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out of ideas valve train/engine noise, goes away when run hard?!

5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

out of ideas valve train/engine noise, goes away when run hard?!

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Old 05-17-2018, 12:55 AM
  #1  
FoxbodyKid
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Default out of ideas valve train/engine noise, goes away when run hard?!

Hey guys, back with my shattered dreams. here's the latest news and the whole engine rundown is the 2nd paragraph.summary at bottom

I was driving it on the backroads with my friend in a miata and we had a spirited drive, because despite the ticking its my only car and it runs perfectly fine and has good power. My friend was riding with me also and he is well aware of the ticking sound my car makes. after our spirited drive, we stop at a stop light, and astonishingly, my car sounded perfect. my friend agreed too, it sounded exactly how it should sound. no clattering and rattling throughout the rpm range. so when im going hard on the backroads, and have the rpms really high, its like its gettting the oil it needs or something. after the hard runs it will not clatter for a couple minutes but in town it clatters so much because im mostly driving below 3k. could my new oil pump be only working partially? i just dont know what to do anymore. Im doing my first term of college and I don't have time to yank it all apart, but i will this summer. considering seeing if someone could just build me a new motor and sell what i can of my sewing machine. sorry for the long post, I am just really wanting my car to not sound like this so I can do other things ( like paint it cuz its 6 different colors rn lol)

background
"my motor that runs great but sounds like a sewing machine. So on the stock original motor (never rebuilt) I swapped some junkyard gt40 heads with 250,000 miles on them and installed them, cuz hey, they were 60$ each. So I lapped the valves myself and ported and put them on along with e303 cam, gt40 intake. Everything sounds good, I can tell a little difference in the engine noise but it was nothing bad sounding and I could tell it was just from the cam. No issues. 4 months later, I get this sound and it slowly starts getting worse over weeks until it stopped getting worse. Very soon after the oil gauge showed no pressure so rebuild time. Except I drove it around at least 1k miles with 2lb of oil pressure idle cuz school. So eventually I rebuilt it. The crank and block were cracked so new ones of both. Basically the bottom end is completely new. But the top end... I just slapped the old heads on after driving them around for 1-2k miles with no oil pressure (the heads looked fine) Should I have gotten new heads? Also what about the cam. Could my valve guides, valves (looked fine), cam, or the head somehow be damaged by lack of oil pressure? It doesn't burn any oil or emit any blue smoke.I don't think there is anything wrong with the valve train like pushrod length and lash wise is because it rain quiet when I first swapped the heads/cam, but with the driving with no oil pressure must of damaged something. pushrod length is 6.27 (stock) with stock stamped rocker arms"

summary

brand new bottom end bored 0.030 over
junkyard gt40 heads
new cam but driven with no oil pressure really for about 1k miles
new springs to match cam
stock rockers/pushrod length
new oil pump
very slight to no tick on cold start
clattering/ticking from idle through 4.5k when hot
if i start pushing the car hard and keep the rpms high (3-4k for a couple mins) ticking goes away or I can just barely hear it and I imagine what my life would be like if it just stayed this way.
hot idle 18 psi oil pressure 45+ revving


save me from buying a new motor
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Old 05-18-2018, 02:08 PM
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Derf00
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what weight oil are you using?
when was it last changed?
did you have the junkyard heads fully worked over before installing or just replaced some parts and installed them as-is?

Check the lash clearances on your valves.
Check for weak springs (most likely if you didn't replace them on a 250K mile head...)
That clacking that goes away from spirited driving is gaps getting smaller (clearances getting tighter as things expand from the heat). You'll eventually float a valve and potentially end up with some major damage.

