I have a 03 GT. 4.6 2v. It has 76k on it and it ran great till i did a small build on it this past winter. I put on a trick flow upper and lower intake and adjustable timing gears set at zero and comp cams stage 2. These part were on the car at one time but the previous owner had taken them off. I powder coated all the parts and built the motor. I used all the parts it had but installed the cams and intake. I set the dot (index mark) at 6pm, straight down and folded the chains in have not once but prolly 15 times and marked the ends. Im very ocd and do things a zillion times to avoid these issues. I out the top dot to the top and put the other mark on the opossing link that was marked. I triple checked torques, checked 100 times the intake and everthing before assembl. Zero vacume lecks. it runs great but has a hard knock!! It sounds as if its coming from the center of the intake. Its very rythmic to the motor but the motor seems to run greatr and idle as it would with cams. i have a fuel pressure gauge and it reads about 38. I have absolutly no vacume leaks. I checked and repalced the plugs many times. I did a compression test and the right side was about 180 or 179 and the passanger side was 168-175psi. I checked all fuses and harrnesses, have clean fuel, new oil filter and oil. I rotated the motor like 42 times after installing timining chains ti have all the marks line up again and to listen for anything hitting. Everything looked good. Nothing in the valve train either. When I raise the rpms the knocking speeds up. It sounds like a rod knock on a old push rod motor or like after u change your oil and you first start it up and it knocks, well thats how it seems to sound so I completely lost!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
first start...major problems!!! i need help!!!
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musclemustangcb
Member
- Nov 20, 2011
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wmburns
SN Certified Technician
I did not take pics. I did of everything else aside from the chains. I took pics of the chains originally. I went by the book and a few write ups on the install. Ive built many 5liters but this is my first time on a mod motor. I have buddies as we all do that were around occassionally. So Im lead to believe that its a timing issue or whats your thoughts??
trinity_gt
10 Year Member
A hard knock sort of suggests something may have dropped into an intake port and is now embedded in a piston crown, kissing the head each TDC. Any missing parts (nuts, screws, bolts...) during assembly?
fshawn50
Member
I've got one of these to hear inside the motor? It's Cheap $ an you can hear everything internal bearings, grinding, or knocking? Rod knock. You can go down each side of the block an listen for the knock an kinda pinpoint which cylinder?
And got a deal on one of these? You could probly rent one?
But I.can check each cylinder an see what's goin on? Like your issue. Might be a foreign object in a cylinder or piston to valve knock? Being from cam timing or degree?
Like ta know.what you find or hear?
And got a deal on one of these? You could probly rent one?
But I.can check each cylinder an see what's goin on? Like your issue. Might be a foreign object in a cylinder or piston to valve knock? Being from cam timing or degree?
Like ta know.what you find or hear?
No i did have any missing bolts but tomorrow im prolly at some point pulling off the upper and scoping the motor. I cant believe i would have screwed up the timing either if i had one mark on each dot, meaning on chain and one gear. it was all lined up. I hope. before putting on the intake i stuck a shop vac on all the ports and in each cylinder and a megnety in the cylinder. maybe the magnet fell off?? if some thing is wedged into the piston if i get it off is it okay prolly you think??
fshawn50
Member
Ouch. What magnety thing was you sticking in the chambers? An like the magnet fell off? Don't really.follow ya on that and a vac? yoU can check. Or I should.state I check mine. When I pull the plugs in each cylinder? Don't really "have to" pull the head? Or valve cover. Now.if.your checking timing degree yeah I see removing valve cover.
As far as being "damaged" the piston? Probly not would be more of a valve? Intake or exhaust one? Flip a coin? A damaged piston would.more than likely cause the exhaust to smoke. Like a ring or wall damage or hole/crack in piston.
As far as being "damaged" the piston? Probly not would be more of a valve? Intake or exhaust one? Flip a coin? A damaged piston would.more than likely cause the exhaust to smoke. Like a ring or wall damage or hole/crack in piston.
usaf_branham
15 Year Member
are you SURE the cams are degree'd correctly? i get lining the end links on the dots, but how do u know that the prev owner didnt have the cams advanced or retarded. If you changed the timing on the adjustable gears, you very well could be putting your valves into your pistons. ie; if the gears were set at 8* retarded to get the icl at its correct number, then by setting it straight up you are now at 8* advanced...
The cam gears were at -3 when i got them handed over. The privious owner said it was at-2 because he had a procharger on it at one time and backed it off for boost according to him. Im having a hard time believing something fell in the motor while assembly but i guess its time to pull the dame thing apart which isnt bad aside from the fact i have to pull my break booster off because i cant get the bbk valve cover off with the break boost in place. im so stumped!!
compression on drivers side is approx 180ish all the way across. on the passanger side im around 170s and i had one at approx 165. Also when I spin the motor its very smooth sounding and id imagine if I had anything wedged into the crown or lip of the piston id hear it When I spin the motor over with out starting it. The plugs looked okay for the most part. I took one of those telescoping type pencil extending type magnets and went in each cylinder and as i said put a shop vac on each port. This was all done before assemably of the intake going on it. Man the kicker is my car runs pretty damn good and idles decent too for having cams and junk. Maybe my timing is off???? would that make sense why the compression is different????
