detonation problems opinions

[Randy N Connie]

I am told that I hade detonation problems. I am tone deft
so I have never heard my SC doing this above the blower
whine.

I took my heads off because of leaking head gasket.
After looking the headgasket, piston tops,
combustion chamber over I see no signs of detonation.

I need to know what I can do to stop detonation?
Can you list some things I should look at, or do
to lessen this. Spark plugs gap, timing, fuel,etc.

I am running 20% overdrive with MPIII After it
was tuned by David Dalke it seems to run just fine.
but when I floored the car it seem to blow the
head gasket. I had around 3000 to 4000 miles on gaskets.

Thanks Randy

[DamonSlowpokeBaumann]

Switch to EVans coolant..With a proper tune its about teh best thing you can do for your car to avoid detonation besides teh addition of thermal coatings on teh piston tops and combustion chamber faces

[David Neibert]

I am told that I hade detonation problems. I am tone deft
so I have never heard my SC doing this above the blower
whine.

I took my heads off because of leaking head gasket.
After looking the headgasket, piston tops,
combustion chamber over I see no signs of detonation.

I need to know what I can do to stop detonation?
Can you list some things I should look at, or do
to lessen this. Spark plugs gap, timing, fuel,etc.

I am running 20% overdrive with MPIII After it
was tuned by David Dalke it seems to run just fine.
but when I floored the car it seem to blow the
head gasket. I had around 3000 to 4000 miles on gaskets.

Thanks Randy

Randy,

In addition to improvements to the cooling system....the following things will either help to prevent or will at least reduce detonation.

Pulling the octane plug...this will reduce timing by 4 degrees.

Using a methanol injection system and not adding any aditional timing.

Reduce the blower speed.

Run plugs that are one or two ranges colder.

David

[Randy N Connie]

Switch to EVans coolant..With a proper tune its about teh best thing you can do for your car to avoid detonation besides teh addition of thermal coatings on teh piston tops and combustion chamber faces

I was using Evans, and I did not have any problems running hot.
before using EVANs.Or after running EVANs coolant.

I have done a lot of mods to keep my car runniing cool.

So I know it has nothing to do with motor temps.

Thanks Randy

[SCaddict]

I was using Evans, and I did not have any problems running hot.
before using EVANs.Or after running EVANs coolant.

I have done a lot of mods to keep my car runniing cool.

So I know it has nothing to do with motor temps.

Thanks Randy

So does that mean I have to stop running 25%OD so I don't continue to pop HG's too?


Marty

[Randy N Connie]

Randy,

In addition to improvements to the cooling system....the following things will either help to prevent or will at least reduce detonation.

Pulling the octane plug...this will reduce timing by 4 degrees.

Using a methanol injection system and not adding any aditional timing.

Reduce the blower speed.

Run plugs that are one or two ranges colder.

David

1. There is no way to improve my engine cooling system. Its the best
that It can be.

2.With octane plug removed, I think I was told my motor was reduced
in timing another 4 to 6 degrees.

3.I have snow injection, but it was not installed. So it is going on
to see if it helps.

4..The blower speed was increased 10% to 20% when gasket started
to loosen.If i go less. the car is not competitive, AT 10% OD.
So I will either need to go 15% od, Or throw the MPIII in the
weeds and try the A/R. But I have no idea of its overdrive or
the boost number it will put out.And end up with the same
problem that I all ready have.

5.I was running normal stock plugs. .045 gap. when problems started.
.I have bought colder plugs to use. I was suprised to see how far my
old plugs reached into the combusion chamber. this can't be right.
Maybe I did have the wrong plugs.I will double check.

Thanks Randy

[Andy 94SC]

Are you doing anything with the PCV system to keep oil vapors entering the combustion to a minimum?

IE a catch can, or filter of some sort?

[Randy N Connie]

So does that mean I have to stop running 25%OD so I don't continue to pop HG's too?
Marty

Marty I don't know yet. I have been tring to find out what I am
doing wrong for the past year. Can not find a reasonable answer.

When I do have problems it is usally combination of three to four
things not just one easy fix.

Thanks Randy

[SCaddict]

I only had my heads tourqed to 70ftlbs, maybe that is not enough for 19psi. This time I will be going to 85lbs and see if the heads stay on the car.:D

Marty

[1FASTSC]

Water injection IMO. Or raise the octane of your gas.

[Randy N Connie]

Are you doing anything with the PCV system to keep oil vapors entering the combustion to a minimum?

IE a catch can, or filter of some sort?

No, Do you think I should be?

Randy

[Randy N Connie]

I only had my heads tourqed to 70ftlbs, maybe that is not enough for 19psi. This time I will be going to 85lbs and see if the heads stay on the car.:D

Marty
I had my head bolts torque to 100lb

[Randy N Connie]

Water injection IMO. Or raise the octane of your gas.

