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Torque Spec
2021 Chevy Silverado 1500 4.3L Complete Torque Specs List
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Chevy Silverado 1500 4.3L OHV Engine Repair Information
Here you can find information regarding the assembly of the Chevy 4.3L OHV engine. In this guide we willstart from the inside of the engine including thecrankshaft, connecting rods, and piston ring installation and then move outwards all the way to the pulley beltsystem. Along the way correct procedures and torque specswill be given to aid in the assembly of the engine. Feel free to start from the beggining and work your wayoutwards or skip ahead to your current position in the engine for what you may need.
Crankshaft Main Caps Installation
The 4.3L engine block main bearing caps should be inspected for any defects or flaws before installation.Be sure to lubricate the bearing surfaces prior to installation. Once prepared you can place the caps onto the crankshaftand begin tightening the bolts down in a multi stage process. The first being 10 ft-lbs starting from the middle and going outwards.The second time around you can go to 15 ft-lbs and then for the third time you do an additional 75 degree turn for each bolt.Once finished you should be good to continue with the rest of the engine.
Chevy Silverado 1500 4.3L OHV Main Cap Torque Specs : 15 ft-lbs + 75°
Piston and Connecting Rod Installation
To install the pistons and connecting rods you must first install the piston rings into each piston. Be carefulnot to stretch the rings or break them during installation. Make sure to put the correct rings in the correctpositions, this can be determined by looking atthe instructions given with the new rings. Each ring manufacturer is different so be sure to check for yourspecific rings. Once the rings have been installed you can now fit the connecting rod bearings into the end capsand lube them up with oil or lithium grease. The piston can now be lowered into the cylinder, make sure the dotor mark is facing the front of the engine and that you don't scratch the cylinder.Once installed you can match the connecting rod caps with the correct rods and start to torque the connectingrod bolts to 20 ft-lbs and then an additional 70 degree turn for each bolt. After all are done rotate the crankto ensure all pistons move smoothly in and out of their cylinders and nothing binds.
Chevy Silverado 1500 4.3L OHV Connecting Rod Torque Specs : 20 ft-lbs + 70°
Oil Pump Installation
When installing the oil pump be sure to use the proper sealant around the pump base if neccessary to ensure that oil pressuredoesn't drop due to leakage. Both surfaces should be cleaned and preped prior to installing. After preparing the contact surfaces carefullyinstall the oil pump onto the bottom of the engine block right onto the rear most main cap. There should be two pins which hold the pump in placeso that it does not shift during installation. When placing the pump onto the engine be sure that you have the pumps drive shaft held in place andthat both sides are well connected. It should easily slide into the holes without much force. If everything is good you should be able to place the pumpand shaft into place and then hand tighten the single pump bolt. Once hand tighten be sure that the pump functions when the shaft turns. The single oil pumpbolt can be tightened down to 65 ft-lbs. The oil pump pickup tube gets installed onto the pump directly and simply presses into place. Be sure to have thepickup at the proper angle for you oil pan. Having this wrong will cause the pan to hit the pickup or the pickup to not access enough oil. The angle should beabout 15 degrees from the engine block flat surface. I personally will spot weld the pickup tube onto the pump so that it does not shift. However this step is notneccessary.
Chevy Silverado 1500 4.3L OHV Oil Pump Torque Spec : 65 ft-lbs
Cylinder Head Installation
The first thing you must do when installing cylinder heads is to ensure both the block and head surfaces arecompletely clean from dust, oil, and any debris. The next thing you must to isto set the camshafts to their correct positions to prevent any valves from hitting pistons during installationand torquing of the head bolts. Much the same you have to set the pistons to their correctlocations, typically this means putting the #1 piston to TDC or Top Dead Center. Once everything is ready youcan install the head gasket onto the engine block by aligning the alignment dowels.Something I usually do is spray down the head gasket with some engine copper spray from permatex which you canfind here, this ensures that any gaps that could be present between the 2 surfaces gets filled with thespray. Italso helps to transfer heat between the 2 metals. With the gasket in place you can set the cylinder head ontothe gasket and block, if needed have someone assist with this process as the head can be heavyand you don't want to scratch anything or drop it! Once the head has been placed you will want to startinstalling the head bolts to make sure it doesn't move. Be sure to buy new head bolts as many manufacturersuse TTY or Torque to Yield head bolts meaning they stretch during torqueing and cannot be used twice. Also makesure to lubricate the bolts in clean engine oil before installing them into the head. On Chevy OHV engines there is occasionallybolt holes on the engine block that cross into water passages. Any hole that does this should be installed with some silicon sealant.A little goes a long way in this step and you can check holes by shining a flashlight down them and looking in the water jackets.Once all the head bolts have been installed and finger tightened you can start the torqueing process, almost allhead bolts have a multi-step process for torqueing. The 4.3L OHV engine uses 3 different sized head bolts being 5 long ones 2 medium sized ones and6 short ones. The shorter bolts go on the outer side of the cylinder head and get tightened down to 22 ft-lbs and then a 55 degree turn. The long and mediumsized bolts go in the center of the cylinder head where the oil can access. The medium ones go on the outer edges of the head. If you are not sure when you dropthe bolts into the holes they should all start out at around the same height. If one bolt is higher up than the others it is in the wrong hole. The longerbolts get tightened down to 22 ft-lbs and then a 75 degree turn. The medium sized bolts get tightened down to 22 ft-lbs and then a 65 degree turn.Be sure to tighten the right bolts to the right specs as this is a critical component of the engines functionality.
