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TR3 or 4 combustion chamber, head gasket questions

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kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
Ladies and Gentlemen:
I am building an engine for my 1960 Italia. The original engine was lost, so this is from a TR4. The engine is back from the machine shop. I wanted to increase compression ratio to about 9.75:1. I decided to do the combustion chamber modifications that are described in Kastner's competition manual before making the final mill of the head. did that work, and got chambers cc'd and now all same at 60.2cc on a stock thickness head. Carefully calculated the amount to mill and came up with 0.080" after my combustion chamber modifications. This is with my plan to use the 0.058" Lucas head gasket.

My quandry now is that it appears that if I mill the head this much, that I will (nearly) lose the eyebrow over the intake valve and then lose the sealing surface necessary to use the stock head gasket. I have read that I can use copper and shape the gasket to fit this irregular shape as the racers do. I was trying to avoid this, as have read that copper headgaskets can be finicky to seal. Also, copper forces higher tolerance of the liner protrusions, which I am struggling with a bit at present. Am I correct in this prediction regarding the resultant sealing area after an 0.080" mill? All my modifications are presently inside of the 91mm circle traced onto the head from my gasket.

So here I am, needing to decide on a plan. I have obviously made the rookie mistake of modifying the combusion chamber like a racer might do, but not planning to go that far. If I could use a thinner composite gasket, then maybe reduce the mill amount and retain the sealing surface. What about the steel shim gasket? Is that better than the copper, or even more difficult to seal? What ideas are out there? Or is copper my only option now? And what thickness would you recommend if using copper?

My plan is to just have a fast street tune engine. 270 cam, balanced engine, 87mm bore, period Webers. If I have to go to copper, I read that I will need thinner Fo8 gaskets. Have some 0.014" copper now, and they are too thick. Where can I get some 0.010" copper Fo8's? Is the recommended liner protrusion for the copper gasket 0.002"?

Thanks for help. I have lurked on this site some, but this is my first post. I did some searching but did not find this exact question or problem.



Edited 1 time(s). Last edit at 2018-05-09 07:15 AM by kindacreeky.

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JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Robert,
Lets start with head gaskets and liner protrusion first. Stay away from the solid copper head gasket if you can.
I use the solid copper gasket due to the way my motor is configured. I run 13.2:1 compression.
The solid copper gasket from Gasket Works is the most finiky of all and demand spot on liner projection
of .004, .003 at a minimum with lower compression ratios. Your better off with the shim steel gasket, there are some out there
in that style that are copper and more desirable than steel both are good. I used to use them and I believe they are .027" thick.
For race motors we use .012" copper wire o-rings but not necessary for anything less than 12:1 CR.
In the picture below you can see the copper o rings on a solid copper gasket before copper coat is applied.
What your missing are the reliefs in the liners at the intake valves. Once you remove the eyebrow from the combustion chamber
it leaves a shelf on top of the liner which kills gas flow past the valve.
Not that the eyebrow pocket didn't already but at least the pocket had smooth edges.
The shim steel/Shim copper gaskets already have the eyebrow relief built into them.
It's that square edge that kills the flow. As far as figure 8's go you can buy individual base gaskets from
Mordy Dunst at Gasket Works ( who makes the solid copper head gaskets ) but you are limited to common sheet thicknesses.
I use Mordy's base gaskets as well but still have to hand mill my liners to a very exact projection. Hand milling is another conversation.
I think I've written a procedure on that somewhere. I'm currently using .012". Mordy is a TR4 racer by the way and built some of the craziest motors
you can imagine. http://www.headgasket.com/
We can get you through it but these wet liner motors have to be done a certain way or you end up blowing head gaskets. It all starts with good liner projection.
I've discussed this subject on this site at length but have yet to figure out how I can look up my own past posts.
Jim g


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kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
JimG,
I sure appreciate the reply. Your post offers me hope. I certainly don't want to go to solid copper unless there is not other option.
You mention shim steel or copper shim style gaskets with the intake eyebrow relief already in place. You suggest that these will give me better reliability for my "fast street" engine build. I am all for this plan. I have seen the shim steel gaskets from various sources, but some recommend not to use due to potential corrosion issues. If there is a copper shim style, wonder where I could get this type gasket? Do the "shim style" gaskets have the pressed shape in the edge of the combustion chamber like the Cometic gaskets?

My engine machine shop suggested Cometic, multiple layer type gasket. And I found one in their catalog for TR4, but it says 88mm dia. My big bore Lucas composite gasket measures 92mm, and the intake relief looks like it will get into that gasket sealing ring, so I don't think the Cometic will help.

