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Engine help

Babaganoosh

Babaganoosh

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I search and found mixed answers, what is the best spot to hook a vacuum gauge up to tune my carb? Also if it's not so much to ask could someone possibly use a picture to describe what they are talking about?

Thanks
Ben
 
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I dont see why there gonna be much difference as long as you hook up under the throttle plate or directly to the mainfold like where the brake booster or PVC goes. Probably be helpful to also have a needle valve in line to help dampen the needle from bouncing or just find a liquid filled vac gauge.
 
You've only got three ports on the carb proper, at best. Manifold vacuum, ported vacuum, and some carbs had an "open" port that was hooked to the air cleaner, so little if any vacuum.

Easiest way to tell which is which is to simply put your finger over one of the ports. If it's got vacuum at idle, it's manifold vacuum.

But normally, you are safe with the fittings at the very front base of the carb.
 
Ok, I got the vacuum gauge on and got it tuned right so i think. The idle is smooth as a baby's but. I was so excited I fixed it, I went to emissions again. I got it on the rollers and went to start the test they hit the gas pedal and it just died. I have noticed over the past few days I have been driving it that it now has developed a nasty tick. I had my Dad listen to it and he seems to think it's internal in the engine.


Anybody have any ideas? It's a stock 78 or 79 350 crate engine.
 
What kind of carb?

My Q-jet was very sensitive to timing changes, couple of degrees made a huge diffeerence in how it accelerated.

From what I've heard, those testers (no idea why they should be the ones operating your vehicle, but I digress) tend to absolutely mash the pedal off the bat, if it's not tuned right, the engine will definitely fall on it's face with pedal application that aburpt.
 
it's a quadrajet. the timing hasn't been changed unless it jumped a tooth or something. Yes, the test starts out with a smash of the peddle. Whats weird is on the way there I drove the dickens out of it. :rolleyes:

I forgot to mention it sounds like marbles are inside the engine.

Any help is very appreciated, I have no idea what to do. :1zhelp:
 
Babaganoosh said:
it's a quadrajet. the timing hasn't been changed unless it jumped a tooth or something. Yes, the test starts out with a smash of the peddle. Whats weird is on the way there I drove the dickens out of it. :rolleyes:

I forgot to mention it sounds like marbles are inside the engine.

Any help is very appreciated, I have no idea what to do. :1zhelp:
Click to expand...


That my friend is detonation or pinging as people call it. Everytime you hear that sound the engine is starting to self destruct. Detonation is caused by timing being incorrect, a vacuum leak, engine overheat, basically the cylinder temp is too high and the fuel/air charge is being ignited before the spark plug ignites it then when the plug fires the two flame fronts hit each other causing the sound.
 
4X4HIGH said:
That my friend is detonation or pinging as people call it. Everytime you hear that sound the engine is starting to self destruct. Detonation is caused by timing being incorrect, a vacuum leak, engine overheat, basically the cylinder temp is too high and the fuel/air charge is being ignited before the spark plug ignites it then when the plug fires the two flame fronts hit each other causing the sound.
Click to expand...

Would this cause the engine to run to rich? Where would you suggest starting first? I sapose I can check for vacuum leaks as a start.

Thank you for the reply.
 
Here is a goofy question. Is their a way I can time my engine at home using no light? I ask this because my cover or harmonic balancer don't match up and can't be timed correctly. When Dad put the engine in they gave him wrong parts but bolted up correctly, we had it put on a machine and dialed in to where he thought it was good. For the past 18 years it's worked flawlessly. :haha:

Thanks
 
Does anybody have any experience with a timing pointer? I think this would solve my issue, at least I would know my timing is correct.
 
There is, but the timing cover and or the harmonic balancer is wrong and doesn't match up.

Also how much does it matter what size of balancer I get for the tab? I think it would not line up correctly?
 
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Have you determined where the timing marks are located at when the piston is at TDC? There are two locations for timing tabs and also for two different dampner diameters this is why i ask.
 
No I haven't personally. When my Dad put the crate engine in people told him this and that would work. He tried everything and couldn't get the engine timed correctly. They slapped it on the machine and dialed it into where they "thought" was good and bolted it down.

The balancer is off the original 305 and Auto Zone sold him the wrong chrome kit, which included the chain cover, valve covers, oil pan and dip stick. For example the dipstick is on the drivers side where on a 78 engine it's supposed to be on the left side.

This was 18 years ago so his memory has slipped a little.

I very much appreciate your help thank you.
 
Most 305 engines have the timing mark directly behind the water pump and there is no bolt on timing tab for that balancer. You will have to either change the timing cover for the correct one or change the balancer to the correct one for a 350 with the timing tab to match. I can link both the balancer and timing tab if you wish to go that way (easier IMO).

This balancer...http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-161358&N=700+115&autoview=sku

With this timing tab...http://store.summitracing.com/partdetail.asp?part=PRO-141-202&autoview=sku
 
It's the style thats not behind the water pump. :woot:I measured my balancer and it seems to be 6.5 inches but I don't see one? This may not have been a completely accurate measurement especially sense its a complete motor bolted in. What would happen if I bought one to big or small?
 
If there is no timing tab on your timing cover then buy the 8" balancer and the tab i linked for you. You can use either size balancer but the larger the better.
 
Could I get away with not buying a balancer and just a timing tab? I'm just trying to not sink a whole lot of money into this truck in the form it's in.

I very much appreciate your help, it may sound like I'm contradicting what you are saying though. Without you I would be so lost as to what to do.
 
If you want to buy only a timing tab then you need to get the engine to EXACT TDC and find out where the mark is sitting on the balancer so you know what timing tab to buy.

I will be very surprised though if the timing mark on the balancer doesn't end up at about the 12:00 o'clock position behind the water pump (almost every 305 balancer was like that).
 
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