High Comp Motor on Pump Gas

[NY87SS]

Once you have done what has been suggested you can always try water injection.
Alot of old school built motor benefit from running one of these setups.
Some high compression motors of the 60's came with these units!

 

[85montemj]

The only gaskets that werent changed were the head and timing chain cover. We lubed up the valve train and used diesel oil for break in. Almost everything got switched over from my 350 onto there. But Ill have to look into the timing chain. Ill see if that'll jog my dad's memory in regards to that whole setup. But someone mentioned carbon build up in the cylinders causing the pinging. They suggested spraying water through the carb to clean it. Has anyone ever tried that?

 

[NY87SS]

Water works OK, but it actually takes alot.
You could get a few cans of sea foam, start the engine getting it to idle and suck a can up through a vacuum hose, quickly sh*t it off if it doesn't stall out on its own. Wait 1/2 hour or more then start it up and let it runs. It'll smoke like, well, like a brush fire is going in your yard and thats the carbon crap comming out. The second can can be used in the tank to help clear out the crap in the tank, lines and carb!

 

[CHRIS.O]

It really just sounds like the engine was not set up for street which your finding out. I doubt trying to steam clean your engine is gonna do anything. I wouldn't go any further until I checked what has been listed for you. When you have an engine that you know nothing about and have problems it makes you want to pull your hair out. This is probably more than you want to do but I would pull it out and tear it down to know EXACTLY what you have and make adjustments to it for the street. 10:1 is fine for pump gas even with iron heads. Whatever your problem is probably lays in the timing as listed or the camshaft.

 

[85montemj]

I think i'll pull the timing cover over thanksgiving break and see what it looks like. I'll replace it while i'm in there. What should i do if i find the crank is advanced?

 

[Blue86Monte]

Take it apart and see what's inside. That's the only way your going to figure it out, you can chase your tail for a long time and get mad. Do it once and do it right. 😀

 

[pontiacgp]

I think i'll pull the timing cover over thanksgiving break and see what it looks like. I'll replace it while i'm in there. What should i do if i find the crank is advanced?

it's not the crank that's advanced, it's just the gear if is which would 3 settings on it, 4 advanced, 0 and 4 retarded...you could just relocate the gear but since timing chains aren't expensive I'd put a new double roller in.

 

[85montemj]

I'll put a new chain in for sure. I cant tear it down though. I'm in the navy going to school pretty all day during the week. I dont have anywhere to do work like that.

 

[gto nate]

Tearing down the engine seems like a big PITA to me. 10.1 is ok comp for pump gas also. What kind of dizzy do you have? (i.e. is it a MSD or a HEI, ect... vac advance?) you said the engine did not want to run at 18deg at idle, but would run at 14deg. Usually if you advance your timing (18deg vs. 14deg) the engine should idle higher, not stall out. I ask about your dizzy, because if you have an MSD, you can tune your advance curve. Too me it sounds like you are bringing in the timing to fast, to much advance at too low of an RPM. What is your total timing, and at what RPM is timing at total advance? It is possible that your dizzy has been locked out? On a circle track car or alot of drag cars the timing is locked out, or fully advanced. The only time a engine needs less timing is at off idle and low RPM's, or how a street motor gets driven 😀 Let me know what you find out. I have a pretty good grasp on timing and advance curves.

 

[85montemj]

Its an accel HEI distributor about 5 months old, no fancy modules or anything. The flyweights work fine and everything else is in good condition. What do you mean by dizzy?