Head gasket problem please help

H

hgw

Member
I have a reoccurring problem whit the head gaskets on my Vette.
I can run it between 2 month to 2 years but eventually it seems to blow.
It usually start whit a slightly ruff running engine and a slightly higher oil pressure (probably a viscosity change) then it start to take water from the upper coolant reservoir. (If I have a leak it takes coolant from the lower reservoir)
I can usually drive the car for a couple of mount from the first sign to when I have to change the gasket.
The temperature at the thermostat is spot on 160-170 whit a 160 thermostat I set the fans to kick in at 162 and 168.
But at low rpm the sensor for the temp gage show a slight elevated temperature at low rpm.
I used to use felpro 1003 gasket and what happened whit them was that the fire ring creped in to the combustion chamber usually on number 1 in front and you could see some sign on nr 7 back 2 front and 8 back that is was doing the same thing.
So the last 2 times I used felpro mls gaskets (I don’t remember the P/N)
Whit the mls the gasket blow on nr 5 on the intake side this time it had actually water filled the cylinder. that was whit the old heads,
I finally gave up thinking it must be a problem whit the water jackets in the old heads and bought a set of AFR 195 competition which is on the car now.

Some of the things I tried Over the years
3 different water pump brands currently steward.
Change the radiator. A bunch of thermostats.
Flushed the coolant system.
Always checked the block for being straight when changing the gasket
And had the heads checked and milled usually it wasn’t necessary.
Arp headbults at least 2 different set whit theirs thread sealant and lubricant, calibrated torque wrench. Cleaned the treads in the block torqued in stages in the right sequence and on the last try even re torqued the bolts, after couple of heat cycles.
Fuel pressure ok
I need to map it after I change the heads it’s running slightly lean and I do have some slight knock between 3000-4000 RPM According to the log 2-3 degrees. But at least I know the knock sensor is working.



Car;
Corvette 1990. I owned it since 1997.Low 13s daily driven
12.88s 108mph personal best on a perfect day
ZZ4 short block
Head used to be AFR 180
Now AFR 195 competition
Intake:
Edelbrock base
ASM runners
Holly 52mm trottlebody

 
without very clear detail pictures of both the block surfaces and gaskets in the areas the gaskets failed along with the matching head surfaces Id just be guessing , but the most common reason for head gasket failures , is use of the wrong coolant ,which can lead to corrosion, lack of proper block surface prep , which won,t allow a good seal to begin with, use of the wrong head gasket or the wrong size head gasket,or badly done machine work and the very common damage done by detonation, due to crappy low octane fuel, but keep in mind aluminum expands and contracts as it cools at a different rate from cast iron, so the more consistent you can keep your engine temps,and the less often the cars subjected to below freezing temperatures, the less temperature induced stress the seal on the head gasket there will be. theres links and info you might want to read thru below .
TPI corvettes are notorious for vacuum leaks or detonation related damage due to inconsistent engine temps, in most cases if you add a effective oil and trans cooler it goes a long way toward reducing maintenance issues that result from repeated damage from minor detonation, that generally results from crappy fuel and the knock sensor not instantly retarding the ignition timing, and the oxygen sensors constantly trying to keep the engines air/fuel ratio at or near 14.7:1 for low emissions which also keeps it firmly in the detonation range rather than in the 13.8:1-14:1 range while cruising and 12.7:1-12.8:1 range under heavy loads,where it runs better and is less likely to get into detonation


Overheating,

Engine overheating is a common cause of head gasket failure. Extreme heat from the engine can cause thermal expansion between the engine block and cylinder head, which in turn exerts pressure on the armor surrounding the head gasket and crush it. The crushed armor can then start leaking coolant or compression. The driver should first determine the cause of the engine overheating and then replace any damaged or leaking components to correct the problem.
Preignition

When fuel ignites before the spark plug fires due to a hot spot in the combustion chamber, preignition results. Preignition increases stress on a head gasket which, over time, can lead to failure. Preignition can be caused by engine overheating.
Detonation

Detonation results from such causes as low octane in the engine fuel, a lean fuel mixture or over-advanced spark timing. Detonation can lead to head gasket stress and failure, and is often accompanied by a knocking or pinging noise that can alert the driver to engine problems that need correction.


