After a first successful start yesterday, things went south.
I managed to get my hands on a compression tester today. Even though I did get her running, I wanted to check the compression before I started buying parts for it.
I screwed the tester into the top cylinder. It screwed in just fine with normal resistance. The compression read 90psi. Great.
Removing the tester was a different story. It had a lot more resistance on the way out. It didn't require a lot of muscle, but definately didn't feel right. Once it was out, big pieces of thread came out with it. Some of them came out almost complete circles. So there was the end of my compression test. :'(
Fearing that pieces also fell into the cylinder I didn't turn the crank again. I went ahead and pulled the head and yes there were pieces in the cylinder also. So good for me not making things worse. The cylinder walls were both smooth with a light coat of oil all the way around so that's good news too.
I also removed the cylinder head cover. I was very careful, but 3 bolts broke in the process. It's probably good I removed that too because the passages in there were all clogged with what looked like hardened sheetrock mud. Dirt and minerals I suppose. The jackets around the cylinders were clear though.
I've got some penetating oil soaking in so I'll try to get the studs out in a day or so.
I'll look into getting the threads repaired at one of the local shops. Might as well do them both while I've got the head off.
Putting in a helicoil isn't a big job, but the kit to do it is kind of pricey so it may be worthwhile having a shop do it. But if it turns out to be impractical for some reason consider doing it yourself. The most important thing is to tap squarely.
As for the remaining screws, if there are still studs sticking out, heat the head up with all the heat you can get from a propane torch or better yet with MAPP gas. Once it's as hot as you can get it, try to unscrew the studs with a pair of vice grips.
Do not attempt to use any form of "ez-out"! If they're broken flush, drill them out.
You will find helicoil kits at a very reasonable price at any tool and die shop supplier. There are several in my area, I dont know about yours but the yellow pages is always a big help. Make certain that you do tap absolutely square or you will be in big trouble. A helicoil is a great and easy repair if performed correctly, not only in this situation but countless other industrial applications.
As stated above, heat is your best friend to get "frozen" studs out. Keep the heat there even when it starts to move as it wil contract again in a real hurry. Best to re-tap carefully once the stud is out and cooled down to clean the thread out. This wil make replacement easier and safer.
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1985 Doral 164 1985 140hp Johnson EZ loader single axle trailer all = a whole lot of family fun !!!!
I have both propane and MAPP torches. I meant to ask if the MAPP torch got hot enough to damage the aluminum head. Since you suggested using the MAPP torch I'll take that as a no.
It's really impossible to melt down a head with a MAPP torch. Very small or thin things like the shift rod coupler access cover (don't ask!) can be if you really go after it. But a head: no.
Coat your bolts in gasket sealant before re-installing and they'll come out much easier next time.
I attempted to move the broken studs with a MAPP torch and vice grips. All 3 broke off.
I know the owner of a Yamaha/Snapper dealership & small engine repair place here. He's got the stuff to repair the threads. In fact it sounds like it's a routine thing for him. I'm more concerned about the broken studs at this point. Anyway, the part is in his shop now and I should know something in a few days.
Most of the time we trade services (I work on his computers), so hopefully he'll get it fixed and it won't cost anything.
what I do for snapped studs is to carefully center punch the center of the stau, and then drill a small pilot hole in the center, then followed by a bit slightly smaller than the diameter of the stud. Be sure to select a bit that won't partially remove the threads too. The idea is to leave a thing shell of the stud including the threads inside the hole. After drilling, the remaining threads of the stud can usually be removed with a sharp tool such as a pick or fine scribing tool.
The purpose of the pilot hole is to help keep the larger bit drilling straight in the stud, otherwise it may wander and damage the aluminum threads in the block.
what I do for snapped studs is to carefully center punch the center of the stau, and then drill a small pilot hole in the center, then followed by a bit slightly smaller than the diameter of the stud. Be sure to select a bit that won't partially remove the threads too. The idea is to leave a thing shell of the stud including the threads inside the hole. After drilling, the remaining threads of the stud can usually be removed with a sharp tool such as a pick or fine scribing tool.
