Knocking + major loss in power, help diagnosing

[psylens]

Hello all,
I am rather new to these forums. I just bought a '79 last week and it's been running great until this morning. I was going fast up a steep hill (which i've been doing regularly - it's fun) and there was this clicky-clacky sound which i've heard before (mostly under load) and always thought was the valves (maybe needing a little adjustment) - then the noise got a bit louder and i started losing power dramatically.

I slowed down and put in the clutch and the engine immediately died. I was at the crest of the hill, so i could coast back down the other side. I coasted for a minute or so, then let the clutch back out and the engine runs again, except it has no power and a pretty loud knocking sound under any kind of load. It idles fine, but obviously something is very wrong. It sounds to me like just one cylinder is having the problem: maybe a busted valve?

I never saw any smoke, and i checked the oil and it doesn't look low or burnt. I pulled it into the nearest shop, and It is sitting there for now; and they're going to run a compression test on it tomorrow (or today if i'm lucky and they can get around to it).

Any thoughts? I'm hoping someone knows exactly what it is from the description, and that the solution is going to something affordable

Thanks,
.jt

[manoa matt]

The compression test should help narrow it down, but my guess is a blown head gasket between cylinders #3 and #4.

[psylens]

I've spoken with 3 people experienced with Fiats for 30-40 years and all 3 suspected the oil pan got dented and busted the oil pump dongle-thingy (not exact terminology used). I am having it towed to one of the fiat mech's to see what's up. According to him he'll most likely need to remove the oil pan and at least replace a bearing, maybe more. Sounds like a minimum of about $500 if all that is true. I took some pic's and vid w/ my phone, i'll see if i can get it into this post to get a second opinion. I'm not sure exactly what it should look like... but it doesn't exactly look perfect

http://www.youtube.com/watch?v=N4sJ5a_sfx0

[ClarkTheShark]

well ive been through the whole replace a bearing deal. might as well tear the egnine down and rebuild it all. if youve spun a bearing, there is 99.99999% chance your rod journal is destroyed and needs machine work. also, if your drove it for an extended aount of time, the crankshaft could have warped due to heat.

[TulsaSpider]

The oil pan doesn't look bad. Unfortunately at this point it's just guessing, but something is severely amiss. perhaps you could find a good used engine?

[psylens]

Well, the local fiat mechanic (has a shop with LOTS of fiats) has had a listen and taken a look. Without removing the oil pan he has determined that the oil pan was indeed hit hard at some point before i bought it, and the oil pump inlet tube thing has been busted and at least one rod bearing is bad. It'll cost me 3-400 to find out more - for him to remove the oil pan and have a look-see.

He says that it'll be a minimum of $800 to fix if i'm lucky, and upwards of $3k (full engine rebuild or replacement) if i'm not lucky.

I'm on the fence about paying him the 350-ish to take out the oil pan and figure it out, or just have it towed and turn it into my next full-on project, and do it all myself. I'm not that familiar with fiat mechanics, but I believe i can tackle it. Altho i don't have the big tools, like a cherry-picker or engine stand.

I'm open to suggestions

[bwilson27]

Make Harbor Freight your best friend and dive in.

[Zippy]

Did the mechanic do a compression test? It sure sounds like a blown head gasket to me. Your symptoms are exactly the same as when my head gasket went. After I confirmed it was the head gasket I did the repair myself with the help of several members consulting here and of a machine shop to mill the head. It wasn't too bad. I took lots of pictures as I disassembled things and labeled both side of every wire and hose connection to make sure I got it back together right.

[majicwrench]

He must be a heck of a mechanic to determine all that without removing pan. I would encourage you to find a mechanic who runs tests to determine what is wrong. Yes, it could be a bearing. Yes it could get expensive. If bearing IS bad, absolutely have to have new/reground crank and resized rod, basicly rebuild engine.
Head gasket issue can make knocking noise under some circumstances, compression test would be quick and easy. Even easier, disable ignition system and crank engine. Good engine with good compression will sound like this:
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
Engine with bad compression will sound like this:
RRRURRRURRRURRRURRRURRRU........
The above really works, you can easily hear the difference. Although, maybe it works for me cause I have been listening to engines for 30 some years.
Pan looks OK to me.

