Tough one here: Warped an O-ringed head, now what?

[sweet97]

I blew a coolant hose and warped my O-ringed head. It will require removing about .030" to clean it up removing the O-ring grooves. My cams have lifts of .425" intake and .416" exhaust. The pistons are Wiseco's notched more than stockers. With a standard .062" thick gasket is there a chance I will have proper piston to valve clearance? Anyone removed this much from a head and used it this way? I have heard of thicker head gaskets but have not seen anyone with them so far.
OK you experienced racers who must have had your heads surfaced more than once or twice, what can you typically get away with? Thanks, mark

 

[GVR4592]

Doing some quick math, I think your going to have some issues. I think a lot of it depends on how far in the hole your pistons are at tdc. Taking .030 off, you are going to lose a lot, if not all of your quench area and you are also risking piston to valve contact. On top of that I think shaving .030 off the head puts it past acceptable tolerances. I'm sure there is somebody more knowledgable than me that could more accurately answer your questions though.

 

[sweet97]

The Wiseco's are not in the hole, they are about even with the deck. I would think this has come up before with someone. A thicker gasket would solve the problem but i am not familiar with the gaskets for our 4G63's. Mark

 

[GVR4592]

Are you using the mitsu mls gasket? As far as I know that is the thickest gasket you can get without going to copper.

 

[sweet97]

I was, .067". The coppers I have seen are .062". But I read they are available in different thicknesses on www.ffwdconnetion.com Mark

 

[snox135]

Some does make a shim for heads that need to br cut down alot. I used one on my Laser when the timing belt slipped. I'm not sure who the manufactor was. The machine shop sold it too me from $20.

 

[dnhieu]

my buddy just had this problem with his setup. hes running custom voila (think thats how you spell it) pistons with 9:1 compression. he was using a "stock" 1g head that has been shaved twice. i dunno how much was taken off but it was on the edge of the service limit. But sure enough when he started up the car we herd them valves just nipping the 9:1 compression pistons just barley.

i dont know what compression pistons you have but i know you have cams and thats going to make the clearance even closer...

hope that helps
david

 

[sweet97]

I have 9:1 pistons. Cams? Yeah I have monster cams. Crower stage 4's.
Intake: 218* duration @ .050" and .425" lift
Exhaust: 216* duration @ .050" and .416" lift. For comparison the popular HKS 272's have these specs:
Intake: 213* duration @ .050" and .406" lift.
Exhaust: 213* duruation @ .050" and .386" lift.
This is not looking good. I am going to do some searching but also ask here. Headgaskets. I know Cometic can make thicker gaskets upon request. I feel that the MLSS is a better gaskit due to the fact that it is OEM and for the most part OEM parts are the best choice. I could get a .092" cometic but that would seem to make a larger area for the gasket to fail since that is where the failure occurs so why make that area wider? So far that is the only thicker gasket I have found. Then there is the question of to copper spray or not. My current head does not seem that smooth to me yet my MLSS held up well as overheating caused the failure due to a hose failure. Maybe composite with a O-ringed head?
I guess since I started this thread I can alter course a bit and ask about gasket prefference and sprays or not. What's the most opopular way to go at 30psi? I have 112 leaded available and if I run pump I back off the boost. Thanks, mark

 

[sweet97]

I have 9:1 pistons. Cams? Yeah I have monster cams. Crower stage 4's.
Intake: 218* duration @ .050" and .425" lift
Exhaust: 216* duration @ .050" and .416" lift. For comparison the popular HKS 272's have these specs:
Intake: 213* duration @ .050" and .406" lift.
Exhaust: 213* duruation @ .050" and .386" lift.
This is not looking good. I am going to do some searching but also ask here. Headgaskets. I know Cometic can make thicker gaskets upon request. I feel that the MLSS is a better gaskit due to the fact that it is OEM and for the most part OEM parts are the best choice. I could get a .092" cometic but that would seem to make a larger area for the gasket to fail since that is where the failure occurs so why make that area wider? So far that is the only thicker gasket I have found. Then there is the question of to copper spray or not. My current head does not seem that smooth to me yet my MLSS held up well as overheating caused the failure due to a hose failure. Maybe composite with a O-ringed head?
I guess since I started this thread I can alter course a bit and ask about gasket prefference and sprays or not. What's the most opopular way to go at 30psi? I have 112 leaded available and if I run pump I back off the boost. Thanks, mark
PS: Which 1G head has the larger studs/bolts? Does the 1G 7 bolt head fit a 6-bolt block as I have a 6-bolt. Thanks again.

