{"id":1447,"date":"2026-09-24T09:43:03","date_gmt":"2026-09-24T01:43:03","guid":{"rendered":"https:\/\/www.changweiintl.com\/en\/?post_type=ccm_blog&#038;p=1447"},"modified":"2026-09-24T09:43:04","modified_gmt":"2026-09-24T01:43:04","slug":"flywheel-housing-sae-size-pto-guide","status":"publish","type":"ccm_blog","link":"https:\/\/www.changweiintl.com\/en\/blog\/flywheel-housing-sae-size-pto-guide","title":{"rendered":"Flywheel Housing: SAE Size, PTO Opening and Cast Marks"},"content":{"rendered":"<div class=\"wrap\">\n<h1>Flywheel Housing: SAE Size, PTO Opening and Cast Marks<\/h1>\n<p>The flywheel housing is the largest casting bolted to the back of a diesel engine. It is also one of the easiest parts to order wrong, because two housings can look identical in a catalogue photo and still differ in the pilot bore by half an inch, or have the power take-off aperture on the opposite side.<\/p>\n<p>A housing that does not fit is not a small problem. The transmission will not line up, or it will bolt on and then run out of alignment and destroy the input shaft bearing.<\/p>\n<p>This guide covers what the housing does, how the SAE size is determined, why the PTO opening position matters, and how to read the marks cast and etched into the part itself so you order the right one the first time.<\/p>\n<h2 id=\"table-of-contents\">Table of Contents<\/h2>\n<ul>\n<li><a href=\"#what-the-flywheel-housing-actually-does\">What the flywheel housing actually does<\/a><\/li>\n<li><a href=\"#sae-j617-the-number-that-decides-whether-it-fits\">SAE J617: the number that decides whether it fits<\/a><\/li>\n<li><a href=\"#why-heavy-diesel-housings-are-cast-iron\">Why heavy diesel housings are cast iron<\/a><\/li>\n<li><a href=\"#where-the-pto-opens-left-right-or-centre\">Where the PTO opens: left, right or centre<\/a><\/li>\n<li><a href=\"#the-sensor-pad-and-the-machined-faces\">The sensor pad and the machined faces<\/a><\/li>\n<li><a href=\"#what-the-marks-on-your-housing-tell-you\">What the marks on your housing tell you<\/a><\/li>\n<li><a href=\"#part-numbers-sinotruk-az-series-and-cummins-c-l-series\">Part numbers: Sinotruk AZ series and Cummins C\/L series<\/a><\/li>\n<li><a href=\"#how-to-order-a-flywheel-housing\">How to order a flywheel housing<\/a><\/li>\n<li><a href=\"#faq\">FAQ<\/a><\/li>\n<li><a href=\"#about-changwei\">About Changwei<\/a><\/li>\n<li><a href=\"#related-reading\">Related reading<\/a><\/li>\n<\/ul>\n<h2 id=\"what-the-flywheel-housing-actually-does\">What the flywheel housing actually does<\/h2>\n<p>It does four jobs at once, and all four are structural.<\/p>\n<p>First, it connects the engine to the transmission. The rear face carries the bolt pattern that the gearbox bell housing bolts to.<\/p>\n<p>Second, it carries the flywheel and clutch assembly. The flywheel spins inside the housing, and the clutch release mechanism mounts to it.<\/p>\n<p>Third, it locates the starter motor. The starter nose sits in a machined bore on the housing, and that bore position sets the mesh between the starter pinion and the ring gear. If the starter mounting face is not square to the housing centreline, the pinion sits at the wrong depth and chews the ring gear teeth on every start.<\/p>\n<p>Fourth, it carries the weight and the bending load. In a truck the engine and gearbox are a single rigid assembly, and the housing is the joint in the middle of it. Under torque reaction and over rough ground, that joint sees a lot of bending.<\/p>\n<p>That fourth job is why the housing is as heavy as it is. It is not a cover. It is a structural member.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Large flywheel housing held by a worker, showing the size of the casting\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-handling-scale.jpg\" \/><\/p>\n<p>Size is the first thing to get right. Housings in our range run from about 6 kg to over 20 kg, and the difference between a small industrial housing and a truck housing is visible before you put a tape on it.<\/p>\n<h2 id=\"sae-j617-the-number-that-decides-whether-it-fits\">SAE J617: the number that decides whether it fits<\/h2>\n<p>Flywheel housings follow SAE J617, which fixes the flange dimensions so that any compliant engine will mate to any compliant transmission of the same size. The size is written as a number, SAE 0 through SAE 6.