SHOVELHEAD REBUILD

Words and bad pix Dan R

EDITOR’S NOTE: OK, this might fly in the face of the “If I can do it” scenario, I trusted a local ‘performance’ shop to set up the clearances for the KB pistons and bores, and I had confidence that they were probably correct. I obviously should have checked it out before reassembly, but I didn’t and the engine seized. I was concerned that more than the bores and pistons might have been affected in the seizing, so I begged Dan R here to replace the pistons and give it the once over. I was hopeful that just a new set of pistons and a quickie bore job would have me back on the road, boy was I wrong. I knew nothing about V Twin engines when I assembled this one around ten years ago and it’s a testament to the design that I have had years of riding with this engine even with the lurking disasters that were evidently ready to erupt below. Now, I have extreme confidence this engine will get me to the Smoke Out 6 in June. Thanks Dan. -Englishman

First, a bit of history on myself and how this rebuild all came about.

I’m not a motorcycle shop owner and I don’t work for one. I’m just your average “clown” that has a passion for riding and tinkering with Shovelheads and even though I am licensed to do motorcycle repair, I just don’t have the time or desire for a shop of my own. I also want to point out that these are my views and you may or may not agree with them. With any luck, I may pass on a few pointers and this won’t blow up in my face. Englishman’s Shovelhead has had a history in the mag from its start as a pile of mostly unrelated parts. This engine has gone through some growing pains as you may recall. I have bumped into Englishman a few times here and there I have heard the story first hand of how his shovel is running…… or not. It’s painful for me to hear about problems when I know there is a cure. Those of you who build engines or really do any type of repairs know that the more hands that have been on something, the more things tend to get screwed up. This engine was no exception and it had problems, oh boy did it ever. So without picking on the Englishman much more, here we go.

When starting into any type of engine project, I more or less start them all the same. First start with a careful inspection of each and every part as it comes off. I like to look for signs of any problems such as why did this part leak here or maybe why did it make that strange noise. What I am getting at here is don’t just blindly rip into anything without carefully looking over each and every part. Just remove a single part and inspect it every which way you can dream of. A lifetime ago I went through some tech schools put on by FoMoCo and the geezer that was the instructor used to say “take in the big picture” your problems will show up 99% of the time. The guy was right and I have never forgot it.

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This engine’s repair parts list started with replacement cases. My first choice in replacement engine cases has been S&S. Why? First thing they come complete and are ready to build right out of the box. One of the many nice features of all S&S replacement cases are that they come standard with the pinion race line lapped and sized ready to go. With other brands if you don’t have a case bearing lap set and the measuring tools needed, count on extra added time and costs. These cases are not just standard replacements either; there are many improvements over the original factory design. On OEM and most of those ‘others’ you need to work over the breather window opening to correct the breather gear timing but not these, it’s already done. These have a breather cavity in the crankcase area that is of a streamlined ported shape, no more hours of welding and machine work to slick up this area. The oiling system on these 70-84 Shovelhead style cases are set up for the most proven of oil pump designs, the 81 and up split system. Any 81-91 OEM pump will just bolt on, nothing to modify. With a simple set screw plugging operation you could use an 80 or older design pump. I tend to think S&S just couldn’t leave well enough alone with that oiling system though and they have made some improvements. First thing I noticed was where the oil scavenge port is located in the gear case. The scavenge port location has been moved to get it away from the turbulence caused by oil pump drive gears. The oil scavenge intake port is now located near the cam cover gasket surface area and this change alone will help prevent oil carry over out of the crankcase breather passage. The top end and tappet oil circuits have been rerouted from the OEM design. No longer does the oil galley run close to the cylinder bores. OEM cases have cracked here and if you ever think about going to big bore cylinders that passage could be bored into causing a major internal oil pressure leak. There is still a tappet screen used to trap oil born contaminants in these cases unlike some of those other brands.

