Please help, NO POWER!!!

[anofzinger]

85 K5 w/ a lightly modded 350 (from what I was told). Truck ran great at 4200 ft elevation. I moved last year to 6200-6500 elevation and truck has nothing in it. Carb is a 600 CFM Edelbrock on a Edelbrock Performer Intake. I do not know what size the cam is (I was told the truck should be 400-450hp, Pretty sure I was lied to). Anyway, truck sounds decent at idle, no audible misses, but once in gear it dies or has no power at all. I replaced stock jets and rods with ones Edelbrock recommended, haven't replaced step-up springs yet. My first thought was 180 off but a buddy said it wouldn't run smooth/at all at idle. #1 on my cap seems to point pass. side front, but rotor when in point pass side rear. Second thought was vacuum leak, I measured 7-9 Hg coming from the large port on the front of carb. We are pulling carb and intake today to check proper seat/seal. Any thoughts/recommendations?

 

[K5dreamer]

youve taken the truck up in elevation by 2000 feet. time to have the carb retuned to factor that in. Im much more of a diesel/MPFI guy, but by my understanding the air is thinner up there, and youre more likely running pig rich. some others here should be able to offer more informed answers, but that would certainly be my first step.

 

[Yo]

I was gonna ask exactly what you rejetted to. You'll probably need to start from a factory calibration to set a baseline and work from there.

Do you have the entire calibration kit, or did you just but specific jets/step ups?

 

[K5dreamer]

for what its worth... 7-9 Hg sounds realllly low. if memory serves my camaro, at just above sea level here in virginia pulled 20 Hg when tuned up right. but low vacuum dosnt have to mean a vacuum leak. if the engine isnt running right it will pull less vacuum. if the truck ran fine, and the only chage was altitude, im pretty firm that its a carb tuning issue.

 

[anofzinger]

UPDATE...
Carb was jetted from stock, .098 primary/.095 secondary to .095 primary to .092 secondary. I changed the rods too but don't remember the numbers. The Edelbrock Rep gave me the part recommendations.

Pulled everything off and no vacuum leaks. Manually turned motor and set timing index mark on zero while motor was TDC. Reinstalled dizzy and checked all wires. Fired it up and the timing index mark is straight up, no where near the gauge. REALLY CONFUSED!!! Motor is running, but very rough.

Could it be fuel pressure???? How about the wrong timing cover??? Running out of options and patience....

 

[ktmoutfront]

Does your balancer have t marks on it? I ran into that on an aftermarket balancer. Confused the crap out of me.

The truck should have still ran at altitude without rejetting. Just not well.

Now you are saying it runs but like crap. I would say it is something else or a combination of things. Without having my hands on it, I am no help.

 

[anofzinger]

Still having problems....


UPDATE!!!
Changed plugs (black), wires, rotor (rusted) and cap (rusted). Still no power. Planning on changing ignition coil this week, verify TDC and do compression test. Any other suggestions???

 

[ktmoutfront]

Are you sure the cam is not going away? I had a 454 that did this. Lobes were almost found. Not sure what push rod travel should be on your engine, but that could be a checked if the other stuff does not help.

 

[anofzinger]

It is possible, but I want to try everything else first. It has a supposed big cam that was installed by the builder. I was told it was a power motor but I have yet to see it...I just want the thing to run. I guess that will be my next replacement part...

 

[pblaze725]

Here is a link to the Edelbrock Carb Tech videos.http://www.edelbrock.com/automotive_new/misc/tech_center/install/tech_vids.shtml

I learned more than I thought I knew by watching these videos.
Based on my experience of these things I have learned a bit.
-For every 1000 ft increased in elevation you should adjust your carb 1 stage richer.
I live at sea level but when I drive up the mountains I can tell the difference when I get to about 4-5K. Most of the time I go back down to sea level in the desert so I don't bother making adjustments.

- My rig doesn't run well at TDC. It is recomended to start at 8* Before TDC at idle with the vacuum disconnected and the port plugged.
I have a "slightly built" 305 with an oversize cam. My engine runs best at 12* Before TDC.
IMHO You should not try to make Carb and timing adjustments at the same time. I would set the timing first, then adjust the carb.

 

[Jessie James]

Stop replacing parts. If you start replacing all sorts of random parts you may mask the real issue.

At 6000 feet you lose a lot of power, period. What you need to do is be 100% sure it is timed properly. If your timing marks are off, fix that first.

If you think your cam is shot, it's easy enough to remove a valve cover and watch the rockers action.

However, you should slow down and be sure the basics are right - compression, spark, and gas. Obviously each of those has to be within spec, so find out what the specs are and start there.

 

[pblaze725]

Jessie James gives good advise.
He has been called the Dr Phil of CK5. I think it should be DR. Jessie James IMHO.

 

[anofzinger]

Sounds like very solid advice. THANK YOU!! Conveniently all the parts I have replaced were bad anyway. I plan on doing the compression check this weekend and I am getting plenty of fuel. I purchased a Mr. Gasket timing tape, I hope that works. Again, Thank you for your help, I will keep you advised.

 

[Jessie James]

Thanks pblaze!