The purpose of the pilot hole is to help keep the larger bit drilling straight in the stud, otherwise it may wander and damage the aluminum threads in the block.
Yessir... That might do the trick. These are pretty small bolts (head cover, not head) so that makes it a little trickier. I don't own a drill press though and I don't trust that operation to me and a hand drill so we'll see what happens. Good tip though, and like I said if I had the proper tools I might have attempted it.
Well, I got the head back and they did a heck of a job. All the broken bolts were drilled and tapped and the spark plug hole was repaired nicely. It was some type of thread repair insert made just for spark plug holes.
Well, I got the head back and they did a heck of a job. All the broken bolts were drilled and tapped and the spark plug hole was repaired nicely. It was some type of thread repair insert made just for spark plug holes.
All I need now is some new gaskets and bolts!
Thanks all.
Glad you got sorted out. Keep us posted on the next stage of the job. The thread inserts come in a multitude of sizes from small to huge. Just a quick question, when you were heating the studs to try and remove them....where were you concentrating the heat ???
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1985 Doral 164 1985 140hp Johnson EZ loader single axle trailer all = a whole lot of family fun !!!!
Well since metal expands when heated, ideally I'd want the metal around the studs (and thus the hole) to expand but not the bolt. So with that theory I heated up the metal around the studs as best I could while trying not to put the flame directly on the stud.
The guy at the shop recommended I put hardened bolts back in when I reassemble. Sounds good on the surface, but wouldn't that mean if I ever broke a bolt I would be impossible to drill out?
Just run sealant all over the screws. It works great. If they had done that in the first place, you wouldn't be into all that.
The thermal expansion rate for aluminium is much greater than that of steel, so you have that working for you too. I think that's really the main thing.
I thought you guys might be interested to see the repair...
Edit...
For some reason Google doesn't like linking directly to the pics in my album. It's a shame because I can upload them straight from Picasa. Would have been nice to keep up with my pictures with one piece of software. Guess I'll have to upload them to my web space or photobucket.
Anyway, the pics of the repair are in the gallery, just click my sig.
My new gaskets, impeller kit, carb kit and points set came in today. The points came with a wick which I thought was nice.
It rained cats and dogs when I got home so I couldn't work on it too much. Also picked up some J-B Stik weld for those cracks, some sealant and some acetone.
I still need to get some new bolts to replace the ones that broke off and see if someone's got a torque wrench I can borrow.
I'm optimistic that it'll be running again before the end of the week.
Water pump is done. Everything went back together suprisingly easy. Even the shift linkage wasn't too bad.
I didn't get the head back on yet...
I went to a local fastner supplier today in the industrial park. He couldn't quite match up the longer of the 2 bolt sizes that hold the cylinder head cover on. He gave me some washers to "shorten" the bolts, but I really don't like the looks of that. I might see about using my dremel to cut the bolts he gave me down some.
I didn't have any problems with the head bolts (flange bolts) during disassembly but I am debating whether I should replace those with new ones or not. They cleaned up pretty good with my dremel + wire wheel. I think I'll go back to the fastner place tomorrow and see if he has those. I'm gonna look like a jackass if I break a bolt reassembling this thing.
I don't know why, but it just makes me nervous having the engine in an incomplete state.
the longer bolts can be cut off . put a nut on the bolt and cut to lingth . use grinder to slightley round the tip like the factory end and take the nut off . that shouln streighten any burs on the end .
i would try to git ss bolts or go to a motor repair place and git some bolets . i probabley have some as i have torn down several 50 hp and some older motors . saved all the bolts . guess i am one of the old pack rats d
You find that a lot with J/E bolts. Most of them are strange lengths, like the long fasteners in that head are 1-1/16" and the short ones are 5/8. Often you can just subsitute a 3/4" screw if you clean out the threads with a tap first (which you should do anyway). Check first though and make sure none are bottoming out.