Chevy Silverado 1500 4.3L OHV Cylinder Head Torque Specs (Shortest): 22 ft-lbs + 55°
Chevy Silverado 1500 4.3L OHV Cylinder Head Torque Specs (Medium): 22 ft-lbs + 65°
Chevy Silverado 1500 4.3L OHV Cylinder Head Torque Specs (Longest): 22 ft-lbs + 75°
Timing Chain and Camshaft Installation
On the Chevy 4.3 OHV engine the timing system is ran by the use of a chain. This chain system consists of a sprocket on the single center located camshaftand one sprocket on the engines crankshaft. Since the camshaft is located in the center of the engine it needs to be installed from the front side of theengine. The camshaft bearings get installed using a special cam bearing installation tool. The tool simply presses the bearings in and out of the bearing holesusing different sized plates to press on them. Be sure that all of your camshaft bearings are in good condition prior to installing the camshaft and building theengine as this is a critical part of the engine. If all bearings are good and in place the camshaft can be lubed and placed into the engine. It should slideinto the bearings with ease, if it gets caught do not force it as you risk damaging the bearings. Simply move the camshaft end around until it slides in. Onceall the way into the engine you will need to install the camshaft retaining plate and its bolts. Depending on your specific chevy engine the camshaft retainingplate gets installed impediately after the camshaft is slide into place or after the timing gear has been installed. Depening on how you took apart your engineand the new parts you are installing you will need to adapt accordingly. The retaining plate bolts need to be tightened down to 8 ft-lbs. The camshaft timingsprockets simply slide onto both the crankshaft and the camshaft end. Be sure that you install the system all together with the timing chain marks lined upwith the dots on both sprockets. Since there are no tensioners for this system it will only go together like this. On the camshaft side it aligns usinga dowel pin that sticks out of the camshaft. There are 3 bolts which hold the camshaft sprocket onto the camshaft.These bolts need to be tightened down to 21 ft-lbs. The crankshaft pulley will hold thecrankshaft sprocket into place so no need to tighten any bolts down there.
Chevy Silverado 1500 Camshaft Sprocket Torque Spec: 21 ft-lbs
Chevy Silverado 1500 Crankshaft Position Sensor Torque Spec: 8 ft-lbs
Chevy Silverado 1500 Camshaft Retaining Plate Bolts Torque Spec : 8 ft-lbs
Chevy Silverado 1500 Rocker Arms Torque Spec : 20 ft-lbs
Chevy Silverado 1500 Valve Lifter Retainer Torque Spec : 12 ft-lbs
Timing Cover Installation
The timing cover on the 4.3L is used to cover up the internals of the engine and hold in massive amounts of oil. For this reason I recommend usingsome silicon sealant along with a new gasket during installation. Be sure to clean all of the metal surfaces prior to installation and placing the silicon onto the metal.With everything ready to install be sure to double check your timing and engine internals before placing the cover in place. Another tip is to lube up thecrankshaft seal with some oil so it seats better. If everything is good to go then place the coveronto the engine block and begin to tighten down the bolts hand tight. Once all of the bolts have been set in place be sure to follow your sealants instructions by waiting the recommendedtime. Once ready the timing cover bolts can be tightened down to 10 ft-lbs. Be sure to not overtighten these bolts as it can be easy to do so.
Chevy Silverado 1500 Timing Cover Torque Specs : 10 ft-lbs
Oil Pan Installation
Much like the timing cover on the 4.3L the oil pan plays an important role in keeping the engine oil inside theengine. For this reason I recommend using a new gasket as well as some silicone sealantduring installation. Using the same technique as before with the cover you clean the surfaces of both the oilpan and the engine block and then install the new gasket onto the block and then followit up with some silicone sealant. Be sure to follow your sealants instructions to ensure you get the best sealfrom your application. The oil pan bolts torque to 15 ft-lbs in a cross pattern design.Along with the pan is the oil pan drain plug, this gets removed and reinstalled quite frequently and can betorqued down to 15 ft-lbs.
