I use ceramic paste on everything I can :-) On the hold down bolt holes I run a tap; I will mark depth with a wrap of tape and use that as a depth gauge for the holes. Carb cleaner and compressed air. I follow up with swabs until I get no traces of anything.
On the injector bores I have had no need to cut them. I just use wire brushes. Final polish via a chunk of doweling with a piece of scotch brite glued on the end (and followed up with cleand swabs). Sealing washers will take care of a lot of minor surface distortions. Only time cutting is necessary is if things are really bad: keep in mind that reducing the height of the seat means that the injector hold-down will have reduced clamping force, though probably nothing that would likely cause any issue; BUT, unless you have the complete history of a given engine/head throughout its life you don't know if someone before you has made significant cuts on the seats. Speaking of the hold down clamps, put a dab of grease on the "ball" part as that helps allow the clamp to pivot as it gets torqued down: yeah, it's really not moving much but it reduces friction there and makes for a clean torquing of the hold d0wn bolt.
I'm a wimp, I do only ONE 90 TTY pass. Someone measured actual bolt stretch between ONE and TWO 90s and found that there wasn't any difference. My rationale for signing up to doing only ONE 90 is that these heads aren't new any more and all the heat cycling and changes of hold down bolts is likely to have reduced the holes' thread strength; again, hard to say if this is a concern but I'm pretty certain that things haven't gotten stronger. As someone who was blessed with a messed up head (a moron didn't stop digging at a broken GP and ended up trashing a GP hole) I learned that these heads aren't cheap! (it actually motivated me to do a full engine swap- lots of other reasons for the decision but suffice it to say it worked out well- it was a big restoration project). I have, however, heard of folks who have broken off these bolts: I suspect the main cause was debris at the bottom of the holes.
One other thing to note is to plug the holes in the fuel rail. I just leave the lines on and rotate them around and away from the valve cover (the injector end of the lines will be pointing down so no worry about dropping crap into them).
I self-limited my power goals when I replaced old injectors with new stock ones. Can't justify replacing these new injectors (to increase fuel flow) so I'll just have to live vicariously through you :-)
Looking forward to see what you end up with for the IC piping.
Oh, and nice engine bay! (it's so much nicer to work on stuff that's clean!)
I don’t see how the second turn would make no difference, unless somebody has reached exactly the point where the force levels out in the curve. It is something you expect to see at yield, though, so not impossible. I’m just going with the factory spec on this to play it safe.
I’m not worried about the threads in the head, as I’ve done inserts before on an OM642 and it’s not a big deal to drill tap, and put an insert in place.
I disagree on the idea of reduced clamping force, unless somebody is actually bottoming-out the bolts. I counted 19-20 turns each, and that’s quite a bit further than they go in when they are actually holding an injector down. I didn’t count what was actually used, but could see where the used threads stopped and removing them after running them all the way down. Holding them up side-by-side, I could see that we were going ~20% further when purposely going to the bottom of the hole. What you experience when torquing is force via the injector and the interface with the seat.
I only touch them up lightly with the reamer, barely any metal is removed, anyways. I doubt I’ve even removed .001”.
I’ve dealt with broken glow plugs before on an OM642 engine with black death, and it was a slow process of soaking in solvents (including my secret weapon: oil of wintergreen), tapping the remainder of the plug, inserting all-thread, and working it out with a coupler nut and a socket. No fun, and slow, but it worked. I can’t say enough about the relief I felt — I would have hated to have to remove the head!
Your trick with leaving the high pressure lines in place and just swinging them out of the way is smart. I might do that next time. Plugging fuel rail holes is more of a concern if things are going to be apart for more than a short period of time. I often take nitrile gloves, cut the fingers off, slip them over the fitting, and zip tie them in place. Fact is, you might notice I’ve done this in places when I get the pump video finished and released. That was a more in-depth effort and involved cutting metal (aluminum dust everywhere), so it was super-important on that job.
My intercooler piping is done, the pump is in, and I’ll be releasing more videos. I even came up with a way to get a temp sensor on the fuel line this weekend. All the hardware for the upgrade is installed, so when I start getting tunes, I’ll start sharing those results, too.
I agree that the second 90 HAS to produce some extra stretch but as I'd read the amount was pretty much imperceptible (I suppose it all comes down to the tool used to measure). My first CDI is approaching 18k miles (it's got a stage 1 tune) and there's no sign of problems. I also make a mark on the bolt heads (with a permanent marker) as an additional aid to monitor for any bolt movement, though I have no idea if these bolts are prone to spinning loose even if they're a bit loose (or a second 90 isn't used, or whatever).
It really pissed me off to find that botched GP job: shysters peened the broken/top of the broken GP into the head trying to get it to ground in order to quench the CEL. The hole was too far gone to helicoil (or Time-sert:): I consulted with several professionals. I've never broken a GP. Ceramic paste on the GPs and it'll never be an issue. Had a stuck injector that took a good three days to remove (had to destroy the injector)- and the engine was OUT of the vehicle!
I don't trust that something couldn't drop down into the line holes in the fuel rail. For me, any time I don't go real anal I end up finding out that I should have. The fuel system is one thing you just cannot take chances on. I have silicone plugs (used a lot in powder coating) to stop up lines and such if things are apart for any significant period of time.
Anxiously waiting for Drew to get his website up. And I really am interested in IC piping solutions (especially after popping one of my silicone hoses off! [put it back on tighter and while it seems to be holding I'm not all that confident, especially for my wife to drive the car]).
