Stingraynut

I posted several weeks ago that, while having new valve seals fitted, the compressed air holding the valves closed, pushed water out of a coolant hose, suggesting I had a leaking head.

http://forums.corvetteforum.com/show...28&forum_id=48

At the time I had absolutely no symptoms.

So I had the coolant chemically tested for exhaust gases and the result was negative.

Now I have BLACK smoke coming from the exhausts when hot. I did a new search today and everyone else with suspected blown heads had WHITE smoke coming from the exhausts.

It's hard to tell but there MAY be tiny bubbles in the coolant with the radiator cap off - v hard to tell.

I've organised for another chemical test of the coolant on Monday - but I'm wondering why my exhaust smoke is black and why it shows most when the engine is warm?

Could the valve seal job have gone wrong ?

S'nut

Morley

White smoke=coolant
Blue smoke=oil
Black smoke= RICH

FD2BLK

THere is a simple test a local shop should be able to preform. They hook up a test set to the radiator cap and it measures Carbon Monoxide. The test rig has a fluid (Blue if I remeber corectly) and it will turn color if any exhaust gases are leaking into the radiator.

Stingraynut

Thanks Morely, the smoke is definitely not WHITE, and FD2BLK, that's the test I had done a few weeks ago and which I'm going to get done again on Monday - if there's no CO in the coolant then my problems would seem to be elsewhere. I haven't been using oil. Fuel economy seemed OK.

If the coolant test is negative I'll see if I can arrange to have the exhaust gases analysed with a 'sniffer'.

I was advised to do a leakdown test in my previous post a few weeks ago - but so far I haven't located that equipment here.

S'nut

ittlfly

If you are looking for the test equipment itself then here you go:
http://www.tooldesk.com/products/def...ak%20Detection

It would probably cost just as much to have a shop do it than just to buy the guage set.

Stingraynut

Thanks for the link Ittlfly, Unfortunately the shipping to Oz adds a lot to the cost, I expect I can locate the gear here, but as you say, might be just the same to get a leakdown test done at a shop - if i can find one that knows what they're doing in my area.

Re Black exhaust smoke = too rich a fuel mixture - a mate has just sent me this advice -
"with unleaded cars I don't particularly think exh smoke colour's as relevant as in 'the old days'; when black meant vehicle was running rich or had carby probs.

As far as I know too; it's not so much exh gas going into coolant that indicates a blown or leaking head gasket, rather it's OIL that you'll be looking for..."

Anyone else agree ?

S'nut

CFI-EFI

No. To both theories. It isn't the lead that make gasoline burn with black smoke. Put some gasoline (unleaded) in an open container in a safe open place and light it. Observe the color of the smoke.

Have him explain to you how OIL is going to get into the coolant, with a blown head gasket. I wanna hear this. Except for the drain back from the heads, there is no oil at the head gasket, and that oil is under no pressure. The coolant is.

RACE ON!!!

bogus

more then likely, one would see coolant in the oil versus oil in the coolant. Just as CFI-EFI stated, there is no oil pressure at the head gasket.

korvette4u

please listen to the previous two post made by bogus and CFI-EFI..

to check for head gaskets failure:
do a leak down test

do a block -check test . this detects if carbon monoxide is present in the cooling sytem

check Cylinder #7 & # 8 spark plugs, if they seem lighter in color then the others chance are that the head gasket is or aleast starting to fail. this a common problem rite from the factory(head gasket failure)

AND DO NOT REPLACE THE HEAD GASKET WITH FELPRO 1010 period. i had very bad experieince with this gasket, USE the regular head gasget that comes with the kit. PROPERLY TORQUE and make sure of this!

good luck

Stingraynut

Thanks everyone - I had the coolant tested today, bubbles were actually making foam in the neck of the radiator - worse than yesterday.

The chemical test showed positive, there is Carbon Monoxide in the coolant.

Because I have a bad back I won't do this job myself, so I've dropped the car off at the workshop that replaced the valve seals recently and discovered the suspected blown head. (They pressurised the cylinders to hold up the valves to replace the seals, and on #4 cylinder, water shot out of a coolant hose, also slightly out of #6.)

I knew about the gasket problem with #7 and #8, but this appears to be in the middle.

I should know in a day or two what the problem is - here's hoping it's a gasket and not a crack.

Edit - korvette4u - I have my interior lights delay module repaired, but not fitted and tested yet. It was the largest transistor that had blown - we found a modern replacement. I've been away for several weeks, I'll will post the complete circuit and parts list after I have run it for a week or three and made sure it's a good fix.

S'nut

Stingraynut

RESULT - A shop pulled the heads of my 88 vette yesterday - there is a track between cylinders #4 and #6 showing that the gasket was leaking there - the heads are now being reconditioned, they will pressure test them to make sure there are no cracks. I'm getting the injectors cleaned and tested also.