As far as the compression being different, on stock bottom ends I have seen up to 10% variance between cylinders which is considered within tolerance. Yours is 9% and many would consider that acceptable but I find it curious that the variance seems to have chosen sides. I would think that you either have a timing difference on that bank or something. Maybe a poor surface for sealing the head gasket? IDK but I would suggest that if you have the time and means, find the cause. You can do a leak down test to see if the cylinders, rings and valves are sealing and compare sides - this will give a clue as to if it is a sealing or timing issue. Regardless of timing, leak down should be close as it is testing the seal of the rings, valves and head gasket. If the results come back the same for both sides, you know that the working compression of the bank is less which would be caused by opening or closing events of the valve occuring at a different point than the other bank. Check it out and let us know.
Ill be doing a leak down test this weekend. Lastr night I pulled the valve cover on the drivers side to take a peek. I see zero so far. Im gonna put a scope down in the cylinders to take a gander at the top of the pistons and being a wide angle scope i should get a so so view of the vlaves and domes. I didnt see anything in the springs or anything. Im so fricken stumped! Ive built probably 30 motors plus over my 40 years of walking this green flat earth. If it was off even one tooth it would run and idle like ass. no hard start, it fires right up, idels great also. Ill let u guys know how it goes over the weekend but if anyones looking for some powder coating let me know. Im pretty good at it and ill get some pics on here too soon. Im beginning to wonder if something got into the cylinder but when i soin it i hear nothing at all....but when i put on the cams, comp stage 2, and when i rotated the engine by hand 42 revolutions it sounded good. However i heard a faith click on the drives side rear. My brother heard it to but we chose to ingore it as we both though it was nothing to worry about...but???
fshawn50
Member
What's the lift on those CompCams? They "H's" or "AH's" You didn't see any spots ontop of the piston where a valve might be knicking or hitting the piston?
You just stated that they were Stage 2 cams? Might be a high lift set? Just a shot in the dark?
You just stated that they were Stage 2 cams? Might be a high lift set? Just a shot in the dark?
trombonedemon
Well-Known Member
For some problems you need to ask your self very simple questions, like what would sound like rod-knock but its not rod knock?! If after hours of deliberation you don't have an answer, then you have your answer.
If it was a timing issue, would'nt it be a valve issue as well, and since our engines are interference engines, wouldn't the car be smoking, burning lots of oil as well; thus bending a valve and result in the valve not seating properly?
Is this a rebuild kit you acquired w/items like new bearings and gaskets and etc......
If not then you might of think of how hard you were on the car's power train, if it has the original bearings and crankshaft.
It does not take much to scar a bearing, a crankshaft bearing for that matter. A piece of sand can do the job when it gets in the oil journals around the crankshaft; which would result in lost of outer coating of the bearing.
Either way a knock while the engine is idling, when it is obviously not fuel or air causing the problem, a rebuild should be in order, at least analyzing every moving assemble.
If it was a timing issue, would'nt it be a valve issue as well, and since our engines are interference engines, wouldn't the car be smoking, burning lots of oil as well; thus bending a valve and result in the valve not seating properly?
Is this a rebuild kit you acquired w/items like new bearings and gaskets and etc......
If not then you might of think of how hard you were on the car's power train, if it has the original bearings and crankshaft.
It does not take much to scar a bearing, a crankshaft bearing for that matter. A piece of sand can do the job when it gets in the oil journals around the crankshaft; which would result in lost of outer coating of the bearing.
Either way a knock while the engine is idling, when it is obviously not fuel or air causing the problem, a rebuild should be in order, at least analyzing every moving assemble.
trombonedemon
Well-Known Member
Although a car's engine can run with an bent valve; wouldn't there be a smoke show from seals not being able to do there job?
1987stangman
Member
- Jul 12, 2006
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Yes they are interference engines so there are no take backs if it's set to far out of whack. I can tell you from an experiance I had last year that my 60K PI motor had a broken guide and skipped time by a single tooth. Just enough to cause a whole bank to miss-fire, but not enough to throw a miss fire code and the engine ran rough. It did, however throw a rich condition on the affected bank. In my case I had no odd noises or any PTV issues. If I had to guess on this guy's issue would be likley that there is a timming issue that is causing PTV in one or more cyl's since really only the cams and timming components were being installed. The bore scope would be a good idea along with checking the timming again before you restart it.
Also in my case when I first started diagnosing my problem I did a comp. test and a leak down and both were normal. Also although there was a rich condtion the PCM picked up on the CEL had not come on yet but was picked up by my scan tool.
I have seen threads before with similiar issues as his and it's always after a cam swap or someone who had to re-time the engine for whatever reason and the end result was always a miss-timmed engine.
I bought a Milwaukee scope. I have only the drivers side valve cover back off at the moment and with the scope the tops of the pistons look like the usual, carbon and jazz, however.....the second one from the front on the drivers side has a gash or a mark of some sort and is shiny as if something is hitting it. It looks to be about a quarter of an inch and looks like (as of first quick peek) the outter indentation of the edge of a valve. idk yet but I will be tearing into it as soon as i get a free momnet this weekend. crap and i have 180 for compression on the side too so idk how thats possible but yet i guess i do. I wanted to be on phase 2 of this winter build, not going backards. Thanks for all the help so far.
fshawn50
Member
Looks like your valve might have kissed your piston?
Hopefully has not caused to much damage.
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