Serious problem with knocking/clacking...Help me..

latham83 · May 11, 2004

Hey alright well i just got my 90 5.0 running a couple weeks ago...
i got a dss short block 306 with thumper heads with the updated springs, 3-303 cam, gt-40 intake, and bunch of other stuff that doesnt matter right now..
im using the STOCK pushrods and rocker arms.... we did adjust them in the base circle correctly i think when it was on the stand and had them torqued...
now i put about 600 miles on it so far...around 300 mile mark there was a super loud clacking, knocking noise coming from the engine...i could not tell ya what it was...it almost sounded liek alot of air/exhaust fluttering very loud...it did this for a couple mins..then stopped. had it out and put 300 miles on it and in the meantime it never came back....i just started beating it up alittle after the 500 miles cause they said its ok after that...now the other day it just came back... its pretty loud...it kinda sounds like its only coming from the drivers side...it kinda echoes through the upper manifold cause u can hear it in there too...could this be unadjusted or somethign wrong with my rockers/pushrods? the sound goes and comes? sometimes its there but not very loud..and then it will increase unexpectedly? im so confused and upset...
also when it starts doing this i seem to have an overheating problem..dont know if it has anythign to do with it..i have a 180 thermo in there..and it went to about 205 the other day? its hot as hell when u open the hood?
by the way the car seems to run good tho acoount to all this? i dunno...help me!

DJTR · May 11, 2004

I don't mean to sound like a jerk but hows your oil? Check for filings.....does it seem to increase alot with the revs or is it kinda steady...... Almost sounds like a bottom end bearing but it could also be a lifter giving up the ghost if it is that loud.

DJTR · May 11, 2004

Oh sorry one more thing..... you losing power at all?

latham83 · May 11, 2004

hmm i cant really notice loosing power...i dunno tho but i would be very upset if a bearing was messed up...i would not wanna pull the engine again..i did all the work here myself with my dad...ugh...they should be fine.dss set them up not me...hmm...my oil seems ok i changed it twice? it had very very small filings in there but everyoen saids thats suppose to happen with everthign being new..also...my lifters are brand new... when u say bearing tho...what woudl actually happen for it to do this every now and then...louder or softer at different times? it is possible it can be a rocker or somethign right? im taking the covers off tomorow

latham83 · May 11, 2004

can someone help me out? i just pulled off my covers...none of the rockers seem loose or anything...i mean we did the whole zero lash procedure and everythign right...i mean if it is reccomeneded to do them over again i will...am i suppose to?
i was told it could possibly be a lifter causing this noise? like dirt in the hole or something i dunno...i would think that if the rockers were misadjusted..this loud wrapping would be all the time? as for a bearing also.... this loud wrapping only comes up once in awhile..seems liek when she gets hot...if that makes sense...i need help

DJTR · May 12, 2004

honestly I hate to say it but if you have done everything you have done the next thing to do would be to pull the top appart and check your lifters. Did you have the crank machined when you put the new bearings in?

BlueThunder1988 · May 12, 2004

I'm running a fairly similar combo (Thumper heads, but with a Tmoss lower, Crane 1.7 RR's) on a stock short block and I had some concerns with noise in the first few weeks I was running the new engine. My problem turned out to be a simple exhaust leak--retorquing the bolts helped a bit but did not eliminate the noise. Turned out that the gasket had delaminated and broken around the number 5 cylinder so no amount of reefing on it would have fixed it! Put on a new gasket (with a touch of hi-temp RTV) and no more noise! In short, pull and check your header gaskets!

latham83 · May 12, 2004

honestly..i think im 80% sure that is it detonation..i just thought of it..it soudns exactly like a can of marbles...my timing is at 16-18 and my fuel presuure is probobalby too high or low...plus it starts making that noise when it gets hot...it all makes sense...
im gonna reset everythign to stock settings and take it from there? sound like thats the problem to anyone?

MurdockSVT · May 12, 2004

yea that sounds like detonation to me, back the timing off to about 12 degrees and have the fuel pressure set around 42 with vaccum.

ill advised · May 12, 2004

There have been two occassions when my car made the type of noise (in the same area) you are describing. Once it was a header gasket. The second time the noise was noticably worse, but similar, and turned out to be a busted lifter. Hopefully it's your timing or a header gasket.

cardudeusa · May 12, 2004

Yeah could be detonating w/ the timing that high. I keep mine around 14*. I have driven it before with it as far as 21* w/ no problems though.

thumper460 · May 12, 2004

Back the Timing off... have a mechinical oil pressure gage installed to keep an eye on the OP when the noise starts.... coming and going can be a lean condition with the heat and the hot plugs... 38 psi with vac off is a good starting place... timing ?? back it down and start at the lower settings and bring it up 2* at a time!! Some thing intermittant like that is usually NOT something mechanical, like you said... lifter will pump and then loose prime and rattle and then stop... marbles...?? I agree!! fuel pressure and ign timing!! Cool?? By now you have done all this.... so??? what's up??

Just me..............................

Thumper

latham83 · May 12, 2004

hey thanks guys i apprecite the opinions and help...i didnt get to work on it yet but tomorow ill probably get **** back together...and ill set my timing back to 12 and turn my pressure down...and see what happens..
also do u think the lucas oil stabiler stuff that kinda thickens your oil would help out with my new engine and everythign? i hear good things about it..

Serious problem with knocking/clacking...Help me..

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