A snow injection is one item that I am installing in the next few days.
I think this will help reduce detonation to,

Thanks Randy

[Scott Long]

Autolite 104's gapped at .060" and get a Screamin' Demon coilpack.

What octane is the premium by you? I can usually get 92 or 93 here. Some places you can only get 91. Also the pcv filter is a good idea. I think I saw someone selling them, maybe spinning wheels. I know we aren't supposed to plug vendors, but I'm just trying to help you out Randy and not trying to pimp Victor.

I'm gonna be cutting it close to make it this year with a running SC so hopefully you and Connie will have a safe trip and a good running weekend. See ya there.

[DamonSlowpokeBaumann]

The evans coolant isnt meant to make teh car run any cooler but will reduce steam pockets and heat spots within teh system helping drastically reduce detonation...If anything people run higher temps with EVans for more power with less chance of detonation

[Andy 94SC]

No, Do you think I should be?

Randy

I've hear that oil vapor tends to drastically reduce the effective octane of your fuel. These being supercharger / intercooled vehicles likely will have more trouble than most typical vehicels with that, especially when modified.

You have the excessive crankcase pressures blowing more through the PCV system, then you have a big intercooler condensing the vapor (Notice the big puddles of oil that tend to come out of the intercoolers?) and top it off with a motor that requires high octane, it could be a source of detonation.

A lot of guys are using some type of fuel filter in the PCV line to catch the oil. I'm not sure which one, look for one that you can attach the 3/8 PCV hoses to, and has a nice complicated path for the air to flow through - that along with the filter element will get most of the oil out.

I'm using a small inline filter for air compressor lines, with the little glass bell so I can see how much oil is getting caught.

[David Neibert]

I use an inline fuel filer in the PVC hose that attaches to the backside of the inlet plenum. It looks to be catching about half of the motor oil. An actuall oil seperator would be much better, but I haven't got around to buying one.

David

[DamonSlowpokeBaumann]

go to home depot.They sell oil seperators for compressores and whatnot...Thats what I use...

[Randy N Connie]

I will try the oil seperator. My motor has 100,000 miles on it.
So it does have a high rate of blow-by.

Before stopping the engine. it was blowing black smoke when
i would go over 50 % throttle. So the combustion chamber
was black soot so I could not easly read what was going on.

I do beleive my sparkplug condition,heat range, gap is part
of the problem.I think I would notice a oil fouled plug,maybe
not detonation though. It should be a big help.I will get
some different heat range sparkplugs and install a oil seperator.

After inspecting the pistons, combustion chamber plugs,etc.
I do not have severe detonation. there was some very very
small amount of detonation pitting on the heads deck,flat part
of the combustion chamber.

Well thanks everyone for the ideas.I will fix what I have over looked.
Plugs, oil seperator.Any more ideas?
Thanks Randy

[David Neibert]

go to home depot.They sell oil seperators for compressores and whatnot...Thats what I use...

Damon,

I tried one of the cheap air compressor oil seperators from Harbor Freight. It did a great job of removing the oil but only lasted about a month before falling apart. I guess the heat was too much for it. I've seen much nicer ones for sale by Victor and a few other places, for around $45.

David

[Super XR7]

How can one tell by looking at the spark plugs if the engine is having detonation? I have looked at mine under a 30x microscope, I can see what appears to be aluminum specs on the insulator. Is this a sign of detonation?
I am running NGK TR5-1, 110 unleaded race fuel and 25 adv timing at WOT 6000 rpms. Inlet air temps are approximately 140 F at the end of the 1/8 mile with ambiant 88F.
If the above is detonation, based on the suggestions above and some internet surfing, I will change my plugs to TR6's (one step colder) and change out my coolant to Evens waterless to reduce hot spots in the cylinder head.
Any comments from the experts?

Mike

Randy did not mean to hi-jack your thread but instead hoped that this will also help you.

[DamonSlowpokeBaumann]

You cant get water seperators but oil seperators..The ones at home depot I had in my v8 bird which has massive blowby..Never fell apart. And always collected oil..Ask Pablo how much oil he seen em!..

They are all made by teh sam emanufactuere but some gave different filters depending on application

[Pablo94SC]

I've hear that oil vapor tends to drastically reduce the effective octane of your fuel. These being supercharger / intercooled vehicles likely will have more trouble than most typical vehicels with that, especially when modified.

You have the excessive crankcase pressures blowing more through the PCV system, then you have a big intercooler condensing the vapor (Notice the big puddles of oil that tend to come out of the intercoolers?) and top it off with a motor that requires high octane, it could be a source of detonation.

A lot of guys are using some type of fuel filter in the PCV line to catch the oil. I'm not sure which one, look for one that you can attach the 3/8 PCV hoses to, and has a nice complicated path for the air to flow through - that along with the filter element will get most of the oil out.