[baltobernie]

Hello JT, and welcome. Sorry that your Fiat experience has been short-lived. It's entirely possible that the PO correctly identified the noises you are now hearing and dumped the car. I agree with others that suggest a compression test to pin the cause on the Top End or the Bottom End. If ifs the head or gasket, that is something you can repair yourself. Bearings and the like mean pulling the engine and a teardown. This is not a trivial matter; hundreds of dollars in machine shop labor alone. Parts are at least several hundred more.

Have you done a knowledgeable, thorough and impartial evaluation of the car? Fatal rust location check? Electrical system? "Glitter" in the transmission oil? Cooling system effectiveness and leak check? In other words, are engine repairs the first item on a very long list? Is your car destined for a complete restoration, or is it going to be a Driver?

You may know that the '79 was a "transition" year for the Spider between carb and FI. That is significant with respect to repairs and repairability, so let us know which you've got. Please report back with the compression test results.

[narfire]

Where are you located?
If the engine needs a major re-build,perhaps someone has a spare engine that might work (me) Or a rusted out hulk that has decent mechanicals.Take a cruise through craigs list or the forum for cars being parted out. Yes you could be buying someone elses problem but just a thought.
The replacing of the components of the engine is doable with tools and a manual,but any machining can get expensive.

[psylens]

He must be a heck of a mechanic to determine all that without removing pan.

Well, he has been working on Fiats since around 1973. That, plus the fact that he's still in business, and comes with recommendations... i can't say whether he's a "heck of a mechanic" - but i do have some confidence, of course with some measure of caution and speculation.

I would encourage you to find a mechanic who runs tests to determine what is wrong.

I meant to indicate that he did run some tests to determine the issue. Here's what i know he's done so far:
1. He's run and listened to the engine enough to "know the sound" after 37-ish years of listening to busted fiats.
2. He's drained the oil and inspected inside the pan with a screwdriver thru the drain hole (i've heard of this technique elsewhere, too) and said with this method he could tell the oil pump pickup tube is busted.
3. He's over-filled the engine with oil on purpose - i believe this indicated two things: A. the oil light no longer comes on, and B. The knocking goes away (or got quieter, something like that).

He didn't run compression checks, but it does run smooooothly at idle (i.e. RRRRRRRRRRRRRRRRRRRRRR). I called him this morning to ask for a compression check. We had a discussion about giving the car a "shakedown" (includes compression check) to determine if the car overall is worth moving forward with, and what is the best approach.

Thanks for your input; i do appreciate it. I also have some confidence that this guy knows what's going on. I think my description over this medium lacks the efficiency of detail that one can accomplish in a phone or in-person discussion. I'll post back here after the shakedown. I hope this thing is worth keeping and i can do most of the work myself to keep it cost-effective. I'd like to post to this forum frequently to continue to add to the body of information.

[psylens]

The replacing of the components of the engine is doable with tools and a manual,but any machining can get expensive.

This may come off as a bit naive, but if the crank needs machining, I'd actually be interested in attempting to tackle that myself. I recently found out we have this great communal workshop in Denver (http://www.clubworkshop.com) that has just about everything you need to make/fix/rework just about anything. They have a laser cutter, two CNC machines, lathes, car lift, welders, etc... even a 3D printer! I have operated a mill before, so i wonder just how difficult it is to re-work a crankshaft... Sounds like an adventure - anybody here done that kinda machine work?

[manoa matt]

Machining a crank should only be trusted to someone who does machine work and has a history of that type of work. The cheap and quick option would be to find a parts car or spare motor for a few hundred and just switch them out. Using simple tools and little knowhow almost anyone could do the switch in a weekend.

[majicwrench]

Thank you for the clarifacation on your mechanic. From the earlier post it sounded like he just listened to the engine and "determined" just what was wrong.
Keep us posted
Keith