'88 GT Convertible - Croatia, Europe

I need help from someone with real experience.... I will repeat everything done from begining to give some clues.

With money unnecessarily spent in valvetrain (I could have done the bottom bearings for this money), I decided for four stages:
1) Spark plug change and test (done, retest unplugged one-by-one, no change in sound), ignition coil test (done, no change)​
2) Release engine mounts from chasis, lift the engine i air (lifted without unbolting mounts, no change, with unbolting mounts still to be done)​
3) Remove exhaust manifolds from engine and H-pipe, reseal​
4) Remove AOD from engine, run engine... if no change - leave it on the lift and drop the pan....​

Yesterday I stuck wet towels (in order to mute leak) around leaky passanger collector (the point on manifold where four pipes meet above h-pipe flange). No change in knock.
I could swear I can hear knock thru whole upper part of the engine and heads. On oil pan it is a bit muted.
A knock? Or proper word would be clack/tack? I heard numerous I4 engines rod and main knocks, and I would not say/wish/want - this is not it.
Real knock is speed-rattling, whatever You do it does not go away. If You blip the throttle You will move away from I4 knocking engine holding Your pants, for sure.... You don't dare even to wait for oil to be warm. BUT, I (and most of mechanics here) never heard US V8 engines with rod and main problem...
If I push 302 for 3-4k RPM and it settles and quites down, when warm it dissipates. This is the problem...


You can hear knock on idle, and up to ~1800RPM. Then it dissapears. You can hear it also if You blip throttle in lower RPM's, following/slowing down with RPM.
You can't hear knock in drive/acceleration/deacceleration, engine runs strong, no shaking, miss, stumble in any condition. Take the knock away and engine runs like a dream, a raped ape.

What made me looking for exhaust leak is harder acceleration by wall when I heard distinctive "puf puf" sound following the exhaust beat the other day. Otherwise you can't hear, feel, or see (smoke) leak. Also, a knock started at first on cold engine ONLY, until reaching normal coolant temperature
Now the million dollar question is, would such a tiny exaus leak produce knock resonating up to distributor bolt?

Before knock:
- cleaned lifters and restored everthing above them to mint, new condition - was running okay
- restored smog/airpump and system - was running okay
- changed AOD fluid (complete) - was running okay
- found coolant leak at timing cover
- found harmonic balancer rubber sticking - PANIC, I know what it can do, ordered new one!
- first balancer was okay but had vibrations ~1600rpm, drove ~50miles, no knock
- no driving, changed engine mounts, tranny mount, spark plug cables
- no driving, second balancer arrived wobbling and heard FIRST EVER KNOCK on cranking!
After knock ON WARMUP (goes away when coolant temperature nomalizes):
- third Pioneer PB1084N balancer arrived, knock present - HB still on car
- run without serpetine belt, knock there
- checked crank snout runout - within 0.004" when cranking the car (in reality is less due to vibrations, but this is only way how we could check)
- used liqui moly for lifters, no change
- changed timing chain set, water pump, fan clutch, complete front part renewal, M1 5w-30 and new filter - knock there
- new filter
- spark plug wire test, run without belt, knock there
- snake oils (stp oil additive, seafoam) - no change, actually after stp oil additive knock started to be hearable even after warmun
- verified oil pressure with mechanical gauge
After knock ON WARMUP & WARM IDLE:
- changed lifters, pushrods, pedestals, rockers and bolts, 5w-40 and FL1A filter - no change knock there
- here I am, still willing to fix this old guy, waiting for Your suggestions, hoping it is exhaust... found used OEM 302 shorty manifolds in Germany for ~75 usd... possibly a next missed investment, but better to have them at home when they are still available....

Thnx for Your help
 
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I was in respectable muffler shop today, they say it ain't from exhaust, see no black marks...
They said I saw bubbles from temperature. Agreed I will check with shop vacuum cleaner.

When they inspected I played around with stethoscope poking points.
Never crossed my mind before but following dizzy hold bolt, I put stethoscope rod on oil filter. There I can hear tap...tap tap....tap tap tap. Irregular sound between tick and knock. Rev it and it goes away.
I will try another dizzy, I have aftermarket spare :-(
 
Check the tube that runs across the back of the engine, some rust out at the joints or connections at the back of the head, The header to H pipe connection can be suspect too,
If You mean smog crossover tube that one was sandblasted, cleaned, painted, joints ground and polished and gasket between block and pipe in winter. Tigtened two times in between, but I can check or even pull it out again.

