I've got a problem.. Finally go my project truck with the new 400 in it on the road and now I have an issue. Seemed to start mildly at first... here's the deal. Set 10 BTC, and the carb set up wrong, on it's first drive out I heard what I thought was a rattle of some kind. The performance sucked, adjusted for good vacuum( 18+ lbs), adjusted for 14 BTC and took it out again. Performance was better, but the rattle gets worse. Should be 8 or 8.5-1, new 670 truck avenger, Weinend single plane intake, headders, duals, msd coil, stock dist& box. I set it back to 10 BTC..other then the performance getting worse..no change in the rattle.

Doesn't happen at startup, and if you drive it a block or two when cold it doen't do it, even under load. Doesn't ever do it at idle, but once you get it even a little warm, it does it loaded or unloaded when you rev it up. Can't seem to figure it out.

Only happens after 1700 RPM. Seems to happen a tad less under full load, but consitent under partial load. Gets real bad off the gas 2000-3000 RPM Range. In the cab, sounds like bottom end ( god I hope not). Outside, couple friends/fellow engine builders say it's not deep/metallic/thud or low RPM enough to be bottom end..one suggested dump gas and run 94 octane ( just tried that tonight, no dice). Other suggested possible valve train ( although I thought that would be more of a tick). Sounds like a rattle, like marbles in a tin can going round.

2nd to the first- she still runs real hot. Going to buy another set of mechanical guages this weekend, and try to get a better handle on things..the set I had just popped the oil line( so I know there was pressure..lol) and the water never worked right for some reason.

Either way with a good antifreeze/water mix, well bled, and no stat ( same with one in , did it both ways) it pings,bubbles and rattles like an old steam radiator they used in houses... This can't be a good thing either.

Anyone have any ideas for me? Going to change the oil out tomorrow with soemthing thicker but I am sure that will not help things much either.

dump in some 20w50 in there. your max timing should be around 35 degrees If I remember right.


how many miles on the engine?

"new" 400? did you put it together yourself?

your max timing should be around 35 degrees

I think this is where you should start. set your timing where the factory recomends and adjust the carb. then check the total timing. I have never done it on a ford, but on a dodge you can recurve your distributer by changing the springs that hold the weights. if done wrong it can cause problems.

was anything done to the internals of the motor? like higher compression maybe?

If you didn't put on a new harmonic balancer don't bother trying to set the timing off of it. They like to spin. Then everything is off.

I believe you can redo the advance curves on a ford dizzy, but it looks like it'd be a PIA. (compared to HEI)

The motor was built 10 years ago, run a bit then pulled. Got it off an engine building guy- had about 10 motors stored in his shop. He is more of a chevy guy so this one is not as valueable to him. I am beginning to see maybe why it was pulled in the first place. It sat on an engine stand for years before I bought it this winter, pulled it apart. All looked mint/new/clean- no wear and little carbon on anything suggested it hasn't been run much. Had BN 2WD headers on it, 2wd engine mounts and a 800 Double pumper ( god knows why) so I let him keep that.

Put it back together with new gaskets. Everything seemed in order at the time.

One thing i've been asked that I think I am sure of is if the head gaskets got on the correct side..( if not they may be blocking coolant flow. ) I mean I think I did..kind of a hard thing to check now..lol.

Timing seems to have little/no effect on this POS as far as this "knock" goes. You would think so..but doesn't seem to. It sure has an effect as far as perfomance goes though. The vacuum advace works/hold..but have not checked how fast the mechanical advance comes on at how many degrees that it does.

As for the compression..the things been done 30 over, but dished pistons so nothing fancy.. I thought stock 8 -8.4 to 1. In case I was wrong..I gave the 94 octane a shot.. still no difference.

My first bad was only pulling one bearing cap... they looked new/spec out ok..so I just re installed it....maybe should have checked em all.

Going to try and run with the vacuum pulled off plugged and off the distributor see if that has any effect. As stated I could pull it to recurve, but again I am not suspecting that is the knock issue.

