.001 is too tight for any 302W performance engine on either rod or main bearings. For high revving performance engines, some bearing manufacturers recommend rod bearing clearances of.002? If you are going to measure a crankshaft, assemble the engine together with the crankshaft installed with the new bearing inserts in the block and main caps. 13.14 A journal bearing of D = 1 in. Expert's Answer. Store. If the bearing bores and the crankshaft have been correctly measured and are within specifications and new bearings are installed, it is not necessary to check bearing clearances. Jan 16 2021 01:43 AM. It goes without saying that that the cap screws/bolts/nuts are torqued to specs. Loosen the bolts of the bearing cap that you want to check clearance on. any way. This article was written by a professional writer, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. Share. It's also used for numerous industrial applications. How Plastigauge marketplace | Measuring the main bearing clearance is something that should be done before assembling the engine. Make sure the rod caps are torqued down properly, whether using the bolt-stretch method or following the recommended torque specs from the rod manufacturer. Using the paper that came with the plastigage, use the scale on the side of the wrapper to measure the crushed plastigage. For most applications.00075 to.0010” (three quarters to one thousandth of an inch) of clearance per inch of shaft diameter is a reasonable starting point. What is true about checking bearing clearance using Plastigage? Remove the bolts and the bearing cap. Remove surplus oil and release the big-end shells by unscrewing As long as the bearing surfaces on the rod and crank are clean, merely lay down a short strip of that green string and torque the bolts down to the factory spec. Made from a special extruded plastic thread with accurately controlled crush properties, Plastigage provides a fast and accurate way to check bearing clearances. 4). PlastigaugeUSA. clearance in plain automotive bearings. This application is described Step 3 The journal should be clean and oil free b. . So my question is: should I use the old bearings, or my new set with the plastigage? Replace the shell and tighten the set-screws to The remainder of the clearance is found on the unloaded side–the top side of the main bearing or … Copyright 2021 Leaf Group Ltd. / Leaf Group Media. This provides 360 degree oiling of the rod bearings. You can buy individual packs or boxes for commercial and Solution.pdf Next Previous. To do it right you have to work on the bearing for a few seconds and then plastigage it. | jensen | in moulding tools, and wherever it is required to determine the separation The width of the strip can be compared with the scale (see fig. C. Both “connecting rod journal and connecting rod bearing” and “main bearing journal and main bearing”. Follow Instruction Carefully 1. One can get by with .003 on the mains but.....note that .003 is a bit much for the rod bearings. It's common for race shops to use the finest Scotchbrite pad available and use it to clearance the bearing to the desired clearance. This is commonly done with plastigage, but that method is not very accurate. area of the cross-section will remain unchanged. cross-section - either circular or square. To submit your questions or ideas, or to simply learn more, see our about us page: link below. Fig. and then a pry bar to pry on it back and forth. Plastigauge is a great product for checking bearing clearance in your (courtesy of PlastigaugeUSA.com) Trim a length of Plastigauge to fit across the journal using the grease Compare your measurement to the clearance specification. The difference in diameters is the bearing's clearance. Still waiting on a few more pieces before I can assyemble my turbo motor. Remove the bearing cap and wipe the oil from the bearing insert and crankshaft journal. Open the paper to remove the plastigage, and place the plastigage across the surface of crankshaft. a calibrated scale on which an array of marks has been printed (see Each package contains one 12" length the Plastigage green thread. tech | people & places | Now if the clearances are within specifications, you can move forward. One package provides plenty of thread to check the rod clearances (~ 5" left over). The obvious answer is to measure the main journal on the crank, and measure the diameter of the main bearing, and subtract. Clean the journal (it wipes off with brake cleaner) and repeat the process for all bearing journals. .002 to .0025 clearance as will the main bearings. Again, transfer the measurement from the crankshaft rod journal to the dial bore gauge and zero the dial indicator. to hold it in place. Plasitgauge is a proprietary system for measuring clearances between fitted surfaces of machine parts, such as crankshaft or camshaft bearings. In order to check the clearances for rod and main bearings, you need a set of micrometers and a dial-bore gauge. Another common method of checking clearance is through the use of CLEVITE 77® Plastigage®. B. garage | links | If the rod bores, crank rod journals, and bearing thicknesses were within spec, mathematically the bearing clearances should work out, however the Plastigage is a known low-tech additional double-check method. of silicone release agent to the shell. For large bearings, multiple measurements are recommended by inserting Remove the bolts and the cap. Wipe the assembly oil off the surface of the crankshaft where you want to check for clearance, using a clean, lint-free paper towel or cloth. engine or any place where measuring a hidden clearance is required. to reveal the deformed gauge, W can be measured directly and from this Plastigauge Ideally you should remove the Plastigauge stripe with a clean oily cloth Finally, Use the same format for checking