<\/p>\n<p>The counter-intuitive part: the higher the SAE number, the smaller the housing. SAE 1 is a big housing for a heavy truck engine. SAE 4 is a small one for a light industrial engine.<\/p>\n<table>\n<thead>\n<tr>\n<th>SAE No.<\/th>\n<th>Pilot bore<\/th>\n<th>Bolt holes<\/th>\n<th>Bolt size<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>SAE 0<\/td>\n<td>25.500 in \/ 648 mm<\/td>\n<td>16<\/td>\n<td>1\/2-13<\/td>\n<\/tr>\n<tr>\n<td>SAE 1<\/td>\n<td>20.125 in \/ 511 mm<\/td>\n<td>12<\/td>\n<td>7\/16-14<\/td>\n<\/tr>\n<tr>\n<td>SAE 2<\/td>\n<td>17.625 in \/ 448 mm<\/td>\n<td>12<\/td>\n<td>3\/8-16<\/td>\n<\/tr>\n<tr>\n<td>SAE 3<\/td>\n<td>16.125 in \/ 410 mm<\/td>\n<td>12<\/td>\n<td>3\/8-16<\/td>\n<\/tr>\n<tr>\n<td>SAE 4<\/td>\n<td>14.250 in \/ 362 mm<\/td>\n<td>12<\/td>\n<td>3\/8-16<\/td>\n<\/tr>\n<tr>\n<td>SAE 5<\/td>\n<td>12.375 in \/ 314 mm<\/td>\n<td>8<\/td>\n<td>3\/8-16<\/td>\n<\/tr>\n<tr>\n<td>SAE 6<\/td>\n<td>10.500 in \/ 267 mm<\/td>\n<td>8<\/td>\n<td>3\/8-16<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>To identify a housing you do not need the part number. Measure the pilot bore across the register, and count the bolt holes on the flange. Those two numbers put you in one row of the table above.<\/p>\n<p>Two cautions. Measure the bore, do not assume it from the engine model, because the same engine family is built with different housings for truck, industrial and marine applications. And when a housing has been repainted, check that the flange face is still flat and that the bolt holes have not been opened out by a previous repair.<\/p>\n<p>SAE 0 and SAE 1 housings are what you find on large displacement truck and industrial engines. SAE 2 and SAE 3 cover most medium truck work. SAE 4 and below are small industrial and agricultural engines.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Flywheel housing with machined central pilot bore and cast identification panel\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-komatsu-p200-cast-boss.jpg\" \/><\/p>\n<p>A Komatsu P200 housing. The central bore is the register that locates the transmission, and it is the dimension to measure first. The cast panel to its left carries the foundry identification.<\/p>\n<h2 id=\"why-heavy-diesel-housings-are-cast-iron\">Why heavy diesel housings are cast iron<\/h2>\n<p>Almost all of the housings we make are grey cast iron, and the reason is stiffness rather than strength.<\/p>\n<p>The housing has to hold the transmission input shaft concentric with the crankshaft. If it flexes under load, that alignment changes, and the gearbox input bearing and the clutch release bearing take the damage. Cast iron is roughly three times stiffer than aluminium for the same section, so a cast iron housing holds alignment under load in a way an aluminium one cannot without becoming much bulkier.<\/p>\n<p>The second reason is that a housing is a complicated shape. It has a large bore, several machined faces, ribs, and often a PTO aperture. Casting is the economical way to make that shape, and cast iron casts well.<\/p>\n<p>The third reason is noise. A diesel engine radiates a lot of noise through its structure, and the housing is a large flat-ish panel on the back of it. Cast iron dampens that better than sheet metal or aluminium.<\/p>\n<p>Aluminium housings exist, mostly on lighter engines where the weight saving matters more than the stiffness.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Interior of a large flywheel housing showing the ribbed structure\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-internal-ribbing.jpg\" \/><\/p>\n<p>Look inside a housing and you see why it is stiff. The webbing between the central bore and the outer wall is not decoration. Those ribs carry the load from the transmission flange back to the engine block, and the pattern is different on every housing because it follows the load path. When you compare a genuine housing with a copy, the rib layout is one of the things that gives it away.