It's looking more like pulling either the heads and checking the gaskets ( if she is getting that hot that could cause the detonation issues) or the engine and start over. If I do that, guess I will do the 9:5 to one badger pistons I wanted to try in the first place. May as well go all out if I am going to do that. OR...dump the 400 in favor or a 460...but that would mean another intake, cam etc as well as headers and engine mounts. Bummer

I am running a MSD mechanical advance dizzy. I recurved mine it was stupid easy.

1. Whats your oil pressure like?

2. Since it sait for 10 years did you prime the oil system with a drill?

3. Start listing to the engine with a mechanics stethascope or a piece or doweling to your ear. Find where the noise is coming from.

The motor was built 10 years ago, run a bit then pulled. Got it off an engine building guy- had about 10 motors stored in his shop. He is more of a chevy guy so this one is not as valueable to him. I am beginning to see maybe why it was pulled in the first place. It sat on an engine stand for years before I bought it this winter, pulled it apart. All looked mint/new/clean- no wear and little carbon on anything suggested it hasn't been run much. Had BN 2WD headers on it, 2wd engine mounts and a 800 Double pumper ( god knows why) so I let him keep that.

Put it back together with new gaskets. Everything seemed in order at the time.

One thing i've been asked that I think I am sure of is if the head gaskets got on the correct side..( if not they may be blocking coolant flow. ) I mean I think I did..kind of a hard thing to check now..lol.

Timing seems to have little/no effect on this POS as far as this "knock" goes. You would think so..but doesn't seem to. It sure has an effect as far as perfomance goes though. The vacuum advace works/hold..but have not checked how fast the mechanical advance comes on at how many degrees that it does.

As for the compression..the things been done 30 over, but dished pistons so nothing fancy.. I thought stock 8 -8.4 to 1. In case I was wrong..I gave the 94 octane a shot.. still no difference.

My first bad was only pulling one bearing cap... they looked new/spec out ok..so I just re installed it....maybe should have checked em all.

Going to try and run with the vacuum pulled off plugged and off the distributor see if that has any effect. As stated I could pull it to recurve, but again I am not suspecting that is the knock issue.

It's looking more like pulling either the heads and checking the gaskets ( if she is getting that hot that could cause the detonation issues) or the engine and start over. If I do that, guess I will do the 9:5 to one badger pistons I wanted to try in the first place. May as well go all out if I am going to do that. OR...dump the 400 in favor or a 460...but that would mean another intake, cam etc as well as headers and engine mounts. Bummer
See if you could get a IR temp gun, you'd be able to tell if one head (or both?) are blocked off by the immense heat difference.

Thats what I was getting at by asking if you put it together yourself. People that know chevys tend to screw this part up..

Today's update

Bought another set of gauges to check to see if the others were wrong. Possibly, but at least they are consistent. Temp readings when it makes the bubble/rattle and "ring" *( like an old house radiator) that made me think it is overheating.. seem to happen long before you would think. They read 100-160. I am beginning to think the mechanical gauges are not the way to go.... but as I don't have an infrared heat gauge...I can't verify the accuracy. Either way, oddly enough after an hour drive today, and it heating up to 200-210... when I stopped at home...there was no bubbling/rattle/ringing.... WTF? I had topped it up today( rad) and it since has puked a good amount of antifreeze ( time to install an overflow bottle) So...still not sure what to do with respect to this problem. Still undecided if I am going to pull the heads to check the headgaskets...but I think the intake started leaking oil today during my ride....so I may just go in all the way if that needs doing.

Now on to the knocking engine noise...Thought it may have something to do with oil or timing advance. Oil pressure drops off @ idle to almost nil after 160-170 degrees, so I dumped it and changed to 20W50. Better, till it hits 170-190...then same issue... reads 20-40 lbs under load- but drops right off at idle. Added a bottle of Lucas oil stabilizer just for fun... made a differece at the beginning...but then same once warmed up hot again. So nothing good/bad to report there.

Pulled the vacuum line off the dist and plugged it. With no advance, runs a bit rough at idle, but once the weights start to kick in after 2000 rpm, it's ok. Moreover.. the good news was the bad 1700 rpm knock has moved and is mostly gone.

