WC Rod Bearing Clearance
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Topic: WC Rod Bearing Clearance
Posted By: Bob in CO
Subject: WC Rod Bearing Clearance
Date Posted: 23 Mar 2012 at 4:15pm
| I have a 37 WC. Does anyone know the rod bearing clearance for that engine. I think mine are a bit too tight. When I tighten the caps, the crank refused to turn. |
Replies:
Posted By: Gerald J.
Date Posted: 23 Mar 2012 at 5:16pm
|
Sounds like you need shims at the ends of the caps. Last I checked new engine clearance for Ford car engines was rated at .002 to .0025" with a wear limit of .005" checked with plastigage. It may help after checking with plastigage to lubricate the bearings before cranking it over. A heavy oil is good, there is an engine assembly lubricant suggested for that. one engine I used a molybdenum disulfide grease from Dow Corning and that engine started well. Gerald J. |
Posted By: TomMN
Date Posted: 23 Mar 2012 at 5:55pm
|
The WC service manual agrees with what Gerald wrote. "The bearings should have .002 to .003 oil clearance when properly fitted." Now that it is several years ago since I did my WC I can't remember how much shim material was needed on each side of the rod caps. |
Posted By: Chris/CT
Date Posted: 23 Mar 2012 at 6:15pm
| Wondering if you could pull crank out, put cap's w/ bearing's installed, torque and read your ID on the holes. May shed some light on your problem. If it's in the budget, alot of rebuilders like to line bore those bores and rid themselves of the shims. |
Posted By: Bob in CO
Date Posted: 23 Mar 2012 at 6:16pm
| Thanks for the help. I may need to use some shim stock. Our parts house didn't have any shim material in stock. What kind of material is best to use? |
Posted By: Chris/CT
Date Posted: 23 Mar 2012 at 6:19pm
| The few I have seen were brass shim stock. I imagine steel would be fine also. |
Posted By: Gerald J.
Date Posted: 23 Mar 2012 at 6:41pm
|
Look for an envelope of brass shim stock at a hobby shop or hardware store that carries the K&S line of brass pieces. One other thing to check, the bores are never centered in the caps, so reversing a cap is guaranteed to lock up the engine. You probably need shims between where the cap and rod touch. I thought those were original in WC engines. Look in the bottom of your wash tank. Any good car parts place should have plastigage for checking clearance. And might have shim stock. Shim both sides of the rod cap the same ammount. As a test cigarette paper is .003" thick but won't stand up to the engine running. Fastenal and McMaster-Carr I'm sure have all kinds of shim stock, but probably not in the local Fastenal store. Gerald J. |
Posted By: Gerald J.
Date Posted: 23 Mar 2012 at 6:44pm
|
On test I remember from VW aircooled engines was that a rod assembled to the crank without a piston but lubricated if moved to a horizontal position with the crank horizontal should move do the down position by just that weight. Gerald J. |
Posted By: TomMN
Date Posted: 23 Mar 2012 at 6:56pm
|
Small Parts is where I have purchased shim stock online. The thin metal can be cut with a scissor. http://www.smallparts.com/shims-shim-stock/s/16413251/ref=gw_c_m_s" rel="nofollow - http://www.smallparts.com/shims-shim-stock/s/16413251/ref=gw_c_m_s Or you could hone them out to the proper diameter with no shims then you won't need them at all. We did that on my RC: http://home.comcast.net/%7Eold_allis/ac-RC-engine5.html" rel="nofollow - http://home.comcast.net/~old_allis/ac-RC-engine5.html Here is a video of the RC engine assembled with no rings to show there is no drag with all rod and main bearings torqued down and .002 oil clearance on each . [TUBE]5tq7EbSh2kc&list=UUcuxd1GDOT3KuUMf5maX8ug&index=41&feature=plcp[/TUBE] This was of course an extra step and I had to take them out and put the rings on and reassemble but it was fun to see that nothing was dragging. I should add this was only done on the rods, I did use shims on the main bearings, they can be seen in the video. I used plasti-guage to check everything. The crankshaft should roll easily when it is fitted properly, this can be checked before any rods are put on. |
Posted By: CTuckerNWIL
Date Posted: 23 Mar 2012 at 7:00pm
|
I think originally there was .010 shim on each side. The original shim is laminated and is in layers of .0025 so you can take one out of each side as the bearing wears. The biggest problem with these old engines is things get out of round. The best thing to do is bolt the cap to the rod with nothing in it, accurately measure the bore at least 3 ways, vertical and at about 45 degrees each way. If you can't shim it to a round bore that matches the OD of the bearing(minus your crush) get the rods fixed. I got a good set of rods and they worked great but my mains were out of round so I shimmed them to about .002 undersize vertically and honed them with a good Sunnen Hone to the original size. I ended up with .006 shim in the mains and after assembly I had .002 to .003 clearance with plasti-gauge. ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: CTuckerNWIL
Date Posted: 23 Mar 2012 at 8:28pm
Nothing like doing it Right the first time Tom.
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: B26240
Date Posted: 24 Mar 2012 at 7:39am
| Bob you talked about the rod bearings being tight- you also need to check the crank for out of round, as C Tucker said the right shims are laminated and can be pealed down to get the right thickness. also the shims DO NOT go between the bearing shells only between cap and base. the same with the mains. As said when right it should turn freely . remember they will run a little loose but will not run tight. |
Posted By: Bob in CO
Date Posted: 24 Mar 2012 at 4:31pm
| Thanks for all the great help. All was going well and then one of the bolts that hold the caps on stripped. It wasn't even to torque. Now I have to wait until I can get more. |
Posted By: B26240
Date Posted: 24 Mar 2012 at 4:42pm
| Bob another yhing to look at is the castleated (sp) nuts, I was working on one one time and noticed the nut was cracked. |