History - 917 "genes" in the 914 2.0L, The Porsche Racing Dept Engineering input |
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914/4: 70 71 72 73 74 75 76 914/6: 70 71 72
History - 917 "genes" in the 914 2.0L, The Porsche Racing Dept Engineering input |
Tom_T |
Dec 6 2009, 03:35 PM
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#1
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TMI.... Group: Members Posts: 8,318 Joined: 19-March 09 From: Orange, CA Member No.: 10,181 Region Association: Southern California |
UPDATED 12/21/09 & (IMG:style_emoticons/default/santa_smiley.gif) to all!
While the 917 is not strictly 914, it is historical info from the period & definitely original info. from the factory & race drivers of the day. And the pay-off for the link after this "shameless hook", is the info in the thread of how an Engineer from the Porsche Racing Department was able to make the lowly VW 1.7L 4 banger into a respectable "Porsche-bred" 90-100 hp 2L engine - when VW thought it was impossible to go any bigger & had been max'ed out at 1.8L (+/- 200% - recall it started in the 1930's VW as only about 900 cc). See the videos at the link below, & also peruse the additional clips at the sidebar after viewing this one linked below, including those linking to racing 914/6's..... <snipped> If you like racing and the sounds of Porsches, you will love this video: YouTube - Porsche 917 <end snip> Enjoy! Courtesy of our local PCA-OCR membership chair! (IMG:style_emoticons/default/biggrin.gif) Then read the lively discussion on the link between the 917 & 914-2.0 engines, of which even the "Master of 914 O&H" was not aware! (IMG:style_emoticons/default/biggrin.gif) ...Heck! - even I'm learning stuff I didn't know from others of you out there, which I always do! (IMG:style_emoticons/default/biggrin.gif) |
carr914 |
Dec 15 2009, 10:37 AM
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#2
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Racer from Birth Group: Members Posts: 119,021 Joined: 2-February 04 From: Tampa,FL Member No.: 1,623 Region Association: South East States |
I don't recall where I saw the piece on how the 2L was derived in part from the 917's engine. Dang!!!! (IMG:style_emoticons/default/sad.gif) - it was a great connection & I thought I could tie the two stories together. If anyone else has seen that write-up where they talked about engineering the 914-2.0 engine redesign of the prior 914/411 1.7L, in connection with the technology of the 917's 10 cyl. air-cooled racing engine, feel free to add in here! I think it had to do with the cams, timing, etc. on the 917...???? The Connection is Hans Mezger, The Engine Designer. Here is the Qoute from Hans Mezger that I was searching for |
JFJ914 |
Jan 4 2010, 08:38 PM
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#3
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Senior Member Group: Benefactors Posts: 813 Joined: 13-June 03 From: Alpharetta, GA Member No.: 814 Region Association: South East States |
I don't recall where I saw the piece on how the 2L was derived in part from the 917's engine. Dang!!!! (IMG:style_emoticons/default/sad.gif) - it was a great connection & I thought I could tie the two stories together. If anyone else has seen that write-up where they talked about engineering the 914-2.0 engine redesign of the prior 914/411 1.7L, in connection with the technology of the 917's 10 cyl. air-cooled racing engine, feel free to add in here! I think it had to do with the cams, timing, etc. on the 917...???? The Connection is Hans Mezger, The Engine Designer. Here is the Qoute from Hans Mezger that I was searching for I think Mezger meant rod bearings not main bearings as that was the mod that allowed the stroke increase to 71mm. |
Tom_T |
Feb 17 2010, 02:48 PM
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#4
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TMI.... Group: Members Posts: 8,318 Joined: 19-March 09 From: Orange, CA Member No.: 10,181 Region Association: Southern California |
I don't recall where I saw the piece on how the 2L was derived in part from the 917's engine. Dang!!!! (IMG:style_emoticons/default/sad.gif) - it was a great connection & I thought I could tie the two stories together. If anyone else has seen that write-up where they talked about engineering the 914-2.0 engine redesign of the prior 914/411 1.7L, in connection with the technology of the 917's 10 cyl. air-cooled racing engine, feel free to add in here! I think it had to do with the cams, timing, etc. on the 917...???? The Connection is Hans Mezger, The Engine Designer. Here is the Qoute from Hans Mezger that I was searching for I think Mezger meant rod bearings not main bearings as that was the mod that allowed the stroke increase to 71mm. The quote below which TC found & posted above on pg 1 for me was correct - as far as it went: (IMG:style_emoticons/default/agree.gif) However, you're also correct that the Push Rod Bearings were also changed to make them smaller with better materials to allow the 71mm stroke, but the above noted smaller crank bearings made room for that to happen within the center case castings that were also changed a bit for all of that to happen IIRC. So all of the bearings, crank, pushrods & case are different from the 1.7/1.8 is some respect or another to accomplish the 300cc boost, which is why Jake Raby, FAT Performance, et al can only go up to "1.9L & change" with a 1.7/1.8 case, whereas they can go up to +/- 2.5L with a 2.0 case! (IMG:style_emoticons/default/idea.gif) Also IIRC, when I read some other articles on how the 1.7 was enlarged to 2.0 - the Porsche Racing Dept. also tweaked