JUNK! Blowpro

had this failure on a different engine

I had two gaskets fail like this on my diesel 4Runner after putting the turbo on, machined the head after the first one blew, but not the deck, seems the gaskets can't take the extra pressure with a little dishing in the deck... I would measure the deck before worrying about faulty gaskets, your deck could have warped in that time or have a weak spot/crack causing it to warp a little when warm, I do not claim to know much about this stuff.

have you tried a oem gasket since these felpro failures?
 
So, now the dilema.....

I am putting the head back on my engine in the next few days. The block has been decked and the head has been surfaced. I have two head gaskets, a Felpro and a Guarnitauto (Italian) that came with the gasket kit. Which one to use??? It is not high compression at 9.2 to 1. I am kind of leaning towards the Italian one right now with all the negative info on the Felpro.

It is interesting that the original 1979 gasket that I have just removed was showing distress in the 2-3 spot where the Felpro gaskets have burnt through so it is obviously a highly stressed area for the gasket. It has also developed a water leak into the #2 cylinder in the same spot that one of the other Felpros had leaked. The water leak was caused by corrosion on the block deck surface which had undermined the head gasket.

Dave Evans
 
Well,

My head/cam are on the car now with the Felpro gasket and the engine is just about ready to be mated to the trani and installed - I have 2 weeks of vacation left before I start my new job so I really am trying to plan this out and dont want to get into a last minute gasket swap (I don't have a spare at this time).

Also your analysis of the failure on 79 stocker gasket compared to Felpro's are interesting. The commonality is going to be what kind of pressure are we putting on these gaskets? I looked at the thread and didn't find any Felpro failures with a stock setup but maybe I missed it.

My case; I have a PBS style BV head decked. Nothing done to the block. I am also running dual webers. Wrong fuel condition will absolutely make gasket fail and this is a good thing right? But if these gaskets are failing in not so extreme setups then we do have a problem.

Dave Evans said:
I am putting the head back on my engine in the next few days. The block has been decked and the head has been surfaced. I have two head gaskets, a Felpro and a Guarnitauto (Italian) that came with the gasket kit. Which one to use??? It is not high compression at 9.2 to 1. I am kind of leaning towards the Italian one right now with all the negative info on the Felpro.

It is interesting that the original 1979 gasket that I have just removed was showing distress in the 2-3 spot where the Felpro gaskets have burnt through so it is obviously a highly stressed area for the gasket. It has also developed a water leak into the #2 cylinder in the same spot that one of the other Felpros had leaked. The water leak was caused by corrosion on the block deck surface which had undermined the head gasket.

Dave Evans
Click to expand...
 
Another point

Do the pistons push up into the head above the Deck?

My 11.5:1 pistons did and I found that they would rub the head gasket and cause the metal seal to puncture. I removed the pistons and chucked them in my lathe and put a champher on each piston to prevent this.

I also used Heldite Aircraft gasket compound to bond the stock Gasket to the head and block. I have never lost a Gasket to this method of installation.


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TonyK.

Grimsby Ontario Canada.
 
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failures could be due to both exhaust valves being together in that area of the head
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That's interesting. The port ordering of the Fiat SOHC (E-I-I-E-E-I-I-E) is convenient for making intake runners, but you get the two exhaust valves next to each other at cyl 2/3. Coincidentally I was looking at the Bentley manual for the second generation VW Golf / Jetta a week or so ago. The VW SOHC engine from that era is very similar to the Fiat SOHC engine - one might suspect that VW engineers had a peek at the Lampredi design when they designed theirs. The VW valve train is belt driven with shims over buckets, aux shaft drives distributor and oil pump etc. One notable difference is the port ordering: E-I-E-I-I-E-I-E. So, no adjacent exhaust valves. Perhaps this was done to make life easier for the head gasket?
 
Agree.

Keep posting the info guys lots of good points. Seems to be a trend.
 
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yikes...

"Looking at the pictures again, I am surprised by how straight the blow by is. Paul's failure almost looks like it was purposely cut in this area."

Knowing Paul, and his attention to detail, I have no doubt that the gasket failed exactly as shown, in the manner he spoke of, and was in no way modified.

T
 
None of the failed gaskets looks to be very compressed around the water jacket holes, and most show signs of weeping around these areas...so it's like the head hasn't been tensioned correctly.

You haven't got a problem like head bolts bottoming due to the head being severely surfaced have you? All it would take is the first threads of the bolt to bottom or even hit dirty (previously unused) threads and this of course will give a false torque reading...stretched bolts would do the same thing, as would using a straight torque and not torque/angle with the appropriate bolts.

I've used heaps of felpros and never had a problem... but I don't surface the heads by 60 thou either...and I always replace head bolts that don't measure up.

SteveC
 
Great points!

Excellent point to bring up. Don't know what the others have but I have studs on the back and bolts on the front (relative to firewall). I did not recheck the bolts this go but have previously and did not have issue with it bottoming out - will check when I retorque tonight with a paint pen mark. The nuts on the studs did not bottom out on the threads - I could see that. To your point though concerning the compression of gasket what are you suggesting is the failure mechanism? Like describe how you would think the center blew out? This attention to detail is awesome. That adds another variable to the mix too, like does the gasket elasticity variation play into this, for example, over time does it get brittle and not compress properly. My FP gaskets appeared to be old when I got them and they have been on my shelf for a couple years too. The stock gaskets I used as quickly as I got them. Side note I ran the car last night, forgot how stupid fast it was.
 