Now let’s talk cylinder to piston clearance, that’s what parked this engine in the first place. Each piston type, cast or forged and the many different brand names will have their own loose clearance spec. Make sure what the spec is for the pistons you have and for the type of service they will see. Just as a rule of thumb, cast pistons run tighter in the cylinders than forged and street use engines are tighter than race engines. The use of stress plates mounted at the top and bottom of the cylinders are a must to get a true and round cylinder bore while machining. Forget only honing to get to the next oversize, it’s just not going to work. I always take cylinders and pistons both to the machine shop so they can be matched when boring. The shop’s owner who does them for me bores them perfectly true, round and at the correct loose fit clearance needed every time. This shop does not use an automotive type boring bar and does not cut cylinders on a lathe, he uses an inside diameter grinder to resize them. By mounting cylinders by their base in the grinder the bore will always be at a true 90 degrees from the base as they should be. Lon at Sunray Products in Vernon Michigan, 989-288-2972 can bore any Harley type cylinder be it a Knuck, Pan, Shovel, iron Sportster, any Evo type big or small and any Twin Cam big twin engine. Hate to say how long Lon has been doing cylinders but for me it’s close to 18 years with never a problem.
Lets get down to the build now, where do we start? As with any major rebuild, I like to rebalance the flywheels. If you are replacing any major components in the lower end, a rebalance job is a must. I static balance flywheels and have had what I feel are very good results. The balance kit I use came from S&S years ago and it has served my needs well. Before any balance work could be done, all major work such as cylinder boring to fit the pistons, rod bearing race lapping, have the proper rollers chosen to fit the crank pin you plan to use, new flywheel thrust washers replaced if needed and have the wrist pin bushings replaced and reamed to size. There is no sense in balancing parts that will be replaced. There are only a few simple rules I use when balancing flywheels. First is that I never remove weight near the crank pin. If need be, weight can be added to the opposite side. I also like to drill to remove the needed weight from the inside of flywheels. There is nothing worse than looking for timing marks and finding only balance holes. One tricky part of a balance job is in how you weigh the rods. There are three weights for each rod that must be known: the wrist pin end (reciprocating end) the crank pin end (rotating end) and a total for each. The hard part is to have the rods crank and wrist pin ends add up to the actual totals. What I have learned while weighing rods is to hang one end from a string while weighing the other end. I do not use the rod stand provided in the balance kit. The rod stand can and does influence the rod end weight totals. Once I hung the rods level center to center the weights added up much more accurately. I also use an old wrist pin to keep the string from touching the rod sides as I have found that it will influence the weight figures quite a bit. Once you have all rotating and reciprocating weight figures it’s only a mater of simple math to come up with the proper bob weight amount for balancing each flywheel. Once the bob weight is known and in place, choose the proper arbor from the kit to support the flywheel on the parallels and gravity does the work. When the flywheel rolls and stops with the heavy spot at the bottom, its time to mark it and drill to remove weight. I use mostly a 7/16” diameter drill bit and rarely need a larger size for removing weight. It’s best to drill only a very slight amount at a time. I would say that it takes on average for me about 25 trips to the drill press for balancing each flywheel. How do I know how much to remove, it depends on how fast the flywheel seeks it’s heavy spot. If I have a flywheel that drops like a rock to the same spot each time it’s a sure bet that quite a bit of weight must be removed. If the flywheel rotates quite “lazy like” and also rotates many degrees back and fourth I know that the wheel is very close to balanced. I keep at it until there is no movement when placed on the parallels in any position.

