Share Posted June 4, 2017 In my opinion far too much time is spent worrying about ring gaps. What matters most is have enough. An extra .005"gap in your engine isn't worth thinking about if the cylinders have only minor tapering. Use standard rings and drive the wheels off of it. 2 Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 5, 2017 Share Posted June 5, 2017 Hello I wanted to thank everyone who chimed in! I know the information I needed could be found in my old principles of automotive book, but there is no substitute for hands on experience from the fourm members... I will verify taper tomorrow! I picked up these new old stock standard rings and will post Measurements when I receive rings. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 5, 2017 Share Posted June 5, 2017 Those are STANDARD size rings, they will not work in an engine that has been bored oversize. You can use (slightly) oversize rings but you can't use rings that are too small, they will not seal. Modern rings are much better, they seal well and are low tension which means less friction and they don't wear the cylinders. I have seen later model (mid 80s and up) engines with over 100,000 miles and practically no cylinder wear. If your engine is bored .050 oversize and the closest ring set is .060 oversize, get that set and file the rings to fit your cylinders. Don't forget you need a little extra clearance for heat expansion. Link to comment Share on other sites More sharing options...
cahartley Posted June 5, 2017 Share Posted June 5, 2017 My bad.........I misread the bore sizes.......it's FIFTY thousandths....... Get a .060 oversize set and open the gaps. Err on more gap than not enough. Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 7, 2017 Share Posted June 7, 2017 Hey guys sorry for slow response After cleaning up a cylinder and piston top with gas and rag I was happy to find Piston size clearly stamped on it. Douh! But it solves the reason the bores are 3.55 I've ordered a set of .060 over rings I hope they fit correctly Also from the photos attached does it look like honing the cylinders will be enough for the rings to seat properly? Cylinder with the most wear shown Thanks everybody for your replys! Mr Otoole thank you for being persistent and rite on the money?I will post back soon... Link to comment Share on other sites More sharing options...
cheezestaak2000 Posted June 7, 2017 Share Posted June 7, 2017 On 6/3/2017 at 3:06 AM, Karm13 said: Hello all I am new to the forum! I have a 53 nash ambassador custom 252 iron head 2 x 1 bbr carbs It's leaking coolant from multiple places Around the head gasket. But runs! I wanted to replace rod bearings And piston rings for it. While cylinder head is off. The engine has been rebuilt at least ounce before. My question is when I measured the cylinder bores they were all 3.55 the standard bore size for this application is 3.50 and oversize rings come 0.2 0.3 0.60 the oil control rings are worn as well So they warrant replacement also, with little or no lip at the top Has any one seen this before. Is it ever permissible to install 3.60 rings into a 3.55 cylinder bore? Or is it necessary to rebate the block? its possible that the ridge that has formed has made you measurement faulty. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted June 8, 2017 Share Posted June 8, 2017 Well that is a .060 over piston so the bores must be .060 over too. Don't know why your measurement came out .050. So get the .060 rings they should fit without filing although you should check them. Hone the cylinders with a bottle brush hone or ball hone clean thoroughly and you should be good for another 50,000 miles. 1 Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 26, 2017 Share Posted June 26, 2017 Hey guys sorry for slow response After cleaning up a cylinder and piston top with gas and rag I was happy to find Piston size clearly stamped on it. Douh! But it solves the reason the bores are 3.55 I've ordered a set of .060 over rings I hope they fit correctly Also from the photos attached does it look like honing the cylinders will be enough for the rings to seat properly? Cylinder with the most wear shown Thanks everybody for your replys! Mr Otoole thank you for being persistent and rite on the money?I will post back soon... Link to comment Share on other sites More sharing options...
Guest Karm13 Posted June 26, 2017 Share Posted June 26, 2017 Hello all I've managed to find all The parts and gaskets needed for the top end job ,Question does anyone have Any sources where I can find piston rings set For this application standard size is readily available but I need a set that's for nash ambassador custom 252cid iron head 2 x 1 bbr carbs 0.60 over wit 4 rings per cylinder, if you have any leads Please let me know Thxs Karmie Link to comment Share on other sites More sharing options...
Guest Karm13 Posted November 30, 2017 Share Posted November 30, 2017 Hello guys it's been several months since starting this post! I thought replacing the leaky head Gasket would solve the issues I'm experiencing with the Nash. Original problem was external coolant leaks around cyl head/block mating area, low compression on all 6 cylinders (80-90psi) runs but lacks power under load!, also oil leaks into all spark plug wells? Things I've done to engine thus far... 1)replaced rings, honed cylinders 2)replaced rod bearings, 3)replaced timing chain and gears 4)resurface head, replace valve guild seals 5)replace head gasket, used high temp copper gasket spray 6)plugs,wires,points, condenser 7)adjust valve clearance 8)Both Carburetors rebuilt Results: engine runs fine no load But takes to long to get to 30mph (no power)? All plugs fuel fouled? With excessive fuel consumption? Front carburetor has strong vacuum! Obstructing air horn causes stalling! Rear carburetor has very weak vacuum? Low rpm change when obstructing air horn with hand? Any replys would really be appreciated! Karmie Link to comment Share on other sites More sharing options...
Rusty_OToole Posted November 30, 2017 Share Posted November 30, 2017 Have you checked compression? I notice you didn't have the valves done even though you had the head off and resurfaced. Did they all check out perfect with no leakage and no wear on the guides? Link to comment Share on other sites More sharing options...
Guest Karm13 Posted December 1, 2017 Share Posted December 1, 2017 Hi Rusty, The machine shop wanted over $300 To do the valve job! I just had them resurface the head. So I got out the hand crank valve lapper, the seat and valves looked pretty good but no I didn't verify The valve guilds... the compression is Uniformly 80-90 psi on all 6 cylinders before and after repairs perfomed, so I suspected worn rings or timing chain. So it looks I'll have to r an r the head an have it done at the machine shop. And hope the problem lies therein. Question the spark plug wells all have Oil pooling on top of the plugs not causing a misfire! The inserts seem tin or sheet metal. Are you familiar with this Issue and know of a fix? Also I dont think The leaky spark plugs wells would Affect compression would they? I'm not that keen on old school engines I started wrenching in 1981and 20yrs of ca, smog inspection Thanks a bunch, Karmie Link to comment Share on other sites More sharing options...
Rusty_OToole Posted December 1, 2017 Share Posted December 1, 2017 The compression seems low but if it is the same on all cylinders the engine should run decent if not 100%. Don't know why oil should pool around the plugs unless there is an oil leak. Don't know what you mean by tin inserts. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now