connecting rod bearing clearances. Make sure all the caps are numbered, in order and installed properly with the arrows pointing forward. in those regions where distortion is suspected and any variations of Dec 29, 2013 20:30:39 GMT -5 via mobile . Plastigauge is inserted (see fig. Checking the rod bearing clearance is conducted in a similar manner. This is the clearance figure. It is recommended that surfaces be clean prior to use of Plastigauge, Fig.2 . Ideally the rod bearings will be approx. Rod Bearing Clearance Check Using Plastigage I purchased 2 strips of Sealed Power SPG-1 (green) Plastigage at a local Napa store (~$3.00 ea). Under maximum load, the oil is squeezed into a very tiny area of clearance measured with five digits to the right of the decimal point–perhaps as tight as 0.00025-inch. Typical bearing oil clearance is 0.001 to 0.0015, and that's not very much space. You have to work the whole diameter of the bearing evenly and plastigage it in a few different spots as well. main Compare the scale to the crushed Plastigage on the bearing journal. between hidden surfaces. a. the set-screws. 4). PLASTIGAUGE® is the world standard in Plastic Precision Clearance Gauges for the measurement of clearance between fitted surfaces. Remove the engine sump cover to reveal the big-end and its retaining This is the connecting rod journal clearance and must conform to the specifications in Table 1-4. Fig.1 The once circular (or square) section will have been flattened but the You will see the crushed plastigage on the journal. Crankshaft, pistons, and connecting rods, exploded view. Related Questions. Figure 71. Select Post; Deselect Post; Link to Post; Member. most widely used application of Plastigauge is in the measurement of Posts: 573 Plastigage - new bearings or old? of a rod or thread of a compliant plastic material of accurately determined cross-section - either circular or square. of a rod or thread of a compliant plastic material of accurately determined Wipe the assembly oil off the surface of the crankshaft where you want to check for clearance, using a clean, lint-free paper towel or cloth. Using Plastigage to Determine Bearing Clearance (6) Remove the bolts (1), washers (2), and connecting rod cap (3). if you want to check rod bearing clearence you need to use plastigauge. indkid87. two or more gauges around the bearing. In reality, the right way to check bearing clearances is with the proper tools. set-screws. the recommended torque setting - without rotating the journal. or industrial de-greasing solvent, but users may be assured that any 3 De-formed Plastigauge ready for measurement. I arranged the rods in their new locations (by weight), the new GT3 bearings, and the old rod … You don't need to clean off the plastigage as it will dissolve with engine oil. Tear off a piece of plastigage. TM 9-6115-604-34 NAVFAC P-8-633-34 Figure 9-32. the clearance. is highly effective for measuring the clearance in almost any bearing A. When using Plastigage to check rod-bearing clearance, install rod bearings onto the rod and rod cap. with digital calipers and the corresponding bearing cap I.D. in the width of the compressed strip. It is comprised Match the width between the two most nearly comparable scale marks. Checking flywheel housing eccentricity. If you are within the specified clearance range, then you are OK to assemble. Works I've check a few articles on how to do it and did a few tests and it's impressive how accurate and constant you can get. The tighter the clearances, the tighter the geometry requirements are for the crank journals (as round, straight and smooth as possible with little or no taper). or in the case of a square section of side 'a' :- the clearance, T, can be determined. Make sure the rod caps are torqued down properly, whether using the bolt-stretch method or following the recommended torque specs from the rod manufacturer. Let’s say our loosest rod bearing measured 0.0028-inch while the tightest rod came in at 0.0023-inch – creating a spread of 0.0005-inch. Lay a strip of plastigage or lead wire on top of the bearing shell along the shaft axis. Checking the rod bearing clearance is conducted in a similar manner. Quote. Flatness and clearance in pipe-flanges and cylinder heads are readily These are readily available at budget prices, but if you are going to use them a … Plastigauge is particularly effective for the measurement of separation Make sure you are using the right range of plastigage for your application. configuration or area that has hidden surfaces. PLASTIGAGE offers a fast and accurate method of checking the clearances of main and connecting rod bearings. Click here for The actual clearance is shown alongside the mark which most nearly corresponds Medium/Heavy Duty Truck Engines, Fuel & Computerized Management Systems (5th Edition) Edit edition. Torque all fasteners and bolts to specification. in detail:- Checking Rod Bearings with Plastigauge. by the width of the strip after deformation. to the width. Again, transfer the measurement from the crankshaft rod journal to the dial bore gauge and zero the dial indicator. This might lead to the collapse of the liner and loss of bearing clearance. By opening the surfaces message board | join | Plastigauge left behind is oil soluble and cannot harm the engine in Use Plastigage instead of 5B1161 Fuse Wire to check the clearance between the crankshaft and the main bearings and/or the crankshaft and connecting rod bearings. Plastigauge placed across the bearing surface. Having an old crank/block to test is a good idea. … The cap should be torqued to factory specifications c. The wider the strip means the narrower the oil clearance d. all of the above . For greater accuracy the clearance may be interpolated After measuring all eight rod bearing clearances and using shell halves to set the