Ok so long background but I had a 430 motor gone through by a guy and he said all looked good and put some new cast rings on the old pistons, put a TA 110c cam in and put it all back together. Motor is in my 67 gs. When i started driving car around all seemed to be goof for about 100 miles. Then it started to misfire and fall on its face. After troubleshooting forever and help from the forum i found i had the resistance wire going to the pertronix unit inside the distributor. Replaced the wire with new supply coming from fuse panel with 12v constant. Motor ran good then with power for a little bit again. Then started having massive blow by. After being super frustrated and letting the car sit for a few months i got back to it. Did a compression test dry/ wet and leak down test and found cylinders 5-6-7 low. Pulled motor and here’s what I found on the pistons.. now number 5 you can see the casting actually broke off when i got the Piston out. The others have cracks in the casting. Has anyone experienced this? Also when i go back in With new pistons and rods this time, TA said i should use cast rings if I’m just honing my cylinder walls… from what I read everyone seems to say moly coated rings… feedback please guys/ gals… thanks Ryan
Probably preignition from the bad wiring setup did the damage? Just a theory of course. Lucky it stayed together! Don't know the answer on your ring question.
You'd be better off to have ONE thread on this engine, instead of starting multiple threads. Broken ring-lands are typically the result of rings with not enough gap. A failed top land might be a detonation problem, but that doesn't explain the lower ring lands. Did you have "ping" problems? I wouldn't use plain cast iron rings on a lawn-mower, if I could get Moly-faced ring set for it. It's not that hard to get a cylinder wall finish suitable for Moly top rings. Pitch EVERY piston into the scrap bin. Get decent pistons with higher compression height--probably direct from Jim at TriShield. Have the guts rebalanced to suit the lighter pistons. Buick held onto full-skirt pistons FAR too long. Don't get me started on their "center of mass" connecting rod balance theory. Let's just say that if you can upgrade the rods, you probably should. I don't like Chinese product, but that's today's world and unlike more popular engine families, there aren't USA-sourced options that I know of. The block needs to be square-decked. With proper pistons, you shouldn't need much more than that cut off to achieve proper squish/quench.
Detonation.....all 430s are high compression and many times people try to run regular. Even 93 premium is on the edge with carbon buildup.
Ok so for pretty much stock rebuild. Less than 500 hp. What do my tolerances need to be for mains and rod bearings? I’m bringing crank and block to shop and have them measure to see where I’m at and i want to know what they need to be. Ryan
as a big generic answer, .002 on both rods and mains. there are variances for street/strip and basic stock rebuilds, but that specs should work just fine
This thread is for the small block, but is good advise for the big block as well. The tighter you make the clearances, the better your hot oil pressure will be at idle. If the engine will be revved higher than 5500 RPM, you might want it a little looser, but not much. https://v8buick.com/index.php?threads/what-main-and-rod-clearances-for-street-engine.374330/
CLEARANCE may be .002. Most engine families would want a little more than that, but Buicks are sensitive to oil pressure problems. TOLERANCE could be +/- .0005. (Not less than .0015, not more than .0025.) Perhaps tighter-- +/- .0003. Tolerance is how far away from "perfect" you'd consider "acceptable".
O i am at a different shop now! Unfortunately the car motor was done in MN and I did not know JW lives in MN or motor would have went to him! Lesson learned! Its up here in Alaska now. New shop and these guys are very open to what im getting from you guys and are helping me out. Decking block and found cylinder are pretty bad and I need to go to .060 .. sonic test came back good and I know this is as far as i Can bore the motor out!
I need help guys! I drilled out the suction to 5/8 and am an inch shy and have a pin hole through suction tube.. i for sure thought i was aligned just right.. so do i put a 5/8 od copper tube in or hopefully machine shop can patch pin hole? Suggestions? Ryan. im really pissed this happened. I went super slow and thought i was just fine and saw the pin hole happen And stopped!
I just went out to take a picture of the pinhole and did just notice I also broke through on one of the dang oil pan cover bolt holes.. hopefully just some thread tape on that will fix that issue..
I just went out to take a picture of the pinhole and did just notice I also broke through on one of the dang oil pan cover bolt holes.. hopefully just some thread tape on that will fix that issue..