Thnx @General karthief, please see my post above oil filter for additional ideas... Rev it or drive it, no knock. Idle, stoplight it returns. Flip the throttle it will stop for few seconds.... Doesn't make sense
 
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I think I got the knock. It is the knock #$&@#**.
Last one I wanted, crank knock.
I tested new dizzy late yesterday, so before returning old one i tested spark plug cables 1 by one again. Led by some mechanical logic and forces, I disconnected #1 and #5 expecting a stall...
But I got stumbling quite and properly running V6 engine. Knock is gone. Return #1+#5 knock knock who is there... Return #5 knock is there...

Main bearing I suppose? Any other possibility to confirm? I may sound stupid but like flexplate/torque converter, too tight/loose balancer, whatever we may try to confirm 100%.
It is still not clear to me how does it go away on higher rpm or in drive.... Shouln't it shake the whole damn car like I4 engines??!!

If this is 100% main/thrust... Don't know how much damage I have done by driving and looking around engine, lifters, exhausts, testing snake oils, oils and filters...1000miles + idling... :-(
 
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Do you have or can you order one of these:

Amazon product ASIN B0049OCMNQView: https://smile.amazon.com/OEMTOOLS-27061-Ford-Inch-Primer/dp/B0049OCMNQ/ref=sr_1_2?crid=2IKPLCV9TSDEI&dchild=1&keywords=ford+oil+pump+priming+tool&qid=1629492925&sprefix=ford+oil+pump%2Caps%2C188&sr=8-2


My only other suspect might be that perhaps your oil pump has something in it. Have you put your peepers onto the pickup and mains since you've had it?
Yap, I manufactured my own priming tool 20" long so You don't have to lean into engine bay while priming :)

No @Noobz347, but bottom end was about to be checked this winter with front suspension and k-member restoration.
Top and front engine part is what I restored/renewed this winter/spring. Everything above cam and in front of crank/cam is like new or new.
I have sitting in my garage beside car and other parts a new oil pan, pickup tube, melling oil pump, one piece felpro permadry pan gasket, front/rear main.... You see, I had good and pretty noble intentions but she just could not wait.... :-(

Now mechanic told me to make last crank and test idle with 2&6, 3&7 and 4&8 removed also. Apparently 1&4 is first and too wide to pinpoint. He (and me also) still doubts a bit due to knock being in rhythm with ignition, or too slow for crank.

But things come as flashback as I was covering my eyes and ears like a kid: strange metal chirping when warm since I bought it, harmonic balancer rubber slipping out, Rockauto faulty unbalanced HB. I should have pulled the pan then.
Now I just may hope there is no damage apart bearings. It was still runnin strong, drained oil is normal... I'm about to open old filter

Beside proper pulling the engine or k-member, is there any other hint or way to remove pan and peek into her bottoms? Like 4x4" between engine mounts and k-member?
 
We were all hoping for the best and wishing you luck with the knock. Hell that was just the first motor you had in your Mustang anyway. You might need 3 or 4 motors after you get the nitrous. I have had 4 motors in my 69 over the years including a 460 with a C6 for a few weeks. Currently running a Gapp and Roush prepped bogus boss motor. Too bad you are so far away in Croatia those roller 302's are dime a dozen around here. You could always do a crank and one rod and full float the pins so you can assemble it yourself. Mine has bronze valve guides and full floating pins. Build it once right. Now is the time to stroke yours and try to find forged pistons.
 
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My priceless 302 Chevrolet (a DZ motor) did the same thing (spun a rod bearing) and I was heartbroken. I found a remedy in Crankshaft Specialties in Memphis TN. They hard chromed my crankshaft and reground it to standard bearing size for me. Cost me about 800 bucks in the late 80's My connecting rod was still ok and I raced my 69 Z-28 around for years after that. Good luck
 
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Got a couple of videos for You guys, You know that engine as I know Yugo :)

Last run today I think, as I bet I heard some chirping today (or spark grounding)...eitherway sound was nasty when I tested #7 and #3 off.

First one is pushing my phone in tight spaces around engine, maybe You hear something I don't:

View: https://youtu.be/aHRslQm729Q

I don't have to explain engine bay here :)

Other one is spark plug wire test, I was fast as I could to avoid temperature differences:

View: https://youtu.be/fQ7t-btk1co

#1+#5 nice running engine
#3+#7 nasty sick sound
#5 don't be misled, I may have covered phone microphone

Let me know if You hear something I don't.... I would say one of front crank bearings is shot.
 