Crankshaft assembly is next and there are a few simple rules I use with a definite order that must be followed. I like to check all shaft tapers to see if they are concentric. Now and then you may run across a shaft that is off and it makes for much grief when truing flywheels. All shaft and flywheel tapers must be extra clean and dry before assembly. If you have any trace of oil, grease or solvent on any taper surface when you torque the nuts, the tapers will not seat properly and they may go deep. Cast iron flywheels can split and wreck your whole day just because of some oil on a taper when going together. The factory spec for each flywheel’s run-out is 0.003” at the rim edge max. Take your time here, all effort spent will pay off in the next stage of installing the crank pin and rods. I like to use Loctite number 609 on all crank pin and main shaft nut threads. While truing any shaft and flywheel, a lead hammer is always best to use. Lead will not scar the flywheels or the machined shaft surfaces like an iron, copper or even a brass hammer will. I like to start flywheel truing with half of the nuts total torque spec and then check for run-out. I whack the shaft or wheels to adjust them, retorque then check for run-out again. Once you are happy with the run-out, bump up on the torque and start the same drill all over again. I keep at it until torque is at max spec and run-out is at 0.001” or less. These flywheels and shafts trued up pretty good for as many times as they had been apart. I ended up with 0.001” on the flywheel edges and when I installed the crank pin and rods the run-out on the main shafts was 0.0003” on the pinion side and 0.0005” on the sprocket side, all well below the max spec of 0.003” and 0.001”

Once you have the flywheels, rods and shafts true it’s time to mount them in the cases. There is no other way to do this other than with the proper tools. Once you have the crankshaft assembly in the left side case it’s time to install the pinion rollers. These are brand new S&S engine cases so the pinion race is already lapped to size, this made it a simple matter of just picking the proper size rollers for a loose fit clearance of 0.0004” to 0.0008” You may have a favorite gasket goop you use for sealing the case halves, I use an anaerobic type sold by Permatex called “Gasket Eliminator” This red colored sealer sets up as a flexible, non migrating seal. A word of warning here, silicon type RTV sealer will work but be extra careful not to over do it. Any loose bits of RTV will make it into every place you just don’t want like oil pumps and any internal engine oil passage. Loose bits of that RTV has been the cause of many engine problems so you have been warned. After the case halves are sealed and the case studs and bolts tightened to the proper torque, I like to check the wrist pin bushing alignment with the cylinder base gasket deck surfaces. I cannot stress enough how important I feel this detail is. New replacement rods are not always reamed true and replacement bushings in used rods will most often be off. An out of alignment wrist pin will put the piston in a bind with every stroke and rapid wear and piston failure is sure to happen. I made this rod bender tool from a hunk of bar stock and it uses thick aluminum washers that clamp the wrist pin end of the rods. It’s likely you will do damage to the new bushing by using only a bar poked through the bushing or wristpin. OEM factory rods bend with an alarming ease, heavy duty aftermarket rods will take some “Horse Power” No matter what brand of rods you use, new or rebuilt, make sure to check and align them.

Now that the cases are together and the rods are ready to go, I move onto installing the oil pump. Since Englishman’s old oil pump was bad, a new S&S replacement will be used. I like to install the pump drive gear in the cam case before I torque the pump mounting hardware. That way I can roll the pump shaft and gears to check for any bind first. Be extra careful installing that drive gear snap ring and key. It’s best to use a new key and always use a new snap ring. A stretched or used snap ring will fall off and trash an engine quick. Next to go inside the cam case area are the pinion shaft keys and gears. I never drive a key into its slot, distortion is sure to happen. I rub keys on a file or wet stone until they will just slip into their slots. Remember to use a drop of Loctite number 242 on that left hand threaded pinion gear nut. The Camshaft this engine had did bump the case somewhat before. These S&S cases have plenty of room for camshafts with a high lift figure. Camshaft endplay should be kept at the minimum spec if your going to drive a vertical mount magneto like this engine has. Any extra cam endplay will mess with your timing. Points type or electronic ignitions that run direct off the end of the cam are not quite as fussy but close to the minimum spec here is still best. While you’re into the cam case it’s now time to move onto breather gear timing. Breather opening and closing timing should be checked with a degree wheel mounted on the crankshaft. These cases had the proper timing right out of the box but it’s rare that an OEM or other after market case will. The timing spec on this engine is checked from the front cylinder. The breather gear window started to open at 10 degrees before top dead center and closed fully at 75 degrees after bottom dead center. That timing spec works for any stock displacement and also big bore stroked engines. Why bother with breather timing at all? Proper breather timing will help scavenge the air/oil mist from the crankcase area and reduce pressures.

