91 5.0 Knocking sound - Page 3 - Mustang Evolution

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Old 05-23-2012, 06:26 PM   #71
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It's a new flywheel, I have the stock balancer though
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Old 05-23-2012, 06:34 PM   #72
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If you removed spark from the cylinders with a rod bearing the noise would change. Personally it sounds like valvetrain to me the frequency of the noise makes me think that. the valvetrain spins more than therefore bottomend i could be wrong but just something to consider. If you have good oil pressure then the main bearings are ok likely. You could drain oil through a paint strainer and look for copper colored metal if you see that then you have a bearing issue if not then u could pop the valve covers off n check the valve train out
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Old 05-23-2012, 06:43 PM   #73
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Re: 91 5.0 Knocking sound

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Originally Posted by JayKranz View Post
It's a new flywheel, I have the stock balancer though
I'd check both anyways just to be sure.

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Originally Posted by 1990mustang5.0 View Post
If you removed spark from the cylinders with a rod bearing the noise would change. Personally it sounds like valvetrain to me the frequency of the noise makes me think that. the valvetrain spins more than therefore bottomend i could be wrong but just something to consider. If you have good oil pressure then the main bearings are ok likely. You could drain oil through a paint strainer and look for copper colored metal if you see that then you have a bearing issue if not then u could pop the valve covers off n check the valve train out

The valvetrain operates at half the speed of the engine.
If we had some way to measure the frequency of the knocks, then would could determine for sure if it is in the valvetrain or the rotating assembly.


Anyone have any ideas on how to do that?


Maybe take exactly 15 seconds of video recording the knock, put it into an editing program slow it down and try to count the knocks, then multiply that number by 4 and see what the rpm is?
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Old 05-23-2012, 06:49 PM   #74
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Quote:
Originally Posted by Trojan Horse
I'd check both anyways just to be sure.

The valvetrain operates at half the speed of the engine.
If we had some way to measure the frequency of the knocks, then would could determine for sure if it is in the valvetrain or the rotating assembly.

Anyone have any ideas on how to do that?

Maybe take exactly 15 seconds of video recording the knock, put it into an editing program slow it down and try to count the knocks, then multiply that number by 4 and see what the rpm is?
as i was reading this i was thinking almost the same thing. my thought was to make 2 videos and play them at the same time on 2 different devices. this maynot be as accurate but maybe able to tell if one sound is faster.
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Old 05-23-2012, 06:52 PM   #75
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Okay, I'll try the video
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Old 05-23-2012, 09:34 PM   #76
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Quote:
Originally Posted by Trojan Horse
I'd check both anyways just to be sure.

The valvetrain operates at half the speed of the engine.
If we had some way to measure the frequency of the knocks, then would could determine for sure if it is in the valvetrain or the rotating assembly.

Anyone have any ideas on how to do that?

Maybe take exactly 15 seconds of video recording the knock, put it into an editing program slow it down and try to count the knocks, then multiply that number by 4 and see what the rpm is?
Had it backwards opps thx for correction
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Old 05-28-2012, 08:26 AM   #77
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Okay, so my tuner says its a bent connecting rod. Bummer! Anyone got a ready to go short block sitting in their garage?

---------- Post added at 08:26 AM ---------- Previous post was at 08:24 AM ----------

He tapped the knock out with his fingers so we didn't need to take video and slow it down. He said definitely connecting rod and it's probably only slightly bent because all the testing on my engine is good.
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Old 05-28-2012, 01:45 PM   #78
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that sux man. that is probably gonna be something along what trojan said. hiccup in tune. where you running 93 octane it?

the only one that i knw is that one that i suggested before. but if i were you i would put a forged rotating assembly in it. you can even stiffen up your own block and add forged parts to it if you want.
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Old 05-28-2012, 01:48 PM   #79
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+100.. And you know exactly what it has.. It's more affordable also to do it yourself then you can get more goodies.
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Old 05-28-2012, 01:49 PM   #80
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Yup, thinking about going with this: http://www.latemodelrestoration.com/...Forged-Pistons
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Old 05-28-2012, 01:51 PM   #81
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You could buy the parts and have all that done cheaper at the machine shop...
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Old 05-28-2012, 01:52 PM   #82
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i used to thik that was a great deal until someone (probably trojan) had brought to my attention that it comes already poked to .040-.060 over. which is already past factory recomended specs. which is especially not a good idea to run thin piston walls with boost. i say stay away from that.
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Old 05-28-2012, 01:52 PM   #83
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Really? Okay I'll call a shop and see what the rates are. What parts would I buy?
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Old 05-28-2012, 01:55 PM   #84
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you can buy a whole bottom end rebuild kit. check summit racing or jegs for the best price. a kit will come with everything you need.

and if you later on expect to bump up the hp it would be a good idea to add a main and valley girdle.
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Old 05-28-2012, 01:55 PM   #85
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I've seen rebuilt stock 5.0 engines for $500, should I just go that rte? I'm not in a position to go all out yet, but I also don't want to park my car for the next two years while I save up.
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Old 05-28-2012, 02:02 PM   #86
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Quote:
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I've seen rebuilt stock 5.0 engines for $500, should I just go that rte? I'm not in a position to go all out yet, but I also don't want to park my car for the next two years while I save up.
You definitely can go that route. You have to look at your budget and go.from there. Your the only one that can make that decision. Just keep in mind you risk this happening again. I hope not, but keep that in mind.
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Old 05-28-2012, 02:03 PM   #87
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k, I looked at the forged rotating assemblies they are $1200-1500 bucks

---------- Post added at 02:03 PM ---------- Previous post was at 02:03 PM ----------

Do I need the forged crank or just the pistons?
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Old 05-28-2012, 02:06 PM   #88
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I believe the stock pistons are forged. But the crank and rods are not.

