The First Head Had Seen Better Days... Ford Tractor 172ci Gasoline Cylinder Head Valve Job

a couple of weeks ago we had the cylinder head come in from a 172 cubic inch gasoline ford tractor engine but during the inspection after our cleaning we noticed that something was off our magnetic particle inspection quickly revealed that at some point prior during this head's life some major crack repairs have been completed the repairs did look to be very professional and to our knowledge were holding but these heads were known for cracks and from the looks of it this head may have just been a poor quality casting from the factory after discussing with the customer the decision was made to move forward with the valve job on a different head supplied by the customer as to avoid any possible liabilities that could come if these crack repairs were to fail down the road luckily the customer did have access to a spare head which turned out to be a much better core to start with so on this head you can see that six of the valve guides had already been pressed out we drove those out before we baked the head and cleaned it there were two guides that were pretty much super super tight didn't want to budge so we went ahead and baked it we're starting off our work here by leveling up the head on the tcm 25 so that we can get to work driving these last two seized guides out of the head this design is somewhat unique as most press fit guides we see are only around a half inch outside diameter whereas these guides are about three quarter inch od so pretty big even with how beefy these guides are when they're seized like this our first step is to cut the top of the valve guide flush with the casting of the cylinder head if you just keep driving on it as they sit you're ultimately going to break the top of the guide off or at the very least mushroom it to where it won't go through the bore of the head without causing damage if you're new here don't forget to subscribe and check out the description for more information on our small family owned business now what i'm going to do is i'm going to drill part way through the guide with this 5 8 drill bit and what that's going to do is kind of relieve some of the press fit so that we can go ahead and hopefully get them to move and drive on out i'm not going to drill all the way through probably just maybe a little over halfway and that way it leaves a step that we can put this this driver in and drive down against and hopefully get them to drive out at this point you'll see that we have thinned out the guide to around sixty thousandths wall thickness part way down leaving a step at the bottom to drive against with the air hammer in a perfect world this would get it loosened up just enough that when we drive against it it would pop right out but in this case it simply busted the guide into right at the step the one on the left moved slightly but the upper part of the right one didn't even budge that's okay because at this point we can take another driver which definitely did not used to be a nice matco half inch drive extension and drive against the remaining shell from the opposite direction to finish removing the guides from the head still with no damage to the bores to make sure the bores were clean for a new valve guide i touched them very quickly with the ball home to take out any burrs or debris but don't worry we didn't do enough to remove any material and effective press fit all right now i'm ready to get the guides pressed into this head on the combustion side here inside the port this face of the valve guide is about flush with the casting and the intake ports it's actually exposed a little bit in the port but on the top side they're all even so what i'm gonna do is i'm gonna press in my exhaust guides until they're flush here on the casting and when i say press it's a press fit but we're using a driver then on the intake i'm gonna go in and drive them in until on the top side they all match i am gonna be using our crest fit lube like we always do spray a little bit on the guide spray a little bit on the bore and you're good to go those going tough at this point the exhaust guides are in to the correct height so to get the guide height correct on the intake guides we're going to start them in straight before setting a straight edge across the top of two exhaust guides and drive the intake guide until it just touches a straight edge so right out the gate here we're sitting right at 2 000 clearance a lot of the aftermarket valve guides when they come in they're on the higher side of spec on the intake we're supposed to be one to two thousandths on the exhaust we're supposed to be one and a half to three so knowing that our exhaust valve stem is about a thousand smaller than the intake valve stem i have this set to zero for the intake so if we're measuring you know about two thousands sarah on that intake actually a few tenths above that and on this exhaust we're measuring two by what the gauge is set to but that's really about three thousandths what that's telling me is i really don't want to go any larger on the valve guides if i can help it so i need to find a pilot that fits pretty well right here having driven these guides in obviously we've checked the size we're already on the big side so i don't want to hone a lot of material out i do want to go through the guides with the hone just to give them that nice finish on the inside and make sure that we don't have any burrs or any raised edges or anything like that from driving them in so we're just going to go through and touch them up really really quickly here can't feel any excess wiggle which is exactly where i want it to be to be able to cut the seats just like i want them on the 30 so at this point i think the 874 is a good spot might have to hit that hole maybe a little bit more we'll see i got to clean them out too because sometimes there will be something in there that keeps them from running good if i put the 873 gin it also feels pretty good but i can feel and it's you know it's something that you probably can't really see but there's just a tiny tiny bit of wiggle there again we're probably talking you know three or four ten thousandths of an inch but it's there and that makes it that much harder to machine a good seat on the sturdy you can do it it just takes more skill and you don't get as good of results as you do when you have a perfectly fit pilot at this point we're going to move over to the 30 for our valve seat work and get leveled up you can see that the bubble level for the 30 appears to be somewhat crude but the mechanisms of the sturdy machine make up for any misalignments in the plumbness got the head on the 30 i normally like to keep it a little more centered in this tilt fixture you can see we're a little offset to the right side which when we loosen these handles kind of makes it tip back just from the weight being off center but we've got this little bolt right there that kind of hits depending on where i want to put it so i think this will work good and we'll get it going and get the seats cut at this point i'm working on getting my intake cutter set up so that we can come in and cut the intake seats we're using a three angle valve seat cutter insert this