 

[snox135]

http://www.innomach.com/shims.htm Here is a link to a company that makes a head shim. They are .020 thickness. When you install it you use the copper spray.

 

[sweet97]

I think I have found a head but great information! I;'ll file this and give you my thanks and a thumbs up! Mark

 

[snox135]

I just noticed this company also offers the in .030, .040, and some in .060.

 

[GTM]

I understand you are having some head problems and wonder if I might jump in here with some help. You can look at my profile which may help in determining some credibility level.

I've taken .020" bend out of a Nissan L20 head using a torch and a 100 ton press. I don't know how many tons I had on it but it was plenty. This was done over the course of 2-3 days, before going home I'd load it up and then in the morning I'd take it out so co-workers could use the press during the day.

I would check my progress by using a straight edge on the top of the head along the valve cover joint while it was being loaded. For those who don't know and never milled a head themselves these surfaces are parallel in most engines so it's pretty safe to take measurments off either side.

I put a few drops of engine oil in several locations and watched for smoke as I was heating the head. This was just eyeball and estimation but knowing the motor oil will be burned to a crisp around 500F I was in the safe zone as long as there was smoke.
...........

No press, there is another way I've used for taking smaller bends out though it was only cowardice on my part to not take more.

If the bend is in the middle then you put 1" wide thin strips of wood at either end of the block and install your bolts or studs and evenly torque down the middle bolts a little at a time and checking the top with the straight edge. There will be spring back so you will need to figure out how much compensate for this.

If someon has a scrap head and block you can test this for yourselves before playing with an expensive piece of equipment. Rough calculations for the head bolts/studs are around 20,000-25,000 lbs each so using 6 or 8 bolts will probably be more than enough. If you have a warp and a twist sand a thickness taper in one or more of of your wood blocks. I've used laths but had to sand them smooth, then I discovered the wooden paint stirring sticks from the hardware store worked just fine. I wouldn't use hardwood for the compression pressures are quite high and you don't want hard spots while bending.

.......................

I noticed there was a piston deck height issue concern, after all the math is done you need to proof your work. Put some modeling clay on the top of the pistons, wipe a little oil on the valves to be checked. Install the head lightly with only the cam followers for the cylr to be checked for 1 cylr and no gasket. So if you are to time off TDC #1, then #4 will be on the rock so this will have your clay. The oil on the valve keeps the clay from sticking when you pull the engine through and you get a perfect impression which you can measure with a depth gage from a vernier caliper. If you are running closer than the thickness of a head gasket then throw an old gasket on that you know the thickness.

Cheers,
GTM

 

[steel_3d]

That's good info, GTM. I have a couple of questions.

What's the recommended piston to valve clearance, and what are the variables that should be considered for picking the apropriate allowable clearance for an application?

Is there any reason you can't check two cylinders at a time, since there's two at tdc?

Or do you do the measurements with the timing belt installed? In that case you could do all the valves on all the cylinders in one shot. Is there no point to measuring all of them? I know some badly machined heads end up with a slanted deck, which could be bad if not checked.

How do you get measurements if your hydraulic lifters are bled?

How do you accurately measure the thickness of the clay with vernier calipers? To me it seems like it would mush up and/or you couldn't find a flat surface to measure from.

Sorry if my questions sound stupid, but I've been meaning to ask these questions for a long time

 

[sweet97]

Well, I'm going to pull the head and have the local machine shop check to see how much it is warped and go from there. Not sure I like the sound of the shims. Did it hold up long with the shim? Thanks, Mark

 

[GTM]

...
What's the recommended piston to valve clearance, and what are the variables that should be considered for picking the apropriate allowable clearance for an application?

Is there any reason you can't check two cylinders at a time, since there's two at tdc?

Or do you do the measurements with the timing belt installed? In that case you could do all the valves on all the cylinders in one shot. Is there no point to measuring all of them? I know some badly machined heads end up with a slanted deck, which could be bad if not checked.

How do you get measurements if your hydraulic lifters are bled?

