Fast indicates a/f ratio is safe but?

[rtviper]

When the fast system says your runs have a a/f of 10.5 to 11.4 and you have timing at 22 degrees with a max of 21 lbs boost you should be able to make a few runs and not hurt the motor. During a run the datalog said the fast is pulling out 7 percent fuel because my target a/f is 11.1. Knowing all this why would headgaskets go away when using c16? The motor is a fresh stage II with about 10 total runs on it

 

[bruce]

When the fast system says your runs have a a/f of 10.5 to 11.4 and you have timing at 22 degrees with a max of 21 lbs boost you should be able to make a few runs and not hurt the motor. During a run the datalog said the fast is pulling out 7 percent fuel because my target a/f is 11.1. Knowing all this why would headgaskets go away when using c16? The motor is a fresh stage II with about 10 total runs on it

IMO:
No, single sourcing any one item for tuning, is asking for trouble. Plug readings, and EGTs are needed to verify what the WB is seeing is in fact correct. A WB can fail, it can read a false rich, or a false lean.

 

[Otto J]

were you recording duty cycle?
damn hard to believe you blew a gasket on a 14 bolt head,Was this a fresh
setup,Or was the car runs with any other computer befpre the fast?

 

[Joe Lubrant]

When the fast system says your runs have a a/f of 10.5 to 11.4 and you have timing at 22 degrees with a max of 21 lbs boost you should be able to make a few runs and not hurt the motor. During a run the datalog said the fast is pulling out 7 percent fuel because my target a/f is 11.1. Knowing all this why would headgaskets go away when using c16? The motor is a fresh stage II with about 10 total runs on it

If you review your log...was there any Lean Spikes right at or After Shifts??

Also was Timing verified to match Fast Timing Table by Adjustment of Crank Ref. Offset ??

Joe

 

[norbs]

I Would like to see the log you can post it here as a zip file.

 

[rtviper]

The motor had 4 runs with a RA chip and modded computer before I bought the car and never saw over 20 lbs with c16. The motor was fresh before the 4 runs. The car has the BHJ balancer and was checked for being accurate to actual timing. It was right on and showed 22 degrees with timing light to match the 22 in the fast. I dataloged the run and did not see any spikes at shift. I did not have an EGT but datalogged all my runs since I put in the Fast and never saw higher a/f then 11.6 on a run. It had a -7 percent correction the whole run This last run was the highest I had set the boost at and it saw a high boost of 23.3 at 1.5 seconds after launch for .20 seconds and then stayed between 21.8 and 20.8 the entire run. I did notice after the run the intake pipe from the aircleaner to the turbo had popped off from the 1.39 60ft and the thump when the wheels set down but that shouldnt have caused any problems I dont think? The heads and block are grooved by Weber Racing back east. Felpro Gaskets

 

[norbs]

POst a pic of the headgasket, maybe a we can determine something

 

[ChrisChow]

What is an RA chip and how does that work with the FAST?

Also, is your FAST additive fuel limit set at 7%? Or higher?

The motor had 4 runs with a RA chip and modded computer before I bought the car and never saw over 20 lbs with c16. The motor was fresh before the 4 runs. The car has the BHJ balancer and was checked for being accurate to actual timing. It was right on and showed 22 degrees with timing light to match the 22 in the fast. I dataloged the run and did not see any spikes at shift. I did not have an EGT but datalogged all my runs since I put in the Fast and never saw higher a/f then 11.6 on a run. It had a -7 percent correction the whole run This last run was the highest I had set the boost at and it saw a high boost of 23.3 at 1.5 seconds after launch for .20 seconds and then stayed between 21.8 and 20.8 the entire run. I did notice after the run the intake pipe from the aircleaner to the turbo had popped off from the 1.39 60ft and the thump when the wheels set down but that shouldnt have caused any problems I dont think? The heads and block are grooved by Weber Racing back east. Felpro Gaskets

 

[rtviper]

When I bought the car it had a Red Armstrong chip with modded stock computer. The 1st 4 runs were with 20 lbs boost . I added the fast before I made any passes with the car. I dont know about the additive fuel limit. I will have to see how that is checked. If it was set at 7 percent it would only mean my motor would have run richer then the datalog indicated because the Fast was pulling out fuel at - 7 percent the entire run. If there was a limit to only 7 percent then I could have been richer then if the Fast could have corrected more then 7 percent. Am I looking at this the right way? Thanks

 

[norbs]

Were the heads retorqued after a hot and cold cycle at the the initial engine build? What was the spec? Was moly lube used? did you have the fuel injector checked on that cyl? it could have gone lean on one cyl only and taken the gasket out, very possible

 

[rtviper]

The motor was assembled by a guy named Dan Parvel I believe and he is supposed to know his buicks. I was told he has a method of bolting on the heads that takes like a day or 2 to make sure they torqued correctly. They were also retorqued after a heat cycle. If a cylinder went lean that would not show up on the datalog is that correct?

 

[norbs]

Nope nothing " much "would show up. I fear you have maybe have an injector that is bad. The o2 just reads the general a/f of all cyls if one cyl is dead it may only change a few % and since your in closed loop it would try and compensate so your correction may change a bit thats about it. Did you pull your plugs on each run before the headgasket went to inspect any major differences in color?

