Before starting the assembly of your Nailhead V8, your shop or assembly area will need a final cleaning, and all your parts (including the block) should be cleaned and bagged or wrapped up. Don’t leave the parts cleaning until you are assembling them because this will only stir up more dirt. Don’t trust that your new parts are clean out of the box.
Wash all of your parts in hot water with Dawn dish detergent, rinse them off in hot water, and immediately blow-dry them. Use a lint-free rag to wipe down the parts with a light film of oil (particularly the machined surfaces) and bag them up until they are ready to install.
Use a break-in oil that has a content of zinc, or you can treat with a zinc additive to wipe down these parts. You will also use this oil for Buick engine assembly in areas that do not require assembly lube. You can give the block a similar treatment, except use brushes to clean out the oil galleries again and then use a pressure washer to flush the detergent out. Your final flush will be with brake cleaner so that you quickly back blow them dry to ensure that they are clean.
This Tech Tip is From the Full Book, BUICK NAILHEAD: HOW TO REBUILD & MODIFY 1953-1966. For a comprehensive guide on this entire subject you can visit this link:
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Once you have completed the pressure washing and blow drying, move back inside to a clean area to avoid airborne contaminants. You need to work quickly with the block to prevent rust from forming and do a final and more thorough wipe-down with clean oil.
A thorough block scrub down is your starting point before assembly. All of the internal passages, including the lifter bores, get scrubbed with a stiff nylon brush powered by a drill and blown through with the power washer
A power washer is used to flush out all of the soap solution, including the internal passages, and then immediately blown dry before rust starts to form. The cylinders are wiped down with oil as soon as possible using a lint-free cloth.
A variety of different-sized engine brushes from 1/4- to 1-inch diameter are needed to access the main oil galleries, oil passages to and from the oil filter, lifter bores, and the small oil feed lines that run up from the lifter oil gallery through to the block deck, and finally through the head to the front rocker-arm bolt hole. This last passage is easily missed.
After the block has been blown dry, flush each of the oil galleries with brake cleaner. The 1/8-inch discharge tubes will fit into the small passages as well as the larger oil galleries.
If you are lucky, you will find cans of brake cleaner, such as this, that will accept a 1/8-inch plastic tube. They are no longer available in many areas, and the nozzles do not interchange with the regular cans. They are very handy for feeding the tube through the internal passages for that last flush.
You can make a back blower, such as this, from airbag fittings with push-lock fittings. Solder the end closed and drill four to five 0.125-inch holes at a 45-degree angle. The body needs to be turned down to less than 0.400 so it can fit through the three main oil galleries. This back blower is an effective way to give a final cleaning of the oil passages.
Don’t try to flush all the oil lines at once or the brake cleaner will dry up and not be as effective. As you flush a portion of each oil passage and the brake clean is still wet, feed the back blower and blow it clear of any remaining contaminants. You can blow out the smaller lines with a blow gun. It may be necessary to wash the block again and repeat this process if there were foreign contaminants blown around.
You may or may not have the luxury of a dedicated engine-assembly room. An HVAC air filter or an air purifier system will help keep your shop clean by reducing particulates and odors, but that does not preclude the necessity of a thorough cleaning of your workshop prior to engine assembly.
Start off by vacuuming all the floors and shelving areas as much as possible. Then, run a large exhaust fan and blow off everything from all the nooks and crannies. This appears to be clean, but it sure stirs up a lot of airborne particulates. After everything appears to have settled, vacuum again, blow it out again, and let the fan run for another 15 minutes.
Keep all the doors and windows closed to maintain your clean status quo. There are times you may want to lock the door to limit traffic and stop the door opening and closing from the “Watcha doin’?” visitors.
Fasteners
Before you get into further cleaning and assembly, you need to think about the hardware you are planning to use. The wrong grade of bolts and improper tightening procedures are a significant cause of engine and chassis parts failure. (This issue could be a standalone topic for new book by itself and a complete lesson in Engineering 101.) Whether you are rebuilding your new Nailhead or doing other day-to-day projects in the shop, you need to focus on some frequently neglected or overlooked concerns pertaining the nuts and bolts that you are about to use in this undertaking.