Any restrictions here will create an extra oil drag on the flywheels and that makes for extra engine heat. Proper breather timing is as close to free Horse Power as you can get. Tappet blocks like this need to be aligned with the case for best roller life, the tool for this is quite simple as it’s a bolt with a tapered shank. The taper above the threads will align the block by centering the hole over the tapped mounting hole in the case. I like to use the tool in the bolt hole closest to the oil galley near the top center case stud. These are Jim’s brand big axle tappets that will oil the rockers like an Evolution engine does. They oil the top end by transferring oil through the tappets into hollow pushrods and then passing into the rocker arms. I like the idea of this oiling system because oil is under pressure at all points of tappet to pushrod and pushrod to rocker arm contact. The standard oiling on Shovelhead rockers just lube the pushrod ends by splash. One thing I am not sold on are the big axle part of the tappets themselves. There are fewer needle rollers with the big axle type tappets and I view that as a roller that will not carry as much load because of fewer needle rollers making for less contact area. The test of time and mileage may prove me wrong; I hope so but do have my doubts.

Only after you are sure of wristpin alignment the pistons, rings and cylinders can go on. These pistons are S&S cast stock compression replacements fit to the recommended 0.0025“ clearance. They came with a ring set that has a moly insert top compression ring. Once the ring gaps are checked and adjusted if needed, it’s time for placement on the pistons. Ring gaps should never be in line with each other or placed on a thrust area of the bore. The major thrust area is the rear of the cylinder wall and the next minor thrust area is the front. These pistons I have marked with numbers at the positions for proper gap placement. # 1 is where I place the oil ring expander gap. Yes # 1 is located at the major thrust area but the expander does not come into contact with the cylinder bore. # 2 and # 3 are where the oil ring scraper rail gaps are. # 4 and # 5 are for the second and top compression rings. Make sure to use a quality ring compressor, this is not the time to mess up the pistons, rings or cylinders. Once the cylinders are slid down over the pistons and rings I leave the base nuts only finger tight until the heads are in place.

These heads had been gone over about a year ago with no mileage on them. They do have Row Ampco 45 guides with Manley stainless steel valves. The valve seats had been cut at 5 angles. Valve travel was matched for the camshaft used. I did a quick check on rocker arm end play and bushing to shaft fit and then bolted the rocker boxes onto the heads. The head gaskets here are James brand Fire Ring type and will need to be re torqued after this engine has been warmed up a few times. I like to use silver grade anti-seize on cylinder base studs and nuts, same for the head bolts. Once the heads are on with the bolts only finger tight it’s time to align the intake ports with the manifold. Once I am happy with alignment I torque the cylinder base nuts and head bolts in at least 3 stages.

Here you go “Englishman”

Where it goes now is up to you…….

Editors Note (again) I’m confident that this engine will work well as Dan has it set up, but S&S wanted it to be known regarding the breather timing, 10 degrees before and 75 degrees after has been a specification that S&S came up with and has been in print for many years. After additional research was done in 1999, it was found that retarding the breather gear 1 tooth (17 degrees) for an opening spec of 17 degrees after tdc, & closing of 82 degrees after bdc, the level of vacuum in the cam chest and crankcase was increased significantly. This results in better oil scavenging, and less oil carryover. In addition, the hole in the breather gear that sucks oil out of the cam case settling pocket was elongated into a slot rather than a hole to provide more suction time to the settling pocket (and less chance for oil carryover (puking) )

Check out the S&S range of products at www.sscycle.com or give them a call at 1-608-627-2080

 

 
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