 

[rtviper]

No I did not check after each run but this was the 2nd run since I did check them and after the damage the plugs all looked great except for the couple that were damp from water

 

[Joe Lubrant]

The motor had 4 runs with a RA chip and modded computer before I bought the car and never saw over 20 lbs with c16. The motor was fresh before the 4 runs. The car has the BHJ balancer and was checked for being accurate to actual timing. It was right on and showed 22 degrees with timing light to match the 22 in the fast. I dataloged the run and did not see any spikes at shift. I did not have an EGT but datalogged all my runs since I put in the Fast and never saw higher a/f then 11.6 on a run. It had a -7 percent correction the whole run This last run was the highest I had set the boost at and it saw a high boost of 23.3 at 1.5 seconds after launch for .20 seconds and then stayed between 21.8 and 20.8 the entire run. I did notice after the run the intake pipe from the aircleaner to the turbo had popped off from the 1.39 60ft and the thump when the wheels set down but that shouldnt have caused any problems I dont think? The heads and block are grooved by Weber Racing back east. Felpro Gaskets

Just re-verifying your statements again.............

Not trying to be a Detective....but you said the motor had (4) four runs on it..... "Before".. You bought it.".... with a modded stock computer & RA chip. You also said it never ran more than 20# with C-16.

The first previous 4 runs were by the other Owner of the Car/Engine with the Stock Computer before you bought it??

Is it possible that the Head Gasket (s) were on their way out previously?
Could have been a progressive issue ending at the time of the fast runs?

Chip runs and A/F ratios of course could not be determined and partial damage could have ensued prior to Fast installation...and problem appeared afterward.

Possibility??............just Guessing

Joe

 

[rtviper]

Joe you are correct the few runs before I bought it could have been the start but those runs were conservative runs supposedly in the 10.5 range . Well I took the motor apart and it had receiver grooves in the block and o- ringed heads done by weber racing. The gaskets were Felpro 1000s. At first I couldnt see the damage but right between 1 and 3 there was a bend in the ring of the gasket that goes around the edge of the bore opening and a little of the top layer of material missing between the 2 cylinders. The gasket almost looks reusable. I did check all the bolts on the head on tear down and it seems like about 3 of them were looser then the 80 lbs they should have been. That was the only thing I can see that may have caused the problem? The plugs and pistons all look great. One good thing about this is I found pieces of spring dampner in the engine valley and all the seals inside the springs were broken had slid half way down the stems. Luckily the guy who built the motor had installed small screens on all the holes that lead to the lower part of the motor. Every lifter bore had a small allen head bolt screwed into it any ideas?

 

[Louie L.]

One good thing about this is I found pieces of spring dampner in the engine valley and all the seals inside the springs were broken had slid half way down the stems. Luckily the guy who built the motor had installed small screens on all the holes that lead to the lower part of the motor. Every lifter bore had a small allen head bolt screwed into it any ideas?

It is very possible that the oil passing down the damaged valve guide seals may have caused the detonation. The allen screws are normal in a stage 2 block.

 

[S2V6RACER]

Joe you are correct the few runs before I bought it could have been the start but those runs were conservative runs supposedly in the 10.5 range . Well I took the motor apart and it had receiver grooves in the block and o- ringed heads done by weber racing. The gaskets were Felpro 1000s. At first I couldnt see the damage but right between 1 and 3 there was a bend in the ring of the gasket that goes around the edge of the bore opening and a little of the top layer of material missing between the 2 cylinders. The gasket almost looks reusable. I did check all the bolts on the head on tear down and it seems like about 3 of them were looser then the 80 lbs they should have been. That was the only thing I can see that may have caused the problem? The plugs and pistons all look great. One good thing about this is I found pieces of spring dampner in the engine valley and all the seals inside the springs were broken had slid half way down the stems. Luckily the guy who built the motor had installed small screens on all the holes that lead to the lower part of the motor. Every lifter bore had a small allen head bolt screwed into it any ideas?

Check your bore diameter on the block. I would bet you are over 4.00 and you had the same failure I did 2 seasons ago. The 1000 gasket should not be used on a engine with a bore bigger than 4.00 IMHO The wire in the fire ring will slide down in the chamfer of the bore and not seal properly!!!! Your failure was of this reason I suspect.

 

[Otto J]

Buy a set of cometic head gaskets.
Fantastic results with them

 

[norbs]

I think the SCE gaskets are Better than the Cometics, just by looking at the design of them. Any tests yet?

 

[ChrisChow]

When I bought the car it had a Red Armstrong chip with modded stock computer. The 1st 4 runs were with 20 lbs boost . I added the fast before I made any passes with the car. I dont know about the additive fuel limit. I will have to see how that is checked. If it was set at 7 percent it would only mean my motor would have run richer then the datalog indicated because the Fast was pulling out fuel at - 7 percent the entire run. If there was a limit to only 7 percent then I could have been richer then if the Fast could have corrected more then 7 percent. Am I looking at this the right way? Thanks

There are two columns in the FAST. If you have 7 % on the right column, that means you limited your additive fuel (based on the A/F setpoint) to a maximum of 7% MORE fuel. [sometimes this is exceeded by 1% but that's another story). If you datalogged a run, what you see is actual fuel ratio and the added 7%. That's how you should look at it.

If the FAST was pulling fuel, then that means you aren't running lean but rich (but this is dependent on the A/F setpoin again).