I carefully measured the liner protrusion with the 0.014" Fo8 gaskets installed and compressed. There is 0.007" pretty consistent down the left hand side. The right is 0.006" or in a few places, 0.0055", pretty much all the way down the right side. When I removed the copper Fo8's they had taken up some distortions from the seats in the block. (I had torqued to 70 ft-lbs for the test). The engine had 0.010" Fo8's in place when it was disassembled. --Bob

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JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Robert,
Cometic makes a fine gasket, just two things, they are a little thicker than the shim type gasket so compression ratio will go down just a bit.
They make a gasket with 91MM fire rings they don't advertise on the website, you have to call them. Its part # H-0793-SP-4043-F.
This gasket doesn't have reliefs for the eyebrow removed so it mucks up total gas flow a bit but for a street engine you won't notice.
As far as your liner projection goes I wouldn't assemble it with .006- .007 projection.
You really need it between .004 & .005. There is a lot to lose if you start getting water in the oil, like the entire engine.
There may be some on this forum that have assembled and gotten away with .006+ but I've never heard of it done and wouldn't do it myself.
You can hand mill the liners to size. I wish I could find the post I made on this subject but lets try again.
This is what you need;

Granite 12"x12" tile from Lowes or Home D
Aerosol contact cement like 3M
a couple packages of 120 grit emory cloth.
Timer

Clamp the tile to a bench on two outside corners
Lightly coat a piece of 120 & let tack for a few minutes, stick it to the tile
Put a small amount like two tablespoons of motor oil in the middle of the paper and spread it around with a putty knife or something.
Set your timer for three minutes & start it.
With both hands pressing down ( top of the liner on the paper ) make forward backward motions in a zig zag pattern using the whole paper.
While doing this rotate the liner in your hands so it's always cutting a different angle.
I alternate zig zag pattern for a minute and then go in a circular motion for a minute. Three minutes of that I pretty much need a break. I often stop at one minute intervals
to catch my breath a little & restart the timer.
Three minutes on a fresh piece of paper and I can take .001 off a liner. I've been doing it this way over ten years so I have it down pretty good. Your results may vary.
I do all the liners for three minutes each and reinstall and re-measure. Be patient and don't over cut them or you will be needing custom base gaskets and more milling.
Use a new piece of paper each time for consistent results. & keep rotating the liner so you get a square cut.
I'm assuming you are using the cylinder head to re-seat the liners each time. Do not ever trust measurements when just clamping down a liner with a bolt and a washer
from a couple corner bolts.
The liners will rock a few thou in their registers and give inconsistent/inaccurate measurements.

jim g



Edited 1 time(s). Last edit at 2018-05-15 11:34 AM by JimG.

kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
JimG:
First, on the head gasket: I have a common Lucas big bore composition type head gasket with 92mm ID rings in it. How does the Cometic 91mm dia head gasket help my situation? the way the Cometic is made, it cannot be modified, I don't believe. If I cut the head by my calculated 0.080" (using the Lucas 0.058" thick gasket), I lose the round shape. Why is this not just as much of a problem with the Cometic gasket?

I have not done the head milling yet, in anticipation of selection of the best head gasket and selection of the optimum thickness.

If there is an available head gasket that is a copper shim style (or any type that would allow for the extra room around the intake valve), then would that not be better than the Cometic or the Lucas? I would rather not have the gasket extending into the path of the intake valve, of course.

As for the liner projection, I know that 0.007 and 0.006" protrusion is too much. I was going to try to find some thinner Fo8's to reduce the projection. I have read that 0.003-0.005 is best for normal stock type head gaskets. But other head gaskets may be best with a different projection. ( I have read somewhere that solid copper gaskets want 0.001-0.002" projection, but not sure where I read that)

Your technique of hand milling the top of the liners is something I would never have thought of, but sure makes sense. But, would it not be easier to buy or make optimum thickness Fo8 gaskets?

Again, thanks so much for your assistance.

JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
I just thought I'd mention there is a Cometic out there for larger bores.
Anyway, unless you are going to the trouble of matching the liners to the head ( see the reliefs ground in the liners above ) it won't make any difference if you use a composite head gasket that projects into the relief.
The top of the liner will still be there unless you cut the reliefs. If your going to cut the reliefs in the liner I'd go with the shim steel. Don't worry about corrosion, they are plated.
I used to get the same embossed gasket in copper from British Frame & Engine when Ken Gillanders was alive. I haven't actually seen one in about six years.
On the custom F08's or base gaskets, finding the exact base gaskets will be your challenge. Mordy Dunst, owner of Gasket Works can or will do them only in specific thicknesses so unless you can find
someone that can make them for you out of any sheet stock you want there are limitations on how much you can adjust liner height with the base gaskets.
You only need to come down .001 - .003" so you would be looking for sheet copper in .011 - .013". I wish I had an infinite selection of base gasket thicknesses, milling those liners is a PIA I could easily do without.
The cheapest horsepower you can buy is from compression. If your willing to run premium you can get that CR up in the low 10's. I think I said earlier I thought the shim steel gaskets were .027 but I read somewhere else
they were .020.
jim