I'm using a small inline filter for air compressor lines, with the little glass bell so I can see how much oil is getting caught.

It's true that oil will lower the effective octane of gasoline. Your best bet is to install ain oil catcher and then change your ACT. Also, another good idea is to install a colder plug (Autolite APP103). Finally, since you're good at fabbing, why not tap a couple ports in the back of the heads and attach a hose to allow coolant to flow between them. That should help as well.

[Pablo94SC]

Damon,

I tried one of the cheap air compressor oil seperators from Harbor Freight. It did a great job of removing the oil but only lasted about a month before falling apart. I guess the heat was too much for it. I've seen much nicer ones for sale by Victor and a few other places, for around $45.

David

I had really good luck with a cheap plastic fuel filter from Autozone. It's resistant to heat and hasn't let any oil through since I installed it.

[Scott Long]

I will try the oil seperator. My motor has 100,000 miles on it.
So it does have a high rate of blow-by.

Before stopping the engine. it was blowing black smoke when
i would go over 50 % throttle. So the combustion chamber
was black soot so I could not easly read what was going on.

I do beleive my sparkplug condition,heat range, gap is part
of the problem.I think I would notice a oil fouled plug,maybe
not detonation though. It should be a big help.I will get
some different heat range sparkplugs and install a oil seperator.

After inspecting the pistons, combustion chamber plugs,etc.
I do not have severe detonation. there was some very very
small amount of detonation pitting on the heads deck,flat part
of the combustion chamber.

Well thanks everyone for the ideas.I will fix what I have over looked.
Plugs, oil seperator.Any more ideas?
Thanks Randy

New O2 sensors wouldn't hurt.

[Scott Long]

So my autolite 104's are stock heat range? If so they are out ASAP. I was running colder plugs but wanted to go to the coppers to deal with the nitrous because they say don't run platinum plugs on the juice because the platinum coating flakes off.

[DamonSlowpokeBaumann]

BTW..

Paper element oil filters when saturated no longer let air through which will screw up your crancase ventalation..You always want to use a screen or a bronze sintered filter....I know this from personal experience. Can lead to idle problems

[DamonSlowpokeBaumann]

You can check by pulling it off and blowing on it....Just in case your curious..If there is any resistence at all......No good

[Randy N Connie]

How can one tell by looking at the spark plugs if the engine is having detonation? I have looked at mine under a 30x microscope, I can see what appears to be aluminum specs on the insulator. Is this a sign of detonation?
I am running NGK TR5-1, 110 unleaded race fuel and 25 adv timing at WOT 6000 rpms. Inlet air temps are approximately 140 F at the end of the 1/8 mile with ambiant 88F.
If the above is detonation, based on the suggestions above and some internet surfing, I will change my plugs to TR6's (one step colder) and change out my coolant to Evens waterless to reduce hot spots in the cylinder head.
Any comments from the experts?

Mike

Randy did not mean to hi-jack your thread but instead hoped that this will also help you.

Mike
Every post made by everyone is of help.

I could see my detonation pits
after buying some magnifing glass's,with lights on the sides. I had
to buy the glass's to see and measure the margin widths,.008,
of some cuts I added to my 5 angle valveseat job. This is when
I notice some very small pits in the aluminum flat part of combustion chambers.
The plugs were to sooty to read.because engine went
rich when head gasket went. It was blowing more black smoke
than a deisel truck.Ask Dave Dalke he was behide me.

I need to buy some plugs today or by Monday.I Have not desided
on type or brand to use.I need to get them today.So I can install
the plugs and index before bolting heads on this afternoon.It easier
to do this job with heads off.

As far as a oil-seperator, I will buy some cheap one to get by.
Then later weld up a catch can with petcock to drain oil out
of it when needed.

I would agree with Damon on buying oil seperators. I would want
to only use a sintered brass filter for oil. never paper.!

When I had the detonation. I had to run 90 octane. 20% overdrive.
plug gap was, I don't know I did not have a feeler gauge wide
enough to measure. They were above .055. They looked to be
about .065 to .070. I don't know how that happined and got
by me. So plugs, and gas were most likely the biggest contributors
to my problems when they started.

At least Its nice to finaly be able to get back to work on my car again.
It would of be nice to have been able to do this job a year ago.
I wish I had enough time to get all my parts installed before the
shootout.but there just is not enough time.I was hoping with all
my parts I could push on the 13.3 to 12.9 et with a stock long
block with m90. So I need all the help and luck I can get.
THANKS Randy. :)

[Super XR7]

After looking at all my plugs under a microscope, I found #2 and #4 were the only ones that had little specs on the insulator. Not much but they were there. If that is a sign of detonation, and the fact that they were both middle cylinders, would that point towards heat effect detonation? If so would the remedy be to use the Evan waterless coolant?

Mike