Thanks everyone for keeping this thread on the science :)

I never thought of the threads bottoming.

Is it possible that people's torque methods, using oil, anti-seize, or nothing, contributes to a differing force on the bolts and thus possible less than full compression of the mating surface?

not to beat a previously dead horse, but after I warped the last head and blew the gasket due to coolant system failure I measured the block and eyed the surfaces, they appeard straight to me. I dropped it off at my trusted engine machinist. He took .007 off to get the block level between the cylinders. That was why I brought it up before, but given it sounds that you folks have better straight-edges than me that probably isn't the issue.
 
Head surfacing.

I took .120" off of my head and use that gasket. The bolts did not bottom out. I machined the head myself and posted pictures on this form over a year ago when I did it. It was a milled finish, not a mirror finish. Cutter type large Fly head with 1 carbide cutter, single pass.

Head levelled to .010". before machining.

I did retorque the head cold at about 300 miles after installation.

Have run it hard and hot since then with no problems.

TonyK.

Grimsby Ontario Canada.
 
Burned away?

There are obviously more experienced engine builders than me responding, who may be able to answer this question. When a gasket burns out like that, doesn't it take a little head and block material with it?

I've had cast iron exhaust parts that have had to be surfaced after a gasket failure, because the mating surfaces burned away. This was a Lancia Beta cast iron downpipe joint. After multiple attempts at getting this failure prone area to seal, I gave up and welded it into one piece.

Anyway, my thought is that after one burn out of the gasket as shown, I would suspect that the area of the block right there would be burned away enough to cause a subsequent gasket failure there in the future unless the block was checked and/or decked. :confuse2:
 
I did this study years ago.....

But I did it again tonight because my old notes were not very good. When I retorqued the head tonight all but the front middle (the key bolt) rotated to meet torque. That prompted me to redo the study. I have a spare engine, a sectioned head and a head bolt. This is what it looked like:
headboltref.jpg


The short story is there is plenty of room even if you decked the head 0.060". It is possible to get some garbage down there so I would not rule it out as a potential problem but I don't think it is the issue here. Good point and some primo engineering thought, made me scratch my head for a minute.
 
I suppose it would be possible but

before the cast iron was melted away I would expect the smaller bits like the plug electrode to melt from the heat. The cast iron can dissipate a lot of heat and I would expect the aluminum to melt before the iron as well. In my case I did not observe or feel any abnormalities in the iron or alum. I just gave all the surfaces a once over with scotchbrite and brake cleaner, felt normal. We will see in the long term though.
 
Well it could be something to do with shelf life... or even exposure to sunlight that has made the gaskets "harder"... as these non retorque gaskets are supposed to go hard when heated, at least that's what Fiats genuine non retorque gaskets do... the astadur type.

I had (getting off the subject a little) a regular composite (Tako/Payen brand) head gasket give me issues once... on a twin cam... I had the head gasket (still in it's plastic wrapper) on the bench while I washed down all the components with kerosene... some kero got spilled on the bench surface, and found it's way into the plastic wrapper slightly wetting one side (the exhaust side) of the gasket...that side never sealed up, weeping coolant despite several retorques...and the problem disappeared when I replaced the gasket...so odd things can cause a gasket to go bad.

And yes, OFTEN, but not always the gasket getting "cut" like the ones shown will result in some material loss at that point, the fast moving and hot gasses can be like an oxy-acet cutting torch...

SteveC
 
Lost my Felpro gasket at summit point after 2.5 hours (about 8 hrs total time).

motor was about 10.5:1 compression on 93 octane, was running rich, ignition at 35deg total advance, so not what I consider in the range of danger.

I'm now heavily in favor of Felpro being junk, the outer ring on the number 4 cylinder just melted away. pics to follow shortly.
 
Rupunzell said:
~~~~~~~~~~~
For the Fiat 1500cc SOHC, I can manufacture a head gasket in copper, or our CFM-20 (composite fiber w/metal fire rings around bores). I am not able to do this specific gasket in our MLS due to not having the tooling for the needed embossments.

Thanks
Chris Workman
Technical Sales
Cometic Gasket
8090 Auburn Road
Concord, OH 44077
Phone: 440-354-0777 Ext. 133
Fax: 440-354-0350
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[from other post]
Rupunzell said:
Send the failed gasket to:
Their tech folks Mike & Chris:
Technical Sales
Cometic Gasket
8090 Auburn Road
Concord, OH 44077.

I should have two dead ones to send off to Cometic.

Bernice
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Called Cometic and spoke to Mike, he confirmed the above and I let him know I would send him the failed gasket, which he welcomed. I'll take a couple pictures and get it in the mail this week
 
I have a few failed Fel-Pros here that will find their way to Cometic as part of this study/analysis..

One way or another, we will figure out why these are failing..


Bernice

bikesandcars said:
[from other post]
Called Cometic and spoke to Mike, he confirmed the above and I let him know I would send him the failed gasket, which he welcomed. I'll take a couple pictures and get it in the mail this week
Click to expand...
 
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