compedgemarine

so I am bolting together this gen 6 454 with a Scat 4.250 stroker kit for the air boat and I want to know what everyone else is finding. when I started the mains were .0025 mains 1-4 and .003 on 5 and the rods were all .0035. I am now at .003 mains 1-4 and .0035 on 5 and .0025 on all the rods. now the rods are in and the side clearance is .011, .026, .024 and .022 from front to rear. is it just me or are these things this out of wack for new parts. is everyone else having to do this much "adjusting" of things to get the fit they want?

Black Baja

iTrader: (2)

Being cheap isn't always easy and sometimes it gets expensive.

compedgemarine

I cant argue with that but the owner bought all the parts before bringing it to me to assemble so I have what I have, so to speak. I thought that by now the quality of machining had improved. the rod journals were undersized which is why I had so much clearance on the rod bearings. I have to measure the rod widths tomorrow to see why the one is so tight on the side clearance.

ezstriper

some of the early ones were really bad, then they changed to machining in the US and they got better from what I heard, but yes seen B/S from them as well, bought 2 brand new GM crate complete 454's a few years back for my gibson, 1 had a noise(sounded like a piston slap) and a vibration about 1500-1800 from day 1, then at 120 hours the noise got worse, pulled the engine, found that it had spun a rod bearing, never lost any oil pressure, and ran ok. When disassembled found had scat crank in a new GM engine...posted here about it..many thought I was wrong, but nope GM bought a bunch of cranks for the marine program from them, so bought a new one from summit, listed as factory GM balance, well machine shop was barely able to get balanced !!! so to me a lot are crap, best I can figure this one shook itself apart or clearances were crap or both, now this is a engine that never saw 4k never got hot, good oil etc...

horsepower1

What changed to get the final bearing clearances?
.003-.0035 on mains, and .0025 on the rods is fine. The side clearances are fine as well. I usually have very good luck with Scat stuff but for the price it's not going to be perfect. Their rod journals usually measure in the high 2.198X range. Usually have to do some bearing swapping to get decent clearances but that's just part of engine building. Just takes a little more time to make it right.

compedgemarine

had to get different bearings and swap around to get what I wanted. having to cut one rod down a little to match the others to get the side clearance similar all across.

Bawana

What brand bearings did you use? I have used Scat on lower budget builds in the past, and they were dead on. I have found recently that bearings are all over the place, and have to break up sets to get clearances dead on. What did the crank, main caps and rods measure up at?

f_inscreenname

I've used Scat in a couple motors. Have one of their stroker cranks in my main boat's motor for 5 or 6 years. I don't think Scat are the bad guys anymore. It's Eagle.

Full Force

iTrader: (5)

Scat was dead on with my old engines, Eagle was all over, what are you using to measure with?

compedgemarine

bearings are King, measured with micrometer and bore gauges. throws on the crank were .001 smaller than every other crank I have here and the one rod was wider. I dont know where he bought all this from or how old a stock it is. it is all going to work out and be fine, just dont know why this one had issues. could be this was all a blem set from someone and since he doesnt know any different they sent it out to him hoping to get rid of it. I have run Scat stuff in other engines and not had any problems so I didnt know if there is something going on or I am just the unlucky one this time around.