How do you accurately measure the thickness of the clay with vernier calipers? To me it seems like it would mush up and/or you couldn't find a flat surface to measure from.

Sorry if my questions sound stupid, but I've been meaning to ask these questions for a long time

The only stupid question is the one that is not asked. Now I'm going to do a copout and beg forgiveness for brain fade has set in ever since they started giving me senior discount coffee and McDonald's.

I use to figure on a conservative .125" on my hemi engines but I had Kenny Harmon do my custom grinds design to induce valve float. The rational for this is to effectively kick the valve off the seat and cam at high RPM rather than the valve following the cam. This allows a bigger charge with more duration completely skipping max lobe lift rather than waiting for the valve to follow the cam. Risky business with this type of cam follower that has been known to fall out even with that much clearance. Intake normally would be no closer than .080" and exhaust .100" but you need to profile you cams if you are splitting hairs. Also remember depending on profile the closest point may be between 15 degrees BDTC and 5. as the cam.

You must have them bled of all air, oil pressurize them then pull the cam through a couple of times on the bench to have them adjust. This is another argument for solid adjusters.

There is no need unless you have a bent cam. With the belt off you can run the crank backwards 90 degrees and then the cam 180 degrees. Remember if you rotate the cam, valves will hit unless you lift the head or rotate the crank. This is not the time to have brain fade and do something dumb.

You will incline your vernier so it's effectively parallel with the valve stem, you will spot check 3 or 4 places at the max valve head diameter. If you rock the vernier so the base just kisses the clay you will have a good measurment. The advantage of clay is in 2 seconds you can reform it and lower the head back down. If you are not running studs but have some spare head bolts you can cut the heads off a couple to act as guide pins. You can hold the head off the block with a couple blocks of wood so you can reach in to the clay. Once you do it all will be clear.

Cheers,
GTM

 

[GTM]

Well, I'm going to pull the head and have the local machine shop check to see how much it is warped and go from there.
...

I've made my own straight edges for 1/4 the cost of a factory tool. Good hardware stores including Home Depot carry anodoized T6 aluminum bar stock 1/4"x2". Take two pieces and put them side to side on the edge, you should see no light, flip one around and check again, flip the other around and check again. if you really want to split hairs flip one end to end and recheck. There should be no nicks on the edges, have them cut you a 2' long piece if they will otherwise you will have to buy the whole 6' piece for around $12. This material should be within .001" over it's 6' length so close enough for what you need. File smooth the saw cut, drill a hole and attach a shoelace for hanging and like any other percision tool do not drop.
........................

You can now check warpage by first the 2 outside edges then down the center. Next will be diagonals and then across at various points. The manual should have the specifications. You can use a combination of feelers including a go no-go feeler which I like because it's fast. You can get thes at a parts store with a good tool selection or you can buy them by the each from Snap-On. I like a .002"-004" because it's fairly flexable then any combination of straights. Even if it's warped you can take some out with the press/bending before milling rather than having to take a full 10 or 20 off. Machine shops like working with even numbers but you can tell them to leave a particular area and just kiss the high spots. If they don't want to cooperate find another shop.

You can write the actual measure on the head with a pencil which helps. You can also check the block, manifolds etc.

Give a shout if I can be of any help or answer any questions.

Edit:
Argh, I forgot you had an O ring, all the more reason to try to straighten. Can you get me any info on this... depth, width, diameter?

Cheers,
GTM

 

[sweet97]

What are you doing this weekend? The finger lakes are particularly nice this time of year! I believe the O-ring is .041" set into a .035" groove. Local machine shop can get me the basics but I will remove the O-rings before I bring the head to them.
Man do you have AARP threatening you to join? They say they can save me 2% on my car insurance but never back it with a hard number until I send therm the $19.95 or whatever it is. Must mean a lot to them because they are spending a bit on paper to get me. Seems like I was just 23 and now 53.
I am hoping to have the grooves TIG welded in and then have the head resurfaced. I know the welded area will be a little softer but I must save this head as I had it Ported and polished, bronze guides and 1mm OS valves. Just go without O-rings but get suggestions on head gasket for 30psi use.
I like that grinding cams to induce valve float. The only thing I have induced was vomiting. Wish me luck. I may have it off later this evening. Mark

 

[GTM]