The ARP catalogue has a lot of good information that explains in layman’s terms about bolt stretch relative to applied torque, identifying different causes of fastener failures, etc. This page only deals with rod bolt stretch. You can pick up a catalogue or view it online. (Photo Courtesy Automotive Racing Products)
Over- or under-tightening nuts and bolts is dangerous and is an area where many of us err. I am sure you have seen someone hook a couple of closed-end/ open-end wrenches together for some extra leverage. Or you have likely seen others use their torque wrench as their best Johnson bar because it is the longest wrench in the tool box. If nothing else, it probably affected the calibration.
Stressing any tool beyond the intended range is abuse! There are people who tighten a bolt with their torque wrench until it reaches the intended torque or clicks and then give the wrench a little extra push. This can be a dangerous practice. You hate to disappoint your friends, but you should let them know that they are not smarter than their torque wrench or those who prescribed the tightening specifications.
Anti-seize is absolutely essential for a vehicle that will race on the salt flats, but it is good practice for your daily driver and street rod. There are different grades of anti-seize available depending on the application and the type of metal fastener used.
Few people have their wrenches recalibrated, especially those who abuse them. This should be done routinely; the cost is negligible. The quality ones can be recalibrated for no charge by returning it to where it was purchased. Otherwise, you can do it yourself by following a YouTube video.
Smaller fasteners that require an inch-pound wrench are seldom tightened to any spec. It is preferable for you to have more than one torque wrench with differing ranges. Generally, a torque wrench is the most accurate in the middle of the tightening scale. As you approach the upper or lower range of that wrench, the accuracy diminishes.
There is a wealth of information in the ARP catalogue about fastener selection and torqueing practices in laymen’s language. Read this and refer to it regularly. The ARP articles make good reading for anyone who is reading this book or into cars in general.
Assembly oil is used to soak your pistons, rings, timing chain, gears as they are being installed, and other areas of the block you want to wipe down to prevent oxidation. Assembly lube needs to be applied to your bearings during the final assembly. Don’t be stingy when applying either of these. It is your lifeline at initial start-up.
Impact wrenches should only be used in a select few applications when working on your motor. You have probably seen charts for pneumatic impact guns relating air supply pressure to a specific torque number. They are useless. These are not torque wrenches, nor do they or their electric counterparts produce a reliable tightness. You will find that tire shops are the best bad example of impact wrench usage, yet the tool manufacturers have convinced the governing agencies that these tools can be used reliably to torque wheel nuts. Most franchises only give their personnel a cursory training about proper tightening procedures and very few enforce good work practices when it comes to tightening wheel nuts. We have all seen way too many broken wheel studs over the years. One is too many. Broken wheel studs kill people. Over- or under-tightening any fastener with your Nailhead rebuild can have serious and costly implications. You need to put a lot of thought into fastener selection and application through each step of this project.
You may have heard complaints from fellow car enthusiasts about stainless steel fasteners galling, being difficult to disassemble, and not practical for automotive use. To be successful when using stainless bolts, you need to know what grade they are. Lubricate the threads with a nickel-based anti-seize and tighten them to a prescribed torque for that particular grade of bolt. Don’t use just any anti-seize, it must be nickel based. Over-tightening SS bolts and/or not using a proper thread lubricant is what causes threads to gall up. Ask your fastener supplier for a torque chart that includes the different grades of bolts to have the information at your fingertips.
You cannot assume that socket-head or stainless steel fasteners are a better grade of bolt; they are usually only grade 5. Ask your supplier for the specific grade required when purchasing bolts. Grade-8 fasteners should only be used with hardened-steel washers. Utility washers will compress and not maintain your torque settings. Better yet, it is good practice to toss out all of your Grade-2 utility washers and replace them with hardened washers.
