73DATSON Posted February 23, 2012 Report Share Posted February 23, 2012 Can somebody tell me what's the difference between the U67&W58 heads on a L20B motor? And whats a peanut head? THX.:-))) Quote Link to comment
flatcat19 Posted February 23, 2012 Report Share Posted February 23, 2012 http://olddatsuns.com/ Click the SSS Head ID link. Quote Link to comment
datzenmike Posted February 23, 2012 Report Share Posted February 23, 2012 U-67 are the same as the W-58 with one exception. The W58 has round exhaust ports with round steel liners the U -67 has rectangular exhaust ports. U-67 W-58 (exhaust liners) Close up of liners. An open chamber head is at least as big around as the cylinder it covers. There will always be an open space above the piston. Here is a U-67 head below. All U-67 heads are open chamber. A closed chamber head (also called a peanut head because of combustion chamber shape) will always be smaller than the cylinder it covers. There will be places where the piston at TDC is separated from the head by only the thickness of the gasket. This area is known as the quench or pinch area and is very beneficial. The W-58 is almost always an open chamber but there are some rare peanut W-58 heads. Quote Link to comment
73DATSON Posted February 23, 2012 Author Report Share Posted February 23, 2012 THX FOR THE LESSON GUYS...... Quote Link to comment
flatcat19 Posted February 23, 2012 Report Share Posted February 23, 2012 No. Thank you for shouting your praise. :thumbup: Quote Link to comment
ggzilla Posted February 23, 2012 Report Share Posted February 23, 2012 Why do you guys call them peanut? A peanut shaped combustion chamber is indented top and bottom. Others call this shape a "kidney" chamber: Datsun chambers: A Heart-shaped B Kidney C Open Quote Link to comment
datzenmike Posted February 23, 2012 Report Share Posted February 23, 2012 Everyone knows that a 'heart shape' isn't shaped like a real heart but everyone knows what you mean when you say it. The word peanut can also be used to call something small. A six pack up here is often called a peanut and the closed chamber head is smaller than the open. Closed chamber is also cumbersome with too many big words, peanut is easier and everyone knows what you mean just like when you say heart shape. Quote Link to comment
ggzilla Posted February 23, 2012 Report Share Posted February 23, 2012 You might be thinking of the organ. Heart shaped chamber is actually heart-shaped. In a flattened way, but still a heart shape. Has a pointed bottom. Heart figure/symbol And not "everyone knows what you mean" because guys keep asking what peanut head means. Is it possible that "peanut" is just something american 510/Z guys came up with? Non-L-series guys have been calling the non-pointed closed-chambers "kidney" for a looong time. Kidney shape is not pointed on the bottom. Quote Link to comment
EricJB Posted February 23, 2012 Report Share Posted February 23, 2012 Are we talking about kidney beans or the internal organ? I've never seen an actual kidney, so I dont have a mental picture. I do know what a peanut looks like, but had never heard the term "peanut head" before I came here, but I knew what you were talking about. My guess is, if you have to explain peanut to someone, you would also have to explain heart, kidney, and open or closed chamber to them as well. How many people know that a 'Hemi" is just a term for a hemispherical combustion chamber. Most people dont even know what a combustion chamber is. Quote Link to comment
ggzilla Posted February 23, 2012 Report Share Posted February 23, 2012 Yep, people use the same word for different things. Or two different words for the same thing. Makes life interesting. 1 Quote Link to comment
datzenmike Posted February 24, 2012 Report Share Posted February 24, 2012 pea·nut [pee-nuht, -nuht] Show IPA noun 1. the pod or the enclosed edible seed of the plant, Arachis hypogaea, of the legume family: the pod is forced underground in growing, where it ripens. 2. the plant itself. 3. any small or insignificant person or thing. I'd be inclined to believe peanut to mean a small combustion chamber. It doesn't look like a peanut at all but does resemble more a stylized heart shape. What we call heart shape is actually based on the human heart but has morphed into a simplified and symmetrical shape recognized by all. Quote Link to comment
