[guccieng]

isn't all of this in vain until TDC is verified?

[jakeshoe]

Also,
As a general rule I try not to free rev an unloaded engine to open the secondaries. With a Q-jet there shouldn't ever be any doubt they are working or not by sound alone when driving the car.

[jakeshoe]

Originally Posted by guccieng

isn't all of this in vain until TDC is verified?

IMO,
No.

I've "tuned" by ear many times to get a rough tune to start testing.
If the timing marks were off considerably, it would have been evident on the 3 quick road tests we took yesterday.
I moved timing around slightly and did notice slightly audible spark knock with the timing slightly advanced, as I would expect under part throttle load.

TDC will get verified when/if we degree the cam.

First thing on the to-do list is get the proper plugs in the car. Simple cheap things first.

Before any more road testing, while it is cool I am going to recalibrate the transmission governor so we can get a bit more rpm out of it. It's shifting too early.
Another simple cheap mod that will help.

Then we'll road test it and see if it's made any difference.

At that point I'll try to determine if we do have a fuel delivery issue or if we think it is cam timing or other tune related problem.

Cliff may be right, the cam timing may be off. If so, we'll know pretty quick.

[chiphead]

I always remove the stock filter inside the Q-jet inlet and replace with a quality high flow external filter.

What does the cranking compression look like?

[jakeshoe]

We're going to degree the cam.
Cranking compression is 150-160.

Changed plugs today to the R43S.
Modified the trans governor to slightly increase the shift points.
Some improvement but very minor.

It does seem to "want" to pull the secondaries now but not fully. I tihnk it's mostly attributable to the slightly higher shift points.

[1967Tempest]

I think that this thread is awesome! I just love how a real issue is being troubleshot and diagnosed. People are giving great recommendations and the issue is being picked apart.
The thread is why I joined. I have nothing to add except keep the updates coming. I might need this thread tomorrow or 10 years down the road.

Jakeshoe, you are the man!! You are like straight out of HPP magazine!! Keep em coming, I am dying to find out what is wrong or not quite right!!

Dave

[tr709]

Originally Posted by 1967Tempest

I think that this thread is awesome! I just love how a real issue is being troubleshot and diagnosed. People are giving great recommendations and the issue is being picked apart.
The thread is why I joined. I have nothing to add except keep the updates coming. I might need this thread tomorrow or 10 years down the road.

Jakeshoe, you are the man!! You are like straight out of HPP magazine!! Keep em coming, I am dying to find out what is wrong or not quite right!!

Dave

I agree, great use of this forum.

[jakeshoe]

Originally Posted by 1967Tempest

You are like straight out of HPP magazine!! Keep em coming, I am dying to find out what is wrong or not quite right!!

Dave

Dave,

I am dying to know as well.
I have a POS 1980 Malibu "mule" car we use to test transmissions before we ship them. It has a 267 SBC with a Dual-jet on it. Anemic and POS is putting it nicely. I think it also has 2.41 rear gears.

We did a final road test on a 200-4R in the 'Bu today before we pull it and ship it, and then test drove the Firebird.

I think the Firebird would get a jump off the line but from a 30 mph roll, the Malibu would probably be even.

That's how anemic the Firebird is. There is definitely something not right, and it's one of those deals where you would expect it to jump out at you but it doesn't.

[GTOLou]

Originally Posted by Cliff R

I've seen this a few times. The worst one we ever had in here had the timing off two teeth. The engine builder advanced the 9 degree timing set two keyways, the used the standard "dot to dot" to line up the sprockets, instead of counting back two teeth to the left from the new keyway. The engine actually started, idled and ran fine, but would NOT do anything when you matted the accellerator. It acted like the secondaries were not working at all......Cliff

Hmmm, would cranking compression still be okay with that move?

[JohnTN]

I'm dying to know how the cam degrees. I chased the same symptoms on a mild Olds 350 for a year before finally degreeing the cam. Turned out the mechanic had installed it 45 degrees advanced (3 teeth off, dot to keyway instead of dot to dot, like a Mopar). Amazing it even ran. Runs much better now.

John

[kyle_blake]

I don't think I've ever seen a post like this in 6 years where an car owner and a shop mechanic post on one thread. Super! Thanks so much for reporting back with what you find...each time!

[Cliff R]

"Hmmm, would cranking compression still be okay with that move?"

I was hired to "tune" this engine after quite a few others had a crack at it. It actually idled fine, and put down OK compression numbers, but just a tad low for what I would have expected from the combination.

The symptoms were, that it would not rev at heavy/full throttle with any authority. Just slow and boring, and didn't make much power for a 455 with ported #64 heads and a roller camshaft.

I put a different carb and distributor on it, same exact symptoms, so I pulled the timing cover to find the keyways advanced two positions, and the original "dot to dot" still being used to line up the sprockets. This is actually pretty easy to do with a Rollmaster timing set, as their directions are just about useless.

Anyhow, I moved the crank two positions, and lined up the new mark with the original dot on the upper sprocket, and the engine ran great......Cliff

[ta man]

With this combination that cranking compression seems low.Were all the cylinders the same?Did you do a leak down test?This engine really sounds like a buick 455 i saw a few years ago.Ran and idled ok just couldn't pull hard enough.I loaned a good quadrajet of mine to the owner and the engine didn't have enuf ooomph to open the secondaries much at all.Cam timing was way off in this case.I have a nine way billet timing chain on my current engine.Any advanced or retarded position has to be checked as the markings are off a bit.Hopefully the new plugs will help.

[jakeshoe]

I've seen a BBC timing set, just the basic double roller type, that had the mark off one tooth on the cam gear a few years ago.

It was one of those deals where it was a budget motor and normally you wouldn't degree the cam but for some reason I put the degree wheel on it and had to do it twice because I thought "No way" I must be doing this wrong.

[kyle_blake]

I really hope it's camshaft degree! If not I can't wait to hear how to troubleshoot fuel delivery issues. I wonder what would be next after that?

[chiphead]

At this point the cranking compression numbers show that cylinder sealing is good. 150PSI is hard to do with a burned valve, blown headgasket or broken rings. However, it doesnt find things like out-of-time cam, marginal valvesprings, rocker geo issues, fuel delivery, ignition, restrictive exhaust, etc.

If the cam degree is good, I'd check the rest of the valvetrain. Vacuum readings at idle and cruise would help too. Next is fuel, exhaust, etc.

What really worries me here is the detonation. A 9:1 engine shouldnt be so detonation prone. Shortblock related would be the cam, the deck height or the piston selection.

[67ramair4]

Two words - chassis dyno!

[guccieng]

Originally Posted by 67ramair4

Two words - chassis dyno!

no point in wasting money, only to confirm what they already know.

[67ramair4]

Not trying to be rude, but what do they already know?

I've never seen a car with 2.93 gears spin the tires let alone "boil" them, no matter what size the motor was! Many senior members have mentioned gears as the cause, and I'm on their side.

[madtexan]

Originally Posted by 67ramair4

Not trying to be rude, but what do they already know?

I think it's that the car is not putting enough power to the pavement. A dyno will only put a number to it but it won't tell them why. That's the million dollar question everyone is waiting for.

Jakeshoe, I'm hoping to also benefit from your skills in getting my 69 GTO 400CI running right too. I'm down in Richardson(east side of Dallas) but my car misses too bad to drive it right now. We'll talk once this one is resolved.