engine rattle

[Phil Martin]

230 with gyromatic blue smoke on first start up then only smokes if running fast and decelerate for a ways then stomp on gas. When taking off it rattles just before letting up for shift. after getting up speed if holding steady pedal I get a slight rattle but if I step on it just a little it rattles like before shifting. No noise when decelerating, at idle or when reving motor. Runs great, any ideas?

[Don Coatney]

Sounds to me like your ignition timing is advanced too far.

[Phil Martin]

Not sure its that kind of rattle but I will check it for sure. Thanks Don

[Robert Horne]

Have you done a compression check???

[1940plymouth]

Bob,

I am by no means an expert mechanic, but you might want to drop the oil pan so you can look at your wrist pins, I had one that was cracked. Check out my thread on it when you get a chance.

[Niel Hoback]

This is way off the wall, but here goes. I had a nasty rattle in the motor that varied under load and coast. I listened intently all the time. The answer came from this forum. It was a loose clamp on the air cleaner! I know its grabbing at straws, but check it anyway so I came tell myself I didn't help when I could have. Thanks.

[Joe Flanagan]

Not as off the wall as you might think. I had the same problem with my daily driver. I suspected the exhaust system and all sorts of things. It turned out that the butterfly nut that holds the top on the air cleaner had backed off a few turns and the lid was rattling on acceleration. I tightened it down and that was the end of it. Next time it backed off, I recognized the noise and went straight to the source. Took at least a couple of years to back off again, which is interesting.

[Phil Martin]

I checked compression a few weeks ago. 90 to 95 on all cly. I' know thats a little low and it probably needs rings. Which would help the smoking. It starts good and runs great, but I need to find the rattle. Haven't had time to do anymore yet.

[Robert Horne]

With compression that low, and engine smoking, you are probably due for an overhaul. You could add STP oil treatment, that may slow down the smoking and rattle.

[Reg Evans]

Some of my old beaters have even lower compression than that. I use non-detergent oil in some of them that are tired and have sediment in the oil pan that I don't want to stir up with detergent oil. I buy 40 and 50 wt. non-detergent oil by the case here. Can't find it locally any more.

http://www.lubriplate.com/products/auto-and-marine/non-detergent-motor-oil.html

[1949P17BC]

I would agree with he overhaul. I was told that a "rattle" is often times main bearings. Bottom line is it runs, probably won't blow up, but to get her sing arebuild is in order.

[41/53dodges]

what should the compression be around, anyways?

[greg g]

That compression readig is't that low. I believe factory was 110/120, and his would likely go up a bit if he shot some oil in the cyls prior to the test, so it doesn't show that low. the important idicator is not so much what the reading is but is it cosistant across the cylinders.

What did your plugs look like when you had them out???

[Phil Martin]

Plugs look real good. Hope to get time for it later this week.