<\/p>\n<h2 id=\"where-the-pto-opens-left-right-or-centre\">Where the PTO opens: left, right or centre<\/h2>\n<p>This is the detail that catches out buyers who matched the SAE size correctly.<\/p>\n<p>Many truck engines drive auxiliary equipment from a power take-off that passes through the flywheel housing. Whether that engine needs a housing with a PTO aperture on the left, on the right or in the centre depends on what the truck is doing. A tipper needs a pump drive. A truck with a crane or a blower needs a different one.<\/p>\n<p>The basic casting is often the same. The aperture position is not.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Komatsu P300 flywheel housing, machined rear face with multiple bolt patterns\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-komatsu-p300-machined-face.jpg\" \/><\/p>\n<p>This is a large Komatsu P300 housing seen from the rear. You can see the machined flange face with its ring of bolt holes, the machined bosses for ancillary mounts, and the large central bore where the flywheel sits. The handwritten &#8220;7459 C051608MC&#8221; is a workshop reference, not a part number.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Komatsu P300 flywheel housing in side view showing the depth of the casting\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-komatsu-p300-side-depth.jpg\" \/><\/p>\n<p>From the side you can see how deep this housing is. Depth is set by the flywheel and clutch pack that has to fit inside, and it is the dimension that gets ignored most often when someone orders from a drawing rather than from a measurement. Note also the machined bore in the lower wall, which is where a shaft or PTO passes through.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Centre drive flywheel housing configuration\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-center-drive-configuration.jpg\" \/><\/p>\n<p>This one is a centre drive pattern. Compare the position of the openings with the housing above and the difference is obvious. Same general shape, different aperture layout.<\/p>\n<p>When you order a housing, the PTO requirement has to be stated. Sending the SAE size alone is not enough if the vehicle drives anything off the PTO.<\/p>\n<h2 id=\"the-sensor-pad-and-the-machined-faces\">The sensor pad and the machined faces<\/h2>\n<p>Modern diesel engines need a crankshaft position signal, and on many engines the sensor reads a target on the flywheel and mounts through the flywheel housing.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Machined sensor pad on a flywheel housing with the sensor bore\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-sensor-hole-machined-pad.jpg\" \/><\/p>\n<p>This close-up shows the sensor pad. Note the machined flat, the drilled and tapped holes for the sensor retaining bolt, and the bore itself. The pad is machined after casting so that the sensor sits at a fixed, repeatable distance from the flywheel target. If that face is not machined flat, or the housing is a reproduction that skipped the machining, the air gap is wrong and the engine will not start or will run badly.<\/p>\n<p>This is the kind of detail that separates a real housing from a copy. It is also cheap to get right and expensive to get wrong.<\/p>\n<h2 id=\"what-the-marks-on-your-housing-tell-you\">What the marks on your housing tell you<\/h2>\n<p>There are two completely different kinds of marking on a flywheel housing, and it pays to know which is which.<\/p>\n<h3 id=\"cast-marks-the-part-number-and-the-weight\">Cast marks: the part number and the weight<\/h3>\n<p>On housings that were designed to carry identification, the part number is cast into the metal in raised characters, along with the casting weight.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Flywheel housing with cast part number AZ1034010008P and cast weight on the side wall\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-az1034010008-cast-part-number.jpg\" \/><\/p>\n<p>On this housing the panel reads AZ1034010008P, with a mould reference above it and the cast weight below. This is a Sinotruk HOWO pattern housing. Because the number is cast in, it cannot fall off or be painted over, and it survives the life of the part.