Scat stroker kit quality question
 

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?

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

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.

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...

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.

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.

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?

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.

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

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.

.003/.0035 on the mains and .0025 on the rods, what is the issue? Seems like one rod is a little wide. I'm only curious....

that is were I ended up. when I started with all std bearings the rods were .0035 which was pretty loose for me, especially on new everything. the mains were tighter but were fine if it was a street motor. the rod throws were cut .001 smaller than any other crank I have here. all the rods were dead on the same except the one for some reason.

Very typical for aftermarket stuff. I wouldn't waste the time worrying about the rod side clearance. You have plenty even on the tight one.

Ahh, gotcha

The crank might have been machined on a Friday around 4:00

or on a Monday morning ...
But like said I've talked to a hundred machinist over the years and most would rather have Scat over a lot of other crank makers. The last Eagle forged crank I bought had to be cut 10/10 because it was so screwed up. I'm sure it could have been less but I wasn't going to get into special bearing and such. I wont even get into the balance that needed to be corrected.

I'll let you know in a couple weeks. I just dropped off 2 scat 4" cranks and rods for the 2 408 Mopar small blocks at Opel Engineering last week. I ran a Scat in my 392 Stroker Hemi with no problems for 80K miles It was perfect out of the box, and balanced easily.