Blown head gasket questions

[michael evans]

I bet its fuel pump volume with the stock lines.

I thought it might have been that also, but the injectors did not try to add more fuel.

 

[Ttype6]

I thought it might have been that also, but the injectors did not try to add more fuel.

To know if the fuel pump is or isn't keeping up,monitor fuel pressure by data logging.It will not lie or guess.

 

[Pronto]

Let's hear what Mr Spool found. I have a few thoughts and would like to see if I'm on the same track.

 

[Mr.Spool]

Let's hear what Mr Spool found. I have a few thoughts and would like to see if I'm on the same track.

It was done In a pm.if the op wants I will explain it

 

[No disintegrations]

Let's hear what Mr Spool found. I have a few thoughts and would like to see if I'm on the same track.

I think he found 26 degrees timing, which is too much for 24 psi.

 

[Pronto]

I concur with 26 degrees being too much but the words duty cycle not rising and top end lean I believe are more revealing. Why is the xfi not commanding more fuel if it's going lean? It can add alot of fuel if needed.

 

[No disintegrations]

I concur with 26 degrees being too much but the words duty cycle not rising and top end lean I believe are more revealing. Why is the xfi not commanding more fuel if it's going lean? It can add alot of fuel if needed.

Sure, I'm with you on that as well.

 

[Ttype6]

I think he found 26 degrees timing, which is too much for 24 psi.

He mentioned 26 degrees when he bought the car which had the stock computer. He now runs xfi.

 

[SCOOBY DOO]

Head gaskets won't last long with 26 degrees of high gear timing...if you're running pump gas.

 

[Pronto]

I'm assuming alky injection unless he's running race gas.

 

[michael evans]

I'm assuming alky injection unless he's running race gas.

yes

Running pump gas with alky injection

 

[michael evans]

Head gaskets won't last long with 26 degrees of high gear timing...if you're running pump gas.

I remember the chip had 26 degrees but the table has 34 as maximum (I will change that).
And being rushed didn't help either as it did not let me get a log so that picture is all I really have to go on.

I do have log where I ran at a 1/8 mile track, but in my case I did not a problem until before the finish line (1/4 mile).

 

[Mr.Spool]

the table has 34 as maximum (I will change that).
And being rushed didn't help either as it did not let me get a log so that picture is all I really have to go on.

as the recall on the xfi showed 34 degrees at a high rpm in top gear regardless of fuel the motor cant live.dont beat yourself up as you have been through enough,just make the changes like we discussed.the car will run better faster and live longer.

 

[Mr.Spool]

He mentioned 26 degrees when he bought the car which had the stock computer. He now runs xfi.

as he posted the timing was way higher with the xfi= 34 degrees,the fuel detonites so fast the computer will not save it.

 

[Mr.Spool]

I do have log where I ran at a 1/8 mile track, but in my case I did not a problem until before the finish line (1/4 mile).

chewed up all the fuel before it could make it.

 

[Mr.Spool]

I concur with 26 degrees being too much but the words duty cycle not rising and top end lean I believe are more revealing. Why is the xfi not commanding more fuel if it's going lean? It can add alot of fuel if needed.

timing was way higher at 34 degrees, afr was too lean.when the detonation is more progressive the computer has a chance but when high cylinder pressure and detonation comes on super fast no computer will save it.i have seen this plenty of times in different kinds of cars mild to wild with 4,6,8,10,12 cylinders engines.there just is no substitute for a fuel and octane cushion

 

[Mr.Spool]

Why is the xfi not commanding more fuel if it's going lean? It can add alot of fuel if needed.

because OCTANE and volume are neccessary to keep the motor happy.most dont realize how timing affects the tune but lets just say timing is one of those things where way too much your broken really fast especially if high cylinder pressure is involved.most blame the fuel but timing should be based on the fuel your running and volume is another key component.

 

[Pronto]

34 degrees of timing is way way too much. We all were going off the 26 which we agreed was excessive. I've never ran more than 23. When chasing a knock issue I had the first thing I did was pull timing in 3rd gear. I've seen several posts here from the gurus showing they aren't running high timing and making tremendous power. Stepping back to the dyno tune, I'm surprised the person doing the tune didn't drop the timing way back.

 

[Mr.Spool]

34 degrees of timing is way way too much. We all were going off the 26 which we agreed was excessive. I've never ran more than 23. When chasing a knock issue I had the first thing I did was pull timing in 3rd gear. I've seen several posts here from the gurus showing they aren't running high timing and making tremendous power. Stepping back to the dyno tune, I'm surprised the person doing the tune didn't drop the timing way back.

ive ran them as low as 12 degrees(pump gas) up to 36 degrees (c16)with the proper fuel and afr and combo.its really the right amount of timing on the fuel that matters,super low timing has its drawbacks as well.timing does make power but boost will make more power than just timing alone.just for example purposes lets just say 10hp on the timing per degree while 20hp can be seen with a lb of boost.the better the motor is the more it has airflow capability and the timing is dropped in favor of increased boost as it nets the most gain.

 

[TurboBuRick]

26 timing is more than you prolly want but does not sound like the root cause to me. When it’s always blows the same cylinder, it’s fueling. Alky is fading. It always gets 1 and 2 cylinder first.
The alky TANK is huge problem.
That’s why so many cars IMO do fine on a dyno, then blow a head gasket on the track. The alky gets pulled away from the pick up on the track. The faster the car, the worse it is.
Need a different tank with the pick up in the rear.

Rick