VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Knocked up

Hello fellow Chervolet lovers! I knew joining the VCCA was a great idea! I don't feel like I'm all alone out here anymore. 29Chevy thank you sooo much for the plate sites!! I have a problem I posed to 29Chevy and now I am asking everybody: I have a 1930 Coach which I think needs a rebuild It has a very scary knock in the engine. I found a guy in Apple Valley Ca, who seems credible. He wants $3000.00 and two months turn around. I love my car, and very much want it on the road. I am also a little new to this hobby.A innocent babe in the woods, as it were. I am an art teacher by trade, and do some lightweight mechanical stuff. (I did rewire the entire car with the schmatic). I heard tell the collector car is a hole in the driveway you pour money, but as a teacher I have little to throw in there. Anybody have a garage they really trust in Southern California? I thank you all very much for your support.

The whole engine may not need to be rebuilt because it has a knock. How well does it run? Does it smoke or leak oil? Is it hard to start? Is the cylinder compression OK?

It starts first crack of the starter. It does not smoke but does leak oil as it's running (Not profusely, but noticeable) The engine runs excellent and strong except the loud knocking at low idle or under pressure. I have good reading on oil pressure gauge and level is good. The mechanic at the corner gas station said it may be a connecting rod. I don't know. I feel so foolish-embarassed, I'm not that mechanical- How do I check the compression? And when I put new spark plugs in I could only get the last one in fingertight. (They are replacement plugs for the ones that were in there, but now I find out they are not the same number as the manual calls for) I'll do whatever it takes...thanks

When you say it knocks loudly at low idle under pressure, is that if you put the engine under load? If you firmly set the brakes and let the clutch slip with the engine under load and you hear more of a pounding noise it's probably a main bearing, most likely the rear main. That is even more likely if it's where the oil is leaking. If the noise is more like a rapping sound you hear at 35 - 40 mph it's probably a connecting rod bearing. The bearings are adjustable by removing or adding brass shims. That info should be in your manual. If your mechanic doesn't know how to do it find another mechanic.

Hey Dave,

As to your spark plug question, you should be using AC C86 plugs or AC C87 plugs. If you have some of the older C86 plugs you will see a stamping on the metal parts that tells you it is a G9.

Thank you guys for your help! I have been on the email (VCCA) for a mechanic who can handle the shims. And I have purchased AC C86 and will install them directly. Heartfelt and sincere thank you. I sure feel like I have brothers looking out for me- it sure feels great! David

If you're so inclined it may be useful, and certainly satisfying, if you might have someone do it and show it to you at the same time.

Basically, it involves taking off the oil pan, removing the bottom bearing from the rod and removing one set of shims. Then you check the clearance with Plasticgauge. Not complicated, but I'll agree that it can be intimidating if you haven't done it before. Once someone familiarizes it with you, though, it's pretty logical.

It's a greasy job with a bit of grunt work, but you do get to do the classic car repair position of laying on your back under the motor with your legs sticking out. Certainly makes you feel like a real old time mechanic.

Well, after hearing from you guys, I'm going to go for it myself. Thanks Ed- I guess I'll try it! No time like the present and all that! Like I said, I love PansyJane and would do anything it get her back on the road. Trying something new qualifies. Thank all you guys- cause if I get in trouble with this, or any project for that matter, I know y'all will be here to help. Thanks. David

Pansy-Jane is Knocked Up????? Ohmyomy!Well be careful undoing her pan! you might get something in your eyes, so use goggles!

I'll certainly take your advice... I'll be sure and use propection this time!!

I suggest that you turn the crank so the rod you are working on is in the max down position. Undo the cap and remove it. Put plastic tubing on the bolts or electrical tape or rubber tube to keep them from contacting the crank. Carefully push the rod up far enough so you can visually inspect the bearing surface. A mirror may be required. If any cracks or craters are seen, it will be necessary to replace the rod or babbitt.

If you suspect that the noise comes from the main bearings my experience is that the center main is likely the problem. The rear may also be worn since there is oil leaking from the rear of the engine. Removal of the main caps will allow checking the babbitt on the inserts on the bottom. And you can plastigage the main bearing but likely you will be fooled as the weight of the crank tends to make the bottom clearance less than the top. Good Luck!!!

Hey Dave,

Did you get my e-mails? Please let me know.

Welcome aboard,
Gotta help a fellow teacher (history here), when you install the new plugs I think you need to set the gap different from what "the book" says. The JYD has the information on this setting and the background, I have forgotten the whys and wherefores.

P.S. I have the same knock in my '32, saving my pennies for a re-build if I can find someone who CAN do the work. So I will follow the advice you get for your engine and see if it helps.

Seems like there are fewer and fewer people out there who can do the work. Figure I need to do the whole re-build now so I can get the most life out of the engine.