Head gasket recommendations for magnum

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Blackhatguy said:
That's a good start though, now that we've eliminated the pistons we just need the numbers off the cam and see how much those heads are shaved down.
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Cant remember how much it was shaved down unfortunatly unless i can get a thickness measurement from a stock head and compare it to mine but idk if castings are consistant to where i can get an accurate reading.
yellow rose said:
BTW, if you are 100% sure that the cam is ground on a 108 LSA you can install it on a 104 ICL and be close. Only if you are sure.
Whose cam is it.
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I got it from American Custom Cams, told them what was working with and recommended this cam but wondering if they accidentally gave me a different one. I remember calling them up a couple months ago to see what the specs were but they get rid of there records after a year and its already been 3 years since i got it.
 
Off the top of my head I don't know exactly where to look, but any variation would be in machine tolerance rather than casting for the fire deck, the only problem is finding a consistent place with two opposing machine two surfaces to take that measurement from. without a head in front of me to look at, I can't think of any machined surface that is 180 degrees parallel from the face. I'll get back with you on that unless somebody beats me to it.
 
schwinger said:
Found the numbers on top of the piston. H814CP Which is Speed pro hypereutectic pistons. Looked it up and its for a magnum engine 1992 to 99 so i believe the cam is whats causing the problem. I frkn missplaced the cam card too when i moved into my new house so im gonna have a long day looking for that. This blows, should of degreed the cam but got to much in a rush for that trip. It ran fine all the way up there too but i do want to correct this problem so i dont have any future problems.
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I looked it up too. I don't care what it's "listed for", I think that's a big part of the problem. IT's THE tallest compression height I can fine for either the LA OR the Magnum. I think a lot of the problem is these companies start whittlin out parts and they themselves sometimes don't even know what the hell they're for. So yeah, don't believe the ruler. It's the cam. lol
 
You can find that same piston all over Ebay listed for the 67-94 Chrysler 318. LOL There are LOTS of different compression heights available. That's part of the problem. They all get lumped in together.
 
RustyRatRod said:
I looked it up too. I don't care what it's "listed for", I think that's a big part of the problem. IT's THE tallest compression height I can fine for either the LA OR the Magnum. I think a lot of the problem is these companies start whittlin out parts and they themselves sometimes don't even know what the hell they're for. So yeah, don't believe the ruler. It's the cam. lol
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Well that’s just fantastic!! Am trying to avoid taking the pistons out but if I have to i will. Need to get a degree wheel soon so I can degree that cam but will keep you guys updated.
 
BTW, with the critical nature of the P-V clearance here, I'd re-check that clearance for a couple of reasons:
  • You put the head on the block without a head gasket. That will reduce the P-V clearance by the gasket thickness multiplied by the rocker ratio. In other word, you have reduced the P-V clearance by approximately .080" by leaving a .050" thick head gasket out.
  • If you have hydraulic lifters in there, you have a chance that this will show a larger P-V clearance than when running if the lifters have leaked down any. You have to duplicate the actual running compression of the lifter to be accurate.
FWIW.. .the 814 piston CH is not all that much taller than any other 318/5.2 piston out there (except for certain older type low compression truck engine pistons). These all vary within about .020-.030" in CH. It is the lack of eyebrows primarily, combined with the .015" lower Magnum deck and the .020" deck milling and an unknown amount of head milling. Eyebrows on aftermarket performance pistons are typically .220-.280" deep so this problem would be unexpected for those using such pistons. And even the smaller eyebrows on 318 pistons are about .100" deep.

You might as well use a thicker head gasket... no quench is gonna happen here. You can buy Cometics to .100" or thicker. How well they will seal with your present deck and head surfaces, IDK. The surfaces are supposed to be pretty smooth for MLS gaskets.

With a .050" thick head gasket, your not gonna need much of an eyebrow to get to what you need. These pistons crowns are gonna be well over .300" thick, probably pushing .400" thick. This pix is all you are going to need for eyebrows in this case: Single Silvolite Coated Piston - 5.2L Chrysler/AMC/Jeep/Eagle (V8) 1967-84

No reason the reliefs have to be angled or much over .060-070" deep, based on what you have so far. Just find where the valve edges are hitting, make a pattern, and a light cut. Practice on an old piston.

Or a different cam. Can you share the cam PN OP? If you have an older style slow ramp cam, that is going to make this issue worse. It may be as simple as changing to a faster ramp cam.... which might be of benefit on other ways, depending on how you are using this engine/car.

And FWIW #2, the static CR here is not all that high....around 8.9 with an educated guess on the chambers.
 
Alrighty finally got my degree wheel and degreed the cam and
did the procedure to verify LSA and got 108 and and moved on to check the intake centerline and got 104! So my understanding is if it’s lower than the LSA it’s advanced or if it’s higher it’s retarded, correct me if I’m wrong on that. But seeing this, it was advanced a total of 4 degrees on the cam and not 2 degrees which I thought since on an aftermarket 3 key way crank sprocket 4 degrees advance or retard on the crank equates to 2 degrees on the cam. Correct me if I’m wrong on that too. Double checked this and it was correct so on the crank sprocket the advance position was not 4 degrees but was actually 8 degrees. Go figure Think it was an off brand timing set.
Took the timing chain off, put it straight up and got 108 ICL which matches my LSA. For ***** and giggles I Just wanted to check what it was being retarded 4 degrees on the crank and verified a 2 degrees retard on the cam at 110 ICL.
Took the timing chain back off and put it straight up. Checked piston to valve clearence using play dough, used no head gasket and got 070int./0.090 exh. Clearence. The play dough was hard to measure so did the measurement twice and got just about the same numbers so I think my problem all along was too much frkn advance.. gonna degree every frkn engine i build now so I don’t run into this problem again. Should be able to use a thinner gasket now too.
 
