Technical 352 FE Timing Jumps Around & knocking

I just rebuilt my 352FE, mild comp cam, stock heads, Edelbrock performer air and fuel, msd 6AL ignition & Distriibutor, but basically stock.
Sold the truck, Got it back 8 months latter. Runs bad…..
“ thanks man, it had maybe 500 miles….”

Checked timing ground up, started fresh, remarked balancer, re-installed distributor, removed valve covers. Fired up, and wasn’t getting oil to the valves? Had a steady knock from #8 (stethoscoped it), spark plugs tells a story of flooding (black soot), compression check says 60-75psi on all pistons!?!? (Test done warm, wide open, no spark plugs) . Ignition passed all electric tests (box to plugs on meter). Next I camera scoped the pistons and they look like there running rich and dry on oil. My oil pressure is on gauge and checks out. Motor doesn’t run hot….. any help would be great.I’m at a loss with out pulling a 500 mile motor and gutting it. Everyone I talked to is baffled. Could it be a clog? I know the oils sensor is before the filter. Maybe a slipped bearing also? But that wouldn’t explain the other issues…. The main oiling comes from the middle bearing as I understand, those cylinders are not knocking. It seams to be just #8. It has a Rough idle and “knocks like a drunk girl at 2am on a Saturday night…..”
Thanks for any advice, I really am not in a location I cam pull the motor…..

 

I had a 390 years ago that was over hauled at a college shop class. Got a knock at high speed and high RPM, not good when we took it apart, the rear plug behind the cam shaft was not in correctly. Was losing oil pressure out this plug and had to put new bearings in.

 

it’s not burning any oil…. No smoke eaither

 

I didn't see any either.

 

Just an observation of my past history not that yours is the same, but a place too look if the engine comes out again.

 

Make sure the correct bolt is in the rocker arm assembly. It allows oil to the rocker shafts.

 

I don't see it even running with the compression numbers you listed, how about a video of it ?

 

my guess would be detonation and he killed the rings/piston in #8, those distributors had a lot of total advance.

 

If it's knocking, I don't see how to avoid pulling it and going thru it. Hopefully the crank will clean up.

 

First off, verify your compression tester by using it to test some other engine, if the compression tester test OK, stick a fork in your engine because it's done.

If you can't pull the engine at this time at least pull the pan, check all the rod and main bearings, take a look at the piston skirts, look for chunks of metal in the pan then let us know what your find.

The picture you posted shows piston scuff marks on the cylinder walls, most likely from the carb dumping fuel into the cylinders. If all the cylinders have these scuff marks, it would explain the low compression, it also means your engine is done.

Nothing about the information you have given us points to an easy, quick or cheap fix.

 

^^^ Well aren't you a ray of sunshine! I mean I agree, but..

Those compression numbers can't be accurate though can they? Piston ring washed out excess fuel maybe? Thought an engine needed minimum around 80 psi compression to even run...

 

If you can drop the pan and check the # 8 rod bearing without too much trouble I'd start there. Then your decision will be made as to what direction you need to go.

You could also pull the the #8 plug wire with the engine running and see if the knocking quits.

 

Carbon On #8 piston????? I sure would check post #7 Each bank oils from a different cam bearing

 

It ran perfect before I sold it, and was running after I got the 60-75psi readings. I grabbed a friends tester and got the same psi readings. It was running. it can’t be the rocker studs as the motor was perfect after rebuild, but I will double check today. I put oil in the cylinders last night and hand cranked a couple times to mix around. I’ll camera scope it and post more pics.
Thanks for all the input, everyone had good ideas.

 

Possibly worn valve guides due to no upper oiling?

 

Truck 64; a friend from church asked me to look at his OT Jeep Wagoneer, the thing was so worn out it only had 30-40 psi in each hole. If you squirted some oil in each cylinder then slapped the spark plugs back in it would fire and run. (And yes, he actually planned to drive it that way)

If I sometimes (perhaps too often) seem to be a "ray of sunshine", it's because so many people who visit this site want to hear what they want to hear, not what they need to hear.

 

Thanks man, i curently have the rings soaking, Gona test it tonight. I’m thinking it’s all from bad oiling. Keep you all posted

 

Tell it like it is , if they don't want to hear facts , they shouldn't have asked !

 

here we go kids!!
Soaked and soft spun motor with oil in pistons over two days, pulled distributor and put it back to out of box specs (springs and limiters). Removed oil and still getting around 60psi on pressure test. Did a full re-wire and contact cleaning to confirm that wasn’t an issue. Cleaned and gapped my cold plugs to 0.35. Replaced my coil and checked it with a multi-meter.
Put my edelbrock carb to first fire settings. Confirmed TDC with a cylinder tool to check balancer marks. Built a oil primer tool using two screw gun long tips (the ones that have a sleeve to keep screws on the tip and a 1/4” Allen tip) reversed the pump to remove clogs. Drained all oil, checked for metal and it was clean. Refilled all oils, Put everything back to TDC, add 10°. Primed the bowls, connected my MSD box and…..
Bang! It fired…
Rough idle, knocking still…
Timing light shows it moving so dramatic I can barely tell where it’s at. There are moments the light and timing mark are on point or showing close to….

