Some differences between RD (Beta1) and XD (Beta2) heads.
01-17-2003, 04:25 AM
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Some differences between RD (Beta1) and XD (Beta2) heads.
Sorry for the jumbo graphics guys, I need to rework these into HTML for viewing by everyone, but I thought I would share.
Here are the originals, but they are HUGE.
http://www.hyundaiaftermarket.com/images/h...ead_info_01.jpg
http://www.hyundaiaftermarket.com/images/h...ead_info_02.jpg
Hopefully, between the forum software, and your browsers, it should resize these automatically
Here are the originals, but they are HUGE.
http://www.hyundaiaftermarket.com/images/h...ead_info_01.jpg
http://www.hyundaiaftermarket.com/images/h...ead_info_02.jpg
Hopefully, between the forum software, and your browsers, it should resize these automatically
01-17-2003, 05:17 AM
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i always wondered EXACTLY what our MLA is and what HLAs are. so it's basically just oil? like an oil bearing? and the purpose of these is to compensate for the expansion of metal that takes place after the engine heats up?
01-17-2003, 05:59 AM
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<div class='quotetop'>QUOTE </div><div class='quotemain'>turbulence:
i always wondered EXACTLY what our MLA is and what HLAs are. so it's basically just oil? like an oil bearing? and the purpose of these is to compensate for the expansion of metal that takes place after the engine heats up?</div>No. HLA is Hydraulic Lash Adjuster. Its a little oil filled "baloon". It keeps the valve closely following the cam lobes. Without it, over time, "lash" or free play between the top of the LA and the cam lobe would develop. The "baloon" is on the underside of the LA cup. It is inflated by oil pressure, and deflated by cam lobe pressure. It is constantly inflating with oil and deflating of oil as the cams rotate.
MLA is Mechanical Lash adjuster. They are little discs of metal (shims) of varying thickness. You install thicker shims to reduce clearance, and thinner shims to increase clearance. To much clearance leads to the cam lobe pounding on the lash adjuster. It is both audible and bad for wear. Too little clearance puts constant pressure on the Cam Lob and Lash Adjuster, leading to decreaseed power, increased friction and increased oil/engine temps.
The HLA system as the oil regulator to regulate oil pressure, and direction of oil flow though the head.
The MLA does not need that oil regulator, as it does not need all of those little oil passages to feed each HLA.
the HLA system is virutally no mantenance. The MLA system requires valve shim checks/adjustments every 25,000 miles.
[ January 17, 2003, 01:02 PM: Message edited by: Random ]
i always wondered EXACTLY what our MLA is and what HLAs are. so it's basically just oil? like an oil bearing? and the purpose of these is to compensate for the expansion of metal that takes place after the engine heats up?</div>No. HLA is Hydraulic Lash Adjuster. Its a little oil filled "baloon". It keeps the valve closely following the cam lobes. Without it, over time, "lash" or free play between the top of the LA and the cam lobe would develop. The "baloon" is on the underside of the LA cup. It is inflated by oil pressure, and deflated by cam lobe pressure. It is constantly inflating with oil and deflating of oil as the cams rotate.
MLA is Mechanical Lash adjuster. They are little discs of metal (shims) of varying thickness. You install thicker shims to reduce clearance, and thinner shims to increase clearance. To much clearance leads to the cam lobe pounding on the lash adjuster. It is both audible and bad for wear. Too little clearance puts constant pressure on the Cam Lob and Lash Adjuster, leading to decreaseed power, increased friction and increased oil/engine temps.
The HLA system as the oil regulator to regulate oil pressure, and direction of oil flow though the head.
The MLA does not need that oil regulator, as it does not need all of those little oil passages to feed each HLA.
the HLA system is virutally no mantenance. The MLA system requires valve shim checks/adjustments every 25,000 miles.
[ January 17, 2003, 01:02 PM: Message edited by: Random ]
01-17-2003, 08:16 AM
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hmm, so since i have MLAs, i need to have my valve shiims checked? i have 37,000 miles. what's involved in checking this? is it on webtech or in the shop manual? also, this little "balloon," is it actually a balloon made out of something? if so, is it in the pictures you have?
[ January 17, 2003, 03:17 PM: Message edited by: turbulence ]
[ January 17, 2003, 03:17 PM: Message edited by: turbulence ]
01-17-2003, 08:23 AM
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<div class='quotetop'>QUOTE </div><div class='quotemain'>turbulence:
hmm, so since i have MLAs, i need to have my valve shiims checked</div>Plz read which vehicles have HLA's and which have MLA's at the top of the article.
hmm, so since i have MLAs, i need to have my valve shiims checked</div>Plz read which vehicles have HLA's and which have MLA's at the top of the article.
01-18-2003, 05:17 AM
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the upsides:
ligher cams. The MLA cams have thinner lobes than the HLA cams do. This means MLA cams are about .5 lbs lighter than HLA cams.
more precise valve timing. The HLA's "squish" when compressed and can affect valve open times and close times.
simplication of head design. Look at all those damn oil holes that need to be drilled into the HLA head. Extra cost when producing the head, extra labor, extra machines, trained personell to do the work, and to service/assemble the completed unit
engineering simplifcation. Granted, the R&D work is already spent, but it is more expensive to R&D a HLA head than a MLA head
MLA's never go "bad", they just need shim replacements. When HLA's go bad, you have to replace the entire unit. When an HLA "collapses" it seriously alters valve timing, when an MLA goes out of spec, you just end up with a noisy valve and SLIGHTLY altered valve timing
there are others, but those are off the top of my brain.
ligher cams. The MLA cams have thinner lobes than the HLA cams do. This means MLA cams are about .5 lbs lighter than HLA cams.
more precise valve timing. The HLA's "squish" when compressed and can affect valve open times and close times.
simplication of head design. Look at all those damn oil holes that need to be drilled into the HLA head. Extra cost when producing the head, extra labor, extra machines, trained personell to do the work, and to service/assemble the completed unit
engineering simplifcation. Granted, the R&D work is already spent, but it is more expensive to R&D a HLA head than a MLA head
MLA's never go "bad", they just need shim replacements. When HLA's go bad, you have to replace the entire unit. When an HLA "collapses" it seriously alters valve timing, when an MLA goes out of spec, you just end up with a noisy valve and SLIGHTLY altered valve timing
there are others, but those are off the top of my brain.
01-18-2003, 09:35 AM
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ah. I was very happy that my car came with HLA, but now I'm kind of not sure. Probably doesn't matter much at all, mostly I just need my car to be dependable, and it is.
[ January 18, 2003, 04:36 PM: Message edited by: blue2000 ]
[ January 18, 2003, 04:36 PM: Message edited by: blue2000 ]
01-21-2003, 08:09 AM
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ok i have a question i have the early engine the hla in my 97 tib fx i just put the 2002 elantra gt intake cam in my car but that intake cam goes out of the later engine the mla and since one of the upsides to mla is lighter cams (.5Lbs) and they have thiner lobes so is it safe to use mla cams in the hla engines when you change thickness of the lobes or is this nothing to be concered with? it just seems like a good stupid question 