When you advance the cam, you lose intake valve clearance and gain it on the exhaust.

As you retard the cam, you lose exhaust clearance and gain on the intake.
 
Not trying to make life harder for anyone, but going from the the exhaust valve hitting the piston (as reported) to .090" clearance with 4 degrees of retard is not making sense. I suspect that the lifters were either pumped up before (giving less clearance that in actual running) or they are collapsed now (showing less clearance than they will actually have running), or both. I could be wrong, but I question the test setup and what the lifters are doing here. Going from lifters pumped up to collapsed will change the valve opening by as much as .200".
 
nm9stheham said:
Not trying to make life harder for anyone, but going from the the exhaust valve hitting the piston (as reported) to .090" clearance with 4 degrees of retard is not making sense. I suspect that the lifters were either pumped up before (giving less clearance that in actual running) or they are collapsed now (showing less clearance than they will actually have running), or both. I could be wrong, but I question the test setup and what the lifters are doing here. Going from lifters pumped up to collapsed will change the valve opening by as much as .200".
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Yup. Something is hinky for sure. Something just doesn't add up.
 
Yes.... a steep ramp cam will have maybe as much .005" lift change at the lifter per degree..... change 4 degrees and that is .020" at the lifter or .030" at the valve.... not the change of around .100" as being reported. That is what is concerning.

I just don't want the OP being fooled because the lifters have bled down and are not opening up all the way, and he ends up with a problem. One way to doublecheck would be to measure the actual full lift at the valve to see if it is about what it should be.
 
nm9stheham said:
Not trying to make life harder for anyone, but going from the the exhaust valve hitting the piston (as reported) to .090" clearance with 4 degrees of retard is not making sense. I suspect that the lifters were either pumped up before (giving less clearance that in actual running) or they are collapsed now (showing less clearance than they will actually have running), or both. I could be wrong, but I question the test setup and what the lifters are doing here. Going from lifters pumped up to collapsed will change the valve opening by as much as .200".
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Welp crap Now thinking about that its possible the lifters bled down. Did some research on getting a more accurate reading so will recheck the clearence again soon and keep you guys updated
 
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So how do you do it if they bleed down, and you can't use the hydraulic roller rocker to dial indicate lift right? So use like a wooden dowel or something? Carpenter blood sorry ! And what is the procedure to find pushed length on these puppies
 
nm9stheham said:
Not trying to make life harder for anyone, but going from the the exhaust valve hitting the piston (as reported) to .090" clearance with 4 degrees of retard is not making sense. I suspect that the lifters were either pumped up before (giving less clearance that in actual running) or they are collapsed now (showing less clearance than they will actually have running), or both. I could be wrong, but I question the test setup and what the lifters are doing here. Going from lifters pumped up to collapsed will change the valve opening by as much as .200".
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Sorry forgot to update the post, from what i remember the lifters did collapse which threw everything off

nm9stheham said:
Yes.... a steep ramp cam will have maybe as much .005" lift change at the lifter per degree..... change 4 degrees and that is .020" at the lifter or .030" at the valve.... not the change of around .100" as being reported. That is what is concerning.

I just don't want the OP being fooled because the lifters have bled down and are not opening up all the way, and he ends up with a problem. One way to doublecheck would be to measure the actual full lift at the valve to see if it is about what it should be.
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I ended up using a used lifter from a previous engine build and took the lifter apart, shoved something in it to make it mimic a solid lifter, put that in and did my clearence checks and from what i recall it just got around .015 int/035 Exh clearence. I put the engine back together with a .045 thick head gasket when crushed, fired it up and dang thing ran smooth!! Took it for a test drive and hard launched it several times, no ping what so ever and ran strong!! i ended up selling the car 3 months later after the repair due to financial reasons.
 
schwinger said:
I ended up using a used lifter from a previous engine build and took the lifter apart, shoved something in it to make it mimic a solid lifter, put that in and did my clearence checks and from what i recall it just got around .015 int/035 Exh clearence. I put the engine back together with a .045 thick head gasket when crushed, fired it up and dang thing ran smooth!! Took it for a test drive and hard launched it several times, no ping what so ever and ran strong!! i ended up selling the car 3 months later after the repair due to financial reasons.
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Boy, that is a delayed update but appreciated. Good outcome except for the last part. Yes, if things are close, you have to mimic a solid lifter with the slack in the valvetrain juuust all taken up.

BTW, I just caught this phrase from the 1st post: "made my day a happy go shitty day". Might be a typo but I think I am going to use this phrase.... whenever my wife doesn't have her hearing aids in LOL
 
nm9stheham said:
Boy, that is a delayed update but appreciated. Good outcome except for the last part. Yes, if things are close, you have to mimic a solid lifter with the slack in the valvetrain juuust all taken up.

BTW, I just caught this phrase from the 1st post: "made my day a happy go shitty day". Might be a typo but I think I am going to use this phrase.... whenever my wife doesn't have her hearing aids in LOL
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Yeah that last part sucked but had to do it which it did save my ***!! And that phrase That ain’t a typo lol and your welcome to use it lol
 
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