Uh oh - WF won't pull

Scott Boito · Posted: Mon Jan 28, 2013 8:49 am Post subject:

Thanks guys. I should have just bought a new one, but I'm the trusting sort. Occasionally I get burned. If nothing else I could pursue returning this one to the seller since it didn't last more than 2 minutes. But I have to work fast since the timeline is the end of this week to initiate anything.
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John Matthews · Posted: Mon Jan 28, 2013 9:50 am Post subject:

Hate to ask this but you did put oil in it before you started it the first time didn't you?
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Heartbeat Power, LLC.

Scott Boito · Posted: Mon Jan 28, 2013 10:04 am Post subject:

Not a problem. Yes, I put in exactly 16 oz of 30 weight oil. And when I drained it it looked pretty good, I thought - like new.

I have run 4-strokes before for my son (clone motors in a clone sprint series) so I know about the oil. I just never dove into the innards of those motors, so I didn't know what to expect when I got into this one. It's a fair bit more complicated than the old 2-strokes he ran...
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John Matthews · Posted: Mon Jan 28, 2013 10:25 am Post subject:

Yes, more complicated mechanically but also more forgiving for most home mechanics....

Crank bearings can go for many reasons, I've had oil compatibility issues cause problems before that just didn't make sense without the technical explanation Dave Klaus (Briggs Racing) gave.

Of course I'm just guessing as to what the problem is but if it is the rod you'll need a new rod, crank, rings (hone the cylinder), and gasket kit. If your seller is willing to take it back in pieces he's a pretty good guy IMHO.

Did you get the sidecover off yet? Does the seller know you're this far into it?
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John Matthews
Heartbeat Power, LLC.

Max Wood · Posted: Mon Jan 28, 2013 11:20 am Post subject:

Scott Boito · Posted: Mon Jan 28, 2013 12:39 pm Post subject:

Thanks, guys. I did email him a few times before I got too far into it so he was aware of the situation. We both hoped for a good resolution to it and I kept going until I realized it was farther into the motor than I was expecting.

This is just a sucky situation - especially for me. Two minutes of run time and boom it seizes. It's not 2 hours old and through no fault of my own (honestly I don't know what I might have done to cause this) I'm going to be out a few hundred $$$ more than when I thought I was ready for the season. Incidentally that few hundred $$$ makes up the difference from what I paid and a brand spanking new motor direct from Briggs. But at least I'll have an essentially new motor after the changes I guess.

He suddenly is not very interested in returns and refunds. I get that. Fortunately I've never been in his shoes, but I can imagine that it would not be on my list of favorite things. In a corner and only one likely way out - pay the piper and get all of the new stuff installed and start fresh. At least there won't be any possibility for weird oil compatibility problems or anything else like that.

I didn't got any deeper with the oil seal or anything. I was waiting to see if anything magical might happen here first. Looks like I'll dive back in tonight to see what I can see.

Thanks again for the advice and guidance.
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Max Wood · Posted: Mon Jan 28, 2013 12:59 pm Post subject:

Scott,

Personally - I would try heating the side cover around where the bearing is with the hopes the side cover would release from the bearing. Then you could check the bearings and rod without worrying about pulling the flywheel.

Scott Boito · Posted: Mon Jan 28, 2013 1:09 pm Post subject:

Thanks, Max. I'll try that first tonight. Maybe I'll get lucky and that will be the seized bearing. But I won't hold my breath... Sad

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John Matthews · Posted: Mon Jan 28, 2013 3:31 pm Post subject:

I've built, and rebuilt probably a couple hundred motors. For the most part things go fine but when they do go wrong I tend to work it out with the buyer. Of course when you do it for a living and your reputation is on the line you're a little more motivated to keep customers happy. I made a policy of always running my engines on the dyno harder than I ever expected them to be run on track and that mostly kept me out of trouble. I'd much rather have to repair something I broke than explain to somebody why their kid can't go racing this weekend....

