Noise in new engine HELP

[skline]

I got the new engine all together but ran into a snag. While I was putting it all together very carefully and checking everything as I went, I got it all together with the valve train and everything but the vavle covers. I turn it over by hand as I was doing during assembly to make sure it was right and now I hear a deep clunk inside the engine. Sounds like metal on metal. Every 180 turn on the flywheel I hear a click, click from the bottom end. It's coming from the front of the engine it sounds like. Below the distributor. Any ideas what it could be??? I am starting to really stress here.

[DDS]

Cam gear mounting screw whacking? IIRC This can happen when the end play isn't set. Try whacking the crank to one end of its end play, spin the engine then to the other end of its end play, spin it again. No stress. Good luck.

Dave

[skline]

Ok, I tried that and now it is more pronounced. I am running a straight cut cam gear and when I installed the high volume oil pump I thought it was pretty close clearance wise so I ground off some where I thought it might hit. Maybe I did not take enough off? Has someone had this problem before? I have not put the engine back in the car yet and I am going to fire it up before I install it this time to save me the trouble of pulling it back out again.

[Dave at Pelican Parts]

How's the end play on the crank? Do you feel the click through the fan and/or flywheel? Do you feel it in the distributor rotor? Have you localized it with a mechanic's stethoscope or piece of vacuum hose?

--DD

[John Rogers]

Stress when assembling an engine is NOT good. Start taking things apart until you find what is making the noise or until it stops. Since it is metal to metal you should see some sort of marks. Take pictures as you go with a digital camera. Good luck

[skline]

Here I sit in my garage with none of the tools to check what you just told me about. I cant even check the end play on this thing. I am almost ready to give up and take it to Ray Stevens or someone to have them redo the whole friken thing. That will take weeks.

[skline]

Actually, I am going to quit for the night and sleep on it. Maybe things will be clearer in the morning.

[M. Hendrix]

Good luck buddy, I hope a good night's sleep helps.

Sorry you have trouble.


M

[woodman]

Scott, did you check clearances on the rods? Could one be hitting the cam? You could pull off the jugs and do a visual without splitting the case again. Feelin' yer pain dude!

[Zeke]

Every 180 o of crank is 90 on the cam, times 4 bolts = one clunk each 180.

[DDS]

Have a good sleep?
Are there any end play shims installed yet?
You don't need to check the end play yet, you can confirm whether it is the cam bolts by pushing the crank to one end of its travel and turning the engine, - you have to be a bit careful because the crank may tend to 'walk' back to the other end of its travel. You could also rock it back and forth over the 'clunk point', hten push (or tap with a mallet) the crank toward the other end, then rock it again. If the clunk goes away, there's your problem.

Dave

[DDS]

Its all coming back now...
There is a thread here some where about that cam thing - I remember it because whoever it was was baffled because the engine did it in one rotational direction only. What was happening was that turning one way, the crank 'walked' toward the flywheel, and turning the oppisite way it walked away from the flywheel. It fouled those bolts at one end only. IIRC, Dave Darling nailed it, but I can't remember for sure.

Also, my cam had bolts with really thin heads, can't remember if they'd been machined or not, but they were noticeable thinner than a normal bolt, like 2/3 or less.

If you have to take it apart, (and hopefully you won't) another thing you might check is piston skirts whacking the case webs, with my 2056 I had to clearance this area a bit.
FWIW, get used to this sort of frustration, it just takes a different mind-set to ... enjoy it. I found setting up the valve train geometry and getting my fuel system and webers sorted to be the most frustrating parts of my rebuild.

Dave

[maf 914]

Skline,

Good luck solving your engine problem.

Stressing out is not good, but it might not be caused by your engine woes. Could be that dog of yours watching you!

Mike

[skline]

Thanks to Steve Stromberg for coming over to help me find the problem. Turns out it is the valve train causing the noise. Only on one cylinder. When the lifter clears the lobe the high pressure springs send the gear from one tooth to the other. Something about a +3 as opposed to a 0 gear. I am just going to run it now that I know it is not anything hitting that could be catastrophic. It may wear in after the intitial break in. If not, I will pull the cam gears I waited so long for and put in the stock spiral type. I have to try it though. Thanks to all who offered advice.

[DDS]

That's interesting, gear lash. So is the idea that with everything spinning properly that that the gears will stay loaded oin the one direction and won't... backlash?
What was the advantage of the straight cut cam gear?

Dave

[skline]

They say that there is less stress on the cam bearings and less thrust on it letting it run easier. I got it for the noise. I heard a 914 pull up one time in Long Beach awhile back and I thought he had a six but it turned out he had straight cut gears. I liked it.

[DDS]

Thanks. Right, I should have thought of the thrust. That was probably why the crank was 'walking' in the example in my earlier post. Ya learn something every day!

Dave

[Zeke]

I don't think excessive lash is a good thing for valve timing. If Steve S. says it's OK, then it may be. I'd run this one by the Type4um.

[Joe Sharp]

So, whats up?

[skline]

I decided not to rush perfection. I will finish it and install it during the week. I think it will be fine once I fire it up and break in the cam. Joe, you going to D&G this morning? If so, I will see you out there.