In reply to # 1533293 by kindacreeky JimG:
First, on the head gasket: I have a common Lucas big bore composition type head gasket with 92mm ID rings in it. How does the Cometic 91mm dia head gasket help my situation? the way the Cometic is made, it cannot be modified, I don't believe. If I cut the head by my calculated 0.080" (using the Lucas 0.058" thick gasket), I lose the round shape. Why is this not just as much of a problem with the Cometic gasket?

I have not done the head milling yet, in anticipation of selection of the best head gasket and selection of the optimum thickness.

If there is an available head gasket that is a copper shim style (or any type that would allow for the extra room around the intake valve), then would that not be better than the Cometic or the Lucas? I would rather not have the gasket extending into the path of the intake valve, of course.

As for the liner projection, I know that 0.007 and 0.006" protrusion is too much. I was going to try to find some thinner Fo8's to reduce the projection. I have read that 0.003-0.005 is best for normal stock type head gaskets. But other head gaskets may be best with a different projection. ( I have read somewhere that solid copper gaskets want 0.001-0.002" projection, but not sure where I read that)

Your technique of hand milling the top of the liners is something I would never have thought of, but sure makes sense. But, would it not be easier to buy or make optimum thickness Fo8 gaskets?

Again, thanks so much for your assistance.

JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Some pictures of the process.

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kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
JimG:
I re-read last night the stuff that Kas Kastner wrote in the Competition Manual regarding this subject. I had forgotten that he recommended the shim steel gasket. His description of the gasket as having two fire rings, and that you have to remove the inner ring made sense. Since I have never seen the shim steel gasket, I did not know that it was made with pressed fire rings. (kind of like the Cometic) If you think that following Kas's recommendations in this regard will result in a reliable installation, then I think that is what I will go with. I will follow the procedures to cut back the gasket around the intake valve and also chamfer the edge of the liner in line with the extra shape on the head and gasket.

With the shim steel gasket, what liner protrusion would you recommend? Or should I stick with the manual's 0.003-0.005" protrusion? If I just use the steel Fo8s that I have, my protrusion measurements will drop to 0.003 on one side and 0.002 on the other. The steel will not mash into all the irregularities of the block's sleeve seats, so they might be a little higher at 0.004 on one side and 0.003 on the other.

I attached a technique that I found on the web for making your own Fo8's in any thickness that you can find shim stock. You might want to try this instead of hand milling sleeves.
Thanks for the pics on the milling and the clay technique for marking where to cut the sleeves chamfer.


Attachments:
making Fo8's.pdf    377 KB

JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Larry Young, he's a good guy, one of the most knowlegable guys on Triumph's you will find anywhere.
On the current generation of shim steel gaskets the reliefs are already there, you don't have to do anything other than apply
copper coat. The fire rings you refer to are not the folded type you would see on a composite gasket. The entire head gasket is embossed to create sealing rings.
Shoot for .004" all around. When you use clay to transfer the relief clean the liner at the relief with brake cleaner and grease up the combustion chamber so the clay sticks to the liner & not the head.
jim

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kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
Jim:

Great info. Now I have a good plan. One more question, who has the shim steel gaskets that already have the relief cut into them? do you think that they all are like that? I have been dealing with BPNW and Moss so far on parts.

I spent 5 years repairing the body of the Italia, making panels, sills and repairing all rust damage. That was an adventure in itself. Finding rare parts has been a long term challenge too. Now, with this engine work, I am into a whole new phase of the adventure. Once I have the engine back together, the chassis assembly is next. I am sure that will be a whole new phase of this adventure. Anyway, it is for sure that I won't get bored.

Thanks again for great info and your time and effort.

