Pinto 2.0 Engine Knocking

[Monty_CZ]

My pinto started to make a horrible knocking noise. Just like that:

When I start it from cold it's ok for a few seconds and then it starts to make this sound. Any ideas what can it be guys? I checked valve clerances and they are ok.

[cb750]

Last time I heard that it was my camshaft! If yours is unworn check you are getting oil through your spray bar

[Guest alexpink]

Probably big end bearings. Mine made a similar noise when they went recently.

[Guest mcramsay]

If the knock is as loud and pronounced as that video then i would be looking a pulling the engine for an inspection and rebuild. Sounds like cam or big ends, either through a loss of oil pressure or blocked oil spray bar,. If it's cam related you might get away with only pulling the head.

[Guest mcramsay]

Either way you will have sent a load of rubbish and swarf through the engine. You need to work out why it failed in the first place also,

[Monty_CZ]

Spray bar is brand new. I've installed it like a month ago. Works very well, I checked it today. Camshaft looks normal without any signs of wear.

[Bob Tucker]

Did you check the oil level?????

 

I reckon its a camshaft. It's not fast enough or deep enough to be big ends.

Plus pintos were well known for knackering cams.

 

But I dont understand why it is ok for a few seconds after starting from cold?

 

Get a large, long screwdriver, or a long 1/2 inch extension bar.

PLace one end against the head, & put the other end in or against your ear.....no Im not joking.

It acts like a stethoscope you will hear if the noise is close (cam) or distant (big end)

Try putting the end on different parts of the engine for a better diagnosis.

Either way, thats not a good noise.

[Bob Tucker]

What made you fit a new spray bar?

Did you also fit a new camshaft?

They need very specific running in....

[Guest 2b cruising]

As Bob says. If you fitted a ne cam or cam bearings and did not run them in correctly to harden the running serfaces, you will more than likely need another new cam.

 

While your cover is off, make sure all your rocker gear is running right.

Place a thumb tip on them one at a time and press. See if you can make a difference to the noise.

If all is ok up the top, it's not good news.

 

If all the bearings are ok, it can be a small end , broken piston ring or cracked skirt.

Be methodical on your diagnostic inspection and try to find the cause, not just the cure.

 

Just a quick one before you start stripping. Does it still run smooth even though it is knocking.

Edited April 26, 2016 by 2b cruising

[Monty_CZ]

so I've changed spray bar because I did valve clearances. So I thought it's a good idea to change spray bar for a new one, just to be sure. I've also changed valve cover seal and engine oil for a 20w50 and filter of course. I did not fit a new cam. Cam was there when I bought it (CFR33).

Weird thing is that the old spray bar had significantly bigger holes that the new one. But I changed it anyway. I had a suspicion that someone drilled bigger holes just to be sure that it will not clog.

After that, guy from local bike shop came to synchronize and tune my carbs (car was running good under load but it was coughing during city driving when I was slightly on throttle). He did his job and car was running quite good. He said that I should test it and then check the spark plugs. He should stop again and decide what to do next. So I did one trip about 100 km long. No slow driving. Car was running good but still too rich (very bad fuel consumption). No weird noises. But it stared raining so I had to stop the engine and start it a few times. So I've decided that I will do another test and check spark plugs immediately after that.

So next weekend at Saturday I went for a small drive. I did 20 km and I noticed this knocking sound. I stopped and towed the car to my garage and leave it.

Next day I went to the garage and start the car for a few seconds. No knocking noise. I gave it a two taps on throttle and it sounded alright. But as I said, engine was running just for a few seconds.

Yesterday I went to the garage for some things and I had to move a car. I started it, it sounded alright. I've put it in reverse and gave it a few taps and knocking noise appeared again and stayed. It sound like it's knocking around 4th cylinder on the top. So I though that I messed up something during valve clearance setup. So I put down a valve cover and checked if everything is alright. All nuts was tight and I didn't noticed anything wrong. I disconnected carbs and spark plugs and I turned the engine with starter. Oil was flowing from the spray bar nicely. No knocking during that. I've put it back together and started it. Still knocking.

When I came home I can make a video from cold start.

 

to 2b cruising: so I can start the car without the valve cover ? Wouldn't be the engine oil spraying everywhere?

Engine is running quite good even though it's knocking.

[cb750]

Oil will be flung off the cam lobes. If you alter the idle as slow as possible it will minimise the amount of oil that comes off.

[cb750]

If you do remove the cam cover whilst running the engine, cut some cardboard like a sleeve and put it round the head ( not yours!) to protect the carbs etc. Keep it away from rotating parts and the hot exhaust.

[alantoon]

The major change seems to be the spray bar so it may be the problem, I have known a new one to be blocked, so it could be starving oil to one end of the cam. if you still have the old one try putting it back on to eliminate it from the investigation.

[Jez Morton]

I had a similar knock which caused a major panic. Turned out to be the vac advance on the dizzy which was only connected to one inlet on twin 40s. Dizzy was advancing each inlet cycle on cylinder one. Disconnect to check should be easy enough.

Hope it's this simple

[Monty_CZ]

So I made a video how the knocking sounds.

First video is cold start. Notice that knocking starts at 0:52.

Second video is made after a while when the engine was running.