the pistons, rings, sleeves, valves, etc. in both desing & materials to improve the performance, reliability & longevity of the now somewhat over-bored & over-stroked motor - in VW's opinion anyway - but not in Metzger's because he'd used the "better materials" in his racing engine for the 917 & earlier racers. Ergo, these are all "connections" between the 914 & the Rodney Dangerfield "I don't get no respect" 914-2.0 !! (IMG:style_emoticons/default/biggrin.gif) Also, someone was opining somewhere else here on 914world that Porsche went to water cooled technology on their motors at least in part to be able to use 4 valves per cyl. &/or DOHC. However, a quick look at McMark's post of the 917 12 cyl. engine on pg 1 clearly shows 4 valves & DOHC each side of that AIR cooled engine. IIRC, the 1950's souped-up 356 Carrera motor was likewise a $-valve DOHC air-cooled motor, albeit a limited production one. (IMG:style_emoticons/default/idea.gif) And in all cases, when we call our motors "air cooled" - they are in truth "air + oil cooled"!! (IMG:style_emoticons/default/biggrin.gif) So I hope I now stand redeemed for starting this post topic in O&H - in Pat's eyes at least - that there was in fact a fairly critical link between the 914-2.0 - and Porsche's Racing Dept. & their 917s of that same period. (IMG:style_emoticons/default/popcorn[1].gif) |
Bleyseng |
Feb 18 2010, 09:25 AM
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#5
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Aircooled Baby! Group: Members Posts: 13,035 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
I don't recall where I saw the piece on how the 2L was derived in part from the 917's engine. Dang!!!! (IMG:style_emoticons/default/sad.gif) - it was a great connection & I thought I could tie the two stories together. If anyone else has seen that write-up where they talked about engineering the 914-2.0 engine redesign of the prior 914/411 1.7L, in connection with the technology of the 917's 10 cyl. air-cooled racing engine, feel free to add in here! I think it had to do with the cams, timing, etc. on the 917...???? The Connection is Hans Mezger, The Engine Designer. Here is the Qoute from Hans Mezger that I was searching for I think Mezger meant rod bearings not main bearings as that was the mod that allowed the stroke increase to 71mm. The quote below which TC found & posted above on pg 1 for me was correct - as far as it went: (IMG:style_emoticons/default/agree.gif) So all of the bearings, crank, pushrods & case are different from the 1.7/1.8 is some respect or another to accomplish the 300cc boost, which is why Jake Raby, FAT Performance, et al can only go up to "1.9L & change" with a 1.7/1.8 case, whereas they can go up to +/- 2.5L with a 2.0 case! IIRC Jake likes to use the "W and EA" cases as they are stronger for the larger motors. The 2.0L cases have less metal in certain areas and show fatigue quicker. |
Tom_T |
Feb 18 2010, 11:53 AM
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#6
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TMI.... Group: Members Posts: 8,318 Joined: 19-March 09 From: Orange, CA Member No.: 10,181 Region Association: Southern California |
[quote name='Bleyseng' date='Feb 18 2010, 07:25 AM' post='1275359']
[quote name='Tom_T' post='1274986' date='Feb 17 2010, 12:48 PM'] [quote name='John Jentz' post='1258099' date='Jan 4 2010, 06:38 PM'] [quote name='carr914' post='1250852' date='Dec 15 2009, 11:37 AM'] [quote name='carr914' post='1247288' date='Dec 7 2009, 01:12 PM'] [quote name='Tom_T' post='1247138' date='Dec 6 2009, 11:16 PM'] [/quote][/quote][/quote][/quote] IIRC Jake likes to use the "W and EA" cases as they are stronger for the larger motors. The 2.0L cases have less metal in certain areas and show fatigue quicker. [/quote] I just looked at his website again, & everything from 2270 up say either 2L required or preferred. Not having spoken to Jake personally, I can't say for sure whether he prefers the 1.7 EA/W cases for larger than 2.3-2.4L & up builds (i.e.: his custom race engines), but if that is the case - it may be more related to him wanting to machine the thinner spots in a case for his own engines' needs - rather than those appropriate for the mid-displacement Type IV motors. However, I have spoken with Ron at FAT Performance here in Orange & he prefers the 2L core for most "street-worthy" upbuilds (we never discussed a race engine for my 73 2L). Likewise, the guys at GoWesty will only use the 2.1L water-boxer for their bigger upbuilds, as I've discussed them for our 88 Westy - primarily at my wife's prodding to soup-up "her car" after she saw me looking at Raby's engines for "my car" (914)! (IMG:style_emoticons/default/dry.gif) BTW - those "less metal" areas are part of what I was referring to as having come from Porsche Racing/Mezger's input. |
SirAndy |
Feb 19 2010, 03:03 PM
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#7
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Resident German Group: Admin Posts: 41,679 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
Not having spoken to Jake personally, I can't say for sure whether he prefers the 1.7 EA/W cases for larger than 2.3-2.4L & up builds (i.e.: his custom race engines), but if that is the case - it may be more related to him wanting to machine the thinner spots in a case for his own engines' needs - rather than those appropriate for the mid-displacement Type IV motors. Jake has mentioned on numerous occasions that he prefers the 1.7L case over the 2.0L case for his large displacement builds ... (IMG:style_emoticons/default/shades.gif) Andy |
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