Is this OEM exhaust header?, Exhaust header |
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Is this OEM exhaust header?, Exhaust header |
Gatornapper |
Oct 5 2023, 01:43 PM
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#1
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Senior Member Group: Members Posts: 1,235 Joined: 22-September 17 From: Woods west of Richmond, VA Member No.: 21,449 Region Association: South East States |
After a year working very slowly, my 2056 engine top-end-rebuild on my '76 914 s nearing the end.
Tranny is rebuilt and ready to go. Body repainted & ready to go. There has been a problem fitting the original 2.0 exhaust headers into the new heads. One suggestion is that these may not be original. Can "The World" tell me if this is an original header or not? TIA, GN (IMG:http://www.914world.com/bbs2/uploads_offsite/hosting.photobucket.com-21449-1696535014.1.JPG) |
rfinegan |
Oct 5 2023, 02:27 PM
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#2
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Senior Member Group: Members Posts: 973 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region |
yep that will fit a 75 /76 exhaust system
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rfinegan |
Oct 5 2023, 02:30 PM
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#3
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Senior Member Group: Members Posts: 973 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region |
Install tip:
exhaust manifold shrinkage and the studs do not line up? place a small bottle jack or even a cheep floor jack between the 2 drop pipes and press them back a little till they fit.. they are typically real hard to pull them off without a side hammer too |
rfinegan |
Oct 5 2023, 02:31 PM
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#4
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Senior Member Group: Members Posts: 973 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region |
worry not, I have 4 replacements if you need them
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brant |
Oct 5 2023, 02:38 PM
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#5
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914 Wizard Group: Members Posts: 11,632 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
you'll notice that style (stock) of exhaust from 75/76 goes forward first... then loops to the back.
that restriction robs about 5+ HP over the earlier style of 914 heat exchangers and the early style is a bolt on if you have exchangers, muffler, and hanger all from an early car a lot of people back date to pick up free horsepower the SSI stainless style of early exchangers also have a slightly bigger diameter pipe so a desirable choice to get more efficiency I believe the SSI ones use the same tubing on the 1.7 and 2.0 models so that gives you more options if you find 1.7SSI ones... but the muffler and hanger, will have to match either 1.7 style or 2.0 style to do the back date. |
rjames |
Oct 5 2023, 03:09 PM
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#6
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I'm made of metal Group: Members Posts: 3,948 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
*edited*
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Shivers |
Oct 5 2023, 03:17 PM
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#7
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Senior Member Group: Members Posts: 2,408 Joined: 19-October 20 From: La Quinta, CA Member No.: 24,781 Region Association: Southern California |
I thought those were for buses. I’ve never worked on a late 914
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JamesM |
Oct 5 2023, 04:17 PM
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#8
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Senior Member Group: Members Posts: 1,915 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
you'll notice that style (stock) of exhaust from 75/76 goes forward first... then loops to the back. THAT^ with the 75/76 stub pipes they point to the front of the car and the secondary pipes make a U turn. that being said, get a different system, the 75/76 setup sucks. |
cgnj |
Oct 5 2023, 04:34 PM
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#9
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Senior Member Group: Members Posts: 623 Joined: 6-March 03 From: Medford, NJ Member No.: 403 Region Association: None |
What does the rest of it look like. Backdating will be expensive. The days of good used SSI heat exchangers are gone.
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914Sixer |
Oct 5 2023, 04:52 PM
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#10
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914 Guru Group: Members Posts: 8,897 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
Some later versions had heat shields on them.
Attached thumbnail(s) |
JeffBowlsby |
Oct 5 2023, 09:25 PM
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#11
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914 Wiring Harnesses Group: Members Posts: 8,524 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Those pipes are called thermal reactors as they are a thick mass of metal and absorb heat to assist in burning off unburnt fuel hydrocarbons. They were devised as an emissions feature.