Read more: http://www.ehow.com/facts_7691707_cause ... z32H4elrIf

I have not lost a head gasket in 35 plus years since I swapped to thin (generally .021-.040 COPPER head gaskets) and installing them with a good damp copper coat spray, (read the links)but I also go to great lengths to keep my oil temps consistently under 230F and coolant temps under 220F if I can with auxiliary oil or trans fluid coolers and a 190f t-stat with 6 holes in the flange, and a high flow water pump, large radiator, and 7-10 quart oil system on most engines as keeping the engine temps consistent is important to durability, and detonation can, and will quickly kill any head gasket, piston or ring set
RELATED INFO

http://www.aa1car.com/library/gasket_failure.htm

http://www.autorepairtips.org/autorepai ... s-fail.php



Head Gasket Roughness (ra)

I've installed my heads now, getting ready for when the headers come back. I noticed the surface finish of the aluminum heads, they seemed to be very rough. But what is rough, how do you quantify roughness ??? Try telling your buddy what you mean when you say "it was very rough". The most...
garage.grumpysperformance.com

http://garage.grumpysperformance.com/index.php?threads/sbc-head-gasket-choice.11070/#post-79067

http://garage.grumpysperformance.com/index.php?threads/head-gasket-related.1859/#post-50617

http://garage.grumpysperformance.com/index.php?threads/head-gasket.10085/#post-39429

http://garage.grumpysperformance.co...ad-gasket-for-aluminum-heads.4403/#post-26317

http://garage.grumpysperformance.co...asket-bore-size-vs-bore-size.2681/#post-11603
 
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Unlike Grumpy, I prefer Fel Pro Race Headgaskets.
Stainless Steel Fire Rings with a Pre Flattened Steel center core support for Iron Heads, & Copper Center Core for Aluminum Heads.
All have thier bench race opinions.
Grumpy speaks from his experience.
Its mine I share too.

RA - RMS Cylinder head & Block Deck Surface very important.
Should be smooth. 5-15 RA.
CHECK WIRH A DIGITAL SURFACE PROFILEOMETER WITH A RUBY OR DIAMOND STYLUS TIP.
 
87vette81big said:
Unlike Grumpy, I prefer Fel Pro Race Headgaskets.
Stainless Steel Fire Rings with a Pre Flattened Steel center core support for Iron Heads, & Copper Center Core for Aluminum Heads.
All have thier bench race opinions.
Grumpy speaks from his experience.
Its mine I share too.

RA - RMS Cylinder head & Block Deck Surface very important.
Should be smooth. 5-15 RA.
CHECK WIRH A DIGITAL SURFACE PROFILEOMETER WITH A RUBY OR DIAMOND STYLUS TIP.
Click to expand...

youve got a great deal of company , most guys seem to prefer those Fel Pro Race Headgaskets, I get a bunch of guys giving me odd looks about my choices , but I just say when and If I start having issues Ill start looking into changing, until then, I see no reason to change know winning horses in mid stream!
 
I might Try Copper head gaskets someday Grumpy.
I have no personal experience with them.
Hemi 426 & Nitro requires Copper headgaskets I was told by late friend.
He liked Copper too.
 
Thanks for you fast reply.
I totally understand that it must be almost impossibly to diagnose my trouble without seeing it
And I really appreciate you effort.

