TIV Cylinder Head Gaskets, what is the official story???? Options

[John]

I am having some leakage problems with a 2.0 4-cyl and I am trying to narrow down where the leak is coming from.

I thought it was an exhaust leak, but have changed heat exchangers, had the new exchanger off several times and Can not seem to see any evidence of the exhaust leak at the copper exhaust gaskets. None of the exhaust studs are loose or pulled.

I even went to the extent of changing cylinder heads, but the leak remains.

When I changed cylinder heads, I did not know of any information regarding the elimination of the cylinder head gaskets, so I believe that I have them installed.

How likely is it that the cylinder head gaskets can be the source of a leak?

My exhaust leak is intermittent when the engine is up to temperature. (It is quiet while it is warming up idling, but after it is warmed up, sometimes at idle you can notice what sounds like a slight exhaust leak. Not real loud, but noticable)

I was thinking that it may be a cracked cylinder (near the mating surface of the head), but the more I have read about the elimination of the cylinder head gaskets, the more I think that the leak could be those aluminum gaskets.




Does anyone have any information with regards to a bulletin released concerning the elimination of these cylinder head gaskets, and could I get a copy? I would greatly appreciate some advice on this matter.

Thanks.

[bd1308]

service bulliten was fir engines made in the 90s or something, remanufactured
.....

[Jake Raby]

The official story is to remove the gaskets from your gasket set and throw them as far as you can out of sight!

The correct procedure is to attain the target CR and deck height without the gaskets. This typically means installing a .030 shim under the cylinder to correct the deck height change from the removal of the .027 head gasket, or making fine tuning adjustments to chamber volume.

We use a piece of glass covered with lapping compound made from water mixed AJAX to true the sealing surface of each cylinder. The consistency of the AJAX mix should be about like toothpaste for best results.

Then using the same compound lap each cylinder into the register of the head that it will be residing when installed onto the engine. This will creat a machined fit that is superior to any fit the gaskets will give you- (stock gaskets or copper)

I use this procedure religously and head leaks are non existant with our engines with this procedure.

I have written an entire chapter in my engine sealants handook on this procedure- its gonna be good reading.

The head gaskets are evil things... created from 3 pieces of .007 thick aluminum and rolled together.... When they start to leak they blow all to hell and melt cylinders and heads like butter on a 90 degree day...

Thestock cooling system doesn't make things any better with its trait of creating uneven running temps on all 4 cylinders. Over heating means over expansion and over expansion leads to the hint of a leak that starts the death of the gasket.

Those head gaskets have been the demise of many engines that would have lasted 5 longer if they had not failed.

Without the gaskets there is nothing to blow- I haven't used them in years. I have engines running 14:1 CR with this procedure and not a hint of a leak-

[John]

I originally re-assembled the engine in the early 90's. I swapped cylinder heads in 95 or 96 when I noticed the noise for the first time.

I haven't driven the car much over the years, but wanted to get it on the road this summer. I tried re-sealing the heat exhcngers this spring, but could find no evidence of leakage there.

My exhaust leakage persists. The car runs strong and idles well. I would drive it more if I could solve the leakage issue.



Anyone have info on the service bulletin???????

[Jake Raby]

Typically head leaks are LOUDER when the engine is cold, unless they are in the later stages. If your's gets louder with them I'd suspect a cracked exhaust port first off....

Doing a hot and cold comparative leak down test would prove the integrity of the cylinder/head seal better than anything else...

Also, cylinder/head leaks can be noted as the engine is rotating before it fires up. As the engine turns over you should hear all compression strokes very pronounced like crankada crankada crankada crankada.... if you hear it more like crankada, crank, crankada then you probably have lower compression due to leak down on just one cylinder. A ton can be learned from the way the engine starts up- we call it the poor mans compression test and you can do it quick and easy by removing the coil wire and turning the engine over......

If you do this test and note a inconsistency in the revolutions/strokes followed by a "shooshing" sound on the same revolution you can guarantee that you have a head leak in the later stages- tear it down-

[John]

Jake,

I'll try that tomarrow.

I can also do a compression test, but I don't have a leak down gauge to measure leakdown.

One question. How do you safely remove spark plugs from a hot aluminum cylinder head? (that one has always bugged me)

I had always read NOT to do that.

[Jake Raby]

Break torque on them before getting it "Hot".. just barely tighten them and fire it up and let it idle up to temperature..... Then remove them slowly..

Or remove them, coat the threads with Milk Of Magnesia and reinstall them..... The MOM works wonders as anti seize and stays slippery when hot to aid in plug removal.....

[Elliot_Cannon]

Milk of Magnesia? How the hell did you figure that one out? Or is this an old remedy?
Cheers, Elliot

[Jake Raby]

The "Other" aircooled engines i used to work with were Turbo Shafts.... Our ignitor plugs installed into an 85,000 buck combustor section and had a tendency to seize with the extreme temperatures. If they seized it wiped out the combustor....

We could not use anti seize on the ignitor plugs because it effected their grounding and would zap our ignition exciters (400K+ volts)..... So the standard practice was MOM- and it works very well....and does not effect grounding because the magnesium is a slight conductor.

