TireSmoke.org

With all those days off this weekend, there's no excuse for not having it running by Wednesday. Right? I know TireSmoker was driving his around last night...

-BP

ANYTHING????

She runs, she runs, she runs......
I did the half hour cam break-in - good thing most of my neighbors were back at work!!!
But I still have the - same - dam - problem.
I can't believe it. It idles great. Smooth as glass, (smaller cam). Steady vacuum. Drop her in gear, nice smooth steady idle. Give it some gas, and it's still got a miss. Well.....going with a valve train issue, it can only be springs. I gave 'em a good visual inspection upon head re-install. All looked fine - nothing obvious.

Or...... possibly a lean condition. This is an easy adjustment/tweak. That's next. And, as I anticipated, an oil leak at the front cover/pan area. I gooped it all up pretty good, when I put the cover back, but I've never had any luck on cam changes, when the pan stayed in place.

I'm open to any suggestions/thoughts of what may be causing my persistent miss.


My sig should say-
"I'm trying to go as fast as I can afford"

I'd safely say at this point that if you drive it, you're not going to hurt anything. I'd start but taking one plug off at a time and driving it and see which one effects it the least...it might help you determine the missing cylinder.

Or is there any chance at all you have a balancer issue? I would think though, that out of balance is out of balance, and you'd feel the vibration consistently at certain rpms.

Did you say you changed carburetors yet? Cleaned the jets/passages yet? Fresh gas?

Rough year for old Chevys.

-BP

I don't think I can hurt it either. Nor am I gona go out and stand on it. It hasn't goen over 2000rpm in gear. I've got a date for this Saturday, with and old neighbor, who is a service tech at the old Clay Matthews, in Euclid. It's under a new name now.... I help him cut down a tree, he helps me with my car. That's how he works things. I trust him, and am curious as to what he thinks.

The balancer/flexplate are used 400 stuff. Definitely, the correct 400 specific units. When revving from under the hood, it's real smooth. I feel the rotating assembly is balanced OK. I've emailed the Smoker himself, requesting the temporary acquisition of his unused Holley. It's worth a try.

The current fuel supply is two months old. Should be OK. The carb still looks virginous. I still plan on opening things up - smaller rods/larger jets. (Edelbrock 650) I'll look into what the user guide suggests. The smooth 850rpm idle is a nice change!

No regrets, just headaches, and lots of consumed Tylenol.

There is one other option but that involves a large quanity of explosives. Guess you haven't got that far yet!

Naw.... She's been in the family too long, since 1988. She dates back three girlfriends before my wife. Yes, Colleen is aware of this.

I keep telling myself, It's gota be something simple. Something I've overlooked. She starts right up, no knock, no smoke, just a lot of fan noise - a rather large 7 bladed clutch fan. And the ever pleasing rumble of the mighty SBC - even on 7 cylinders.

At the risk of sounding wimpy.... I'm at my wits end. It's time to have someone else look at this. And so, my old neighbor, Chuck, has accepted to stop over this afternoon. He said he wasn't in a tree cutting mood.....

It's about time you finally signed on, Mr. 72Deuce!

Well, Chuck made a visit, and we went for a ride. "It's hitting on all eight", he says. "You don't have a miss problem, you have a balance problem". "But, I've used all the 400 specific stuff - balancer, and flexplate", I said. After filling him in about what I used to build the engine, Chuck feels the crank may internally balanced. All the 400 stuff I'm currently employing, is just throwing it off. The crank is low buck - but new, not a re-grind. Some of you may recall a runout problem I had with the first crank I got. Sheeesh, more crank issues. Monday, I'm calling Speed-o-Motive, and inquire about their cranks.

The fix, or at least an attempt, will be to change out the balancer. If that shows some sort of improvement, then, dreadfully, I'll look into changing out the flexplate. Engine, or trans, one has got to be pulled for this change.

Now, if ya'll will excuse me, I'm gona step out and get the biggest bottle of Tylenol I can find.

If you have a balance issue, I'd be very surprised if it was due to using a 400 balancer and flexplate. All of those kits use the external-balance balancer/flexplate -- certainly the lower-end stuff that is based off of stock Chevy cranks. It costs a bunch of money to re-balance them internally. Although re-reading your message, you said it was a new crank, not a re-grind.

I would definately call Speed-O-Motive before you try changing balancers.

-Dave

It's my fault.
No, this isn't a marriage thing, where the husband is always wrong by default! It's an engine building thing. I took the Nova to Commercial Engine, and had the owner and another employee take a look. After a little brake/torque in reverse, it was unanimous - out of balance. Even if the crank is internally balanced, the 400 specific external stuff would make things drastically shake.
After a short discussion with the guys, I now have a full understanding of why one needs to balance the rotating assembly. The only time you wouldn't, is if the rotating assembly 'kit' came already balanced. Live and learn. Under Ideal conditions, I figure 25 hours. Remove, dissemble, send out (3-5 days to balance) re-assemble, and re-install. Or, about late August. I think I'm gona call on my neighbor - 72Deuce, to help. This will reduce the time required.

So, I'll be spending less time on the PC, and more time in the garage - again. I'll keep ya'll updated on major events.

It may not be practical from a time or money standpoint, but it'd be interesting to see the current weights of each piston/rod assembly, so as to know what kind of weight difference would cause a balance issue.

Interestingly, the new issue of Chevy High Performance that arrived yesterday had an article about three different small-block builds for $5500 (cover story). The interesting part was they listed the weight in grams of just about every component in the rotating assembly -- not just rods/pistons, but also including rings, piston pin, maybe even the rod bolts. It was a very complete list. I've never seen this info in an engine-build article.

Any particular reason you did the brake-torque in reverse as opposed to drive?

-Dave

If I understand what you are saying - you currently have a crank and flywheel to externally balance a 400 and your engine is internally balanced.

Are you planning to take it apart to balance it or just change the balancer and flexplate to parts for internally balanced engine?

If it is a teardown, what exactly are you going to do? If you want to improve your ET by a couple tenths then by all means balance the inside parts, otherwise you might have better ways to spend your time.

I think we have a misunderstanding.....
From my conversation at Commercial Engine, IF I had in internally balanced crank, (it's not) and added the 400 stuff (balancer and flexplate), the vibration would be horrific. It's not horrific. I mentioned trying a 350 balancer, to see if that improved things, but I think at this point, that's not the answer.

If you're headed up north, I'm 15 minutes from Basement Paul. It's still together, I'd be curious to hear what ya think.

I'm with Mark on this -- if you were to mix external-balance style balancers and flywheels with internal-balance cranks, the problem would be waaay worse than what Mark is experiencing.

If you consider that in the past, most of our builds have re-used the same parts that came out of a running engine, they were already balanced, at least to a minimum factory-spec. Taking those same parts to a machine shop and getting it balanced took that balance to a much higher-grade spec. I think this is what Andy is considering optional (and I would tend to agree).

But in a situation where you're taking a new crank, rods, and pistons that have never been together as an assembly, I now think it is required. If I thought it was optional before Mark's incident, I would now consider it required for this kind of build in the future.

And if this is the case, shame on S-O-M for a) not automatically balancing what they sell or b) not making it *perfectly* clear to their customers that they *must* have the parts balanced before assembly.

-Dave

Hi all,
Just an F.Y.I, I wasn't the last person to use your engine stand. In fact I never did. I borrowed my brothers when i did my oil pan job.