--Bob

JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Bob,
All the shim style gaskets have a relief but may require a small bit of file work to fully clear the relief. You want to make the relief fairly small, don't go past 50% of the liner thickness.
Just to be safe you can also use duct tape like gorilla tape on the inside of the liner for protection so you don't nick the bore. I use an air die grinder with carbide cylindrical ball nose or flame tip.
http://www.panamericantool.com/carbide-burs.html?gclid=EAIaIQobChMIoKDVzs-K2wIVDtbACh2ueQdxEAAYAiAAEgL0HvD_BwE
Ace hardware often carries them.
Since your doing the motor yourself may I ask who set up the bottom end as far as main and rod bearing clearances? I've had to send more than one crank back to the grinder because
clearances were too tight. Since TR4s only have three mains they get a lot of crank flex and thus require more clearance. .0025 on the mains & rods. .0022 at a minimum.
I'd be happy to work with you all the way through it. If your using the Chris Marx Viton rear main seal we need to discuss that too. There are things you need to know that are not
published in the instructions. I have prep, build and first start up check lists I can send that may be useful to you.
Note, some may say I've missed some steps but I don't start on this list until I've already done one mock up assembly and verified all clearances with inside & outside mics and dial indicators. Pre-assembly is another list.
jim



Edited 1 time(s). Last edit at 2018-05-16 11:30 AM by JimG.


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kindacreeky Robert Slayden
Nashville, TN, USA   USA
1960 Triumph Italia "Italia"
Jim G

I am in Nashville. I got the machine work done by Shacklett Automotive Machine. They are the best engine machine shop around here I have heard, especially used by the racers. They don't normally work on British engines however. I took a copy of the engine clearances and dimensions from the factory manual to them when I got the work done. I have not installed the crank yet. They said that it did not need turning, just polishing. (both mains and rod big ends) So I bought new standard bearings. I know about Plastigage and have some. Have not used it before, but read about how to do it. They removed all the bungs and cleaned out the oil ports and then reinstalled. I had them balance the crank with the flywheel. I will go with the electric fan and thin belt conversion, so dont have all that unbalanced stuff sticking out on the front.

I had the flywheel modified to take a TR4A-TR6 clutch, and while they were at it, I had some weight removed. But only had about 7 lbs taken off.

I bought the rear seal that does not require you to machine the crank. But it is the modern improved version. I think I got it from BPNW, but have forgotten for sure now. I have borrowed a seal install tool from a buddy that is supposed to be made for this seal.

One thing I was going to ask, while my head is back and forth to the machine shop, they could ream out the valve guides larger if necessary. I told them I wanted 0.003" clearance. I have bronze guides. But I have read some forum posters say to do the exhaust 0.0035 - 0.004" clearance. Do you think I should have them enlarge the clearances on the exhaust?

JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
OK, good on the std/std crank. With that you can't get too tight. I'm glad you went the right way and went to a good machine shop. Just so you know, sometimes even the best shops can get it wrong
if you don't go to them with all the right clearances to begin with. Very few understand all the little bits you need to know about TR4's & wet liners, 3 main cranks.
Before I started building Tr4 motors I had done a dozen or so SBC,BBC/SBF/BBF's and all but good practice fundamentals went out the window when I got to TR4's.
It really sounds like your doing everything right, especially asking all the right questions. Unless your planning to do more motors from ground up in the future I'd continue to let
the machinists do your measurements. Plastigauge is subject to too much interpretation. Really good inside & outside mics are really the way to go but also take some practice to use correctly.
That rear main seal ( Viton type )was invented by Chris Marx, one of our very best TR4 drivers/builders in Germany. He's now racing, along with his TR4 a very radical IMSA TR8.
There are a couple things you need to know about it which we can cover.
On the bronze valve guides ( which I use ) you do want .0035 - .004 or they seize up.
Is that same machine shop going to mill the head ? They should CC the combustion chambers to get it right.
jim


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JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
While I'm thinking about it I thought I'd post a few pics.
Put the cam in first, you can handle it better without the crank in place, lube the bearings, if you have some good cam lube thats tacky you can do the lobes after it's in the block.
a good cam lube will be a little sticky and leave strings when you pull your finger away from the lobes.
1st pic put some paper towels & masking tape above the rear main. When you drive in the felt in the rear main seal it pushes the permatex out the joint and it runs down the block and right into the rear cam bearing. catch it with the paper towels and masking tape.
Pics 2,3 & 4 are folded shims made out of thin copper sheet. Right after you assemble the rear main seal you cannot spin the crank until the next day or it will hork up the seal placement.
I drive in these copper shims between the crank flange and the seal itself. As you assemble the seal housing you need a flatblade screw driver to press the seal back into its housing.
If you don't do that it will try to push back out of the housing up against the crank flange. You go four or five points around the seal with the shims. I fold strips in half creating wedges
and then press one strip inside another and tap them in. When all is done there is only about 1/8" clearance between the seal and the crank flange so you have to check your flywheel bolts.
If they project out the back of the flange they will chew up the seal.


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JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
A couple more.


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