DATSUN671 Posted November 30, 2012 Report Share Posted November 30, 2012 which on makes more power and compression Quote Link to comment
datzenmike Posted November 30, 2012 Report Share Posted November 30, 2012 A smaller or closed chamber head makes more compression. For example on an L20B a closed chamber head bumps it to 8.903 On an L18 it jumps to 9.00 On an L16 the compression drops to 8.21 Raising the compression ratio one point (8.4 to 9.4) ads only 3-4% more power. That's 3 or 4 hp on an L20B. Not cost effective or worth the bother plus having to run a higher octane gas. However raising it to 10.4 adds about 6.5%, 11.4 adds about 9.5%. Best left to race engines. Quote Link to comment
wayno Posted November 30, 2012 Report Share Posted November 30, 2012 It has been refered to a peanut head for a while, as well as closed chamber, I only heard of kidney here on Ratsun, this all really depends on where you are(forums, meets, auto parts store, ect.) on how they refer to differant things in their world. I posted a link below, I hope it works, it refers to heads from the 620 point of veiw. early cyl. head ID It seems that all descriptions are covered in this link. Quote Link to comment
Dawa Posted November 30, 2012 Report Share Posted November 30, 2012 ima start callin the peanut thread "pretzel head" see if it catches on...jk Quote Link to comment
Tristin Posted November 30, 2012 Report Share Posted November 30, 2012 Quick thread jack so I don't need to make a new thread for a small question about L20 heads... I know the L20 block is aprox. 3/4in taller than an L16 block, but what about the heads? Will the shorter L16 valve covers (with the shorter cover bolts) bolt to an L20 head? Quote Link to comment
Laecaon Posted November 30, 2012 Report Share Posted November 30, 2012 Quick thread jack so I don't need to make a new thread for a small question about L20 heads... I know the L20 block is aprox. 3/4in taller than an L16 block, but what about the heads? Will the shorter L16 valve covers (with the shorter cover bolts) bolt to an L20 head? They arent shorter? I have a 68 finned cover bolted to a U67 head. Just need shorter bolts. Quote Link to comment
Tristin Posted November 30, 2012 Report Share Posted November 30, 2012 Was just checking to see if it's only the cover bolts that were shorter and not the actual valve trains. Thanks Jacob. Quote Link to comment
DATSUN671 Posted December 3, 2012 Report Share Posted December 3, 2012 Is there any difference between the L16, L18 and the L20b heads.... Quote Link to comment
datzenmike Posted December 3, 2012 Report Share Posted December 3, 2012 Ha ha ha ........ yes. A little reading.... http://www.olddatsuns.com/html/tech/head_ID_2.htm Quote Link to comment
its_karl Posted December 3, 2012 Report Share Posted December 3, 2012 http://phoenix.craigslist.org/evl/pts/3416177449.html Quote Link to comment
DATSUN671 Posted December 3, 2012 Report Share Posted December 3, 2012 Ha ha ha ........ yes. A little reading.... http://www.olddatsun...h/head_ID_2.htm so if i buy a race cam for the L series head would it fit any of the L series 4 cylinder motors.... Quote Link to comment
datzenmike Posted December 3, 2012 Report Share Posted December 3, 2012 It will physically bolt on to any L series motor but compression ratios may be higher or lower than you want. Race cam??? Are you racing an L motor? because there are only a few heads worth using on a race engine. Quote Link to comment
BigBlack620 Posted March 21, 2013 Report Share Posted March 21, 2013 I know this is an old thread but, if you were to race a L20b engine with weber 44 or 48 DCOE carbs, then which head would you want? I'm guessing a U67 Quote Link to comment
datzenmike Posted March 21, 2013 Report Share Posted March 21, 2013 219 or a re-issued 912 L16SSS head. Has large 1.5" intake ports and closed chamber. L20B compression would be 8.9, but U67 would be my second choice with a port match to the intake. Stock compression. If your intake has coolant in the runners you would have to drill two small holes in the head. Quote Link to comment
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