Timing question

New to the forum and to blown alcohol set-ups but I've got a timing question. I have all aluminum 598 4 1/2in stroke motor with head hunter heads, has a littlefield 10-71 non-hi helix with 2 quick fuel 1050s fed by a enderle 80a-1 pump and the big aeromotive bypass regulator and the timing at 32 degrees, we had a 58 bottom pulley and a 50 top pulley on it with 188 jets and collector headers leaving at 3000 and shifting at 7400 and the car ran great at Bristol, went to Columbus and went down to a 48 top pulley and up to 192 jets put zoomies on still leaving @3000 and shifting @7400 car was .03 faster to 1/8 and .06 faster to 1/4 but was down almost 3mph to the 1/4 and the egt's were 1525, pulled the plugs and 2 were missing the porcelain changed plugs went to up 196 jets and was .100 faster to the 1/8 then nuked a piston just past the 1/8 and and only .050 faster to the 1/4 @ the same mph as the previous run and the egt's showed 1567. So my question is am I'm running enough timing in y'all's opinion cause when we pulled the pistons out all the ring gaps had moved around. Any and all input is appreciated and thanks in advance.

 

I would not advance the timing more than that.

What did the weather do between Bristol and Columbus?

I bet your piston damage was started when the porcelain was broke out of the plugs, then it got a little worse for the next run and you really noticed it...


I bet it was just too lean, probably mostly because of the humidity as I would guess the carbs do a pretty good job of "self" adjusting for the barometric pressure & temp.

 

Hmmmm! Makes me wonder if your running out of fuel?

Blessings........Ron C

 

Well I thought it was running outta fuel too but we've talked with the guys at quick fuel and enderle and both tell us we have plenty of pump and there's no way we're draining the bowls. I'm lost as heck guys lol.

 

Is your fuel pressure regulator boost referenced?

 

I think he's draw thru rather than blow thru.

Blessings........Ron

 

Right, wasn't thinking.

 

While you may have (or not) enough fuel supply do you still have single needle and seat bowls?

Dave Koehler
http://www.koehlerinjection.com

 

The regulator we're running does have a the boost reference hook up but we don't have it hooked up. We're running the single needle bowls we called quick about that dual needle bowl they sell but they swear up an down we can't possible be draining the bowls.

I was mistaken about the timing, we had the timing at 30 degrees.

 

Could we possible have to much jet in it that causing it to detonate and burning the excess in the pipes.

 

Maybe not but you have 2 .192 jets being fed by 1 .150? needle and seat.
Ya gotta wonder.

Dave Koehler
http://www.koehlerinjection.com

 

Do they know that you are running alcohol and have the single needle and seat? Even if your pump is big enough, you can only send so much fluid through a certain size hole in a given amount of time. Sounds to me like you are already too lean, this is why it picks up when you richen it up and then it runs out of fuel (quicker due to the bigger jet) further down the track resulting in mph drop and melted pistons. If you are in fact on the lean side of the fuel curve you are going to want to make a big jump of fuel going into the engine because a little one may put it in the sweet spot where it burns more than a couple electrodes and a piston. There's a reason not a lot of folks run carbs.

 

Well see that's what me Andy one of my motor guys kept saying but the guys at quick fuel swear that 150 needle is big enough.

Yeah we told the guys at quick fuel exactly what we were building and that we were going to be running alcohol.

Piston and rod came in today and we got a dyno lined up for Monday afternoon so we'll see.

Do y'all think that champion c59cx is the right plug?

The first race we ran we had collector headers on the car and it ran great at Bristol I guess I'm curious too if switching to zoomies would change the tune-up a bunch?

 

No disrespect to the carb guys but you can't depend on high pressure to get through that .150? N/S and feed the equivalent of a .275 hole. Makes for a frothy aerated mess.
It's just a bad flow path.

IF you finally determine it's a lack of fuel problem get some of those double N/S bowls and keep the pressure between 6 and 8 lbs. Trying to turn a carb into an MFI with high pressure has never worked for anyone that I ever ran into.

It's either that or step up the pump, put a hat on it, change a pulley and go racing.

BTW: You do have a front mounted tank I hope.

Dave Koehler
http://www.koehlerinjection.com

 

If that collector is too small, I would believe that switching to zoomies could lean the engine, but I've never done it or helped anybody to do this.

 

You'll get no agreement from me, to me the math on the size of the jets and the size of the needle don't make sense to me at all. Seems to me that we'd start draining the bowls.

We're running the fuel pressure at 8, the tank is in between the seat and the blow shield.

They were the 2 3/8x2 1/2x5in kooks.

 

Well we got everything back together and went to Reynolds ga this past weekend and I think we're still alittle lean but we're headed in the right direction.

We put the 50top pulley back on with the 58bottom pulley which put us back @ 16% over drivin left the 196 jets in and put the full headers back on and she went 4.316@163.34 to the 1/8 and 6.736@201.07 to the 1/4 still leaving at 3000 and shifting at 7400 and crossing at 7550 and the egt's @ 1360's.

I think we had her lean in Bristol but just didn't know it because of the shitty air and no egt on it yet and we just made it worse up there at Columbus changing a bunch of stuff at one time with no real info.

Also spoke with quick fuel again and they said I can safely run up to a 200 jet with the single needle and seat, so I already @ 196 so the dual needle and seat pro bowls are probably going to be a winter upgrade.

 

if the carbs are not alcohol carbs they will not deliver enough fuel regardlus of jet size. the emulsion tubes will be too small along with the bossters, Its not as simple as some may think just adding more carbs, you must have alcohol carbs as the tubes and boosters are setup for methanol, plus the floats are they brass or comp?. bowl extensions will help but thats a band aid. in the old days we had a nos jet & fitting plumbed into ea flot bowl nad at WOT they would help keep the bowl full but its real hard to set up. try not running any jets in it at all. this will tell you if the tubes and bossters can deliver, if it doesnt change much or at all then you know the answer.

 

Those egt's are very hot..... But the real question is how do the plugs look, you need to run ngk plugs so you can read the burn on the cadmium plating. Also why not just sell the carbs and put fuel injection on it. It will be happier in the long run and run better.

 

I ran QF Alcohol carbs for yrs, you will never be able to pass it enough fuel through carbs. I had to make a small injection system with .050 jets in the runners with a separate small electric pump and regulator set at 7-8 lbs that I triggered when I pulled it into high gear. I had bowl extenders and a mechanical pump it would go lean and lay over at 1000'. I installed this poor mans injection I made up and life was good.