Once you have your parts cleaned and ready for assembly, bag them up. It is good practice to keep them that way or you may have to clean them again. You do not want that kind of interruption while you are trying to focus on assembling your new Nailhead.
You may think that this fastener rhetoric has strayed from the topic of this book, but the moral of these comments is very basic. Whether it is the quality of bolts, nuts, parts, or tools you buy, or the quality of your work practices, all of these will combine to affect the outcome of your Nailhead rebuild. If you let any one of these fall into mediocrity, the fi nal product will be mediocre. As the level of performance you want to build into this motor increases, the quality of the parts and practices you input must also increase. Let’s move on to assembling this beast.
Short-Block
The pistons, pins, and connecting rods have been cleaned, assembled, and bagged up after balancing so they are ready to be installed. You will need the aluminum or plastic jaws in your vise again and use a pair of ring-installation pliers.
1 Have your rod bearings and rings cleaned and lay them out on a clean, dry surface.
2 Take the #1 connecting rod and install the bearing inserts into the connecting rod and the rod cap. The inserts must snap in place. If they fit loosely, the rod size must be rechecked. If this is the correct size, the bearing insert should be replaced.
3 Secure the cap so that the inserts can’t come out, and mount it in the vise with the piston end facing upward.
4 Install the oil rings first. Use your ring-installation pliers to set the compression and top rings. Be sure to align the ring gaps as per the ring manufacturer’s directions. Ring pliers are not expensive, easy to use, and have much less of a chance of ruining a ring. Bag up this piston and continue with the remainder of the pistons. Set them aside when they are ready for installation.
With each phase of the rebuild, you want to have all of the parts, tools, sealants, and lubricants required for that portion of the job laid out in order of assembly. Your tools also need to be clean and ready for use. In this case, lay out all your plugs in order, particularly those that have a dedicated location.
You should take care when removing or installing the cam rear retaining snap ring. These are available through any of the Nailhead dealers, but when you need one at the eleventh hour, you will not find a replacement at your local parts store.
5 Start by visually checking the alignment of the cam bearings; particularly that the front one has clear passages to the lifter galleries.
6 Install the three oil-gallery plugs in the front of the main oil gallery and the two lifter galleries. Be sure to use the thin plugs. They should fit flush with the front face of the block. Check that they do not obstruct the secondary passages to the lifter galleries or to the heads.
7 Screw in the right lifter gallery rear plug and be sure to install the freeze plug in the back of the block.
8 Next, install the rear main oil gallery and left lifter gallery plugs with a petroleum compatible pipe dope. You can use that same sealant to seal the two 1/8-inch pipe drain plugs at the center of the water jackets on each side of the block.
9 Next is the internal snap ring behind the rear cam bearing. Some of these have a sharp edge on one side that should face outward.
10 Install the frost plugs with a light coating of shellac based sealant such as Permatex Aviation Form-a-Gasket. It is easier to install these plugs using a correct-size mandrel so the plugs go in square, particularly on the shallow plug at the rear of the cam. Because of the narrow lip on that plug, use a center punch at three different quadrants to stake it in position. Install the plugs with the outer lip flush with or slightly below the outer block surface.
The easiest way to install frost plugs is to use a dedicated mandrel to fit different-sized plugs. The mandrel should be 0.040 inch smaller than the inside diameter of the plug. Use a good shellac-based sealant to install the plugs to ensure that there will not be any leakage.
A good driver helps keep the plug square to the hole. Only drive it in deep enough so that the top edge of the plug is at the bottom of the bevel. This is one of the very few applications to use a hammer while working on your motor.
11 Put in the upper halves of the main bearings with a very light coating of oil on the bearing surface only. Check that the back side of the thrust bearing lips, the #3 bearing cap, and the block where they fit are clean before they are installed.
12 Lower the crankshaft in place and secure it with the #3 and 5 bearing caps.
13 Mount a dial indicator with the tip riding to the front of the #1 journal. Rotate it slowly to verify the crankshaft is not bent. In this case, the reading was less than 0.0001.