I have checked everything…. Is there a chance there timing chain or msd box could be the problem?
The fact it knocks even at idle (sounds like the #8 area)
Is baffling. Oiling has been ruled out. I Primed motor with covers off…..
Here are some pics from idle, fyi it is also firing (timing light) with no timing marks in sight.
White mark is TDC 0° and The pinkish mark is 9°.
I have video in slo-mo with timing light.
Email me joshlinkey@mac.com and I’ll send it.

I’m out of ideas……

 

I don’t think this is your problem, but it was a FE motor. Had a “rock knock “ so I replaced the short block and still had the rock knock. figured it out, the fuel pump arm spring failed and the arm was banging on the eccentric on the cam. Maybe more than one problem?

 

When it's idling remove the rear plug wires one at a time and see if the knocking quiets down. If it's a rod bearing it should go away. If it doesn't you may have some other issue.

 

If only I was that lucky, using some extra heater hose as a stethoscope it definitely is coming from the drivers 7-8 cylinder realm…. Also fuel pressure is around 5… in specs

 

Bite the bullet; tear it down, you'll find what failed. Then figure out why it failed and you can fix it with confidence.

 

What time should I tow it over? J/k
Unfortunately I’m not able to pull the motor at my house. I have a car lift, machine shop, and plenty of space. It was the selling point when I moved to this house…. My land lord is trying to get me out to raise the rent… aka My glory days of working on the truck standing up are gone . I been working on it at night to stay low key….
Question… timing chain slop at idle wouldn’t make it bounce?? It’s quiet up front…
I just pulled the distributor and I’m Gona lock out the mechanical timing just to remove another variable….
I did notice cap points are a bit cooked…

 

If the truck has an automatic transmission, check the flexplate for cracks, also make sure the torque converter bolts and flexplate bolts are tight. If it has a manual transmission, I'd make sure the flywheel bolts and pressure-plate are tight.

With your ignition timing all over the place I'd check the mechanical advance, check the distributor for worn distributor bushings, wrong or worn distributor gear, or defective timing chain. To test this pull the distributor cap, then using a brakeover bar on the crank bolt move the crank clockwise/counter clockwise until the distributor rotor just begins to move. If you find lots of slop the engine has a serious problem.

Did you re-do your compression test?, if so, what was the compression in each hole?

In your post you mentioned you "removed oil and still getting around 60psi on pressure test", can you explain exactly how that was done?

Something that has bothered me from the beginning of this post is you mentioned that the engine has been rebuilt, exactly what parts did you replace? Did you have new cam bearings installed?, was the block "hot-tanked"?, crank ground or polished?

 

If the truck has an automatic transmission, check the flexplate for cracks, also make sure the torque converter bolts and flexplate bolts are tight. If it has a manual transmission, I'd make sure the flywheel bolts and pressure-plate are tight.

With your ignition timing all over the place I'd check the mechanical advance, check the distributor for worn distributor bushings, wrong or worn distributor gear, or defective timing chain. To test this pull the distributor cap, then using a brakeover bar on the crank bolt move the crank clockwise/counter clockwise until the distributor rotor just begins to move. If you find lots of slop the engine has a serious problem.

Did you re-do your compression test?, if so, what was the compression in each hole?

In your post you mentioned you "removed oil and still getting around 60psi on pressure test", can you explain exactly how that was done?

Something that has bothered me from the beginning of this post is you mentioned that the engine has been rebuilt, exactly what parts did you replace? Did you have new cam bearings installed?, was the block "hot-tanked"?, crank ground or polished?

 

Sorry I’ll detail…
I got the truck in poor mechanical shape.
Sucked it up and a short blocked it at a local machine shop. Re-assembled and drove like a dream for a year. Not daily driver but put about 400miles.
Sold to a friend, Covid found hit and he couldn’t afford the truck anymore. I don’t know what happened over the 1 year it was out of my hands. It ran like this when I got it back. I’m trying to get this 500 mile ( he put 96 miles on the od ) rebuilt motor healthy. The knock is 100% motor not fly-wheel, still got the 3 on tree I rebuilt. I’m sorry to keep posting but every other gear head I know is scratching there head also. I’m reaching out for some hope this has happened before. I really appreciate all ideas
Also pressure test was 60-75 psi before and after oiling, warm carb open all that. I also tested with my neighbors meter…. I was shocked, didn’t think it could fire with that low pressure

 

Firing order correct ? Distributor 180 out ?
Check the distributor closely . Had a broken shaft on a 390 one time , engine would idle fine , but wouldn't rev took a long time to figuire it out .only discovered it as I pulled the distributor and happened to notice the rotor didnt turn immediately as you reversed the shaft .

 

It’s been 50 years since I had a 352, and almost that long since I’ve had any FE. But I’m trying to think how you’d screw up a good engine in 96 miles. IIRC, the 352 floated the valves a a pretty low rpm. 3 speed, new driver……? Have you thought of turning it to TDC and running a leak down test? Or just air in #1 and looking for air at the intake or out the exhaust? With the cranking compression not changing with/without oil the rings are good. Maybe even jumped a tooth on the timing chain (can’t remember if those had chains or gears). None of this explains the timing light jumping, but since all you need is to pull a valve cover and compressed air, maybe worth a shot?