Just a question
- Thread starter MoreHP68
- Start date
Pk in oregon
Member
Turk bros buy 2
JanGaLanG
Member
My understanding is that the motor is only ever balanced when the crank is perfectly in line with the piston which is 1% of the time in the motors rotation. At no other point are the counter weights in line in with motors rotation leaving the other 99% of the time the motor is out of balance. Completely different from a normal v8.
mike97760
Site Supporter
I had a pull start failure one time and luckily on the pull that tore everything up the motor started. I bought 2 from Turks just to have spares and it seems like every race somebody comes over wanting to buy one. And no I dont have a parts trailer. Nice to be able to help someone out. Ive probably bought and sold 12 of them in the last couple of years.
The secret to long life with them is to NOT pull the string to the end. Ive seen guys yank hard enough to lift both right wheels off the ground.
The secret to long life with them is to NOT pull the string to the end. Ive seen guys yank hard enough to lift both right wheels off the ground.
Reign-Check
Member
22, and even 26 lb springs are a little light if you're trying to turn the motor that high. I'm building a motor right now with a .308 cam, 2:1 rockers and 45 lb dual springs, BECAUSE I'm aiming for the 8k+ range.
Not going to pretend I'm some motor guru, but 22's will likely float well before 8k with a cam that big.
Just my opinion...
Not going to pretend I'm some motor guru, but 22's will likely float well before 8k with a cam that big.
Just my opinion...
it will be alright until it lets all the smoke out, then you cant put it back in. For sure a rod and flywheel, and still don't hold it at 8500 too long.
MoreHP68
Member
LMAO, 45 Ib spings!!! That must have been a pain to put on! Yeah, 8+ is a lot more than I realized at first. I think I will be shooting for something around 7.
Reign-Check
Member
Valve spring compressor, it's pretty easy and done in just a couple minutes. By hand, yeah, a pain would be just the beginning of what I'd call it if I had to do it like that.
FYI, I wasn't originally going with springs that heavy, but after consulting with Jody at ARC on how, where and why I'm building the motor, he's the one who said to go that high on the springs.
MoreHP68
Member
Oh good, I would have probably shot myself after trying to get those in by hand. The 22's I just put on were difficult because the valves would slide down with the tiniest touch. After about 20 min of trying I put compressed air into the cylinder and they went in easy.
Reign-Check
Member
Yeah, with the head still on the block it's definitely a cursing session, sometimes even with 18# springs. Going to stainless valves (which I pretty much always do) you have to pull the head anyway, so after struggling one too many times, and wanting to throw things across the shop, I decided I'd give the spring compressor a go, and am very glad I did.
If you only have a motor or two and rarely have to mess with the springs, sure, by hand will do, but I have two karts with usually three spare motors each, plus a couple of mini bikes so I'm constantly tinkering with things on them...the spring compressor was a must have.
One Fast Kat
Member
It is my understanding that balancing only helps in multi cylinder engine. I have had many V8 engines balanced. But that is a whole different process.
And blueprinting is worth every second.
As far as pull string, I've redone mine with paracord. I know several who have, and have no problems. Some say last a few years or so. We haven't been racing that long to see how durable, but it's been good enough.
I've been wondering how someone would balance a single cylinder engine.
I've been wondering how someone would balance a single cylinder engine.
MoreHP68
Member
I just looked it up, and the source says "
No, you can never fully balance a single-cylinder engine. No matter what else you do to an engine, you will always have to contend with the reciprocating mass."