I use ceramic paste on everything I can :-) On the hold down bolt holes I run a tap; I will mark depth with a wrap of tape and use that as a depth gauge for the holes. Carb cleaner and compressed air. I follow up with swabs until I get no traces of anything.
On the injector bores I have had no need to cut them. I just use wire brushes. Final polish via a chunk of doweling with a piece of scotch brite glued on the end (and followed up with cleand swabs). Sealing washers will take care of a lot of minor surface distortions. Only time cutting is necessary is if things are really bad: keep in mind that reducing the height of the seat means that the injector hold-down will have reduced clamping force, though probably nothing that would likely cause any issue; BUT, unless you have the complete history of a given engine/head throughout its life you don't know if someone before you has made significant cuts on the seats. Speaking of the hold down clamps, put a dab of grease on the "ball" part as that helps allow the clamp to pivot as it gets torqued down: yeah, it's really not moving much but it reduces friction there and makes for a clean torquing of the hold d0wn bolt.
I'm a wimp, I do only ONE 90 TTY pass. Someone measured actual bolt stretch between ONE and TWO 90s and found that there wasn't any difference. My rationale for signing up to doing only ONE 90 is that these heads aren't new any more and all the heat cycling and changes of hold down bolts is likely to have reduced the holes' thread strength; again, hard to say if this is a concern but I'm pretty certain that things haven't gotten stronger. As someone who was blessed with a messed up head (a moron didn't stop digging at a broken GP and ended up trashing a GP hole) I learned that these heads aren't cheap! (it actually motivated me to do a full engine swap- lots of other reasons for the decision but suffice it to say it worked out well- it was a big restoration project). I have, however, heard of folks who have broken off these bolts: I suspect the main cause was debris at the bottom of the holes.
One other thing to note is to plug the holes in the fuel rail. I just leave the lines on and rotate them around and away from the valve cover (the injector end of the lines will be pointing down so no worry about dropping crap into them).
I self-limited my power goals when I replaced old injectors with new stock ones. Can't justify replacing these new injectors (to increase fuel flow) so I'll just have to live vicariously through you :-)
Looking forward to see what you end up with for the IC piping.
Oh, and nice engine bay! (it's so much nicer to work on stuff that's clean!)
Thanks for your comments!
Nice approach on the bolt holes.
I don’t see how the second turn would make no difference, unless somebody has reached exactly the point where the force levels out in the curve. It is something you expect to see at yield, though, so not impossible. I’m just going with the factory spec on this to play it safe.
I’m not worried about the threads in the head, as I’ve done inserts before on an OM642 and it’s not a big deal to drill tap, and put an insert in place.
I disagree on the idea of reduced clamping force, unless somebody is actually bottoming-out the bolts. I counted 19-20 turns each, and that’s quite a bit further than they go in when they are actually holding an injector down. I didn’t count what was actually used, but could see where the used threads stopped and removing them after running them all the way down. Holding them up side-by-side, I could see that we were going ~20% further when purposely going to the bottom of the hole. What you experience when torquing is force via the injector and the interface with the seat.
I only touch them up lightly with the reamer, barely any metal is removed, anyways. I doubt I’ve even removed .001”.
I’ve dealt with broken glow plugs before on an OM642 engine with black death, and it was a slow process of soaking in solvents (including my secret weapon: oil of wintergreen), tapping the remainder of the plug, inserting all-thread, and working it out with a coupler nut and a socket. No fun, and slow, but it worked. I can’t say enough about the relief I felt — I would have hated to have to remove the head!
Your trick with leaving the high pressure lines in place and just swinging them out of the way is smart. I might do that next time. Plugging fuel rail holes is more of a concern if things are going to be apart for more than a short period of time. I often take nitrile gloves, cut the fingers off, slip them over the fitting, and zip tie them in place. Fact is, you might notice I’ve done this in places when I get the pump video finished and released. That was a more in-depth effort and involved cutting metal (aluminum dust everywhere), so it was super-important on that job.
My intercooler piping is done, the pump is in, and I’ll be releasing more videos. I even came up with a way to get a temp sensor on the fuel line this weekend. All the hardware for the upgrade is installed, so when I start getting tunes, I’ll start sharing those results, too.
I agree that the second 90 HAS to produce some extra stretch but as I'd read the amount was pretty much imperceptible (I suppose it all comes down to the tool used to measure). My first CDI is approaching 18k miles (it's got a stage 1 tune) and there's no sign of problems. I also make a mark on the bolt heads (with a permanent marker) as an additional aid to monitor for any bolt movement, though I have no idea if these bolts are prone to spinning loose even if they're a bit loose (or a second 90 isn't used, or whatever).
It really pissed me off to find that botched GP job: shysters peened the broken/top of the broken GP into the head trying to get it to ground in order to quench the CEL. The hole was too far gone to helicoil (or Time-sert:): I consulted with several professionals. I've never broken a GP. Ceramic paste on the GPs and it'll never be an issue. Had a stuck injector that took a good three days to remove (had to destroy the injector)- and the engine was OUT of the vehicle!
I don't trust that something couldn't drop down into the line holes in the fuel rail. For me, any time I don't go real anal I end up finding out that I should have. The fuel system is one thing you just cannot take chances on. I have silicone plugs (used a lot in powder coating) to stop up lines and such if things are apart for any significant period of time.
Anxiously waiting for Drew to get his website up. And I really am interested in IC piping solutions (especially after popping one of my silicone hoses off! [put it back on tighter and while it seems to be holding I'm not all that confident, especially for my wife to drive the car]).