The head bolts are nothing special. My entirely unscientific tests show them to be somewhere around Grade 2, and probably a little south of that even.
When I used to grind down a fastener to shorten it, I found it was usually a straight forward operation to put a taper back on the end of the screw by mounting it in a drill chuck (like on a drill press or hand drill) and hold a file on the end of the screw at a 45 degree angle while spinning it. In just a couple seconds a perfect taper was formed for easy starting. Some screws were more difficult to mount than others, but usually a nut or something could be employed to make it easier.
Now with a small lathe in the shop, this operation really takes no time at all.
I spent what daylight I had after work shortening bolts. I just used a few cutoff wheels in the dremel to take about 2 threads worth off. It made a very clean cut. I had to file a couple of burrs off but no biggie. I test fit all the bolts and looks like we're good to go with that.
I also test fit everything. Good thing I did. It looks like those bottom 2 head bolts are gonna be boogers if I put the cover on the head prior to installing the head which was my original plan.
I may have it back together tomorrow if I can (1) Get my hand on a torque wrench and (2) Wife doesn't have other ideas.
Speaking of torque wrenches I better go check my manual for the torque values for the cover and head bolts...
You'll want an inch-lb reading one for both. Cover screws at 70inch/lbs and 180inch/lbs for the head bolts. That works out to 15ft/lb on the head bolts which is pretty low for a clicker type 100 ft/lb wrench.
Hang onto it, after you run it hard once you'll need to retorque the head. Not all manual give the order it's:
7--8
3 o 4
2-1
6 o 5
10-9
If you can see a head in my ascii art there! Not really very critical but might as well do it right.
You're welcome.
I always go to the middle of the stated torque range. Except for a very few things like the 105ft/lbs on the flywheel nut. If you don't have cleaned threads you'd best go for the top though.
Torquing seems like a critical operation but there's a good 30% error due to the unknown friction coefficient. It's really all about controlling the error and not letting it get out of hand
I got everything back together today. I forgot to charge the battery so I had to pull the rope like hell but IT RUNS! Compression is about 100psi in both cylinders.
Thanks to all that helped me undo this mess I made!
It runs, but doesn't run well. It was hard to start and smokes like hell. I also broke the plastic carb "control panel" when I let go of the rope (a $30 screw up). I still have a lot of things to check before I start asking questions about that stuff. Those are problems for another day and another thread.
Thanks again!
Edit:
It has been said that confession is good for the soul. As embarrasing as it is, I'm going to tell you what got me into this mess...
Some days after the fact I noticed a little circular mark in the center of my top piston. Not a scratch, not a dent, but more like a little chrome that rubbed off the compression tester. See, I used the long threaded adaptor and not the short one. The piston came up and hit the screw-in adaptor for the compression tester. In a case like this, something has to give. Luckily in my case it was the plug hole threads. The tester is not damaged at all so I'm guessing the plug hole had weak threads to begin with. Like I said before, my compression is fine now. Also there does not appear to be any play so I think the damage was limited to just the spark plug hole. So, hopefully someone can read this and learn from my mistake. I know I sure did.
Well guys, I thought I had put this thread to rest finally but it appears my troubles are not yet over.
I was running the engine this evening checking things out and I decided to stop it and take a look at the plugs. Well, the dang thread repair insert came out with the plug. I don't know what thread adhesive product they used to lock the insert in but it didn't hold. It looked like a grey crumbly/powdery substance. It all came out with the shop-vac.
I'm considering putting some red Loctite and see if that'll hold it. If not, I'll just have to get another head.
Sorry to keep dragging this thread up. I'm as sick of looking at it as you guys are.
I've used high temperature loctite red with great success. The only trouble is if you need to use a spark plug to wind it in. If you do, put a little grease on the inside of the insert's threads and remove the plug about 10 minutes or so after torquing up to prevent having the plug loctite'd in.
Helicoils are supposed to be self-locking. Must be another type of insert.
'69 Evinrude 33HP: Stripped Spark Plug Hole
Linear Mode