Too bad you are so far away in Croatia those roller 302's are dime a dozen around here.
Trying to keep it as stock as possible pal.
I was thinking about it.. seriously... to find an good spare AOD and HO engine and ship it in container with muscle car like cheap 'blown' donor engine reported to customs.
I know a guy who chases oldies (60,70's) in US and ships them here, 10 miles from me...
Anyways we have guys here patching blown engine blocks, so nothing is impossible to fix. Only question is V8 inexperience, time and money

First step is to confirm knock source, assess the damage... I won't abandon this car, it is in my heart now, all the TLC done. As wife, You know. I hate him cause of knock he gave me, but I love him :)
 
Hi guys!

In last 10 days I was busy reinforcing concrete floor in garage with another reinforced 3-4" layer to accomodate fox on jack stands for "operation oil pan". To keep the story short, that is it :)

What should have asked You in between is a sludge in oil filter we found. We opened filter used before new lifters and it was pretty full of sludge. Here and then You can find metal particles, but mostly sludge.

A little bit of reminder:
In december last year, we found a good sludge buildup under lower intake (fixing a intake leak and clogged pcv) and valve covers. Cleaned all I could to "as new" look. I knew there is some at the bottom but I had no space in that garage to drop the pan... stupid hope and some 1000 miles later with four religious oil/filters changes in between I have a knock at oil filter.
What confused and digressed me is that knock started after harmonic balancer change...
Yes, I have used Seafoam but in desparation AFTER knock started. Oil pressure was even then fine (manual gauge), knock only at idle. Therefore, we changed tired valvetrain parts from lifters to rockers doubting they knock, but no go. Only several miles after new lifters, oil and filter knock is even more audiable (last run when recording above videos).


According to Your experience with 302 and knock from video (still was knocking at idle only):
- how do You, and can You tell that oil filter/pickup is clogged and You are in oil filter bypass mode?
- may I get lucky and have an knock due to oil pickup/oil pump blockage or oil starvation?
- or have I actually severely damaged bearings or just killed the engine?
Eitherway, oil pan dropping is unavitable project. For everything we find, may the force be with us....

Thx and wish me luck :-(
 
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Metal particles means something is bad. When you pull the pan you can pull the bearing caps and check the bearings. Make sure not to mix them up. I did a new crank and bearings in a mustang without taking the engine out by dropping the k member and pan. It isn't an easy job and you will need a micrometer to measure the crank and a bore guage to check the connecting rod and bearing caps.

We didn't do that and polished the crank with a leather belt strap. Used standard bearings. Engine ran great when it left but don't know how long it survived. The crank just had one scratch at one of the main journals. No idea how much wear on crank though.

Now that I'm older and more experienced, when I see metal or bad bearings it's time for rebuild. Fine metal can get anywhere in the engine and mess things up.
 
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Now I have more importaint stuff on my mind with this car.... but could You guys check this picture and tell me what may be the reason behind rocked arm......dont get me wrong for wrong expression but like "chamfering" pushrod... you'll see on picture what I mean...

Rockers were tight. What is the story behind this kind of damage in 302?
Was this a bad lifter and I didn't swap them pointless eitherway? Or is the problem in bridge
between two rockers? Or more deeper... ?
This is fourth position passanger side counting from front of engine, which should be cylinder #2, exhaust valve.
 

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That is lack of oil damage. Most likely the lifter is not letting oil thru to the pushrod, Install a direct pressure gauge to check the oil pressure. Replace the pushrod and the rocker arm. Pull the intake check the camshaft lobes for wear and that lifter in particular. The early roller blocks used to let a lifter go sideways once in a while

Check the oil pressure with a direct pressure gauge. Use the tap near the oil filter. There is no test for the oil filter bypassing. You can cut the filter apart and check for sludge. The oil pump pickup tube is what will be plugged if the silicone oil pan gasket deteriorates. The silicone chunks will make it to the filter and be trapped. Real common on 2.3 Mustang and Rangers. Car will have little to no oil pressure and will be okay after replacing the pickup tube. If you can't find a new pickup tube in Croatia, then clean it out. Just cut the screen off clean the tube in solvent and re weld the screen.
 
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All the 302 roller engines can have a lifter break a dog bone and ride the camshaft sideways. I've seen it a few times. Happened to me on my 347. Didn't really over rev it either. Wiped the camshaft and destroyed the lifter. My push rods and rockers were all OK. Happened on just one lifter.