Other things to check, pushrod condition. Flat spots where they meet the bucket on the valve rocker (increases the gap and leads to noise) again, replace those.
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Old 05-19-2018, 03:38 AM
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08'MustangDude
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I would not have used any cam that was ran without oil for a mile or so.
You said the new cam was run for 1K miles with no oil, that's 1000 miles,
I sure hope not, that cam would be toast...
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Old 05-19-2018, 08:41 AM
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wbrockstar
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The valve springs should have been replaced because they're not sufficient enough for the stock cam,let alone an aftermarket cam with even more lift.If the valvespring,at the suspect cylinder,is completely worn,it may be causing the valve to stick,triggering the noise.I would check compression at the suspect cylinder and the cylinders directly beside it.If the suspect cylinder is much lower than the surrounding ones,you know that valve/valvespring has an issue.
If youve got a air compressor,a compression tester with a quick connect fitting and a valvespring removal tool,you can replace the valvesprings without removing the heads. I would,at a minimum,replace both valvesprings at the suspect cylinder, to see if the noise stops.Connecting the air compressor to the spark plug hole,with the suspect cylinder at tdc on compression, will also show whether the valves for that cylinder are sealing or not.If air is heard escaping into the intake,the intake valve is leaking.If its heard at the headers,the exhaust valve is leaking. That means the valve is bent,seat is bad,valvespring is worn,etc.
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Old 05-19-2018, 06:58 PM
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FoxbodyKid
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Im using 10w30, and I did my best to rework the heads. all I really did was take the lapping compound, put it on the valve seat and turn the valve with a drill to smooth out the seats. The springs are brand new stiffer springs from alexs parts, they are made for gt40 heads and cam lift of .550 (which i have the e cam so that should be good). I've also bought new rocker arms (same as stock stamped ones) and hardened 6.27" pushrods. when I took the other set out, I didn't see any unusual wear on either the rockers or the pushrods (they looked the same as when I took them out). the way I tighten the rockers is, get piston at top dead center. then tighten the rocker bolt by hand until pushrod doesnt spin, then tighten down to 22 ft lbs. before I had it tightened 3/4 of a turn, but the second time I went through I tightened to 22 ft lbs which was almost half a turn.

as for the cam, I was under the impression it would be fine to reuse. yes, I did drive it for about 1k miles with 2 lbs oil pressure at idle and 25-35 driving. I took the cam to the machine shop guy who was doing the whole rebuild thing and he didn't mention anything about it looking bad or anything. I cant really remember if I pointed out to him that I had been driving the car for quite a while with no oil pressure. So is my cam forsure toast? I did have a feeling it could be the culprit, but I really dont know. and the reason I dont think I have a compression issue is because it runs perfect. wouldn't it have issues running if the compression was an issue?
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Old 05-22-2018, 12:38 AM
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FoxbodyKid
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any ideas? to me it really seems like the rockers are not getting enough oil at idle-2500 rpm. if I drive it hard keeping it above 3k for a couple minutes, it quiets up and goes back to sounding exactly how it should throughout the rpm range. in town, it clatters away, but cold starts it sounds quiet and how it should too.
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Old 05-22-2018, 01:40 PM
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Derf00
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Only way to know about the cam being toast or not is to have the cams speced out and see if they are within spec. It's easiest done out of the head but, if that's not possible, it can be done in the car. It's just for all the work to get to do the measurements in car, you may as well remove them and have a shop regrind them while your at it so there's no question. Second, replace the springs as already mentioned and measure your pushrods before you start putting backtogether to makes sure those are to spec as well.
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Old 05-23-2018, 07:40 PM
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FoxbodyKid
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I have measured my pushrods. They are 6.27" stock length pushrods, they are hardened. The springs are BRAND NEW stiffer springs that can handle the lift off the cam, and they are installed right. My engine builder must of checked the specs on the cam, because I remember he specifically asked me to bring it. So the cam should be fine ( it was brand new as well, just driven with low oil pressure for a while) my whole bottom end is brand new. It is so frustrating, and I don't know what to do at this point. I take it to mechanics and they tell me I've already done everything they would do. I don't wanna build a whole new motor, cuz I just did that! This is driving me crazy. Should I just buy new heads, roller rockers, pushrods and put them on? With my luck that wouldn't fix it.
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Old 05-23-2018, 07:48 PM
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TheBabyBadger
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Blame your friend's Miata?
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