---------- Post added at 02:06 PM ---------- Previous post was at 02:05 PM ----------

The girdles aren't necessary until you get closer to 450 hp and up.
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Old 05-28-2012, 02:06 PM   #89
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Okay
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Old 05-28-2012, 03:59 PM   #90
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Re: 91 5.0 Knocking sound

If the rest of your shortblock is ok, why don't you just put a good set of forged rods and crankshaft along with the DSS main support system? I am assuming your engine already has forged pistons?

Check out Ford Strokers. He appears to be very good at building them and from what I have read he is very knowledgeable about Ford small blocks.
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Old 05-28-2012, 04:12 PM   #91
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Yeah, my compression is even like new. Maybe I'll check that out.

---------- Post added at 04:12 PM ---------- Previous post was at 04:01 PM ----------

Any idea what a shop might charge for that work?
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Old 05-28-2012, 04:24 PM   #92
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Re: 91 5.0 Knocking sound

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Yeah, my compression is even like new. Maybe I'll check that out.

---------- Post added at 04:12 PM ---------- Previous post was at 04:01 PM ----------

Any idea what a shop might charge for that work?
No idea for your area, but around here $60-$75 per hour is common.
Which is part of the reason I have always done my own repairs.
The other parts is that I just don't trust anyone that I don't know really well to work on my vehicles.
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Old 05-28-2012, 04:26 PM   #93
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Is there any special tools I would need to do that? I'm willing to try it myself but I do t have any presses or anything.
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Old 05-28-2012, 07:08 PM   #94
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My local machine shop would do it for around $400
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Old 05-28-2012, 07:10 PM   #95
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With the motor out of the car, or in the car?
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Old 05-28-2012, 07:12 PM   #96
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Yeah just take them the short block.. They will hone it magna flux it new freeze plugs bearings rear seal etc.. Then they will re assemble the bottom end an have it like new.. Also re-ring the pistons.. Either some clevite77's or total seal rings will handle that boost
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Old 05-28-2012, 07:28 PM   #97
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Hey guys I would pull the motor and take the short block to a engine shop. They will check it out. If the crank is ok I would use it and go with a good set of hbeam rods and forged pistons. They will check the cylinder bore and let you know if it needs bored or not. .030 over if needed usually will clean them up.
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Old 05-28-2012, 07:31 PM   #98
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Very true... Ive seen the stock cranks last longer than the stock block.. But the h-beam Rods would be a great addition
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Old 05-28-2012, 09:01 PM   #99
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Re: 91 5.0 Knocking sound

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Is there any special tools I would need to do that? I'm willing to try it myself but I do t have any presses or anything.
You might need to have the piston pins pressed in along with installation of the pistons, but other than that a torque wrench, some feeler gauges and maybe a set of calipers should get you by as long as you have hand wrenches, sockets, screwdrivers, etc..

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Yeah just take them the short block.. They will hone it magna flux it new freeze plugs bearings rear seal etc.. Then they will re assemble the bottom end an have it like new.. Also re-ring the pistons.. Either some clevite77's or total seal rings will handle that boost

Aren't Clevite 77's engine bearings?
A good set of Chromoly Piston rings will serve.

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Very true... Ive seen the stock cranks last longer than the stock block.. But the h-beam Rods would be a great addition

If he were naturally aspirated I would be inclined to agree that the stock crank would be ok, but with forced induction he would be much better off with a forged steel crankshaft. The forged steel rods are a must at this point.
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Old 05-28-2012, 09:08 PM   #100
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True.. Yes clevites are bottom end bearings lol that's my bad.. Some moly's will work well

---------- Post added at 09:08 PM ---------- Previous post was at 09:05 PM ----------

The previous owner of my car said I have a forged Scat crank stock stroke.. It doesn't make since to me I would strike it if I bought a new crank they are nearly the same price. He also replaced the rods.. Is there a way to verify my crank isn't stock without pulling the pan?
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Old 05-28-2012, 09:28 PM   #101
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Re: 91 5.0 Knocking sound

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True.. Yes clevites are bottom end bearings lol that's my bad.. Some moly's will work well

---------- Post added at 09:08 PM ---------- Previous post was at 09:05 PM ----------

The previous owner of my car said I have a forged Scat crank stock stroke.. It doesn't make since to me I would strike it if I bought a new crank they are nearly the same price. He also replaced the rods.. Is there a way to verify my crank isn't stock without pulling the pan?
Not unless you can visually tell the difference from either end or it is marked in some manner.
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Old 05-28-2012, 10:24 PM   #102
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I really don't have a clue. I'm just curious. It won't matter next yr anyways if everything goes as planned then project 408 will be done...
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Old 05-28-2012, 10:55 PM   #103
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Get project 408 done now and I'll buy ur current motor
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Old 07-05-2012, 10:59 PM   #104
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Here's the update. Pulled the engine today, took a head off and.... Check the pics
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Old 07-05-2012, 11:00 PM   #105
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Need a used 5.0 HO short block bad. Wouldn't mind a stock set of heads either.
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