Local machine shop can get me the basics but I will remove the O-rings before I bring the head to them.
Man do you have AARP threatening you to join? They say they can save me 2% on my car insurance but never back it with a hard number until I send therm the $19.95 or whatever it is. Must mean a lot to them because they are spending a bit on paper to get me. Seems like I was just 23 and now 53.
I am hoping to have the grooves TIG welded in and then have the head resurfaced. I know the welded area will be a little softer but I must save this head as I had it Ported and polished, bronze guides and 1mm OS valves. Just go without O-rings but get suggestions on head gasket for 30psi use.
I like that grinding cams to induce valve float. The only thing I have induced was vomiting. Wish me luck. I may have it off later this evening. Mark

I'll be lurking around the phone,waiting to see if my son is having trouble installing a fuel pump some 2300 miles away in OH. Never been up your way in Spring, bet it's lovely this time of year..

AARP had me on their prime mailing list for I would get stuff from them 2-3 times a week when I turned 55. This went on until 60 and now it's once or twice a year. I'm a little leery of any group that would want me as a member. Decades ago they were a little to Right of center for me as a flaming liberal, they have improved their public image and dropped some of the politics though still are a very powerful loby in Washington representing our rights and needs. Just watch out for depression, I had that for 10 years and it almost got the best of me.
.........................

I'm not so sure about the O rings being that effective so it won't hurt my feelings if you weld them up. It's possible they contributed to your problems. You could get some solid copper wire and some silver solder and remake them more to your liking.

I've used Kopper Coat(sp) on hundreds of gaskets including those that said no sealer needed, never had a problem. I think it was Fel Pro site that had a several page article on why head gaskets fail, some interesting reading though not everything I agreed with. I'm also not convinced that all metal gaskets are the way to go. More on gasket a little further down.

The valve float seems to have fallen out of favor once turbos became more common place. Still, knurling guides and sanding valve stems so the scratches are parallel will get you more RPM.

As I recall in the head gasket article they had the math supporting the metal crush rings they use to line the gasket edge at the cylr would support more than twice the pressure that could ever be developed.
.....................

So back to my opinions on head gaskets and water flow. I wrote to 2 gasket makers including Fel Pro and never got an answer but let me run this buy all you and see if it doesn't cause your privates to shrivel

When the factory built these they had the concern of emissions, as part of that they balanced the water flow through the head for the heat exchange for a given HP (BTU). So here you guys come, trying to pull 300 and 400 ponies out of the same engine and yet done nothing about changing the water flow. Thirty years ago the water passages were twice what they are today, look at the gaskets you take off, some will completely blank off block to head water passages. Some are scarcely 1/8" in diameter in non critical stressed areas.

I'm suggesting you get with the drill and Dremel to open these up if you are to give the engine a chance to move some more water through the block and head. Most important will be the exhaust valve side and further from the thermostat should be larger. You don't want the cooling water to take the path of the least resistance which would have the most flow around one cylr closest to the Tstat. Another concern is developing some turbulance in the water to break up any lamanar flow for you want it to exchange as much heat in critical areas as the combustion chamber dome rather than sliding along the top in a jet and out the T'stat.

The laws of physics say if you take that 1/8" hole and enlarge to 3/16 you will double the water flow, if you take it to 1/4 it will quadruple. I'm not suggesting you do enlarge them to 1/4" but see where you can be the most effective.

I've not compared a factory type gasket to the metal replacements but it would be worth the effort to see if they made any improvement.

Cheers,
GTM

 

[Turbo Shogun]

Wow, and I thought the Datsun/Nissan and MG/Mini crowd were the only people to have more mature followers. Fine by me!

I ran the Mitsu 4 layer metal gasket for 15k miles without a problem. Most people recommend the copper coating on the mating surfaces to seal, but I didn't use it and haven't had any problems. It probably lowered my compression ratio a pinch, though, as I didn't have the block or head milled to accomodate the extra thickness.

I don't mean to jack your thread, but I've heard that MLS gaskets can be reused, is this true? I really don't feel like investing in another $86 headgasket ... Especially with all the work that needs to be done on my car.

 

[GTM]

Wow, and I thought the Datsun/Nissan and MG/Mini crowd were the only people to have more mature followers. Fine by me!
...
I didn't have the block or head milled to accomodate the extra thickness.

