Tearing Down the Big Block
Well after deciding to try and give my build another go,I got the motor out of the car and on the stand.
I had been having problems with a little overheating and believed it to be the timing because it just would'nt start beyond anything over 30 total advance.Ran like a dog,sounded like exhaust coming out of the carb,not popping but a rumble and just refused to idle in gear.
While trying to time it,i noticed the timing mark on damper was jumping between two spots,back and forth.Also heard a small knock and traced it to the timing cover.Sounded like chain was hitting or fuel pump shaft,ruled out fuel pump.Well with this info,i decided to tear into the chain,got it all apart and didn't notice any rub marks and chain was right on.Grabbed the crank snout and was able to move it up and down.Not alot but enough to see the chain slack out abit...
Well i knew then that the motor had to come out,I pulled motor and got it on the stand and pulled the intake,another prize an "S" shaped push rod,oh joy!
Well im going to finish the tear down now and try it again.I will probably go with a different cam and replace the domed pistons with standard flat tops.I was told by several people i had to much cam for my motor anyway.When i built it,i had intended for it to just be a weekend warrior but i want more than that now.Maybe not a daily driver but definately more miles than it sees now.
Sorry to rant but i gotta vent!
Maybe someone here could give me some tips on cam choice and whatnot.here is what i have in it now...
76 454 .30 over
Chrome moly plasma rings
heads 781 casting number,open chamber,rebuilt for this motor locally,the heads they had to replace/remove the rotaters(?) and they had to turn down,i think the guides to get the umbrellas over them.(?) something like that
cam: edelbrock 7162,
adv duration int 300° exh 306° @ .050 int 240° exh 246°
lift @ cam int 0.330 exh .337 @valve int 0.560 exh 0.573
timing @ .050 intake open 10° BTDC intake close 50° ABDC exhaust open 57° BBDC close 9° ATDC
centerlines lobe seps.112° intake ctrline110°
edelbrock 5762 valve springs,matched to cam,standard ratio,
roller tipped rockers
.250 domed hypert pistons
edelbrock 7161 performer plus dual plane intake
edelbrock 1407 750 cfm carb
Edelbrock double true roller timing chain
Well i got it all tore down and the verdict isn't great...
well as i said in first post,first thing i found was the bent push rod on #4.so i tackled the pass head.With it off i found that the push rod did not hit the piston.So i don't really know how it got bent,it was like an "S" and broken at one joint...
so i pull the other head,pistons looked like all the rest.I start pulling lifters and uh-oh.#4 exhaust lifter is totaly concave so bad there was a hole in it!Also found #8 intake and exhaust also both totally galled out...After pulling the cam found #4 exhaust lobe totally round,#7 exhaust same and #8 intake and exhaust totally round...
So this has probably been like this from initial start up.I never was able to do the proper break in where you let it run at the set rpm for so long as soon as it first starts.It kept dying and spitting,popping.I finally did get to do the process but not til after several failed attempts and restarts to keep it running...
Also the knocking....Still not sure where this was coming from.I checked all the main caps and rod caps and all the bolts were still torqued to what i had set them to.Found nothing loose and no marks anywhere that there had been anything rubbing...
Pulled first main cap closest to cam sprocket.found a deep gouge right in the center of the bearing,so i pulled the next cap back and founf the same thing,not as bad as the front though.the front was really deep.It would appear that when i sent it out,they just polished it and the oil galleries werent't chamfered because thats right where the marks are.Either that or i got a little dirt in every cap right in the center.Not!Well needless to say the crank looks like it's gone,has a lot of wear on the front and where i pulled the 2nd cap the journal there also is grooved....
So i'm adding it all up and wondering if it would just be worth buying a crate motor or trying to work out this one and hope i can do a better job this time.
Crank,Pistons,bolts,cam/lifters,cam bearings(cam came out ugly the block looks fine,i couldn't even feel the little ridge at the top of the piston bores,of course this only had less than 500 miles on it...
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