The felpro 1003 is what AFR recommend.
I instructed the machinist to get the Ra and Rz really low per felpro spec, on the heads (he is a very god machinist bean in the business 30-40 years and a personal friend)
I didn’t check the numbers but they were really smooooth.
The block surface I can’t guaranty but I couldn’t feel any imperfections whit my fingernails. (Never decked it)
I will back of on the Ignition advance to get more of margin.
The AF is about 11.9 to 12.2 in PE according to wideband lambda I know it’s too rich but right now I rather lose some HP then another head gasket.
I can’t do much about the 14.7 since I have to pass smog tests.


A bit more information for what it’s worth.
Oil temp ca 180-190 and I have the original coolant to oil heat exchanger (oil cooler).
I would like to run it hotter both coolant and oil temp but whit my history of head gaskets……
No obvious coolant restriction in the block.
No sigh of corrosion in the block or heads
I always run 50/50 Castrol coolant meeting GM spec and distilled water and changing it at least every other year.
I checked for galvanic currents in the cooling system it was ok.
Stock converter so no extreme transmission temps.
Oil fully synthetic Mobil 1 5w/50 changed at least twice a year.

Water pumps:
First out was an Edelbrock really nice looking curved vanes but it was actually less effective than the stock pump at low rpm.
Next a floowcooler it was the best at low RPM
Last a steward which was between the stock and floowcooler at low rpm.
All performed good at high rpm.
If you have any suggesting on a better water pump I would really appreciate it.

The gas in Sweden seems to be quite good compared to some of the horror stories I read about the gas in the US
They probably most make it good so the SAAB and Volvos can run on it :D
They only advertise the RON and it come in two grades 95 and 98.
From what I been able to find out if about the MON it would be about 90 and 93 octane in the US (RON+MON/2)
 
do you store the car, for days at a time when its not in use in conditions where it may be subjected to well below 32F temperatures ?
over heating an engine tends to cause aluminum heads too expand and contract at a different expansion rate than the iron engine block, but so does rather large changes in temperature while the cars sitting stored. the reason i bring this up is that I have a friend that lived in Maine , who had a head gasket fail after the first winter he spent up there after moving and has not had that happen since he added a block heater to his car, even though the cars not driven in the winter , he says the local corvette club guys say its use while the cars in storage tends to lower maintenance related issues
obviously theres several versions , it might not be your problem, but its something you might consider and if you have a heated garage its unlikely to be an issue
http://www.northerntool.com/shop/tools/ ... _200379472

http://www.engineeringtoolbox.com/therm ... d_859.html

http://www.engineeringtoolbox.com/linea ... -d_95.html

viewtopic.php?f=51&t=10464&p=43788#p43788


WITH ALUMINUM HAVING A SIGNIFICANTLY HIGHER THERMAL EXPANSION RATIO, CHANGES IN TEMPERATURE OR HEAT MAKE A DIFFERENCE,ESPECIALLY REPEATED AND FAIRLY RAPID SWINGS OVER LARGER RANGES LIKE FROM BELOW FREEZING TO ABOVE THE BOILING POINT OF WATER in your climate you could easily have coolant and engine oil temperature swings that vary by well over 60-70 degrees in excess of what I see here in Florida
colte2zx%20(2).png

colte2zx%20(1).png

colte3zx.png

colte4zx.png


viewtopic.php?f=52&t=4403&p=38976&hilit=thermal+expansion#p38976

viewtopic.php?f=51&t=2692&p=6978&hilit=thermal+expansion#p6978

YOU MIGHT ALSO WANT TO READ THRU THESE THREADS AND SUB LINKS, I POSTED BELOW
keep in mind the head gasket bore must be larger than the block bore diameter and in spite of printed directions suggestion installing the gaskets dry in most cases , I install all had gaskets sprayed with a good damp coat of copper coat on both surfaces and torqued in place while damp/tacky, after first carefully cleaning with acetone and drying surfaces on heads and block.
copperspray1.jpg

bolthread.png

viewtopic.php?f=57&t=2991&p=7851#p7851

viewtopic.php?f=57&t=74&p=35559&hilit=anodes#p35559

viewtopic.php?f=50&t=2988&p=9055&hilit=head+gasket+clamp#p9055

viewtopic.php?f=50&t=827&p=4572&hilit=+gasket+copper#p4572
 
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If you have the old headgaskets, with a Calibrated 0-1" Micrometer (.0001" Accuracy preferred) measure all around the fire rings, Water ports. 50-100 spots.
All should measure .0002"- .001" of each other in compressed used thickness.