S'nut

Dominic Sorresso

korvette4U,

I have been having a heck of a time trying to find an oil leak that seemed to originate from somewhere near the China Wall. Changed the intake gaskets on my Xfire. I am running TF 23d heads with mods to the motor. CFI is familiar with it. Anyway, a mechanic friend of mine told me it could be an oil galley plug leaking that is located under the rear top of the head/block interface on the drivers side. That necessitated pulling the head. 5 years ago I installed the TFS heads with ARP bolts using a Felpro 1010 head gasket. Here's what I found on #7




I found that the fire ring was also beginning to pull away from #1 CYLINDER.
On 3rd Gen. org. one of the moderators told me FelPro had this particular type of defect with the 1010 gasket. After calling TFlow, I bought a set of the 1003. Although the compression thickness is .002 more than the supposed .039 on the 1010, the tech at TF said they use the 1003 on all their engine builds and have never had a problem with them. AFR recommends the 1003 for their 195 heads as well. Needless to say, I just pulled the passenger side. It wasn't quite as bad as the drivers side, but the #8 cylinder is showing signs of the same defect. The fire ring is actually pulling away or separating from the gasket material. There was no sign of coolant in the oil, but I was having a hard time getting air out of the coolant system. And I have been struggling with a stumble at idle although cruise seemed to be fine. The oil leak led me to find another, more serious problem.

Slalom4me

Nice to read a thread where the head gasket problem gets
diagnosed and dealt with BEFORE coolant turns the engine
into scrap.

Was glycol/water used for coolant? How frequently was it
changed? How far back do you know the history of the car?

.

Plasticman

Dominic,

I also had the same type of failure (#7 using 1010 Fel-Pro gaskets) on my 87 Vette. It looked exactly like yours.

However, I found the actual problem in my case was due to a failure of the head surface. It had a very localized dip right where the fire ring pulled away. It was difficult to check for and find, because it was so localized and small.

I had the heads milled .003" (which was enough to remove the dip) and we will see if the dip returns. Probably will, but it has lasted for about 6K miles so far. They had been milled .010" previously about 44K miles before the most recent failure due to a port/polish job (that's why they had the Fel-Pro 1010 gaskets). Initially, I blamed the gaskets as well.

Engine has never been overheated (and I run a 160F thermostat - don't start on that, I have heard all the reasons for and against - and it never goes above 211F in the hotest weather, in stop & go traffic, with the AC on), so the cause of the localized dip is a mystery. Although the rear most cylinders certainly can run hotter due to being the farthest from the radiator.

I have used the 1010 gaskets on several engines (race, marine, and street), with no failures up to this one.

Plasticman

Dominic Sorresso

Slalom,

If you are asking me, I am the original owner of the car. And I have used a Prestone/ Distilled water 50/50 mix since I put the AL heads on. Just went to check on the Pass side gasket and it was failing in almost the exact same spot the drivers side was, ie cylinder #2, the mirror image of the drivers side.

Dominic Sorresso

Plasticman,

These heads were brand new. Also, I could understand a localized dip on one cylinder, but so far, I have evidence of the fire ring detaching from the gasket at 3 separate cylinders and on either side of the motor. As I posted previously, pretty good authority at Third Gen told me this was a known defect of the 1010 gasket. Good evidence my set was one of the batch. What I am wondering is if the gasket failure was causing my oil leak.

Morley

I bought a set of Summit's gaskets (full upper engine set) and had the same failure you describe, The fire rings puled free at cylinder #8, mostly pulled free on #7, starting to pull free on #1 & #2, all within 1 year of installation. I'm wondering if Summit used those Felpro gaskets in their kit...Also from that kit I used the warer neck gasket, valve cover gaskets and distributor gasket, ALL of the gaskets I used from that kit failed in less than 1 year.
I mentioned this to Summit, and they looked at my previous orders, found that I had purchased the gasket set from them and refunded the cost of the gasket set.

Stingraynut

I'm the originator of this thread and I'm disturbed to hear of these problems with the Felpro gaskets - especially as I thought they were one of the best.

The heads have been tested now - no cracks - and are being skimmed and reconditioned, I need two new exhaust valves and all new valve guides.

I have just bought an top end gasket set, which came in a Felpro box - I don't know if they are the 1010 gasket - hey'r at the shop I'll have to go and check.

The head will be fitted tomorrow or Tuesday - what should I do ? get a different brand gasket ? which one ?


S'nut

korvette4u

the kit contains all gaskets needed to do upper cylinder rebuild. the intake gaskets must be placed so that the small hole IS AT THE REAR and will be marked this side up. YOU could modify the gasket by enlarging the (small coolant) hole to an 3/4" X 1"oblong hole or make it the same as the front hole,
AS for the head gasket, if it was part of the kit It should be marked PT9, this is the proper gasket for aluminmin head install. These gaskets can also be modified,, IF YOU WANT TOO, the smaller coolant holes between the center cylinders can be enlarged to 13/32". this will then be equvalent to the coolant flow style of the 1010 which is good. how ever the 1010 gasket itself NOT reccommended.

remember to torgue the head bolt down is sequence (MAKE SURE OF THIS). if you reusing the old bolts( perferr new) add 3 ftlbs extra..

korvette4u

i was waiting for a reply to this . what transistor did you use for replacement? and which circuit are we referring to the small (mine)or was it your (larger)