I don't mean to jack your thread, but I've heard that MLS gaskets can be reused, is this true? I really don't feel like investing in another $86 headgasket ... Especially with all the work that needs to be done on my car.

No need to dance around it with "mature", I'm an old fart and know it. Sometimes I feel like 40, others more like 80 when I can't remember things that happened at 25 or 40. Part of the rewards I get from this site are the mental gymnastics required to deal with:
1) car problems
2) communication skills
3) the younger set with few skills but big egos
4) engineers with MB discussing electrical or ME discussing physics egos
5) one line answers or the shorter "me too"
6) off the wall unqualified responses sometimes based on urban legends
.......................

I have read this about MLS but since I can't credential the source it must be considered hearsay until shown different. That said and claiming professional license I have reused composition factory gaskets on cars with 50k but came apart looking like they were new. They were taken apart because of leaking valve guide seals and blue smoke. These were not TTY bolts thus no problem over-torque of 10%.

Let me remind everyone here, I am not a DSM expert, my wealth of knowledge comes from having worked on every major imported and a good number of minors that ever came into the US until I burned out over a decade ago.
........................

Hopefully sweet97 will have some good news to report for he needs someone to cut him a break. I don't think we are jacking his thread for we are just waiting for him to come back from under the hood or the machine shop with a progress update.

Cheers,
GTM

 

[steel_3d]

Hey Mr. GTM, I just noticed you're an SAE member. If you'd be able to pull down SAE Paper 931679 electronically and share it, I'd be grateful. It's a paper on torque plate honing, which I'm interested in at the moment.

Back on topic (sort of). I still have some questions about your method of checking piston to valve clearance.

I don't understand why "running the crank backwards 90 degrees and the cam 180" gets you the minimum clearance... Can you explain this in more detail, over PM if it's really off topic, or point me to some documentation.

I feel stupid about this subject because I feel that the only way to get the real minimum clearance (assuming no float) would be with the timing belt set, and the crank and cams turning thogether like under running conditions. Even changing cam timing with adjustable gears could change the clearance in my mind.

To pump up the lifters, do you just immerse them in oil and squeeze? Do they really settle down after a few turns on the cam? To me it seems like the internal valve is completely closed and the lifter is solid when it's full of oil. Although I have heard that you can compress them in a vice, so maybe they do allow oil to leak out, I just don't know how they're designed internally and how long it takes them to settle under spring pressure.

The .080" and .100" numbers you gave are for DSM's?

 

[GTM]

...
If you'd be able to pull down SAE Paper
...

Back on topic (sort of). I still have some questions about your method of checking piston to valve clearance.

I don't understand why "running the crank backwards 90 degrees and the cam 180" gets you the minimum clearance... Can you explain this in more detail, over PM if it's really off topic, or point me to some documentation.

I feel stupid about this subject because I feel that the only way to get the real minimum clearance (assuming no float) would be with the timing belt set, and the crank and cams turning thogether like under running conditions. Even changing cam timing with adjustable gears could change the clearance in my mind.

To pump up the lifters, do you just immerse them in oil and squeeze? Do they really settle down after a few turns on the cam? To me it seems like the internal valve is completely closed and the lifter is solid when it's full of oil. Although I have heard that you can compress them in a vice, so maybe they do allow oil to leak out, I just don't know how they're designed internally and how long it takes them to settle under spring pressure.

The .080" and .100" numbers you gave are for DSM's?

Sorry, can't help you out with the SAE request.
..............

On a 4 cylr _inline_ engine the firing order is 1342, thus when 1 and 4 are up 2 and 3 are down, by rotating the crank 90 degrees either way all 4 pistons will be level. There is no way in he*l you can ever foul a valve on a piston if you want to rotate a cam. You do have to worry about valve to valve contact but you feel that if you are pulling the cam through by hand. I prefer going backwards (CCW) this way I then always come forward (CW) up to 1 and 4 again rather than 2 and 3 up. The 180 was to get you to #4 on the rock and then bring the piston up. You were asking about doing both pistons at the same time and you can't unless you rotate the cams which you can't do unless you move the crank.

