ya i am looking at some of those. I think it would be nice to have a motor built by pros that do it all the time like they do, but i could get away with just buying a new piston and rod and stock block from junk yard but i am kinda nervous about it not getting built properly and it may start to use oil and blow up again someday
that is a possibility, Would being lean lead to a valve dropping down? cuz thats what happend
THIS^^ Says to me that there was probably nothing at all wrong with the components used but that the entire assembly grenaded due to being WAY too lean.
Some of you guys that build and tear down motors like Legos can confirm or deny.
What Are Some Tips To Build A Long Lasting Reliable 347!!!
THIS^^ Says to me that there was probably nothing at all wrong with the components used but that the entire assembly grenaded due to being WAY too lean.
Some of you guys that build and tear down motors like Legos can confirm or deny.
The secret to building a long lasting and reliable 347 is easy......don't build a 347. They, by their nature aren't designed for this purpose. The 302 based stroker kits are designed to add torque and horsepower, not sustained reliability. The rod angles are too excessive for high mileage duty. Going with a 331 stroker is better for longevity and sticking with the 302 is better still.
If you want cubes and are starting from scratch anyway, start with a 351W block and build from there. The block is wider and therefore their rod angles are far more forgiving than that of a 302W.
I have yet to see anyone produce a 347 kit capable of sustaining what I would call high mileage.
that depends on what you consider high mileage. a properly built 347 should go about 100k miles before you should have to go through it these days. i also agree that a 331 would be a better combination if you want a long lasting engine, and it doesnt lose much to the 347 in the area of actual useable power output.
yeah it does seem like the mixture was rather lean. as for it causing the issue, no. he said he dropped a valve, which means either a bad valve spring, or the valve itself broke, and unless the motor was running really lean, that wont be the cause of his broken motor.
that depends on what you consider high mileage. a properly built 347 should go about 100k miles before you should have to go through it these days. i also agree that a 331 would be a better combination if you want a long lasting engine, and it doesnt lose much to the 347 in the area of actual useable power output.
While I don't think there's a magic equation to calculate exactly how much more wear each individual combination is contributing to, I will say that it seems the higher displacement/longer stroke combinations contribute the most. This is based on both the results I've seen from running and broken engines after a few miles and simply by doing the math.
Of all the 347's I've seen running around, I don't think I've ever seen one with more than 50,000-miles on it. Generally, the car ends up sold or broken, (to become someone elses problem as made apparent in this thread) or a different combination is built before any of them see any sort of mileage. I have on the other hand seen pics of ones that the owners assumed were running fine, only to find visual evidence of excessive piston skirt scuffing, and/or cylinder bores polished to a mirror finish from wear in a relativity short period of time. The angle of the rods in a stroker kit puts a LOT more stress on the cylinder walls and piston than your standard 302 does. This fact is irrefutable. How much additional stress is really going to depend on how much the rod angle is increased.
This was exactly the reason I chose my 331 over the 347. While I know it's not going to knock out 200,000-miles like a basic 302, it should be good for a good portion of that and most certainly will outlast a 347, while providing as good, if not better performance characteristics in return. That 15lbs/ft of torque I miss out on with the additional displacement is more than made up for by the "revvy" nature of a more square bore vs stroke combination and additional longevity of a less stressful engine combination.
In the end, I decided the performance vs longevity ratio of the smaller stroker was an acceptable compromise for me to live with.
how can you guys tell it running lean? because the pistons or what?
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