Engine knock

[nateo]

Your first post

hum...good catch, I did say that. I misspoke when I had the throttle cable on I had the idle screw turned out to where the plat wasn't touching the screw. Perhaps the throttle cable got bumped out of adjustment. Maybe it is still just timing adjustment. I was trying to do the adjustment while at the ramp (granted on a weeknight when they're not that busy) but still people interrupting me. I was working my way down on the rpms and it died a couple of times and also started knocking so I gave up. Maybe it just needs gradual adjustments on both idle and dizzy. Well we'll see what the pros says, supposedly they might be able to look at it this week.

 

[nateo]

The knocking I'm hearing is not consistent as with bearing issues I've heard on youtube videos. This is more of a occasional detonation sound that I'm hearing. Seems timing related. Buddy mechanic friend thinks might be something related to timing chain/gear. Maybe I just didn't put enough effort into getting it properly timed.

 

[skippy2235]

Use a stethoscope, or long screwdriver to your ear. Touch the pan area and listen while at idle.
If you hear knock then bearing. If no sounds then maybe ok.
Listen when running and determine if upper or lower area.
I sent you a pm.
If you think timing check with you light when running in water and see what deg you are at. Report back.

 

[nateo]

Well sounds like this might actually finally be coming to a conclusion. Got a call from shop today and they indicated that they found 3 spark plug wires incorrect spots. They said took them 3 hours to figure it out. Now I triple checked these wires with the number on the top, but I did put a new cap on it. Is it possible that the cap works on different boats with different firing order? This thought crossed my mind at one time and I was going to check the firing order but never got around to it. Going to pick her up tonight and give it a try.

 

[DeepBlue2010]

Did you index the new cap? The cap has no firing order build into it. You index a post - any one - as your first one (buy having the cylinder #1 @ compression stroke) and the second post - in the direction of the rotation of your distributer - goes to the following cylinder in the firing order and so on. Did you do that?

 

[nateo]

Did you index the new cap? The cap has no firing order build into it. You index a post - any one - as your first one (buy having the cylinder #1 @ compression stroke) and the second post - in the direction of the rotation of your distributer - goes to the following cylinder in the firing order and so on. Did you do that?

Negative. Thank you for that info. well the saga continues. I dropped it in water and started her up. Backfired a little during startup and started idleing at 750 rpm, I immedately knew it was not fixed. To top it off I tried putting it in gear and nothing, it remained in nuetral. What the heck, I did not have that problem before. Owner said he has been working on boats for 30 years. I was skeptical as to his knowledge when i asked him how he set the timing on muffs he didn't see to be aware of the differences in rpms in water vs out. Surprisenly the detenation problem appears to be gone. So basically he charged me $375 to mess up my shifting.

Still have problem with not timing/running correctly. At this point I'm ready to sell it, find a new engine, or take this one apart. Should have listened to Flipbro a long time ago. a 350 would be nice.

 

[81 Checkmate]

nateo - what part of Ohio are you in? You seem to be having some bad luck and dishonest mechanics taking your money. If your close to the Cincinnati/ Dayton area id be glad to try and help out.

 

[Silvertip]

It took a "mechanic" three hours to figure out the firing order was wrong? Good grief -- find a new mechanic and have him fix the shifting after which you send that portion of the bill to the guy that screwed it up. It appears you are shotgunning the troubles with this engine and not really doing diagnosis. Detonation does not occur at idle speed, but it may sound like that if the firing order is wrong as one or more cylinders are simply firing at the wrong time. Get the firing order right and then set the timing. Any remaining noises can then be diagnosed. The idle mixture screws are just that "idle mixture" and regardless where they are set will not cause detonation. If you adjusted them at 1200 rpm they would have had little effect so if the idle speed is now back where it belongs, firing order is correct, and timing is correct, THEN adjust the mixture screws.

 

[skippy2235]

As for finding a Mechanic, at this stage in the game, find a good automotive guy, and get the engine running, at idle and running, IF you really had crossed wires, then by GOD find anybody. 3 hrs is not acceptable. when you are sitting in front of the engine. We are 1000 miles away, almost impossible to fix from here.

 

[nateo]

I checked the cap this morning and it is labeled correctly. If shop did anything at all they screw it up, discovered idle was turned way up. I set the idle and timing today on muffs, it's sounded good so far. I also discovered throttle cable was way out of adjustment which I believe was the last issue that has been plaguing me for last few weeks. I think it spun several turns with all the work I've done on it so far. Silly issue, should have caught that. Taking it to lake tonight to see what happens.

 

[nateo]

Final conclusion, no doubt in my mind now, internal engine damage. Barings minimum. Loud scretching noise when i rev it. Only wish I would have come to conclusion earlier. Thanks everyone for donating your time. Learing I lot and hope to keep learning. Going to pull engine out again when i get.

 

[nateo]

Since you have good heads, and good compression. to get a few years, what I did the first time was:
took engine out, took off pan, took out crank, tuned crank and replaced the bearings, put back together.
less then a week.
DID NOT take off heads or manifolds, Just the bare min to get crank out.
lasted me untill the 5 qt thing happended. My guess it would still be working had I measured the oil height first.

Did you bolt to engine stand or hang from cherry picker when you replaced bearings?

 

[flipbro]

Bad rod bearings don't make a screeching sound.

 

[skippy2235]

I found a 1200 lbs engine stand on craigslist. Mounted it to a stand.
Make sure you measure your oil levels in the pan. I used water and a pitcher and measured were 5, 6, 7, 8 quarts came to in the pan. I fill mine a full as I can, as long as crank does not hit the oil. 7 qts.
Also while engine is out, install a 1/4 turn valve in the pan, to drain oil.
Using this allows you to drain ALL the oil, easily. attach a hose to 1/4 turn valve, when draining oil, run the hose out the bilge hole in transom and into bucket.
Look at ebay for these valves, only $25
This way all the breakin oil and metal debris / contaminates / water, will be removed from the pan.
where do you live?

 

[flipbro]

Just putting new rod bearings in is just half a$$ing. Pull the crank check it for roundness and see if its within spec. Also when you pull the pan you may find a broken piston skirt or two from the over reving witch would cause piston slap..

 

[skippy2235]

I told him to pull the crank, and machine it, polish it, turn it. also when looking in there, you will see if any damage to anything else.
Also might as well replace the timing set, and both crank seals.

 

[flipbro]

Yes I agree with that. Just didn't see were you said that in post.

 

[flipbro]

Only I would do the hole engine. If you pay for all that machine work why wouldnt you hone it at minimum and rering and gasket it and its Kinda hard to pull a crank out off a SBC with all the rods in the way guess you would ondo rod bolts and push the pistons to tdc but why not do it write the first time.And don't forget the plastigage. Unless you're good with a mic.

 

[skippy2235]

Cost. And time.
This can be done in a week at $300 total.
I know here in Seattle, this is prime time fishing.
Doing all that work, would take 3 weeks.

 

[nateo]

Heres a youtube video of noise. Scretching noise when reving it up i thought originally was a belt because it used to make that noise sometimes last when and ran ood but now i think is something internal. Theres also a small thumbing noise which i thought was maybe engine misaligned. Glad i didnt waste time on messing with alignment. Bought to get me a decent engine stand and tear this puply down a little. If theres anything else you guys think i should check first let me know. Will be replacing bearings and timing set minimum and will check other stuff too. Theres definitely something internal as ive been to the moon and back with it and it still wont time correclty. Even after getting it timed and running decent the rmps will start bouncing all over everywhere.

https://youtu.be/-DU6JF35dlc