It was years ago and the machine shop blamed it on Royal Purple synthetic oil. Synthetics got blamed for everything back then.
 
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That is lack of oil damage. Most likely the lifter is not letting oil thru to the pushrod, Install a direct pressure gauge to check the oil pressure. Replace the pushrod and the rocker arm. Pull the intake check the camshaft lobes for wear and that lifter in particular. The early roller blocks used to let a lifter go sideways once in a while
Thnx. Lack of oil is what I am scared of since the knock started. I was waaaaay more careful IMO than anyone here not to drop anything when lower intake was off, so my guess is there was/is a mess of a sludge like it was under upper intake.
I may have disturber things further when I lifter engine by back of the oil pan to change engine mounts... only question is why is the oil pressure still okay?!
Dropping the oil pan to be done.

Anyways, apart from manual - on stock gauge on cold start I have one line above middle of gauge. On warm idle it drops to first white line above red. It goes up with revolutions. I know it should be a simple on/off switch, but eitherway it moves and showes pressure change. Just not as fast and precise as manual gauge.
Few times I saw needle when letting the throttle off to brake with engine that it sink, but I never saw it below first white line since I got the car.

Regarding pushrod and rocker, they are the original ones I have on shelf. There are new ones in, accompanied with a new lifters and rocker bolts.
Question was only in a sense to avoid such a damage of new parts...
When checking valvetrain before lifter change (two weeks ago) with running engine and valve covers off, I saw some 20-30 seconds of dry run then oil started to seep thru pushrods....

Check the oil pressure with a direct pressure gauge. Use the tap near the oil filter. There is no test for the oil filter bypassing. You can cut the filter apart and check for sludge. The oil pump pickup tube is what will be plugged if the silicone oil pan gasket deteriorates. The silicone chunks will make it to the filter and be trapped. Real common on 2.3 Mustang and Rangers. Car will have little to no oil pressure and will be okay after replacing the pickup tube. If you can't find a new pickup tube in Croatia, then clean it out. Just cut the screen off clean the tube in solvent and re weld the screen.
Last time we checked pressure on oil tap by filter it was okay and within spec. That wories me... if it would drop things would be clear....
Filter was cut and there was pretty good amount of sludge.
It was planned for this winter even if the car would run perfect: I have waiting in my garage on stock from rockauto: melling oil pump, oil pump shaft, new oil pan, new oil pickup tube, felpro blue pan gasket, new oil pan bolts...

All the 302 roller engines can have a lifter break a dog bone and ride the camshaft sideways. I've seen it a few times. Happened to me on my 347. Didn't really over rev it either. Wiped the camshaft and destroyed the lifter. My push rods and rockers were all OK. Happened on just one lifter.

It was years ago and the machine shop blamed it on Royal Purple synthetic oil. Synthetics got blamed for everything back then.
Thnx but - no. Two weeks ago I had lower intake off for second time this year to throw in FRPP lifters. Cam lobes were shiny and okay, actually everything what we checked did look okay.
Found just one pushrod and rocker with some wear (cyl2, exhaust, pictures above), and was lucky as dog I found issue and knock source, but it was not.

It may be in my head now, but I may had a feeling that oil needs a lot of time to get to lifters upon first start after new lifters (of course I primed engine also, and additionally cranked engine for 2 minutes before real start just to be sure).
 
Yesterday also I found lower airpump bolt a bit loose and washer dancing freely (airpump to timing pointer bracket). But I wouldn't say it could produce knock, as knock is too much in sync with timing strobe light.
Would it? I am avoiding running engine to verify before I do the oil pan inspection.


Soooo, I am about to drop the pan, but just thinking out loud about possible oil starvation:
- oil needs 20-30 seconds to reach pushrods
- knock by oil filter
- knock on idle, NO knock after 2000rpm
- oil pressure okay (manual&dash gauge)
- everything else we check seems okay...

Now, You know that 5.0 engines - may I have someking of problem with oil pump?


Not pressure related but volume of oil pumped?
Why does engine stop to knock when I increase revolutions (and build oil pressure)?

Anyways, due to Your experience wouldn't a faulty oil pump or restricted pickup clearly show itself on oil pressure gauge check?
 
If there is a restriction in the oil feed line after the oil pressure sensor you'll show higher pressure than can be reaching internal parts. Generally, a clogged oil screen will cause oil pressure to drop as rpm increases.
 
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