You have to start someplace so TDC is the easiest but as I stated previously the actual point of closest contact will be somewhere between 15 degrees and 5 degrees BTDC, this will fall within all... most all cam grinds that you will ever find. You must profile the cams, plot them on graph paper to find the exact closest point. I didn't mean to over simplify the process nor did I intend to write a treatise on the subject.
..............

No, you cannot just squeeze the lash adjusters, they need to be in their bores and something like 15psi oil pressure and then to pull the cam through a couple of times by hand. This assumes they are working correctly and not leaking down. If you have noisy lifters in the morning then in all probability they are leaking.

I don't mean to be flip with you for that's not who I am, I would encourage you to read through some comprehensive repair manuals or books from the library. If you are here in Los Angele area there are at least 3 Pick Your Parts type yards within 20 miles of central city here is one site with 2 locations in the county, there is another in Wilmington about 6 blocks away and there are others.
http://www.pickapart.com/
The above site is having a 4 day 1/2 off sale, they all have 1G DSMs and may have some 2G. Buy a couple of adjusters $1-$2 and take them apart so you learn after you have read.
....................

The .080 and .100 are pretty much minimum industry standards. Yes you can do it with the belt on but if you have made a mistake you got the head bolted down and you can kiss your arse goodbye if you made a mistake. This is not shade tree mechanics 101 type stuff. There may be a tech article on degreeing your cams, I didn't write it but have written a few post in years past. In a DSM or any dished piston you don't have shock wave issues bouncing off the valves as you would in a hemi with a big dome piston. Go read up on desmodromic valves and make a set for a DSM and then see if you can keep the bottom end together. (joke) I had a Norton that came with them from the factory.

Cheers,
GTM

 

[steel_3d]

Thanks for the info man. Seems like this is not a quick hack job given that the lifters need to be pressurized and so on. I'm in a bit of a rush. I just wanted to give it a shot if it was easy, just to be sure. But I think I'll be fine, since I'm not doing anything crazy that noone's ever done before. A little material off the head and block, main bore a little higher due to line honing, but each one of those is only a couple of thou. Cams are 272's, maybe I'll adjust them a couple of degrees on the dyno, again nothing crazy. I'd feel safer with a thicker metal gasket, but I'm going with stock cause I don't want leaks.

How does it sound? I'm guessing I'm fine as long as the pistons are not proud of the deck.

Sorry for the hyjack. It's GTM's fault for being an information whore

 

[GTM]

Thanks for the info man. Seems like this is not a quick hack job given that the lifters need to be pressurized and so on. I'm in a bit of a rush. I just wanted to give it a shot if it was easy, just to be sure. But I think I'll be fine, since I'm not doing anything crazy that noone's ever done before. A little material off the head and block, main bore a little higher due to line honing, but each one of those is only a couple of thou. Cams are 272's, maybe I'll adjust them a couple of degrees on the dyno, again nothing crazy. I'd feel safer with a thicker metal gasket, but I'm going with stock cause I don't want leaks.

How does it sound? I'm guessing I'm fine as long as the pistons are not proud of the deck.

Sorry for the hyjack. It's GTM's fault for being an information whore

I've called a lot of things but that's a new one.

You are right about it not being a quick hack job, we got off onto this when previous posters were doing the math on sweet97's clearances should he have to mill the head. When all is said and done it's best to check the real world clearances. BTW I just remembered another trick if you don't like the vernier depth measurment. Pop the clay in the freezer and use a "knife edge anvil" mike. That may not be the correct nomenclature but the shape is like this "^". I've thought about trying JB Weld or a 5 minute epoxy with sawdust filler to make it thick. I hope I've not scared you into not trying, it's not as complicated as it sounds and could have been done in less time than the time it took to write. Having a well equipped shop at home with spare parts like an old questionable fuel pump to pressureize the oil gallery makes a difference.

I don't like reading you are in a rush, that's how bad things happen. Didn't mean to blow you off with the SAE paper, it's just they charge me almost $10 to download. You might find it or even more current info in the library included in another book. Did you try Cummins diesel site?

Title: Torque Plate Honing on Block Cylinder Bores.
Meeting Where Presented: 1993
AUTHOR(S):
Mario R. P. C. Rodrigues - Cummins Brasil Ltda.
Sidney F. Porto - Cummins Brasil Ltda.
File Size: 139K
Product Status: In Stock


Cheers,
GTM