14 Install the rest of the main bearing caps with a light film of oil and torque to spec. The crankshaft should spin freely by hand. It is good practice, especially since the crankshaft had to be straightened anyway, to indicate the flywheel flange for lateral and radial runout and also the snout of the crankshaft for runout. These readings should both be less than 0.001 inch.
Dropping the crankshaft in by hand is a good way to damage your bearings. Use a couple of 4×1/2-inch NC studs with rubber sleeves threaded into the #1 and #5 main bearing cap bolt holes as guides. Lowering the crankshaft into place with the lifting device will free up one hand to help guide it into position.
A dial indicator is the best way for you to measure thrust bearing clearance. Feeler gages are not very accurate here and may scratch the bearing. Pry the crankshaft back and forth to get your reading.
If the clearance is below specification, tap the shaft back and forth with a dead-blow hammer two to three times and measure again. This may be enough to seat the thrust bearing and give you more clearance.
15 Firmly tap the front and rear of the crankshaft with a fiber dead-blow hammer to seat the thrust bearing.
16 Reposition the dial indicator with the tip riding on the front of the counterweight at the #1 journal. Pry forward on the counterweight and reset the dial indicator to zero.
17 Pry rearward and record the difference; this is your thrust bearing clearance.
18 If the clearance is less than 0.004, remove the dial indicator and firmly tap the crankshaft fore and aft two to three times as you rotate it. Replace the dial indicator and check the thrust bearing clearance again; it should be between 0.004 and 0.008. In rare cases, it may be necessary to sand the thrust bearing to get the clearance required. Hold the bearing halves firmly together so they stay flat on 600-grit sandpaper on a dead-flat surface. Then, slide them back and forth twice. Thoroughly wash and install them to recheck the thrust clearance. You may have to repeat this to get the required clearance. Take it in small steps as you cannot undo excess clearance.
This Tech Tip is From the Full Book, BUICK NAILHEAD: HOW TO REBUILD & MODIFY 1953-1966. For a comprehensive guide on this entire subject you can visit this link:
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19 Next, remove all five bearing caps and lift the crankshaft out of the way. New neoprene rear main seals and the #5 cap side seals are readily available from any of the Nailhead dealers. Don’t even think about trying to use the old rope seals that may have been included in your gasket set.
20 Install the upper half of the rear main seal in the block with the lip facing inward and lightly coat the seal lip with oil.
21 Coat the upper bearing insert surfaces with assembly lube and lower the crankshaft back in place.
22 Put a tiny dab of Ultra Black gasket maker to each end of the new rear seal and add a liberal amount of the assembly lube on each main bearing journal.
23 Install the lower seal halfway in the rear cap with the seal lip facing inward and wet the seal lip with a thin film of engine oil.
When applying ARP thread lubricant, be sure to thoroughly coat the threads and the underside of the bolt head. You may find it easier to squeeze the lubricant on a palate and apply it with a brush. You will not waste as much and can get more accurate coverage.
Plastigauge
The main bearing journals were miked at 2.488, and the bearings were checked with a dial bore gauge at 2.490, which would give you 0.002 main bearing clearance. Verify the clearance with Plastigauge. Even though you had sent your crankshaft out to have it turned, you need to check the clearance; do not assume it is correct. Keep a record of the clearances at each journal. Proceed as follows to check with Plastigauge before coating the bearings with the assembly lube. It is available to check different amounts of clearance; the 0.001 to 0.003 range is the most common for automotive applications.
Remove the #1 bearing cap and wipe most of the oil from the bearing and all of the oil from the journal, place a 1/4-inch piece of Plastigauge on the journal away from the oil hole, replace the cap, and torque to spec. Do not turn the crankshaft.
Remove the bearing cap and measure the clearance using the paper gauge supplied with the Plastigauge package and record the clearance.
Plastigauge can be very useful to check your bearing clearances. You only need a 1/4-inch-long piece. Put a light film of oil on the bearing so the Plastigauge will stick to the journal and not the insert.