Chevy Silverado 1500 Oil Pan Torque Specs : 15 ft-lbs
Chevy Silverado 1500 Oil Drain Plug Torque Specs : 15 ft-lbs
Valve Covers Installation
The valve cover installation is rather simple, there are rubber seals for each bolt hole and a silicone gasketthat prevents oil from leaking out of the engine. It is recommended to replace both the sealsand the gaskets although if they are in good condition you can reuse them. If you do choose to reuse them Iwould use some silicone sealant along with the silicon gasket to ensure it does not leak.The valve cover bolts torque down to 106 in-lbs or about 8 ft-lbs in a criss cross order. Be sure not to missany bolts to avoid having oil leak out onto the exhaust pipes and cause a lot of smoking.
Chevy Silverado 1500 Valve Cover Torque Specs : 8 ft-lbs
Intake Manifold and Fuel Rail Installation
When installing the intake manifold you want to make sure you have all the surfaces as well as intake holescleaned out before placing the manifold into position. Once cleaned you can then placethe intake manifold gaskets onto the alignment pins. If you want you can also use a little bit of sealant on thegaskets to help ensure there are no leaks. With the gaskets in place you can now putthe manifold down onto the gaskets and begin to install the bolts. The intake manifold bolts torque to 15 ft-lbsand can be tightened in a cross pattern. The distributor bolt can be tightened down to 15 ft-lbs and the spark plugs themselves can betorqued down to 11 ft-lbs, be careful not to overtorque these as they can snap and cause big problems.When installing the throttle body make sure that all of the gaskets are in good condition and will hold a seal as you do notwant to be leaking gas fumes around the engine. If everything looks good you can tighten the throttle body bolts down to 12 ft-lbs.
Chevy Silverado 1500 Intake Manifold Torque Specs : 15 ft-lbs
Chevy Silverado 1500 Distributor Bolt Torque Specs : 15 ft-lbs
Chevy Silverado 1500 Spark Plug Torque Specs : 11 ft-lbs
Chevy Silverado 1500 Throttle Body Torque Specs : 12 ft-lbs
Exhaust Manifold Installation
The exhaust manifold can be installed by cleaning the surface areas on both the head an the manifold itself andthen by using the exhaust manifold gasket and putting it in place. Once the gasket is in itslocation you can put the manifold onto the heads and begin to torque it down to 25 ft-lbs. I always use somecopper spray from permatex on the exhaust manifold gaskets to ensure I do not end up withany exhaust leaks once done. When you go to install the engine into the vehicle or if it is already in thevehicle the torque specs for the exhaust manifold to the exhaust pipes or catalytic converter is 20 ft-lbs.The EGR system consists of a series of pipes that range from the manifold to the head.
Chevy Silverado 1500 Exhaust Manifold Torque Spec : 25 ft-lbs
Chevy Silverado 1500 Exhaust Pipe Torque Specs : 20 ft-lbs
Water Pump and Thermostat Installation
The water pump on the Chevy 4.3L engine should be installed by usinga new gasket and if desired some silicone sealant to help prevent leaks. Be sure to clean both metal surfaces prior to installing the pump. Onceprepared the pump can be moved into placed and then the corresponding brackets can be put into place. The water pump bolts go through the brackets and thenthrough the water pump into the engine. The water pump bolts should be torqued to 35 ft-lbs.When you get to it the water pump pulley bolts and the fan clutch bolts can be tightened down to 17 ft-lbs.
Chevy Silverado 1500 Water Pump Torque Specs : 35 ft-lbs
Chevy Silverado 1500 Water Pump Pulley Torque Specs : 17 ft-lbs
Front Dress and Pulley belt Installation
Most of what is left on the engine is just place and tighten objects such as the belt pulleys, belt tensioner,throttle body, oil filter neck, crankshaft pulley, and motor mounts. If the items have a gasket and hold eitheroil or coolant inside the engine then feel free to add some sealant along with the gasket. Always be sure toinspect your gaskets and replace them if there is any deteriation or flaws with them. For thebelt system the crankshaft pulley gets torqued to 70 ft-lbs. The belttensioner can be tightened to 18 ft-lbs and the idler pulley can be torqued down to 30 ft-lbs. When installing be sure theyboth turn smoothly and if they do not then replace them with new ones as the bearings can go bad. The enginemotor mount can be installed onto the engine block if it hasn't been already, the torques forthe mount to the block is 59 ft-lbs and then when installing the mount to the vehicle or frame it can be torqued to35 ft-lbs. Finally the throttle body can be installed on top of the intake manifoldwith a good gasket and some added sealant using 7 ft-lbs in a criss cross pattern. For installing the belt youcan use a tool to move the tensioner into its springed state and install the belt as shown in thepicture. The power steering pump pulley should be tightened down to 14 ft-lbs.
