Hi folks, i'm having trouble sealing up my early style screw down tappet/valve covers, i need to replace the upper tins and was wondering if the tappet adjuster screw/bolt can be removed without removing the heads, in other words can i remove valve keepers and have enough room to raise valve til it contacts the head and screw out tappet adjuster screws? then be able to remove spring and upper tin?
thanks pa, kinda hoping to get away with not pulling the heads. what's your opinion on removing pistons and rings from bore and then reinstalling them? i have been taught to never disturb the rings by removing them from the bore, but to pull the wrist pin and keep rings in bore. if i'm going to pull the heads i might as well remove the cylinders for ease of working on valve covers and to hopefully align intake wye as well...mark
If the pistons and bores are seated to your expectation, I would try to keep them in that position. If you have any doubts, leave the pistons and rings on the rods, remove the cylinders, replace the rings, deglaze the cylinders and start fresh.
I also heard it was good practice to renew rings whenever they are removed from the bore. Having said that, I've also been in the position that I just needed to get the motor back together because the run was tomorrow, etc, etc. Truth is, I've not noticed any ill effects when I just put the rings back into the bore and run it. I've done it with and without honing the cyls's and had about the same results. While you've got the cylinders off, you might want to try a trick I just used. I've always had problems getting the tappet blocks to seal in the engine case. This year, I pulled the tappet blocks, grooved them in the lathe to look just like Sporty tappets, then used the O rings from Sporty tappet blocks on the UL blocks. NO Leaks!! I figure if Harley thought O rings were an improvement, why not? I also use O rings at the junction of the middle and bottom screw cover, and where the bottom screw cover goes onto the tappet block. Ordered a bunch from McMaster-Carr. I made my tappet block puller from an old screw type tappet cover lower. Brazed a small blind end tube to it, threaded the top, then screwed it to the block and ran a bolt down that pushed against the tappet. Out she came... DD
thanks DD, the tappet puller you made is in the works here as well, darn tools are too expensive for infrequent use. the o-ring idea sounds like a worthy upgrade, just got an old lathe this summer, still trying to learn how to run it. a steak dinner after work would probably get one of our machinists from the RR to come over and steer me right. i use the o-rings in the middle and bottom as well. i have 18k on the motor and i'm thinking i might as well go with new rings and hone. at 10k bore was glazed over and hone still there, no wear thru hone, so i should be good and true enough for just rings and a hone. i think i'll make my own upper covers out of stainless steel, the set i have must be V-twin and they have caused nothing but trouble. last summer they leaked because when i screwed them down they would compress the valve spring a little and the gasket would leak, tried the narrower bands for a 45 same thing, this year we tried o-rings and they seal good but when i raise the covers to set the tappets i can;t get the cover back down without a sickening fight and tool marks on the covers from trying to twist and turn them down....they are like Chinese finger trap! and lets be very clear these are UL UPPER COVERS. so i figure something is off spec wise with these covers, i have oem cylinders and the dimensions from tappet block to cylinder/valve guide seem correct.
Your experience mirrors my own as well, concerning upper cover. I've had one that compresses the spring. Funny thing is, it doesn't leak! Oil doesn't seem to get that high inside. Yes, it's Vtwin. Same experience with the o ring at that juncture. A little oil from the old trusty oil can at that joint seems to help the o ring slide around somewhat easier. DD
DD, i filled every crevice with lube and still they bind up tighter than you can imagine....they have to go! i want turn turn down some stainless steel upper covers with a groove machined in them for an o-ring, i don't have any spare parts right now to spec dimensions from, i think springs are 1 3/16 dia. and i'm hoping to have enough clearance to make the walls thick enough to support a groove. i also am considering making spring spacer as part of the cover, any thoughts
i have also decided to remove top end to do a better job, got a local machine shop lined up for hone and touching up valves, found a shop with a good rep and bike racing history, so i'm comfortable with that. we deal with the same guy i think for alot of our more or less flathead specialty work , but it is several hours travel time for me, so finding someone close by who can do basic chores like hone, bore, valves jobs, etc makes things easier for me, how much quench do you run, piston to head clearance? i;ll be looking for top end gaskets and want to get the quench right. is .035 about right? thanks mark
Yeah, .035 sounds good. I tried to see how low you could go, got contact at .015" head to piston clearance static. Must be rods, wheels, etc "stretch" a little under load. That's with T&O wheels and straight pin, not stepped. Jim Casey years ago machined his own uppers from stainless, just found some notes from him. So, I'm thinking you should have room for an O ring in there, from his description, he did. I also live about 3 1/2 hrs from central Pa. The last trick I want to try is ceramic coating of piston and combustion chamber, If I can find someone who'll do the work. Should keep the heat down some, I'm finding that an 88 flathead with cams can get to run a little hot on a 90+ summer day! DD
I machined some valve covers that use 2 o-rings in the lower and one at the base of the threads on the lifter block. The upper cover does not have a lip and the lower slips over after valve and spring assembly. The lower cover also is one piece instead of the original 2 piece. Attached are some pics (I hope ). The aluminum cover was a prototype and the brass covers were originally made with the knurled ring. After some heat cycling, I discovered that the knurled type was nearly impossible to unscrew. I took them off and machined the knurled ring into 8 sided flats and made a special wrench for it. Works good now.
Thanks, Mark. No, the spacer is not built into the upper. I thought about it, but decided that leaving it out would give me more flexibility later if I want to play with different valves and springs. They work good, except for the hole in the upper for the valve guide. I made it fit much closer than the stock ones (machinist's disease). I discovered when I put the motor together that the oversize hole in the upper is to allow for misalignment with the lifter blocks. Things are not always perfect. I will be opening up the holes next time they are off the motor.
Frankenstein These are the folks that did my UL coatings. They have been around for a long time. They did different types of coatings for the different surfaces. Tops of pistons, underside of heads, inside exhaust ports and inside pipes. F http://www.millerpowdercoating.com