You can read the clearance from the scale on the package. In this case, it appears that the clearance is slightly less than 0.002 inch, which was calculated from the measurement of the bearing inside diameter minus the main bearing outside diameter.
Never use any metal object to remove the material from the journal or insert. Even with a plastic scraper, such as this one, you need to be gentle. Wipe the area clean with lacquer thinner when finished and thoroughly coat the bearing with assembly lube before replacing the main cap.
Use a plastic spreader and clean all traces of the Plastigauge material from the journal and the bearing insert, then wipe the journal and insert with lacquer thinner to remove any traces of the foreign material. Do not use metal or any hard scrapers that may mark the journals or bearing inserts.
Repeat this with the next four main bearings. The clearance we are looking for is 0.002. We had specified both the main and rod journals to be ground 0.002 under when John took the crank.
When using ARP products, use their thread lubricant or thread sealant (if required) and their torque specification for that particular bolt or stud. That number is probably different from factory specifications and only applies to original bolts and without the ARP lubricant.
24 Coat the threaded portion of the ARP main cap bolts and the underside of the bolt head portion with ARP lubricant.
25 Bolt all the bearing caps in place starting with 50 ft-lbs on each bolt for the #1 cap, then the #2 cap, and turn the crankshaft by hand. Then, tighten to 80 ft-lbs and finally to the ARP specification of 100 ft-lbs.
26 Coat the side seals for the #5 main cap with Ultra Black and slide them all the way down until flush with the pan rail. Tap the nail into place to lock it.
27 When the black sealant has started to set, trim it off flush with the pan rail. The crankshaft should still turn by hand but with a little more resistance than before the rear main seal was in place. To install the pistons, use the Amsoil Assembly Lube again, as well as your break-in oil, ring compressor, Plastigauge, and rod bolt rubber sleeves. You will find that the non-adjustable ring compressors are more user friendly than the old-style adjustable units.
28 Position the engine stand with the block at 45 degrees and rotate the crankshaft to BDC for the #1 cylinder so that we can start with the #1 piston assembly.
29 Install the rod bearing inserts and leave the cap off.
The clearance between the head of the Buick bolt and the oil pump is adequate, but the ARP main bolt with the hardened washer interferes with the oil pump body. This can be corrected, but check the height of the stud to the right. There is no way that it could be made to fit under the oil pump.
Apply a generous amount of assembly lube to the rod bearing insert prior to installation. Do not add the assembly lube to the cap insert until after you have checked clearances with Plastigauge. Remove any traces of the Plastigauge material from the bearing and the rod bearing journal before you complete the assembly.
The more you handle your pistons by cleaning them or just putting them in or out of the bag will cause the rings to move around in the ring lands. Check that the orientation of the top and second rings corresponds with the manufacturer directions prior to soaking them in oil.
Slide the piston and rod assembly into the ring compressor, wobble it around so that the rings are properly in place in the ring lands, and push the piston dome down with your thumbs until it is even with or below the top of the ring compressor.
Using rubber sleeves to protect the crankshaft from the rod bolts is a common old-school remedy. Fuel hose is simple. It works and will not deteriorate when exposed to petroleum-based products. Some generic hose will break down and leave particles that you don’t want.
You need something forgiving to tap down the piston without damaging it. This is where the rubber handle grip on your hammer comes into play. These may be forged aluminum pistons, but they are still vulnerable.
30 Slide the rubber sleeves onto the rod bolts.
31 Check the orientation of the top and middle rings to verify they are positioned according to the manufacturer’s guidelines.
32 Use a lint-free rag to wipe the cylinders down with oil.
33 Just before you slide on the ring compressor, thoroughly soak all the rings with your break-in oil, and then slide the ring compressor up onto the piston as you work the piston around until the rings are all captured in the compressor and the piston dome is below the top edge.
34 Put some assembly lube on the connecting rod bearing insert and slide the assembly down the top of the #1 cylinder. Be sure the valve pockets in the piston dome are facing inboard toward the camshaft.