<\/p>\n<p>The cast weight is worth knowing about. It is the weight of the bare casting as it comes out of the mould, before machining. It is not the finished weight, so do not use it for shipping calculations.<\/p>\n<h3 id=\"etched-marks-the-data-plate\">Etched marks: the data plate<\/h3>\n<p>On current production, and on anything made for a major OEM, there is also a machined or laser-etched data plate.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Laser etched data plate on a flywheel housing showing the part number 4947472 and a data matrix code\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-c4947472-etched-data-plate.jpg\" \/><\/p>\n<p>This one carries the part number 4947472 on the first line, with production codes below it and a data matrix code on the right. The code is the traceability record. Scan it and the foundry can tell you which heat of iron the casting came from and when it was poured.<\/p>\n<p>If you are buying housings and the supplier cannot tell you what the data matrix code on their own part resolves to, that is worth asking about.<\/p>\n<h2 id=\"part-numbers-sinotruk-az-series-and-cummins-c-l-series\">Part numbers: Sinotruk AZ series and Cummins C\/L series<\/h2>\n<p>Two families that we supply and that come up constantly.<\/p>\n<h3 id=\"sinotruk-howo-az-series\">Sinotruk \/ HOWO AZ series<\/h3>\n<p>Our Sinotruk flywheel housing range includes these part numbers:<\/p>\n<table>\n<thead>\n<tr>\n<th>Part number<\/th>\n<th>Note<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>AZ1500010012<\/td>\n<td>Standard HOWO housing<\/td>\n<\/tr>\n<tr>\n<td>AZ1500010013<\/td>\n<td>Variant of the above<\/td>\n<\/tr>\n<tr>\n<td>AZ1500019035A<\/td>\n<td>With sensor provision<\/td>\n<\/tr>\n<tr>\n<td>AZ1557010012<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>AZ1034010008<\/td>\n<td>Cast number reads AZ1034010008P, cast weight 7.6 kg<\/td>\n<\/tr>\n<tr>\n<td>AZ1246010019<\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>AZ1095010012<\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The AZ prefix is the Sinotruk HOWO numbering system. Note that AZ1500010012 and AZ1500010013 differ, and that AZ1500019035A carries a sensor provision that AZ1500019035 may not.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"Sinotruk HOWO flywheel housing, part number AZ1500010012, green painted\" src=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-az1500010012-green.jpg\" \/><\/p>\n<p>The AZ1500010012 housing after machining and painting. The machined rear flange is the SAE face; the aperture in the lower left wall is the PTO provision. Both have to be confirmed against the vehicle before the part is ordered.<\/p>\n<h3 id=\"cummins-c-l-series\">Cummins C \/ L series<\/h3>\n<p>The Cummins housing 4947472, usually listed as C4947472 in the aftermarket, is a good illustration of how widely one casting spreads.<\/p>\n<p>It weighs 22.0 kg and is listed against roughly thirty engine models in the 8.3 to 8.9 litre C and L family, including ISC, ISC8.3, ISL, ISL8.9, ISL9, L8.9, L9.3, QSC8.3 and QSL9. Interchange references include 3960668 and 5253952.<\/p>\n<p>That list is the same family we already supply flywheels for. Our flywheel 3415350 and our flywheel 4933490 both belong to the C and L series, which means for an 8.3 or 8.9 litre Cummins rebuild we can supply the housing and the flywheel together, matched to the same engine family.<\/p>\n<p>If you are working on a C or L series Cummins, tell us the engine model and the CPL code and we can confirm both parts against it.<\/p>\n<h2 id=\"how-to-order-a-flywheel-housing\">How to order a flywheel housing<\/h2>\n<p>Send these six things and the part can be confirmed without shipping anything:<\/p>\n<ul>\n<li>The SAE size, or better, the measured pilot bore and the bolt hole count<\/li>\n<li>The PTO opening position, or a statement that no PTO is required<\/li>\n<li>Whether the engine needs a crankshaft sensor provision<\/li>\n<li>The engine model and, for Cummins, the CPL code<\/li>\n<li>The OEM part number if you have it, or the cast number off the old housing<\/li>\n<li>A photo of the rear face from directly behind, and one of the side showing the depth<\/li>\n<\/ul>\n<p>A photo of the old housing is the single most useful item on that list. The cast number, the aperture layout and the depth are all visible in two pictures.