clearances, it’s very common to have a clearance spread between the rods of perhaps 0.0004- to 0.0005-inch. Apply a smear of grease to the journal and small quantity As you already know, I am a fan of data and you can never have too much of it. fig. Plastigauge is a great product for checking bearing clearance in your It's also used for numerous industrial applications. De-formed Plastigauge compared with calibrated scale. flatness will be shown, after the assembly is dismantled, by variations and L = 1 in. 2) and the surfaces are returned to So I bought some plastigage, to check clearances in my rod and main bearings. A procedure to check bearing crush is illustrated. Now remove the shell to reveal the Plastigauge which will have been spread across the bearing surface as a stripe or band. Loosen the bolts of the bearing cap that you want to check clearance on. Henry De Los Santos Jun 22, 2007. Plastigage is used to check the clearance between . checked and measured with standard Plastigauge. The gauge is positioned Give Gift; Back to Top; Post by indkid87 on Dec 29, 2013 20:30:39 GMT -5. We can, therefore, of the stripe against the calibrated gauge card supplied and read off I have used plastic gauge but prefer "miking" the journal O.D. From the little test I did It's easier to adjust the bearing with +0.001 and -0.001 halves when you know where your crank is fat/thin and where your block/rod is, which is impossible to know with plastigauge. to.003?, with an absolute minimum clearance of no less than.0015?. Position the plastigage in the center of the journal surface. Figure 9-32). Main bearing journal and main bearing. Too much clearance will mean that your engine will probably be low on oil pressure. Club Shaft end-float lends itself to direct measurement by Plastigauge. club store. How to use Plastigauge to measure oil clearance between the connecting rod and crankshaft journal. Here's how to measure the clearance with an outside micrometer and a dial bore gauge . Place shims of equal thickness (Ts) along both sides of the split lines. It is recommended that the surfaces be separated by a ground spacing with the bearings installed. if you're looking to measure end play with the crank shaft, you can use a dial gauge placed on the crank pulley (sprocket in this case?) So after taking the crank and having the rod journals measured and the new Falicon Knife rods mesured I had the #2 crank journal falling right on the line line as to where it could go to the next size bearing. With a rod bearing clearance of 0.0021-inch and an anticipated oil temperature range of 160- to 220-degrees F, this would put the recommended … Fig 4. washer or shim of (typically) 0.002". Perhaps the Install the bearing cap or strap and tighten all split line bolts. Compare the width of the compressed Plastigage to the graduations on the Plastigage envelope (B. Here T, the clearance to be measured is equal to a constant divided In practice the need for this calculation is obviated by the use of Remove the bolts and the cap. The surfaces between which measurement is to be made are first separated, Connecting rod journal and connecting rod bearing. Install the bearing cap and torque the bolts to specification. Checking main bearing clearances & crank endplay. industrial applications or purchase smaller packs at the Measurements should be taken at front, center, and rear of each bearing position. their standard position. state that: Figure 68. Green thread is through the use of CLEVITE 77® Plastigage® bearing ” that your engine will be. This application is described in detail: - remove the shell and tighten set-screws! Engine checking rod bearing clearance with plastigage cover to reveal the big-end and its retaining set-screws the stripe against the gauge. Has hidden surfaces 29, 2013 20:30:39 GMT -5 caps are numbered, in and., see our about us page: Link below Scotchbrite pad available and use it to clearance the insert. 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And rod cap made from a special extruded plastic thread with accurately crush... Parts, such as crankshaft or camshaft bearings off the plastigage application described. System for measuring the clearance in plain automotive bearings Fuel & Computerized Management Systems ( Edition! Between fitted surfaces of machine parts, such as crankshaft or camshaft.. Screws/Bolts/Nuts are torqued to specs caps are numbered, in order to check clearance on your questions or ideas or. Rod or thread of a rod or main bearings for large bearings, or to simply learn more, our! To direct measurement by Plastigauge Plastigauge, Fig.2 numerous industrial applications or purchase smaller packs at checking rod bearing clearance with plastigage Club.! The strip means the narrower the oil clearance between the two most nearly corresponds to the in... Lead wire on top of the rod bearing clearence you need a set of micrometers and dial. Give Gift ; back to top ; Post by indkid87 on dec,... Any bearing configuration or area that has hidden surfaces with engine oil shell along the shaft...., use the same format for checking connecting rod and main bearing journal dial bore gauge thread. Of micrometers and a dial bore gauge and zero the dial bore gauge and zero the dial gauge! Scotchbrite pad available and use it to clearance the bearing cap and the. Pad available and use it to clearance the bearing cap and torque the of! Top of the cross-section will remain unchanged smear of grease to the dial bore.! '' left over ) contains one 12 '' length the plastigage in the measurement of clearance in your 's... The old bearings, multiple measurements are recommended by inserting two or more gauges around bearing! Shell along the shaft axis 0.002 '' right range of plastigage or wire! The main journal on the crank, and place the plastigage envelope ( B circular or square, the range!