Times that stand out in my mind are almost always when the customer starts taking the thing apart before they contact me. If I spend good money on something and it breaks before I even have a chance to use it you can bet I'll be on the phone with that person right away. Once I had a guy buy a brand new motor for his kid and the day after he got it the kid calls me up and says it's broke. I tell him to put it back into the box and send it to me but he says he's already taken it apart. After a little back and forth (I actually need the engine back on my bench so I can see what happened) I get a call from his dad. The dad apologizes for the kid and explains that he (the kid) was so excited to get the new motor that he fired it up without putting oil in first. Eventually I did get the motor back and only charged parts to repair it but it was good to know I didn't mess up.

I have however gotten lots of motors from guys who thought they were getting a bargain but ended up with a pile of parts. Some of these have been quite scary when I looked at what the previous "builder" had done inside. There are a lot of really good engine builders out there both pro and amateur but there are some real hacks out there too. It's also very possible for someone to mess something up without knowing what they did wrong. It takes a little experience to figure out exactly what happened on a blown motor, especially if it's in little pieces Laughing

World Formulas are great in that you can just take them out of the box and go racing with them. There is power to be gained by building them but for most club racers box stock is just fine. Keep the oil clean and they usually last a long time too....

So Scott, if you do put heat on the sidecover only use a little bit and be aware that the oil inside the crankcase will probably smoke and may catch fire. If I was going to do this I would use a small propane torch and just heat the cover right around the bearing, the aluminum will expand before the steel bearing. But for most of these I've been able to break them loose with the method I described earlier, hanging on to the cover while someone else taps the end of the crank with a deadblow hammer. Wear gloves since the castings can be very sharp too.

Let me know if you have any questions.
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Heartbeat Power, LLC.

Scott Boito · Posted: Mon Jan 28, 2013 8:31 pm Post subject:

Unfortunately I now know it's not the PTO bearing. I haven't gotten the cover removed all the way because that bearing won't let go, but I did get it off far enough so that it can spin on the crank freely. So it's got to be the other bearing or the rod/crank.

I used my hands to turn the starter ring/flywheel and noticed that it will turn with much less pressure over about half of the range, then the other half is much more difficult to move. Is that what you'd call a "spun bearing" like in a car even though there is no separate bearing on the crank? I, unfortunately, have experience with that in a 91 Civic Si motor from oil starvation on a sustained turn.

I'm to the point where I just want it fixed. But the costs of parts and labor are going to put this over the top of a new motor and it kills me. I thought these things were supposed to last forever with little maintenance! Maybe not forever, but you know what I mean. Compared to the KT100 the maintenance costs and time were supposed to be quite a bit less which is one of the reasons I switched.

The only thing I notice about the motor that I wasn't really expecting to see was the wear on the crank where the clutch key goes. I have a pic on my site that shows it (excuse the glare but it actually shows the wear very clearly): https://sites.google.com/a/betteroffracing.com/www/Home/DSCF6645-001.JPG?attredirects=0 Is that a little too much wear for less than 2 hours of run time?

Maybe Dave Klaus is around somewhere?
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Bernie Lacotta · Joined: 21 Mar 2006 Posts: 168

Larry Andrews · Posted: Tue Jan 29, 2013 12:30 am Post subject:

Scott - I just went through the same thing with my WF kart last year during an endurance event. Never had a problem over dozens of hours of runtime but never ran it an hour and a half non-stop and didn't realize what the oil consumption would be. Stuck the rod about fifteen seconds out of the pit...was a really solid stick and required hammering the rod and cap away from the crank to get the motor apart.

Apparently this is among the few most common BWF failures. Virtually everyone that runs the motor seriously knows of it, but nobody really seems to speak of it so I'm glad we're going there now. And yeah, same idea as a spun bearing - had a '91 CRXsi do that just like lots of D16-STS cars did.

I'm not sure what bugs me more, the seller's attitude about a partial refund or Briggs using a bare aluminum rod as a bearing surface in a high-strung motor. Both are lame ways to make an easy buck and both could be easily fixed. I'd gladly pay $50 more for a motor with a big-end bearing and, honestly, I'd get you a new rod at an absolute minimum if I was the seller. There's no way a new guy is going to know the difference between the feel of a motor that's about to stick and a healthy one but a guy who's been there does - it's not hard.