<\/p>\n<h2 id=\"faq\">FAQ<\/h2>\n<h3 id=\"how-do-i-tell-an-sae-1-housing-from-an-sae-2\">How do I tell an SAE 1 housing from an SAE 2?<\/h3>\n<p>Measure the pilot bore and count the bolt holes. SAE 1 has a 20.125 inch bore and 12 holes. SAE 2 has a 17.625 inch bore and 12 holes. The hole count is the same, so the bore measurement is what separates them, and the difference is about two and a half inches, which is easy to see with a tape.<\/p>\n<h3 id=\"does-the-flywheel-housing-have-to-match-the-flywheel\">Does the flywheel housing have to match the flywheel?<\/h3>\n<p>They have to come from the same engine build, but they are separate parts and are ordered separately. The housing sets the position of the starter and the transmission. The flywheel carries the ring gear and the clutch. What has to match is the engine family and the application, because the same engine is built with different housing and flywheel combinations for truck, industrial and marine use.<\/p>\n<h3 id=\"can-i-use-an-aluminium-housing-in-place-of-a-cast-iron-one\">Can I use an aluminium housing in place of a cast iron one?<\/h3>\n<p>Physically it may bolt on, but you are giving up stiffness, which is the housing&#8217;s main job. On a heavy truck or an industrial engine we would not recommend it. On a light engine where an aluminium housing was the original fitment, replacing it with cast iron is usually fine and often an improvement.<\/p>\n<h3 id=\"what-is-the-cast-weight-on-the-housing-for\">What is the cast weight on the housing for?<\/h3>\n<p>It is the weight of the bare casting before machining. It is a foundry reference, useful for confirming you have the right casting and for foundry records. It is not the finished part weight.<\/p>\n<h3 id=\"the-number-on-my-housing-does-not-appear-in-any-catalogue-what-does-that-mean\">The number on my housing does not appear in any catalogue. What does that mean?<\/h3>\n<p>It may be a mould reference or a traceability code rather than a part number. Housings often carry both. Cast numbers in a catalogue format, like the AZ series above, are part numbers. Short codes, numbers with mixed letters and digits, and anything handwritten are not. Send us a photo and the SAE measurements and we will work it out from the dimensions.<\/p>\n<h3 id=\"do-you-make-housings-that-are-not-in-your-standard-range\">Do you make housings that are not in your standard range?<\/h3>\n<p>Yes. We work from drawings or samples, and we can develop a pattern if one does not exist. Non-standard PTO positions and housings with sensor provisions are normal work.<\/p>\n<h3 id=\"what-is-the-delivery-format\">What is the delivery format?<\/h3>\n<p>Bare castings, or fully machined and painted, depending on what you need. Most customers take them machined and painted, ready to bolt on.<\/p>\n<h2 id=\"about-changwei\">About Changwei<\/h2>\n<p>Changwei Intelligent Equipment is an IATF 16949 certified cast iron foundry in Changyi, Weifang, Shandong, China. We cast and machine flywheel housings, flywheels, ring gears, timing gear housings, cylinder blocks and cylinder heads for truck, construction, industrial and agricultural diesel engines.<\/p>\n<p>We supply standard catalogue parts and custom parts made to drawing or sample. If you have a housing to replace and only a photo, send it over and we will tell you what we can do.<\/p>\n<p>Irene<br \/>\nChangwei Intelligent Equipment<br \/>\nEmail: irene19953662121@gmail.com<br \/>\nPhone \/ WeChat \/ WhatsApp: +86 19953662121<br \/>\nWangke Industrial Zone, Changyi, Weifang, Shandong, China<br \/>\nFOB Qingdao<\/p>\n<h2 id=\"related-reading\">Related reading<\/h2>\n<ul>\n<li>Weichai flywheel housing: <a href=\"https:\/\/www.changweiintl.com\/en\/product\/weichai-flywheel-housing\">\/en\/product\/weichai-flywheel-housing<\/a><\/li>\n<li>Transmission housings: <a href=\"https:\/\/www.changweiintl.com\/en\/product\/transmission-housings\">\/en\/product\/transmission-housings<\/a><\/li>\n<li>Timing gear housing: <a href=\"https:\/\/www.changweiintl.com\/en\/product\/gear-room\">\/en\/product\/gear-room<\/a><\/li>\n<li>Cummins