Help, Engine Ticking sound

jrflyboyVP2 · #1 (**permalink**) 02-13-2008, 07:27 AM

My 4 year engine rebuild saga continues! After installing a new liner set, and finally fixing my nagging oil leak at the distributor, I am left with a bad ticking sound at idle and can be heard while driving at certain RPMs.

So here's the story on this latest rebuild. After getting everything set right, I cranked the engine for about 30 sec with the coil disconnected to circulate oil. Then I fired up the engine, and it started right away and idled fine. I was aware of the caviat not to let it idle too long or the rings won't seat, so after about 1 min, I shut it down, checked for leaks, and then closed the hood and fired it up and went driving to break in the rings. I did the accel and decel at 3500rpm 3rd gear and all went well. After driving about 10 miles, I was going about 40-45mph in 4th when all hell broke loose and the engine made terrible noises. I pulled over and listened to it idle and reved it again and heard horrible noises like something was comming apart inside the engine. I thought about it a bit and figured the timing chain came untensioned, so I loosened the tensioner bolt and sure enough I heard the tensioner spring back. I then pulled the valve cover and retensioned the chain further by levering it with a large screwdriver. I drove home about 5 miles and the engine ran ok, except a ticking sound like loose valve clearances. It sounds like an intake valve. My question is could I have bent a valve by hitting the piston (10-1 pistons), or tapping the exhaust valve due to running with the tensioner loose? Has anyone had the tensioner come loose under power before? I plan to open it up and check the valve clearances tonight. I checked them before installing the engine in the car, and they were close to spec. The other idea I have is to do a compression test, a slightly bent valve will leak bad. I'm not sure what else can make this ticking noise. Rod bearing? But the engine was tight (5k since overhaul) before I tore it down for the liner set. Any ideas?

John

**Tifosi** · #2 (**permalink**) 02-13-2008, 07:39 AM

Just for giggles, have you checked the exhaust manifold to head copper gaskets to see if they are intact and tight?

If they leak even a little, you get a some pretty gnarly ticking type sounds as the exhaust note pulses past said leak.

Alfacliff · #3 (**permalink**) 02-13-2008, 07:47 AM

yes, a bent valve will show up on a compression test. the chain would have to be really loose, or you would have to turn the engine backwards to jump a tooth on the chain. while the cam cover is off, why not check the clearances?
cliff

jrflyboyVP2 · #4 (**permalink**) 02-13-2008, 08:01 AM

Definately not exhaust leak, it is definately metal to metal tapping. Engine never turned backwards, and the timing marks are good, so it didn't jump a tooth. I will check clearances tonight, but the tapping noise sounds like a lot more than just out of spec clearance. I can hear the valve clatter which sounds normal, but this tapping is at about the frequency of the RPM, or half RPM I think.

Thanks

geh458 · #5 (**permalink**) 02-13-2008, 09:37 AM

A poorly lubricated tachometer cable makes a ticking sound that can be heard above the engine noise at idle and cruising speed, not so much during acceleration though. The Super I just bought had that issue.

jrflyboyVP2 · #6 (**permalink**) 02-13-2008, 08:20 PM

Well now I am really confused. First I checked the valve clearances and they were all good, than I did a compression check and it came out ok per numbers below, and the cams were timed as I left them (increased overlap by approx 4deg per Bradens book)

Cyl Intake exhaust compression
1 .014 .018 155
2 .015 .018 100
3 .014 .018 140
4 .015 .018 155

So other than the 100 on cylinder 2 all is good. I didn't try squirting oil into number 2 to see if it came up, but a reading of 100 doesn't indicate any serious problem which could cause the rapping sound. The sound is pretty loud if I put my ear by the valve cover, so I really thought it was a valve. Still I could have a weak valve spring causing a slow return, but before I pulled the engine to do the liner set, I routinely took the engine to red line and it ran great with no bad noises, so I doubt I have a broken or weak valve spring. Now I am worried that I have a bad rod bearing but I don't know how that could have happened. I haven't had the engine over 4k rpm yet. I am not sure what to do next. Any ideas???

red_81 · #7 (**permalink**) 02-18-2008, 01:31 PM

Hi!