cutter has a 45 degree seat angle as the specs call for and it is 60 thousandths wide on the intake here and we're going 60 thousandths on the intake and 80 thousandths on the exhaust that's right in what it calls for on the intake that's a little narrower than it calls for on the exhaust again we're just touching up the seats so it's a battle of matching what we have to work with as opposed to when we're putting in new seats obviously we're setting it based on our valve and based on our other specs so in this case where the seat is you know pretty well worn but it's not completely worn out if our cutter is set up too small we're gonna have to cut very very deep into the head to get our full seat angle to come into the valve if we set it up too wide we're gonna end up with the seat not centered on the valve face i've kind of done a balancing act here of setting this up and looking at where we're going to be on the valve face right now i've got it where i think it's going to be pretty well centered i may end up moving out just a little bit once i start cutting but we're going to see what it looks like as we start cutting here you're going to see the bottom angle coming in first which is what you want to see and usually the seat angle comes in next but in this case we see a sliver of the top angle on the right there followed by the 45 degree seat angle coming in so you can probably tell there that we went from basically our bottom angle coming in to almost instantly all of our seat angle cleaned up and we got a bunch of top angle with the exception of this low spot over on this side checking where we're seating on the valve we're right in the middle right now so knowing that we have room to go out a little bit i'm going to bring it out just a tiny bit more i want a quarter of a turn out on the cutter our biggest focus when re-cutting seats without installing new seats is to avoid cutting the seat too deep into the head and to do this we just want to cut until we have our full seat width all the way around as you can see the sturdy operates on an airflow which allows the spindle head to move between each valve guide once the pilot is inserted into a particular guide two additional airfloats are released which allow the pilot to find the true access and center line of the valve guide at that point the airfloats are locked down and everything is rigid and ready to cut the seats same idea here on the exhaust cutter i've got a three angle cutting insert this time it's 80 thousandths wide it's a 45 degree seat still and i'm just trying to match what's already here we got to work with what we got we could have put seats in but they're nice enough that we're not we're trying to save the customer a little bit of money by not going to the extra expense of installing seats when it really doesn't need it but that being said we have to match what we've got so i've got my cutter adjusted here and we're going to see if we can cut these i should note that this head does already have exhaust valve seat inserts we're simply just not installing new exhaust valve seat inserts we've got bottom angle on half on this half over here you might notice that despite having a freshly sharpened cutter the seat appears what i'm going to call as draggy as such i sped up the rpm quite significantly in an effort to get an improved surface finish i also tried finishing the cuts with a little bit of coolant but even then the seats were still not visually perfect every once in a while we get a head in with seats that just have some sort of material that no matter what you do the finish doesn't look perfect that being said the seats do still come out well and they do pass our quality checks in regards to holding vacuum and having acceptable run out they just don't look as good aesthetically with all the valve seats cut it was time to move over to the surfacing machine but i decided to glass bead in the water jacket of the head because after all of the hammering earlier with the guide work we had knocked loose a ton of rust and debris that the steel shot machine hadn't fully cleaned so i wanted to take care of that before i got the surface done similarly to cutting the valve seats our goal with resurfacing the head is only to cut the necessary amount of material to get an acceptable surface again in this case we're looking for a decent surface finish from our cbn cutter but more importantly we're looking to get the head gasket surface completely flat with no low spots that could result in a head gasket leak i'll clean all the way across here all the way across here and all the way across here up till here and we've got this section in here that isn't cleaned up yet so we're going to take another cut with one more cut for a total of around four thousandths off the surface we had a flat cylinder head with a very nice surface finish with that the machine work on the head was finished so we gave it a quick wash cycle in one of our spray cabinets before moving on to the assembly after the wash cycle we always rinse the cylinder head thoroughly with fresh water being sure to finish rinsing any debris out of any ports passages and bolt holes finally the head gets blown completely dry which again helps to ensure that no debris is left in any part of the head when it leaves our shop we want the head to be perfectly clean just like it would have been when it left the ford factory finally we're on to the final assembly of the cylinder head with all new valves springs keepers and valve stem seals we are reusing the spring retainers each valve will be installed into the cylinder head with assembly lubricant on the valve stem to help lubricate the valve stems on the initial startup of the engine i'll also note that the intake valves do have umbrella style valve stem seals which literally act as an umbrella to keep oil from simply pouring down the valve guide this head also utilizes two different valve keeper designs one for the intake and one for the exhaust the exhaust keepers are kind of tough but overall it's a pretty straightforward assembly there's also one freeze plug that had to be installed in the end of the head so i gave the boar a band of loctite before getting an appropriately sized driver and driving the freeze plug into the head all in all this was a pretty straightforward and fun valve job to get an old fourth tractor back in the field or just in a parade i'm really not sure if you enjoyed the video be sure to give it a like subscribe and turn on notifications and be sure to check out www.jamzyonline.com for more thanks for watching and we'll see you in the next one [Music]

Channel: Jim's Automotive Machine Shop, Inc.

Views: 287,529

Keywords: Engines, Engine Machine Shop, Machine Shop, Engine Shop, Machining, Automotive Machine Shop, Automotive, Cars, Trucks, Tractors, Gas, Diesel, Performance, rebuild, high performance, internal combustion engine, pistons, cylinder heads, jim’s, jim's automotive, jamsi, jamsi online, Blueprinting, rebuilding, engine building, connecting rods, engine block, boring, valve job, engine rebuilding, jim's automotive machine shop, ford, tractor repair, crack repair, cracked cylinder head, engine crack

Id: XiNFcsprjq0

Length: 16min 37sec (997 seconds)

Published: Sun Apr 17 2022