Learned a Bad Builder the Hard Way

Well, as the subject says I learned the hard way about working with a “bad” engine builder for my 206. I’m not here to drag their name through the mud, and the main reason being that the first motor I got from them was dynamite. With that said, it was a little pricey for what I got, but I felt good about it since the motor was strong. However, here was the experience I had recently:

  1. Motor I had seemed to have a pretty big dropoff in performance
  2. Brought the motor to my builder for them to check it out and see what was going on
  3. Builder immediately replaces a bunch of stuff and basically does a top end job (as legal for 206) to eliminate some valve leakage they noticed. They didn’t ask me on this stuff, and they replace a whole bunch of stuff that was probably just fine like spark plug, valve springs, fuel lines, fuel pump, etc. A bit sketchy already.
  4. Builder puts it on the dyno to see how the motor does (note that the builder charges $120 per dyno run). Motor has really low output at about 7.6hp for a senior motor. I understand all dynos are different, but good numbers on their dyno are in-line with Briggs. So a strong motor is around 8.8-9.2 hp for a senior briggs motor. Again, didn’t ask me about this.
  5. Determines that they need to put on a new shortblock. They call me at this point and I agree, he explains a new shortblock is around $350. All dandy, except he hasnt mentioned all of his other expenses already.
  6. Change over to the new shortblock, and the motor now has 8.8hp, so it seems like the issue is fixed.
  7. I get the bill for $1160. That seemed insane to me when you think that all that was needed was changing the shortblock, but I need the motor ASAP for my next race so I don’t have a choice to try to fight this.
  8. Whats worse, the motor was “okay” for about 1 race. It didn’t feel like it was crazy strong, but it was at least in the ballpark.
  9. Next race the motor has another big dropoff and I’m suddenly 8 tenths off people that I’m normally battling with and out-qualifying.
  10. I call the builder and explain the performance, and he is absolutely convinced that the pilot jet is clogged. To me, it feels like the 7.6hp condition did, and I seriously doubt that a clogged pilot jet could cause that. He won’t do anything else for me other than tell me that.

Again, this isn’t meant to drag this builder through the mud, its meant to be a warning that you should examine your builder carefully and consult with another one or two before establishing yourself with one. I say establishing yourself because I do feel that its important to have some loyalty to a builder. Every one I’ve talked to doesn’t want to see you bounce around, and I think as long as you’re not being ripped off and you feel like the motor youre getting is competitive than there’s no reason to bounce around to the next hot thing.

I race KA exclusively now, and I plan on sending my motor to Allison Racing Engines over the winter after the research I’ve done and talking with Brandon on the phone. Prices seem transparent and his motors are clearly doing well, and the people I’ve talked to recommend him.

Live and learn, hope this helps.

Dang, sorry to hear about your experience @DIG78x, but thank you for sharing. Do you have a trusthworthy builder lined up for KA?

Not knowing obviously who you speak of, this almost sounds like it could be down to miscommunication. If a customer takes it to a builder and says fix it (not saying that’s how it went down with you, but is sometimes the case), then to me it’s not surprising they would replace the things normally attributed to power loss in a 206. The power loss due to bottom end, and what I would assume is bad ring seal sounds like either a bad batch of rings from B&S (happened before) or possibly look at the oil used. If it’s defective short blocks than the builder doesn’t really have a lot of control over that. Just kinda playing devils advocate here.

Definitely not ideal to get stuck with that kind of bill unexpectedly, like others mentioned could be a miscommunication aspect.

One point I would like to clarify, you absolutely can drop 1 HP on a 206 with a clogged idle jet and/or a partially clogged main jet. There are a few tracks that just have very bad gas that seems to clog jets more regardless of the fuel filter situation. I would recommend to anyone to learn how to clean both of those items regardless of your builder and where you race, it can instantly save a race weekend for you.

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Doesn’t a nekkid new lo cost like 800 bucks? Seems kinda crazy to spend more than the cost of a new engine on a repair.