I think you may have an aluminum head brineling issuse.
Miroscopic surface cracks.
Have to ZYGLOW DYE CHECK WITH A BLACK UV LIGHT.
 
Thank you Thank you Thank you
I think that you may have found the cause.
I do live in an extreme climate, from -20F in the winter to +85F temp in the summer. I have an electric block heater that I use 98% of the time. But sometimes I have to park the car outside in cold weather -10F .I don’t’ blame AFR or felpro cause they could never have foreseen that someone would be foolish enough to use there products under these circumstances.

I always thought that head gasket failure where due to insufficient coolant flow at low RPM Since the sensor for the gauge located between cylinder 6 and 8 in the head showed a rise in temp at idle but at 1500-2000 RPM rapidly fall but the temp sensor for the ECM at the thermostat always was spot on. I thought that due to the L98 complicated coolant routing and the AFR head and feel pro gasket revised coolant flow (a really big coolant passage between the two Siamese exhaust valves in cylinder 3-5 and 4-6). Combined whit my low idle 600RPM in drive was enough to create a local hotspot that eventually lead to the gasket failure.





http://www.mekonomen.se/bil/reservdelar ... 77a65753sv
 

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Sorry
I'm bad at spelling even in Swedish.
but even I started laughing when I saw it.
what I meant was MOVED
 
I really like your idea about the different thermal expansion rate of aluminum and iron. The big repeated movement between the block and heads would explain why the fire ring would creep or (moweded lol) in towards the combustion chamber.
So what can I do about it?
Iron heads. No not if I can avoid it.
Stop driving the car in the winter. Possibly
Get a gasket that will work under my condition. YES if possibly
I know that there are 100 of thousand cars working whit iron block and aluminum heads under my condition whiteout gasket problem. So I hope that I can get mine to work also.
My thoughts:
Clamping the head harder to try to minimize the moment.
NO I don’t think I can stop the thermal expansion by clamping it harder.
Get a gasket whiteout Fire ring.
Partly my felpro MLS don’t have a fire ring so at the least the fire rings could not creep in to the combustion chamber but I manage to blow them to.
Get a gasket without fire ring that is really slick to allow for horizontal movement and springy for the vertical movement.
Probably the solution but what type?

I know you like the copper gasket and I wouldn’t mind trying them. I know they can take enormous combustion pressure (My nephew used them on his Suzuki GSX1300R Hayabusa that he turbo charge, it made 305 HP on the rear wheel) But at the HP/combustion pressure level I am right now, there might be some better option.
I would really appreciate your input on my thoughts.
Please excuse my bad English
 
Don't clamp harder. The L98 Iron block is not strong enough.
Will destroy it.
Aluminum Brinelling likely culprit .
All I have been told, Copper head gaskets work.
Especially if you O-Ring The Block or heads or Both.
AFR Ok.
Quality don't impress me like Brodix or Trickflow.
My opinion.
 
Can you please explain why you think brinelling would be my problem?
I usually had the old heads milled down when I changed the head gasket, and whit a set of brand new heads whit the gasket that AFR recommended I really don’t understand it.
Please tell me what gasket you think would be better.
The quality of the machine work on my first set of AFR (more than 10 years old) left a lot to be desired. I had to do a lot of deburring.
The new AFR heads had a whole lot better machine work. My only two complaints would be the design flaw whit the rocker cover bolt holes and the quality of the supplied rocker studs.
 
Because its such a mass produced & over rated head.
Everyone with a C4 Corvette bought them.
Think its the best thing ever since Sex.
But they still lose drag race. Steet race too.
 
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