It seemed to moved up to 2500-2700 RPM plus range, but not as bad as it was. Before @ 1700...Used to make the noise bad enough under load, but worse when you backed off the gas. Now with the vacuum line off...it doesn't do it till farther up the range...and then stops when you get off the gas.

I am thinking it's time for a new distributor..something that doesn't pull as much advance with vacuum hooked up...and doesn't advance as much with the weights at full RPM. I have yet to check the curve ( as I need a dark enough place to do it and some help). Will shoot for tomorrow at a buddys garage..and see how much advance comes on ( and when). I am really hoping that after I can nail down those variables, and possibly get a new distributor, this problem will go away.

Still welcoming more suggestions ?
Marc

dunno whats been said so far.

check your base timing. do not trust the harmonic balancer for your timing marks.

also if you have no oil pressure @ idle with 20w50 in the pan your bearings are shot. common problem on these engines.

I'm guessing you don't have a Cat. convertor? They rattle like that sometimes. If it is a light double knock or rattle, it's most likely rod bearings. And if you have no oil pressure at idle it's even more likely.
The 351W in my 88 has that exact problem. No oil pressure at idle and I had this funny knocking sound. Turns out my rod bearings are shot. That's how I know. :mad3:

If it has a cat maby it's pluged. i'd try a mechanical oil gage or a new sender if you havent done so yet, a bad sender will do the same thing.

No cats- headers and true duals. Well thank god it's not my daily driver.. I think on todays trip I got a whopping 4-5 MPG.

As i've been told it's very bad..Dumb question #345: What should my oil pressure at idle be when it's warm? When you are driving..it's steady between 20-40. On fire up cold it's over 60, then seems to hold 20 idling till you head out on the road for a drive. when you come to a stop sign/light it drops to 5 or so..hard to read that low. I know it's low...but I may have or will frag bearings if this is no good.

Tomorrow is re check specs days. I've been advised to do so many things...one is a compression check. Also, as it's running a little lope-y at idle right now with the advance disconnected...I am going to re adjust everything and bump idle to 650-700 ( it's hot idle is only 500 with the advance disconnected) .... re check/adjust base timing and adjust again for good manifold vacuum (was pulling 18 when I last checked). Will check for advance curve as well..as I haven't done that yet.

Stupid question #346- i've been getting conflicted answers as to timed/ported carb vacuum or full on manifold vacuum for the distributor...any suggestions for when I try to hook it back up ?

As for the oil issue...It would be a shame to get it running top notch and have to pull it for an oilpump at this stage...grrr.

My 88 runs fine. I just have the double knock form the rods and screwy oil pressure. 45 lbs at startup and as the engine warms up it drops to 5-10 at load and nothing at idle.
According to my Haynes manual at normal operating temp at 2000RPM you should have 50-75PSI oil pressure in a 351M/400.

ford speced these engines to have 50 psi hot by 2000 rpms.

dunno where I read that from, but it was a while back. idle I am holding 25-30 psi and 50psi @ 1500, 65+ @ 2000. I just rebuilt mine like 3 years ago and I am pretty hard on the mill.

those 400/351M engines almost never have any oil pressure at idle. It's not a big issue. If its not knocking just leave it alone. There is still oil present, just too large of clearances to build up pressure.

How is the vacuum advance hooked up?

Full vacuum or ported?

Went to Fargo for the weekend to see Gary Allan- feeling refreshed I tried to nip my issue in the bud once again. Here are some results from test suggested by helpful folks.

Did a compression check, results as follows

Dry Test
1&2 are @135
3-8 are @148-150 consistently

Seems a little low on 1&2 for my liking on my "fresh" motor.

I re tried dry on 1& 2 two more times, then wet ( added some oil )
Went up to 160-165. For fun I tried 3-4 wet and they went to 170-175.
I was told once way back in highschool this was a good test to see if your rings are ngf or not...

Plugs look mint..I mean like new. A little carbon on the bottom outside of the plug, the electrode looked new with a hint of tan color to it. So that told me nothing.