All good points, thank you! This builder does run their own oil, so maybe that’s contributing to how quickly the motor went off. Stick with 4T!

Its fine to replace things that would be attributed with power loss, I was just more upset about not knowing until I got the bill.

I should have went with Ghost racing engines :wink:

Yes, Allison Racing Engines.


What did you do for break-in on the bew shory block? Any chance the cylindr is glazed?

Some of these “in house” oil programs are a deal where you’ve got to change the oil so frequently, it doesn’t pay to use it. Miss a change and your asking for trouble.

The extra .1-.2 HP is not doing anything for you. You will always over come that in driving and set up.

Sounds like you either have an oil breakdown issue or there is something in the carb.

Invest in a cheap harbor freight ultrasonic. My routine is to clean the carb in the ultrasonic any time the carb has sat for a week. This includes with it being drained of gas. Yes, overkill but never had issue after my first issue.

The gas we use is :poop:

If the builder didn’t break in the new short block when selling it to him, add that to the list of crappy things.

Yeah that sounds like a not great experience.

True sometimes these are based on low viscosity PAG oils. PAG is really not designed for extreme heat, combustion contamination and tends to hold moisture. But it can give a slight edge for a while if you’re willing to deal with the increased rebuild frequency and oil change intervals.

Incidentally I think Tillotson have a dyed spec oil.

They did break it in, but boy did they charge a lot. And again, another thing they didn’t ask me before charging me. I would have broken it in myself.

Brandon is a good guy and builds a strong motor, so you should have a good experience with him for your KA needs.

As bad as it sounds, your experience with the 206 builder does not surprise me. I’ve experienced many builders that are poor communicators, and we as the customer pay the price when we don’t ask a million questions (as I’ve gotten in the routine of doing) to try and get clarity before/during the rebuild. Sometimes they will sell you parts that you don’t actually need, but it can also be tough to get the full picture since every builder is going to be protective of their “secrets”.

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The low-viscosity PAG oils can give a performance edge over a 0W20 oil, but Motul Hybrid 0W8 is likely to be even better and is an actual engine oil!

I’ve said it before and I will say it any time I can:

If someone is telling you there is any performance gains in oil on the 206, they are flat out lying. Given the tight rings on this engine, there is not enough of anything getting into the cylinder to effect performance. And then if you are chasing that 0.001 hp that viscosity or lower oil level gives you, you have already lost.

We have tried every oil type (even those super hot qualifying/proprietary oils) and every oil level (10 oz to 18oz) on our dyno. There is absolutely nothing there. Run 4T or any other well known actual engine oil. Keep it changed often and focus elsewhere.


I know a lot of highly talented people in their trade and unfortunately the majority of them are below average with communication. Sorry to hear about this experience.

The only thing I can add is that anytime an engine is “off” but not broken it’s almost always going to be a financial disaster to get it right…better off breaking a rod or something obvious that lays all the damage out in front of you instead of hiding it away. Going to pay for someone’s time and effort to find these things through a process of eliminations no matter how it plays out.

We had this with my brother’s KA last year with under 2 hours from fresh rebuild. Had a weird void in the power band right in the middle. it’d drive off the corners good and then fall over and then run pretty good up top again. First thing we did was compression check it and while it was maybe 10-15psi down from when completely fresh it didn’t add up so we moved on. Bore and piston looked clean, no signs of getting hot and or damage. we rebuilt the carb more times that we probably care to admit, replaced the plugs, swapped coils, replaced the reeds, swapped carbs out completely for one from a different motor, etc. Wasted 2 horrible race weekends and 2 horrible practice days trying to figure out why the thing just wouldn’t run right in the middle of the power band before we just sent it back for a top end again with very limited time on it. Came back as strong as it ever was even though the builder also didn’t see anything of note with the piston. Ironically this is the strongest damn KA I’ve ever come across but it sure was a headache for no particular reason during that stint.