Using MOM on spark plugs works great... It especially helps on race engines using corrosive fuels that can build up on spark plug threads and wipe out the heads when removed..For those we normally trim the bottom thread off the plug so it doesn't protrude at all into the chamber..

I also use dental floss when assembling engines- learned that one from working with a few lycomings! You can read about that one in my sealants handbook!

[Reiche]

QUOTE (Jake Raby @ Jul 28 2005, 10:38 PM)

my sealants handbook!

Information please! When can we get the Type 4-one-one? Is that for sale yet?

[Jake Raby]

Waiting on the artist to finish the cover and the wall charts...

[qa1142]

Jake
How much time per cyl? got more detail on doing this? I don't recall seeing it in your video.

thanks
Will

Everyone else chime in too

[jd74914]

QUOTE (Jake Raby @ Jul 28 2005, 11:12 PM)

The correct procedure is to attain the target CR and deck height without the gaskets. This typically means installing a .030 shim under the cylinder to correct the deck height change from the removal of the .027 head gasket, or making fine tuning adjustments to chamber volume.

This is a really dumb question, but where would you get a cylinder shim to raise to deckheight. Do you really need them if you are just rebuilding the the engine stock and just want to bump up the compression?

[Mark Henry]

QUOTE (jd74914 @ Nov 12 2005, 10:21 PM)

QUOTE (Jake Raby @ Jul 28 2005, 11:12 PM) The correct procedure is to attain the target CR and deck height without the gaskets. This typically means installing a .030 shim under the cylinder to correct the deck height change from the removal of the .027 head gasket, or making fine tuning adjustments to chamber volume. This is a really dumb question, but where would you get a cylinder shim to raise to deckheight. Do you really need them if you are just rebuilding the the engine stock and just want to bump up the compression?

You really need them if the piston sticks out of the cylinders (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Any rebuild should have the CR checked...most likely the #1 thing that separates the pro's from the amateurs.

Jake or Rimco (or myself in Canada) sell the shims.

On the leak itself...Crank it over with no ignition, if you can hear squeaking you have a big head leak.

[jd74914]

QUOTE (Mark Henry @ Nov 13 2005, 07:28 AM)

You really need them if the piston sticks out of the cylinders (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Any rebuild should have the CR checked...most likely the #1 thing that separates the pro's from the amateurs. Jake or Rimco (or myself in Canada) sell the shims. On the leak itself...Crank it over with no ignition, if you can hear squeaking you have a big head leak.

Compression is swept volume to compressed volume correct? In both you include the combustion chamber volume. Knowing the factory specs, is it really that important to cc the combustion chambers, or is it fine to just recalculate based on a volume decrease since the head gaskets are gone?

[Cap'n Krusty]

QUOTE (Jake Raby @ Jul 28 2005, 08:12 PM)

The official story is to remove the gaskets from your gasket set and throw them as far as you can out of sight! ................................SNIP..................................... We use a piece of glass covered with lapping compound made from water mixed AJAX to true the sealing surface of each cylinder. The consistency of the AJAX mix should be about like toothpaste for best results. Then using the same compound lap each cylinder into the register of the head that it will be residing when installed onto the engine. This will creat a machined fit that is superior to any fit the gaskets will give you- (stock gaskets or copper)

Although Jake and I agree on many things, this isn't one of them. I've been building T4 motors for 37 years, and have had ONE head gasket failure in all that time, due to a heating problem unrelated to the gaskets themselves. Granted, only a small percentage of the engines have been other than stock, but I stand firm on the use of head gaskets. Glass, BTW, is NOT considered a "flat" surface in the precision machining business. You see steel surface tables, and granite ones, but NOT glass. I also vocally oppose the long-ago discredited practice of lapping the cylinders, which in the hands of amateurs introduces another possibility of out-of-plane sealing surfaces. The Cap'n

[Mark Henry]

Hope your math is a bit wrong....or did you rebuild the first 411 to come off the boat (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

I don't have 37 years of rebuilding under my belt, but I do have 15 years+ rebuilding them.

I 've had only a handful of failures... a couple of blown galley plugs, one lifter falure (although I've seen/repaired dozens of them) and one blown head gasket. (Again I've seen dozens of them.)
I haven't used head gaskets since 1991.

Maybe it hasn't happen to you, but I can't believe you haven't seen blown head gaskets.

No one's saying it can't be done (head gaskets) BUT there's absolutely no issue when you do it (correctly) without the head gasket. The bonus is you now have 1 (or shoud I say 4) less thing to go wrong.

[Allan]

Hey Cap'n, didn't BJ have head gasket leak at your place when we stopped by on the way to the WCC?

[toon1]

Is "CR " compression ratio? Can the same compound be used for lapping valves?

[Allan]

QUOTE (toon1 @ Nov 13 2005, 10:19 AM)

Is "CR " compression ratio? Can the same compound be used for lapping valves?

CR = Compression Ratio.

I used valve lapping compound on both the head and the cylinder. No gasket and NO leaks...