Going back to basics I re re timed it, 10 TDC on 1 ( used compression gauge for guaranteed compression stroke, re checked fire order and so on. Took the cap off and looked inside. Found little metal shavings in there...appears to be coming from under the plate ( weight side). Cleaned it out with carb clean, then that non flammable liquid wrench. Wiped her all down and buttoned things up. Fired right up, now had a large lag when you press on the pedal, so much so that if you don't feather it till she hits 2000 rpm..she pops and dies. The more you depress the pedal idle to 2000..the more she bogs. Will re check with a light when I check the curve.

Long story short=Still knocks. With the advance hooked & timed this way it knocks at 2500 now ( instead of 1700) that movement in knock only happened with the advance off before. Haven't tried it unhooked again...curious to see if it moves farther up the range again. Something is still wrong...I guess I am just desperately trying to delay pulling it apart.

Two more tests suggested that I haven't tried. One is the curve check ( how much advance and how fast it comes on)..but I need a buddy for that. Other one is try pulling one plug at a time while its in the "knocking" rpm range..so it would "unload" that cylinder...maybe showing me if one or more cylinders has a rod knock if this is truly a detonation issue.

Any more ideas welcome.

did you pull the plug on #1 and confirm the piston was @ tdc or just look @ the guage on the compression tester?

Are you setting the timing BTDC or ATDC?

Yes I had the plug out ( to use the Compression guage - which was used to make sure of stroke) .I hate loosening a plug and waiting for it to hiss...otherwise yes piston was verified to be at TDC. It was timed at BTC.

take the pulg out, stick a screw driver down the hole. turn the crank and hold the screw driver till it is all the way @ the top of the stroke. See where the timing marks are at. With everything you have posted here I still have not seen where you have verified if the timing marks are correct on the balancer.

take the pulg out, stick a screw driver down the hole. turn the crank and hold the screw driver till it is all the way @ the top of the stroke. See where the timing marks are at. With everything you have posted here I still have not seen where you have verified if the timing marks are correct on the balancer.

Did the stick something in the hole when I put the distributor in 4 months ago. When I re timed it again this week, the markings on rotor/distributor/distribitor cap & shaft that I marked when I dropped it in..all still line up perfect, and the ballancer shows 10 BTC...so in a perfect world that would do it. Now I didn't re time it with a light this time..and that is where the new found lag is from I figure.

The general concensus ( other then something major could be wrong inside) is the stock disctributor gives way too much advance for the motor with my no EGR setup. This knock only seems to come on with advance...more advance= more knocking. I've never in my life had this much trouble.

From your oil pressure, I'd say your 351M is like my 351W, bad rod bearings. Changing the timing just moves, or changes the severity of the knock, but, it never completley goes away. In my engine it's a part throttle noise in the higher gears, but, it doesn't go away in 2nd gear at all... Mind you, my engine is seriously hurting now, I've been driving it like this for a good 5 months...
I've deleted the EGR on both my 300 and 460, and neither had any issues with spark knock with the stock distributor because of it. My 351, it's on there, but, I have no idea if it's functional, it's a $100 engine, and I've never dug that deep into it.

I agree with gettin rid of the fact0ry distributor. I had one that gave 60* of advance by 3000 rpm. Dump it(dist.), ignore the oil pressure issue, and run it.

When you looked at that main bearing, and said it spec'd out ok, did you measure the acutual clearance, or just look at the overall condition of the bearing? I have heard on the 351M/400's that they eat main bearings for breakfast, (be lucky for 100K on them) Ive heard stories of guys who changed em 3 times and are still using orig. rod bearings.
BTW, you should get 10MPG no matter what, so dump that dizzy. I run ported vacuum for my engines.