IMO, the good news is that a guy on the KAC will finally have first-hand experience inside the motor and it won't be the black-box that it's been for years. Sucks how you got there though. Sad

Bernie Lacotta · Joined: 21 Mar 2006 Posts: 168

Larry,I was pitted next to you at the 4 hr. enduro. Before going there I asked various people around the country as to how often I should change oil in that race and the general response was every 30-40 min.. However I had some of the new Briggs/Amzoil 4T oil which wasn't on the market yet. I was assured it could go the entire distance without a change. It did,we did not loose but a fraction of an ounce. I did 30 races last year including that enduro and the same rod is still in the engine. The rod IS NOT the problem. I prefer the Briggs World Formula rod over anything that is currently on the market.
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John Matthews · Posted: Tue Jan 29, 2013 8:00 am Post subject:

As someone who's built a bucketload of 4 strokes and learned from one of the best I'll back up what Bernie says about the WF rod. Many respected open Animal builders choose the Briggs WF rod for it's durability and strength, it can withstand well in excess of 30 hp when properly clearanced. About the only advantage of bearing inserts in a motor like this is when it does stick you don't have to replace the rod (as long as you're confident that it hasn't been weakened by the seizure Surprised

). I'm not just guessing on this, I've had plain bearing rods built for another engine project after long discussions with my mentor who almost had the contract to build the rod in question way back when. I will only re-use a rod and/or crank that's been seized if there's really minimal damage, it's just not worth the chance of a hairline fracture giving way at peak RPM and taking the rest of the engine with it.

I also do warranty work for several power equipment manufacturers and main bearing seizure is NEVER a warranty repair since it's not a failure of materials or workmanship. The only way a rod will seize is improper lubrication, which can and does happen from mixing incompatible oils. I know about this from experience, now I only dyno customer engines with 50wt conventional oil since it's the only way I can be confident I won't run into this problem. Unfortunately, the 4 cycle karting world has a few really good oil manufacturers and a bunch of snake oil salesmen.

FWIW, we just fixed a 1953 Briggs engine that my tech accidentally ran out of oil in our shop. I was able to get a NOS rod for $30 and showed him how to clean the crank with muriatic acid just like Mike Clements showed me. It's now back running like a champ on it's original Simplicity walk behind tractor Very Happy

So, you don't have to believe me but the Briggs WF is honestly a very well designed and built engine. It's this trait that leads people to put literally hundreds of hours on them without proper maintenance (rebuilds). Obviously I don't have the particular engine in question on my bench but I'd be willing to bet a new the price of a new Briggs or ARC rod that this engine was run for a bunch of hours then "rebuilt" by someone who just lapped the valves, honed the cylinder and put in a new set of rings without properly inspecting the crank/rod assembly. Either that or it was overheated/run without oil and damaged prior to Scott buying it.

These motors are very simple to work on and many racers do their own engine work which I highly encourage if you're so inclined. But, there are a few details that need to be attended to whenever you have the engine apart that will bite you in the rear if you ignore them. I highly recommend reading Jamie Webb's Animal building articles on 4 cycle dot com if you want to do your own work, follow his instructions about measuring and cleaning any you'll save yourself a lot of grief.

Cheers,
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John Matthews
Heartbeat Power, LLC.

Larry Andrews · Posted: Tue Jan 29, 2013 9:29 am Post subject:

Bernie - didn't realize that you were next to me last year, wish I did... And thanks for not laughing openly at my tow rig. Smile

I fully recognize that I have that one coming.

I'll also own that I let the oil get too low and realize that my mistake killed my motor. ALso will defer to the experts on the rod but it still seems like it could be made more robustly - an opportunity for improvement. <shrug>

It's hard to know where the line is between 'good enough' and 'could be better' and I think it's safe to say that each of us may interpret it differently.