35 Line up the connecting rod square to the rod journal and use your nondominant hand to guide it in place as you tap it down. Use the rubber handle end of a hammer to tap the piston down. Be careful to momentarily hold the handle in place after each tap so it will capture the ring compressor when it comes free. Don’t let the ring compressor ring fall to the floor. Once it is damaged, it is junk.
36 You are still supporting the end of the rod with your non-dominant hand. Use the hammer handle to catch the aluminum compressor ring and set it aside to a safe place. Continue to tap the new piston assembly down the bore until the bearing is seated on the crank journal.
37 Wipe a thin layer of oil on the rod cap insert and place a small piece of Plastigauge on the bearing insert. Be sure that it is not aligned with the oil hole in the crankshaft. The oil film will hold it in place until you install the cap. It should stick to the shaft and not the softer bearing material.
38 Tighten the rod bolts and torque them to spec, as done earlier when checking the main bearings. Don’t rotate the crankshaft.
39 Remove the rod cap, check the clearance with the supplied gauge, and record the measurement. Use a plastic tool to clean the squished Plastigauge from the journal and wipe it clean with lacquer thinner. In spite of the oil on the bearing, you still need to use extra caution and clean the rod cap insert.
40 Assuming the clearance was correct, thoroughly coat the bearing with assembly lube and replace the cap.
41 Coat the rod bolt threads and the underside of the rod bolt nuts with ARP assembly lubricant and tighten them to 30 ft-lbs, and then again to 50. When using ARP fasteners, always refer to their tightening techniques and required torque. Their specifications are very specific. In this case, it is 50 ft-lbs, while the factory manual calls for a range from 40 to 50 ft-lbs. Always follow the torque specified by the bolt manufacturer (in this case ARP specs).
The single-size ring compressors are a big improvement from the old one-size-fits-all units. As with any quality tool, you have to take care of it. As you tap in the piston and the top ring enters the cylinder, there is nothing to contain the loose compressor. When you get close to the piston leaving the compressor, keep the hammer handle in contact with the piston dome to catch the compressor.
42 Carry on installing the right-bank pistons. Then, roll the block over with the left-bank cylinders canted up at 45 degrees. Lock it in place.
43 Install the four remaining pistons following the previous procedures with one additional step. After you fi nish installing the companion piston and rod assembly, check the rod side-play clearance by simply pushing the rod back and forth on the crankshaft journal to confirm there is clearance. Then use a feeler gauge to determine the clearance and record it. The connecting rod side play has nothing to do with retaining oil pressure and is not a critical measurement as long as you can feel lateral movement and the rods do not interfere with each other.
When using ARP main cap bolts, they have a taller head plus the thickness of the washer. In this case, the rear main bearing bolt interferes with the oil pump casing. If you machine 0.075 from the bolt head and file 0.050 from the pump housing, it will fit with a thinner hardened washer. The main bearing cap bolts were retorqued and will now fit the oil pump in place.
The side clearance checked out fine. You may notice that there are studs in the main caps; however, these were replaced with ARP bolts, as there was not enough clearance for studs under the oil pump housing or with the baffle in the center sump pan.
There are applications where you should use Loctite as you assemble your motor. One of these is the oil pump mounting bolts. For a race motor, I tack weld the pickup tube to the mounting flange as well. There is a lot of harmonic vibration that goes on inside a race engine crankcase.
44 Treat the pump flange bolts with Loctite and torque to 35 ft-lbs.
45 Paint the oil pan flange on the block with a good shellac-based gasket sealant that will hold the oil pan gasket in place should you need to remove it at a later date.
46 Install the oil pan and torque the bolts to 17 ft-lbs. This is out of range for most 1/2-inch-drive torque wrenches, so you need to use a 3/8-inch-drive torque wrench with a lower range to tighten these bolts. Keep in mind that if you are working at the lower or upper limits of the range for your torque wrench, chances are that it is not accurate.
Written by Gary Weldon and republished with permission of CarTech Inc
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