At last drive I had set it to 0 or TDC..with no advance hooked up..and it runs ok...I would 97% knock free..you can hear a tinge at 3000 RPM..but that's it. However..it has no low end, so so mid range( for obvious reasons)...pulls moderately from 2000-4000..stops pulling at 4500. If you keep into it or mash it at 4500..it either starts to bog right down and out to 3000 or just backfires and dies ( I am guessing the secondairies are opening, and with extra fuel and no advance it's just choking it). Still the 4MPG issue running this way, but at least it doesn't knock. Plugs still look like brand new..perfect tan..no deposits, no carbon, nothing odd. No vacuum leaks, no coolant issues ( no oil in coolant, no coolant in the oil, no fuel in the oil)

New friend came by to lend an hand/ear/2nd opinion. We went for a ride, stopped on a country road, and checked the vitals. Advance starts to come on at 2000, full by 3500-4000 I think it was, no change at 4500 for sure. It's pulling 24 degrees ( makes sense as it's a 12L) of strictly mechanical.

Hooked the pod up..it pulls almost 30 on it's own. That would make for way too much advance in the 50-56 degree range..so i'm not overly suprised about it knocking at 1700 rpm with the advance hooked up. To give you an idea of the 1700rpm Rattle..sounds exactly like a 7.3 L Powerstroke...to a T...

Anyways today was explosion day for the distributor. I had been finding metal ( alum flakes) in the dist housing...cleaned it the other day..back again today. But today was impending doom day, distributor let go...advance plate was free to move around, free from the pod, it ripped the wires out of the pickup. I had a few things on me so I patched it enough to idle her home ( I wasn't far)..but I guess I will be getting that new distributor I was going to get anyways. Don't think the knock will be solved by it..but It can't hurt. Besides if I scrap this and start a 460 build..I can use the new distributor anyways.

I had also found what I thought was alum flakes in the oil when I did an oil change a couple weeks ago...now I am finding more in the oil that was coaking around the base of the distributor where it seals in the block..it can only be the failing distributor..or some piston shavings..i'm hoping its all from the distributor...

I'll let you know what happens when I stick a new distributor in it...any suggestions of something good to buy???? Considering some of those Chevy cap in coil HEI distributors...anyone ever run one?

Marc

Well I got a distributor off a buddy, rebuilt it and ran her tonight. It was an 18L * (36 mech degrees) which was a little more then I had before, and I set it at 4 BTDC and ran her with no vac pod ( giving me what should be a perfect 40 degrees advance)... Performs much better ( idle to 5000RPM due to the extra advance)..but still knocks @ 2700+ RPM :(

Unfortunately in addition to that...I Also noted the knock seems to be getting worse( louder)

I think ( as I've known a while now) that I am F#$@$D. Been shopping around for a 429/460 I think this round. All of this has left a bad taste in my mouth and I have a bad feeling about 400's now. Oh I suppose I could take it out and drop it at an engine shop..ask them to figure it out and make it new again...I just don't want this to happen again ( lots of $$$ and way too much time involved. ) So much for my "new engine"

Faced with replacing and grinding internals, as well as a cam that I have no actual specs on and a single plane manifold I should toss...The 460 keeps looking better and better. ( as I will likely be spending a whack of cash replacing most everything again anyways).

Anyone suggest some good 460 build specs..??? Truck is a 3/4 ton 4x4...likely in the 6000 LBS range( I haven't weighed it).

I'd like to be able to tell you something simple that could be causing the problems with your 400, but, it really sounds to me like it's ready to kick the bucket.

I've got an 88 EFI 460 out of a F350 crew kicking around... Complete with computer and harness, flywheel, and P/S pump and all bracketry, basicly it's just missing the alternator and the clutch fan, mounts are on it, as are the mount towers for an 80-97 truck...
I've never seen it running and it's been sitting for a good while though(my buddy bought the truck out of the JY, and converted to diesel) 91,000 KM on it... PM me if you're interested, I like having a spare engine for my F250, but, I really probably don't need it...

the 4.0 in my ranger has the double-knock/rattle. it is coming from my lower end so I assume the rod bearings are going. the oil pressure is normal at idle, but this all occurred after i had a problem. just my f*ckin' luck, i bought a defective oil filter which eventually cracked. there's no way it was hit by anything. my engine ran low on oil, pressure dropped, and it began to knock on an incline. the truck is still running fine but I am getting ready to trade it in.