Anyway, I think the best investment you can make is to purchase a shop manual and a multimeter. While it feels time consuming to read the manual and go through and test all sorts of things, in the end it can save you tons of effort spent wrenching and tons of money spent on parts you did not need.

It also sounds like in this case some of the parts you replaced may have made the problem worse. That's what I try to avoid. If you cause more problems then it will cost more time, and can hide the true - and often - more obvious issue.

 

[Blue85]

Manually turned motor and set timing index mark on zero while motor was TDC. Reinstalled dizzy and checked all wires. Fired it up and the timing index mark is straight up, no where near the gauge. REALLY CONFUSED!!! Motor is running, but very rough.

So how did you find TDC and make sure it was the compression stroke? You definitely need to address the timing before trying to re-jet or anything. Not only were there multiple positions for the tab and marker, the balance cover can also move sometimes. There are a few good ways to be sure you are at the right #1 TDC. When it's there, make sure the rotor is pointing the right way and add your own mark on the harmonic balancer to line up with your timing tab. Or use timing tape - this gives you marks for about half of the engines rotation and let's you set all kinds of timing without the "dial" timing light.

It's also worth going through plug routing again, and go through the dizzy looking for damaged parts. You can run with a broken carbon button or rotor, but it's not pretty.

 

[Amtek]

Pulled everything off and no vacuum leaks. Manually turned motor and set timing index mark on zero while motor was TDC. Reinstalled dizzy and checked all wires. Fired it up and the timing index mark is straight up, no where near the gauge. REALLY CONFUSED!!!

You might have the wrong timing tab for that balancer! I just went through this same thing on my rebuild. It seems that early 80's SBC's had an 8" balancer with the timing tab at 12'o clock, and it is checked by looking down behind the water pump. I replaced my timing cover with a generic chrome one that has the timing tab at 2'o clock and didnt notice they were different.

I had set the initial timing and TDC using the wrong tab and could not get it started and had to keep retarding the timing until it stayed running. With the timing light i could not get the mark anywhere near the timing marks, and when i got it close it would run rough, sputter and backfire. After poking around the net a bit I found it out was a common mistake.

Heres how I fixed it:

Since the engine was now in the truck, I really did not want to have to pull the harmonic balancer, so after removing the PS pump and fan I was able to remove the timing tab from the chrome cover and place it on the original timing cover. From there I bent a solid coper wire to the curve of the balancer and measured the distance between the TDC on both tabs then transfered the measurement to the balancer and painted a new mark. Finally able to time the engine correctly to 10 Btdc, the rest of the issues were fixed easy and got her running like champ.

Hope this helps.

 

[4xcrazy]

. It seems that early 80's SBC's had an 8" balancer with the timing tab at 12'o clock, and it is checked by looking down behind the water pump.
.

I had an '84 305 with this setup.

 

[pblaze725]

It is possible, but I want to try everything else first. It has a supposed big cam that was installed by the builder. I was told it was a power motor but I have yet to see it...I just want the thing to run. I guess that will be my next replacement part...

Having a big cam I suggest going 12* BTDC.

If I took off the dizzy & can't find TDC here's what I do (caveman style)

Take out the #1 spark plug & replace with a wine bottle cork.
Bump the starter until it pops like a champagne bottle just got opened.
Take off the dizzy cap & make sure the button is on #1.
If it's not at number 1 you need to adjust it so it is.
Reconnect the spark plug and dizzy cap.
Turn it over & it should start
Turn the dizzy cap until it sounds good.
Check the timing with a light & I'll betcha it's at 10-12* BTDC at idle.
Remember to disconnect the vacuum advance and cap the port when checking the timing.

 

[anofzinger]

Okay, verified TDC. I had a friend plug the hole with his finger while I bumped motor. The index mark was sitting right about 12* BTDC, so I manually rotated engine until he said it was TDC (was actually at 4* BTDC). Will setting everything up with the motor set at 4* BTDC cause it to not fire? Rotor was pointing at number 2 cyl, so I routed the plug wires from that post on cap as my number 1. I redid my lashing on all valves, I really screwed that up the first time. It is amazing when you actually read and follow directions. Reconnected everything and tried to start, nothing...Well, battery died. I am getting fuel, residue on plugs and I can see it spraying in carb. As far as spark, I can only assume because I do not know how to test for it. I have replaced all portions of the electrical side as I can with the exception of the distributor. Spark plugs are all gapped at 40. On the compression side, can I test for compression with the motor not running. I have a compression kit and was told just to screw it into each plug and bump motor 3-5 times. Does that sound right? Quickly running out of ideas, starting to worry about cam being flattened.

 

[Amtek]

Did you read my post, #16? It seems you are running into the same exact issue with the incorrect timing tab for your balancer. Is the timing cover chrome? is it aftermarket?

after you have verified TDC, hook up the timing light as you crank and if the mark on the balancer is no where near the timing tab and its straight up closer to 12 o clock, then it is not the right one.

Keep rotating the distributor counter clockwise until it starts. dont be surpised if you end up rotating it upto 40-50 degrees. I had to deal with this on first engine start before the cam was broken in, it was very stressful. But once you get the timing in the ballpark and you have fuel and spark, she'll fire right up.