engine flywheel: <a href=\"https:\/\/www.changweiintl.com\/en\/product\/cummins-engine-flywheel\">\/en\/product\/cummins-engine-flywheel<\/a><\/li>\n<li>Cummins flywheel part numbers and which engine they fit: <a href=\"https:\/\/www.changweiintl.com\/en\/blog\/cummins-flywheel-part-numbers\">\/en\/blog\/cummins-flywheel-part-numbers<\/a><\/li>\n<li>Ring gear tooth counts: <a href=\"https:\/\/www.changweiintl.com\/en\/blog\/flywheel-ring-gear-teeth-count-guide\">\/en\/blog\/flywheel-ring-gear-teeth-count-guide<\/a><\/li>\n<li>Request a quote: <a href=\"https:\/\/www.changweiintl.com\/en\/quote\">\/en\/quote<\/a><\/li>\n<\/ul>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Flywheel Housing: SAE Size, PTO Opening and Cast Marks  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1437,"template":"","meta":{"_cw_seo_title_en":"Flywheel Housing: SAE Size, PTO Opening and Cast Marks","_cw_seo_metadesc_en":"Your flywheel housing is identified by its SAE size, its PTO opening and the marks cast into the metal. Here is how to read all three before you order."},"class_list":["post-1447","ccm_blog","type-ccm_blog","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Flywheel Housing: SAE Size, PTO Opening and Cast Marks &#8211; Weifang Changwei Intelligent Equipment Co., Ltd.<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.changweiintl.com\/en\/blog\/flywheel-housing-sae-size-pto-guide\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Flywheel Housing: SAE Size, PTO Opening and Cast Marks &#8211; Weifang Changwei Intelligent Equipment Co., Ltd.\" \/>\n<meta property=\"og:description\" content=\"Flywheel Housing: SAE Size, PTO Opening and Cast Marks [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.changweiintl.com\/en\/blog\/flywheel-housing-sae-size-pto-guide\/\" \/>\n<meta property=\"og:site_name\" content=\"Weifang Changwei Intelligent Equipment Co., Ltd.\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/profile.php?id=61573276931730\" \/>\n<meta property=\"article:modified_time\" content=\"2026-09-24T01:43:04+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.changweiintl.com\/wp-content\/uploads\/2026\/09\/flywheel-housing-az1034010008-cast-part-number.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1200\" \/>\n\t<meta property=\"og:image:height\" content=\"1600\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"17 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide\",\"url\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide\",\"name\":\"Flywheel Housing: SAE Size, PTO Opening and Cast Marks &#8211; Weifang Changwei Intelligent Equipment Co., Ltd.\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.changweiintl.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/flywheel-housing-az1034010008-cast-part-number.jpg\",\"datePublished\":\"2026-09-24T01:43:03+00:00\",\"dateModified\":\"2026-09-24T01:43:04+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide#primaryimage\",\"url\":\"https:\\\/\\\/www.changweiintl.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/flywheel-housing-az1034010008-cast-part-number.jpg\",\"contentUrl\":\"https:\\\/\\\/www.changweiintl.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/flywheel-housing-az1034010008-cast-part-number.jpg\",\"width\":1200,\"height\":1600,\"caption\":\"flywheel housing with cast part number AZ1034010008P and cast weight on the side wall\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\\\/flywheel-housing-sae-size-pto-guide#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.changweiintl.com\\\/en\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Blog\",\"item\":\"https:\\\/\\\/www.changweiintl.com\\\/blog\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Flywheel Housing: SAE Size, PTO Opening and Cast Marks\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.changweiintl.com\\\/#website\",\"url\":\"https:\\\/\\\/www.changweiintl.com\\\/\",\"name\":\"Weifang Changwei Inteligent Equipment Co, Ltd\",\"description\":\"Changwei is a China manufacturer of engine flywheels, ring gears, flywheel housings and gear chambers. 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