on buddy barry's 740 champion grader with a 6-71 detroit in it, started to run funny. it did not have the detroit sound and it was not an injector. so i popped the head off and checked things out. i then whipped up a plate to do and air check on the valves. with the regulator turned down to less then 5 lbs i get bubble with the soap. buddy barry's guys removed the muffler and install some resinator thing which does have back pressure which a detroit needs ( i think). any ideas because it is 1200 kms to the south to send the head out for a valve job. is there any other way of telling if the valves are not sitting properly. thansk KoO Published Author
thansk guys, the engine was running with a shake and a phoooooof out the exhaust pipe. i disconnected the each injectors and got mixed results. this morning i did the liquid test and of course the liquid just poured out the valves. i stripped down the head and got it ready for shipping 1200 kms to the south. looks like buddy barry's visa with be getting whacked for a valve job. also what fan belts are to be on the engine??? they put an AC pump on and ran narrow belts. we don't need AC in the great white north so we would like to to run the big belts and use the fan to tighten them. thansk KoO Published Author
Run Jimmy, Run I see the valves are leaking a little but not really enough that you would notice when it is running...... There is anouther problem other than the valves!!! Next I would check the turbo and then the blower; then, and I supect, fuel problem,,,, maybe injectors? Happy Hunting. Paul
I see that some one has a huge smile running something that is not 60+ years old......... :tong
buggyman, i don't have any pictures from the water test but the valves are burnt. dr.ernie, of course she is smiling because she gets $20.00 cdn a day plus meals at the cafe. how many 11 years old are pulling in that kind of money??? also need some 2009 LEGG pictures. will have to post on redpower because digger will be chasing us down, LOL (cut and paste) the 6-71 of buddy barry's burnt the valves because his mechanic decided to put this little muffler on which is not a muffler. the toy muffler let rain get in to the cylinders too. buddy barry got off very lucky on this one. only have to regrind the valves and a top end gasket set. compared to to toasting a couple of valves right out and damage to the pistons too. a retired mechanic for the mine moved back to town to enjoy his retirment. he is a detroit man and i had him help on this engine and he has never seen anything like this before all because of lack of muffler. he even says it sould be one or two cylinder where the valves leaks, not all of them. buddy barry will be heading south with the cylinder head to get it fixed and visit his lady friends. in the mean time the cat 12 grader will be serviced and ready to go in case the highway department calls for a grader to replace their 2009 volvo which seems to have issuses (yes the dumb computer that thinks that something is wrong) almost every other week, . thansk to for helping on this, just email for buddy barry's visa number and you can have a couple of beverages, . thansk KoO Published Author
King, I have a Gardner-Denver air compressor with a fairly new rebuilt 6-71 in it. I know I'm far away from you but if you want to take a road trip come-n-get 'er!! It's got the wagon style trailer for a pintle hook. I use to have a blast and paint shop and did all my sandblasting with it- kinda overkill but never had to worry about enough air!!! Jeff S
KoO, you have the head off right now, you need to check if you have bent connecting rods, I have seen water in cyl's do this on Detroits before. If I remember correctly, the pistons should come all the way to the top of the liner's. If one is down just 1/8", you possibly have a bent rod and it will affect the way the engine runs.
when checking the leak down test as you did showed leakage but youre puting shop air between valve spring and seat,if spring comperess you have leaky valve''I rember that 4 valve head the springs are lighter and take less force to open valve .If youre shop air is at least 150 psi you can make a leak thats not there .did you try other holes to compare the leak ,,if orignal problem came on suddenly posibbly emergency shut down flaper triped on blower ,,I had a v-6-71 that would run but sounded bad I didn't find it an other mechanic pointed out to me ,,,I hope this helps some Bill
thansk guys, buddy barry headed south with the head ended up getting a new because the old one was cracked. now we have to install it and set the valves. anybody have the valve specs and head bolt specs???? thansk KoO Published Author
Don't remember the head bolt torque specs. But before you place the head you need to make at least two alignment dowels. It's very easy to knock one of those seal o-rings out of position while placing the head without alignment dowels. I think the valves adjustment is .015 cold with the injector fully depressed. The proper adjustment for the injector requires a height gauge tool, but I think the injector rocker is roughed in with .022 clearance. Going on memory, someone correct me if I'm wrong.
ATCOEQUIP, thansk, a fellow on the cat BB gave all the specs. i printed it off and got the head tighten down. we have the head on and now need the rack set. i have the tool, just need step by step instructions because of my wasted youth i seem to have forgetten, LOL thansk KoO Published Author
LoL, yeah, it's tough to get the old memory to work sometimes...like right now! Once you get the rack bolted down, leave the pin out that connects the throttle link. Move the rack lever to stroke the racks of the injectors in and out, it should move freely with no catches in it. If it's tight to move or has catches, it's probably the mount brackets on the ends of the rod are in a bind and need tweaking. If it moves freely, the rack adjustment is just to make sure all injectors go full fuel and full off. Clamp a pair of vise grips on the rack control lever to give you a lever to move racks in and out. Stroke racks fully in until you hit bottom. With a finger, try to wiggle each of the C slots of each injector rack where the lever "ball" goes into each C slot. We want to see all lever ball ends having equal pressure on all C slots. If you wiggle a C slot of one rack and it's snug (the lever ball has that rack bottomed out), that's good, move to the next one. On the next one, you find the C slot wiggles freely, meaning, the lever ball isn't putting pressure on it to bottom out the rack. That one needs adjustment to bottom out the rack like the previous rack. Loosen according screw on rack lever and tighten opposite screw to adjust rack lever. And you move these screws only very slightly. The valves; adjust the valves with injector rocker fully depressing injector. If it's a 4 valve head with a bridge between rocker stems, do not make valve adjustments at the bridge screw, make adjustments at the lock nut and adjuster on the pushrod. The injector adjustment; man, it's been so long since I've done one I'm having a struggle here! I can't remember if the height tool adjusts injector depressed or injector relaxed. I know the end of the tool fits in a small hole at the base of the injector spring. You rotate the tool so the bottom of the square part of the tool just sweeps over the top of the injector spring plate (the SnapOn web site is down so I can't post a pic of the tool to show members, and you, what I'm talking about). If the tool lifts when you rotate the square over the injector plate, or if there's a gap between injector plate and tool square, the injector needs adjusting. Man...it's a lot easier to do this than it is to explain it!!! That's the best I can remember it...somebody slap me if I'm out in left field! :drinkup
I believe you adjust the injectors in the "relaxed" position. For people that don't have the proper injector timing tool, you can use vernier calipers set to the right dimension for your particular injector to set the injector height.
I think that there will be no clearance on the injector, thats why you have to set the height. But I'm not 100% sure, so please someone correct me if I'm wrong.
That's the problem I'm havin' Tom K...can't remember for sure.