Got a old D7 and sometimes it pukes antifreeze out the overflow. Everyone seems to think it's a head gasket took it all apart and putting new gaskets in and truthfully nothing looks bad at all. Someone else told us it could be the pony motor is this true? If it is how hard of a job is it to replace? Or is it something else? Haven't got it buttoned up yet trying to decide if I need to replace something else before I button it up thanks guys.
Possibly a hole in a Precombustion Chamber
Or failed pre-com chamber seat washer. Not likely to be pony motor. Even if the pony head gasket was bad it would only leak while running. Are you sure there are no signs of cracks in the head or block? Any sign of water in the cylinders?
We had the heads checked and reworked while we had them off so I'm pretty confident it's not that. There's no signs of water in the cylinders. We still havnt got the head gaskets installed were getting there slowly but surely in between all the rain.
While you have the head off be sure to check liner protrusion. Should be .004-.006 I am guessing. Someone else will know for sure.
0.002 to 0.006 is normal protrusion range (with liners clamped down). Common to be overlooked and key source of compression leakage. Put heads back on using Permatex 300 head gasket cement.
I also have a D7 17A. And I would bet a dollar against a dime it is a pre combustion chamber.
Thanks guys I'll definitely check out this pretty combustion chamber out along with the liner protrusion. We've owned this machine for 16 years and this is the first time we've been in it so it's a learning experience. Why were talking about 17A machines does anyone have a idea how to adjust the transmission brake it was starting to not go into gear and was grinding thanks guys
Here is the adjustment procedure....
Thank You that will help with that issue. Now sorry for the stupid questions but long story short is we hired a guy to do this job and he decided he didn't want to finish this job before he finished it so were working on it by ourselves lol. i'm going to attempt to attach some pictures of the block with the head gasket on. I've got 2 parts i'm not sure where exactly they go and cat's been no help to be honest this is to old of a machine, getting parts wasn't a issue but apparently service is. the part numbers I've got are # 6L-7814 it should be a small seal that fits over the small ferrule # 7B-2420 these are similar to the ones u set in the block that go into the water diverters that's up in the head. I've circled the spot in the picture with blue,It didn't show up very good but its the hole in the bottom gasket. I'm curious as to if that's where there suppose to be? Also got a Very thick O ring # 8F2691 and i'm also not sure on it. Everything else seems to be common stuff sorry for all the questions Just should of been there when he took it apart. I've got a parts book and can't seem to find this in it anywhere but come to find out it's actually for a 3T machine so it's incorrect our serial number is 17A10379 I need to get the correct book apparently Thanks again guys.
6L-7814 is the seal that goes with the 7B-2420 ferrule. Old number is 7B2419 = 6L7814 = 6L5423. That's the seal for the oil passage going to the cylinder head. The big 0-ring 8F2691 goes to the block end flange of the water line going to the pony cylinder head.
Thank you never gave the oil passage a thought. When I go back together would y recommend the permatex on both sides of the gasket or just 1 side?
Also can the gaskets around the push rods reusable we've already torqued the head so will have to tear back apart to insert this ferrule/seal
Coat both sides of the head gasket. That's a gamble on reusing the push rod gasket. Might work if you use the head gasket cement on it as well.
Thanks I'll definitely do that got my hands on a book and it has 2 different torque specs one for a earlier model it called for the 5/8 being 90 ft lbs and the 7/8 being 100 ft lbs. Then it said if u had the hardened nuts and washers to torque the 5/8 to 120 ft lbs and the 7/8 to 300 ft lbs. Cat had no idea what I was talking abt they kept sending me torques for a 3304. Is there a serial number break on this? When I torqued the first time I only done 90 and 200
Use the same torque step procedure as the D8800.
The higher 120/300 ft. lb. torque was used on the 47/48A D7's. Parts book shows same nuts are used. Your machine is 128 hp pre-turbo (to 17A11,878). With turbo 140 hp. 47/48A is 160 hp w/turbo. Higher head torques came with the higher hp. Higher head torque on the 140 hp would be an option. No necessary on the 128 hp.
That makes sense to me thanks for the info, I find these old machines fun to work on and run. Unfortunately our project is on hold as we're going to order a few more parts Monday. But with rain forecasted again the end of next week I'm hoping we can get it buttoned up for good. I'll let you know if we run into any more issues and let u know if that fixed the issue thanks for all the information it was greatly appreciated.
Just wanted to thank you guys for the help we got it buttoned back up earlier this week and fired it up and let it run for while and it never did spit antifreeze so hopefully that cured it. Still got to adjust the brake and service it before it goes back to work.
Do you have and pictures of replacing the head gasket and can u tell me what all parts it needs. I noticed with mine running and the radiator cap off it was bubbling. So if im correct it is the head gasket. I have still been running it but it doesnt ever get hot
If the radiator have bubble it could be a crack head or head gasket brooked
Head gasket could be brooked? What do you mean
Hectors english is not the best .Great guy knows his stuff . I would imagine he meant head gasket could be blown . But as with the original poster check the precombustion chambers . You don't need to pull the head to check them first .
How do you check it with out pulling the head?
"Check" in this case mean remove each chamber and replace the O-Ring seal on the outside plus the washer underneath it that keep the coolant from going where it shouldn't. The process is for each one is - Remove fuel injector, remove glow plug, then use a special tool and an appropriate wrench to remove the precombustion chamber. Reinstalling them is a more complex process. There are gaskets of various thicknesses used under the chambers so that the glow plug hole falls in the right area when the chamber is tightened. See attached document which is NOT for your engine but should give you an idea of the process. As others have mentioned before, you REALLY need a service manual for your machine - like this one https://www.fagozac.com/index.php?main_page=product_info&products_id=534256
I don't have glow plugs
In that case it makes the process of removal and reinstallation of the chamber slightly more easy but still basically the same. I guess the question is do you have the holes in the chambers where the glow plugs should fit.? If the answer is yes then they are missing. This exploded view shows the O-Ring #6 and the washers #7. Only one of the three washers will be required - they are all different thicknesses.
If you have the old style 2 piece pre cups you will need the 5 piece tool set to pull the pre cups and install them. They use 2 o-rings and 1 gasket each. Good luck Bob