I have the exact scenario and I found problem. Cause i am sort of mechanic it is not so bad to find when u have experiance.
I have damaged bearing on 3rd piston (flyable bearing on the crank, not the stationary one). As bearing gets damaged it forms an air gap between crank and piston rod (100% cause lack of oil in some part of her life), so every time when gasoline/gas detonate it makes metal-click sound. Sound is rev depening and with time it gets worse and worse. You could easily investigate.
1. remove sparkplugs
2. find something suitable (diametar) what could push trough sparkplug opening, of course - long enough
3. put your "rod" mentioned above into the sparkplug hole, and rotate crank MANUALY clockwise
- when rod start to go down - stop the rotation
- gently hold the rod and hit it from above (if you hear a CLICK or something similar you are in trouble as same as I am)
- repeat for every cilinder so you could make assesment of damage

Hope I could help you

ps; I am startin to dissasemble my 1.8ts tomorow

jrflyboyVP2 · #8 (**permalink**) 02-19-2008, 05:34 AM

Thanks for the help. I suspect it may be a rod bearing, but I am not sure how it went bad. I am familiar with the Rod Bearing problem as I ran my Corvette a little low on oil way back in 1978 and was pushing it hard on a twisty mountain road and saw the oil pressure peg to zero. After that I had that rod bearing rapping sound which continued to get worse as I drove the car daily. I eventually pulled the pan and replace the rod bearings in about 2 hours and that fixed it. Unfortuantely if that is the case with the Alfa I will have to pull the engine again. Since replacing the rod bearings with the engine in the car is not really an option.

John

red_81 · #9 (**permalink**) 02-19-2008, 05:56 AM

Well, i dont know what type of engine do you have but usualy they are replacabe without engine removal (flyable ones, and only them) with assumption that crank is not damaged. If u can remove oil pan and see crank, u can easily replace bearings (and only them). I did it without engine removal on 33 1.5 8V qv and on my current 156 1.8ts, on wich it dident help cause crank is obviosly damaged a bit too...so the metal-clicks came back trough 2000miles!!

If the crank is damaged, than;1) maybe engine stays in but gearbox has to be ramoved so u can take crank out and get it polished it, 2) all out - you know the drill...

ps:
I am trying to extract crank without engine removal on 156 but im stuck on right half shaft. left one is connected with 8 bolts but right one is not. trying to figure it out cause i dont like removing bunch of plastic & electronic around top part. (33 was pure LOVE to work with...plenty of room)

..and my appologies for bad english..im a bit rusty

**GTV4EVR** · #10 (**permalink**) 02-19-2008, 09:59 AM

It's not the easiest thing in the world to do, but I've replaced my pistons and liners as well as the rod bearings with the engine in my GTV. (underground parking garage, no access to a hoist).

Alfacliff · #11 (**permalink**) 02-19-2008, 10:01 AM

another way to checkthe rod bearings is to pull one plug lead at a time with the engine running, when the noise goes away, that is the bad cylinder.
cliff

jrflyboyVP2 · #12 (**permalink**) 02-19-2008, 02:18 PM

Thanks for the tip Cliff. Thats what I did on my Vette back in 78 but I forgot about that. I will try that tonight when I get home from work. I am not sure the engine will continue to idle with only 3 cylinders sparking, but I'll give it a try.

John

slyalfa · #13 (**permalink**) 02-19-2008, 05:10 PM

I had the Accel coil fail on me that stoped 2 cyls (I run wasted spark) it still would idle and I drove it home that way. I grabed a ford OEM coil and all is good. OEM has a long Warranty. The Accel has a very short warranty that should have been the tip off.
At the time I thought it was somthing else as I did not think it would run on only 2 cyl. but it did.
I have the stock flywheel and with all that mass it will run.

so if it will run on 2 it should run on 3

jrflyboyVP2 · #14 (**permalink**) 02-19-2008, 08:47 PM

Well, I think I know what the problem is. I warmed up the engine and pulled each sparkplug wire seperately and the ticking sound didn't change a bit. I listened carefully at various RPMs and it sounded very much like the #1 intake valve clacking, and also I hear a whirring noise coming from the timing chain. I pulled the valve cover and checked the torque on the cam bearing caps, and one of the nuts won't tighten at all. It is the one on the inside front of the intake cam, the outside nut torques to 14ft-lbs per spec and all others would tighten to spec. When I try to tighten the bad one the stud must be pulling out because I just see more threads but it doesn't tighten. I paid $800 to have this used head built for me (stock with my old valves) because my origional head had a crack, now I don't know what to do. Can a stud be helicoiled? What are the threads? Do I have to pull the head, or can it be done in place?

John

180OUT · #15 (**permalink**) 02-19-2008, 09:53 PM

Quote:

I paid $800 to have this used head built for me (stock with my old valves) because my origional head had a crack, now I don't know what to do. Can a stud be helicoiled? What are the threads? Do I have to pull the head, or can it be done in place?

John