10sec_rx7

there is your answer...

plugs only loose electrode's from going lean... you have a fuel system or injector problem..

stevieturbo

I missed that comment. Detonation and/or lean mixtures = no electrode.

And worse again...often the electrode can end up down the side of the piston scraping and causing damage.

it would be very wise to pull the pistons and inspect for damage and ringland damage.

lazaris

iTrader: (5)

The E-85 does not have enough detonation resistance with that combination. Its detonating period.

paulbigworm

iTrader: (37)

Here u go.

turbo6man

iTrader: (5)

Hi, I was pondering what you had said about the combination causing the detonation. Would you still say the same thing if he had an intercooler that could keep IAT's below 150 degrees after a hard pull? Or maybe if he was able to pull timing progressively based on If the IAT's got above 150 degrees? How about alky injection? Thanks

Slowhawk

iTrader: (12)

The stock head could of lifted a little and traced the gasket right there. Throw in a few long highway pulls and it will burn threw the head like it did.

It's pretty common for race cars making 20+lbs of boost to go through gaskets alot. Expecially with stock (thinner deck) heads running just 4 bolts per cylinder.

stevieturbo

Any of the cases of torching the head/block like that Ive seen have all happened pretty much instantaneously. Not over any period of time, or even seconds.

hellbents10

iTrader: (10)

I agree with Slowhawk on this one, just lifted the factory casting and simply started nuking the gasket/head.

We have run as high as 40psi on a 10:1 engine on E98 non intercooled. You do need to try and light off as much as you can though. We ran AFRs on the gas scale at 9:1. When we converted to M1 with a alky sensor we seen 3:1 with the eth tuneup just changed for the fuel constant.

pwrtrip75

iTrader: (8)

I think I lucked out on the cylinder.... One cylinder lost the electrode on the plug....pulled it out to look at, the scotchbrite ball took out the scratch with minimal effort thankfully, still a little discoloration but its fine.... The piston is cashed though, electrode got wedged in there and messed up the ring land. I guess $100. piston and $100. set of head gaskets isnt too bad. And im glad I had another set of heads on the shelf. Everything else looks perfect..... a new record for me. Usually im having to build an entire new engine.

*the white speckled stuff on the piston in engine is lithium grease i sprayed on. Not to be confused with severe detonation...lol.

stevieturbo

If that's the only damage, you have been lucky. Especially of the block deck wasnt damaged.
I would definitely remove all pistons for inspection though. Back to my original post, whether it was heard, logged or whatever, I'm back to thinking detonation has been responsible for losing the plug tip and subsequent damage.

Although you can get fancy racing plugs that have a special electrode that is much stronger. It's just a small piece of straight metal welded on at an angle instead of the normal L shaped bent electrode. They are very expensive though, but designed that way to help prevent the tip disappearing.

pwrtrip75

iTrader: (8)

Finally got the heads back on tonight. I used LS9 gaskets. ARP studs torqued to, 30, then 50, then 80 ft-lbs. Then I put my forced air kerosene heater on them for a bit to let them heat up. Not quite operating temp but they were damn hot. I'll let it cool and sit over night and then re-torque them to probably 90. Im going to borrow the torque wrench from work too... Its calibrated so I know it will be perfect.

blackmagicturbo

iTrader: (2)

From my experiences with losing a head gasket over a period of pulls was on a motor that was too lean ,, i had a dyno session that the tuner kept pulling fuel till it blew the radiator hose off ,, took the same car to a different tuner and he said it was too lean , cars been running ever since and makes more power than the previous tuner ,,,,check your tune and run the highest pressure cap on the radiator you can find ,, keep the water pressed tightly to the cylinders to keep the steam from building up ,which lifts the head and can torch the deck ,, good luck !

DrTurbo

iTrader: (3)

Not sure if this has been asked. But have you checked backpressure #'s at those boost pressures??

pwrtrip75

iTrader: (8)

No I havnt.

rotary1307cc

iTrader: (5)

i heat cycled my engine and retorqued on my setup

WCCH LSA heads, 370 iron, ls9 gaskets

was out prepping for track passes and it never moved any water on 16psi and 20*

10:1, e50, with a 5gph nozzle of 50/50

same turbo too

rotary1307cc

iTrader: (5)

i dont know if you are framiliar with diesel stuff but after seeing how much a retorque moves i had to do it atleast once

i have a twin turbo cummins and they use a MLS gasket.... and with arp studs after one heatcycle the initial retorque is ridiculous IMO how much more you get out of every nut

it is less and less every retorque until there is no movement, but that initial one moves alot

pwrtrip75

iTrader: (8)

Well I just had a short nightmare.
Broken ARP stud 3 1/2 inches below the deck


After 10 minutes of "%^&*" I thought and thought.... how the hell do you get to that. I have all sorts of extractors... but nothing that long.

Well it turns out the way it broke, the broken stud itself could be used as a key. Ya I held my breath. Sure enough using the stud and pushing it in while turning, it backed right out. Im glad they are only hand tight.


My next question.... I torqued them all down to 90ft-lbs. I know its 10 more than specs... but it went to about 85 and got about 1/8 turn more, still at 85 and snap.
Faulty stud or is reaching for 90 too much to ask??

Potentially could have been bad night....im walking away while im still ahead.......wheew.
Im glad I also have an extra incomplete set of head stud.

stevieturbo

I have seen ARP studs break before, and also had it happen myself ( Non LS engines ), but I wouldnt say it is common

I also dont see why people would want to exceed the torque spec by so much ?

Failure is probably just a combination of bad luck with perhaps a little too much torque applied.

pwrtrip75

iTrader: (8)

I didnt think 90 was that much more. There was another post a guy did his to 130....lol. Ya that seems a bit excessive.