Pinging after 40-45 mins of driving?

[Mrturner1]

So can a vacuum leak cause pinging or detonation?

[jlsanborn]

One thing at a time. That broken carb is an issue for sure so fix that first.

[davepl]

Yes, a vacuum leak could make it worse, but it's a problem that needs to be fixed on its own. I prefer carb studs (vs bolts) and then use a torque wrench. Easy to break carb corners and thermostat housings.

I'd wager that fixing the carb and the vacuum line routing together will go a long way.

[Redline novdog]

boiling the fuel will make it run lean. if your true compression ratio is over 10/1 then with cast iron heads your gonna have to run more octane. Get used to it if your gonna boost a small block!

[Mrturner1]

Originally Posted by davepl

Yes, a vacuum leak could make it worse, but it's a problem that needs to be fixed on its own. I prefer carb studs (vs bolts) and then use a torque wrench. Easy to break carb corners and thermostat housings.

I'd wager that fixing the carb and the vacuum line routing together will go a long way.

I did some reading and a vacuum leak can cause a lean condition, which has all sorts of symptoms. My creeping temperature a few weeks ago was probably partially due to this. I'm ordering a whole set of those heat resistant ceramic plugs, I'm consistently melting through a different one now and it's making tuning a real PITA.

SO, I don't want to buy two carbs, but I want my truck to run and drive during the buildup of the 383. So I need to get a carb that will feed the 383 later, and also run decent on the current motor. I actually posted about this situation a couple days ago, I'm looking at the Holley 750 Street HP.

[Mrturner1]

Originally Posted by Redline novdog

boiling the fuel will make it run lean. if your true compression ratio is over 10/1 then with cast iron heads your gonna have to run more octane. Get used to it if your gonna boost a small block!

I tried a few different calculators and got 10.4-1 every time. Maybe a little high for cast iron heads It costs about 60 bucks for me to fill up with premium 91 at the pump, and it's 65 bucks for a 5 gallon can of Sunoco 110. I THINK that adds up to about 96 octane ( 14gals of 91 + 5gals of 110 ). I might just start goin to the little airport in town and fill up with 99 or 103 for 6 bucks a gallon.

[Grumpy old man]

Airports don't sell fuel to car / truck owners it's illegal and they only carry 100 LL - low lead and"jet fuel is only kerosene so your not using that . I don't understand why you can't see you should park it until the carb and filter issue is fixed? It's broke don't drive it ! From day one I told you those heads were not worth the time and yet you continue to try to make them work ? There is a reason they had bad reviews .we used to run 12.5 : 1 engines on pump gas advanced timing and hot gas won't fix your problems , your melting spark plugs ? Did I read that right ?

[Mrturner1]

Originally Posted by Grumpy old man

Airports don't sell fuel to car / truck owners it's illegal and they only carry 100 LL - low lead and"jet fuel is only kerosene so your not using that . I don't understand why you can't see you should park it until the carb and filter issue is fixed? It's broke don't drive it ! From day one I told you those heads were not worth the time and yet you continue to try to make them work ? There is a reason they had bad reviews .we used to run 12.5 : 1 engines on pump gas advanced timing and hot gas won't fix your problems , your melting spark plugs ? Did I read that right ?

No not plugs I wrote that wrong, I meant plug boots. My headers have been a pain because they are melting two of my plug wore boots. Davepl sent me a ceramic boot which worked, but now I have another that's a slower melting one that just popped up. A whole set of ceramic plug boots is the goal.

It's parked right now, and will stay that way until I get everything fixed on it. You were probably right about the heads, I definetly didn't see the pinging coming with 10-1 compression when I first built the motor, live and learn I guess you were right though, and I remember your post saying don't bother with them lol

[Mrturner1]

Could the Pro-Topline heads actually be a problem though? I mean with the detonation? I'm getting a new carb and I'll get a fuel filter as well, but when those are fixed am I just wasting my time with these heads?

[Grumpy old man]

Not at this point , I would just set it up to run using the original timing and not try to squeeze every thing you can out of it . I'm the one who is always looking for the best possible deal but sometimes you just have to bite the bullet and pay for quality parts . You'll be fine !

[cleszkie]

Grumpy - I applaud your persistence in guiding Mrturner1 in the right direction with his current set up.

Mrturner1 - Listen to Grumpy. He knows what he is talking about. We've all learned a lot from his posts on this board over the years.

[Grumpy old man]

Originally Posted by cleszkie

Grumpy - I applaud your persistence in guiding Mrturner1 in the right direction with his current set up.

Mrturner1 - Listen to Grumpy. He knows what he is talking about. We've all learned a lot from his posts on this board over the years.

I appreciate that but I learn something new in here everyday . I was self employed with a young family and had to work long hours 7 days a week for many years to keep us Fed and the employees paid , some guys know sports , I had no time for leisure pursuits I had to work hands on and I can't begin to tell you how many nights I spent installing a customers engine or hand sanding a door for the 4th time , or sewing until 5:00 am to finish a job so I'm just adding my .02 where I can hopefully someone gets some use of it . Mrturner1 will get it all straightened out , Hey , it's his first build look what he's already learned !

[Mrturner1]

Originally Posted by cleszkie

Grumpy - I applaud your persistence in guiding Mrturner1 in the right direction with his current set up.

He can't help it, he see's me like his own distant grandson.....online haha