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wonkipop |
Oct 5 2023, 10:21 PM
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#12
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Advanced Member Group: Members Posts: 4,364 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille |
Those pipes are called thermal reactors as they are a thick mass of metal and absorb heat to assist in burning off unburnt fuel hydrocarbons. They were devised as an emissions feature. mr. b spot on as usual. theoretically the 75 1.8 suffered no power loss over the 74 1.8 despite the "log" manifold design (for want of a better word) and the toilet S bend trap exhaust design that looks like a 19th century british sanitary engineer cooked it up. but the power curve is slightly different 74 to 75 and the 75 has to rev a small amount more (can't remember exactly but it might be just 100 rpm higher to deliver its eye watering tyre shredding 76 hp. dunno about the 2.0L, they definitely did lose hp to the 74s. maybe the exhaust did it because before that the 2.0L had that very good porsche designed muffler that was like a 911 mini me muffler. whereas in 74, the 1.8s basically have a bus/412 standard fare VW muffler which is nothing special anyway despite the good work the lovely heat exchangers might have been doing. its possible the twin mufflers etc in the 75s were actually better than the original big single log mufflers so they made up for the toilet plumbing heat exchangers. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beer.gif) |
Gatornapper |
Oct 6 2023, 07:04 AM
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#13
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Senior Member Group: Members Posts: 1,235 Joined: 22-September 17 From: Woods west of Richmond, VA Member No.: 21,449 Region Association: South East States |
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Gatornapper |
Oct 6 2023, 07:13 AM
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#14
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Senior Member Group: Members Posts: 1,235 Joined: 22-September 17 From: Woods west of Richmond, VA Member No.: 21,449 Region Association: South East States |
Thanks to all for all the info and detail.
Bummer on the U-turn design. NOT back-dating - have new SS exhaust already from George. Maybe the upgrade to 2056 will make up for the 5hp loss. Got right header in grinding a bit off (1/2" x 1/16") sides of pipes where they meet head, and same on corners of head stud metal. Few gentle taps with 4 lb. sledge does the trick. GN |
rjames |
Oct 6 2023, 10:29 AM
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#15
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I'm made of metal Group: Members Posts: 3,948 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
but the power curve is slightly different 74 to 75 and the 75 has to rev a small amount more (can't remember exactly but it might be just 100 rpm higher to deliver its eye watering tyre shredding 76 hp. (IMG:style_emoticons/default/laugh.gif) |
914_teener |
Oct 6 2023, 01:03 PM
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#16
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914 Guru Group: Members Posts: 5,201 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
theoretically the 75 1.8 suffered no power loss over the 74 1.8 despite the "log" manifold design (for want of a better word) and the toilet S bend trap exhaust design that looks like a 19th century british sanitary engineer cooked it up.
(IMG:style_emoticons/default/av-943.gif) Got to make it to NZ. Almost got there but landed in French Polynesia. I won't repeat the joke about the French flag there..... Anyway...having had both SSI's and the stock 2.0 exhaust...I found the stock acutally gave ...at least by the "butt" feel...better low end torque. May plan was to exothermically paint them for heat savaging purposes...like they used to do for the Hot Rods to increase the flow characteristics. Maybe a project for later...but I found that the steel stock exhaust was better and that because the SSI's stress relieve at different rates....a property of SSI...had a tendency to crack and were absolutely hell to take off and reinstall if needed because of it. My "Worldly" thoughts. |
slapshot |
Oct 6 2023, 02:58 PM
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#17
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Member Group: Members Posts: 58 Joined: 11-June 23 From: Utah Member No.: 27,409 Region Association: Rocky Mountains |
My question is has anyone tried turning them around and fabricating a pipe to attach them to the stock muffler? Something thats been on my mind for a while.
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wonkipop |
Oct 6 2023, 04:57 PM
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#18
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Advanced Member Group: Members Posts: 4,364 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille |
theoretically the 75 1.8 suffered no power loss over the 74 1.8 despite the "log" manifold design (for want of a better word) and the toilet S bend trap exhaust design that looks like a 19th century british sanitary engineer cooked it up. (IMG:style_emoticons/default/av-943.gif) Got to make it to NZ. Almost got there but landed in French Polynesia. I won't repeat the joke about the French flag there..... Anyway...having had both SSI's and the stock 2.0 exhaust...I found the stock acutally gave ...at least by the "butt" feel...better low end torque. May plan was to exothermically paint them for heat savaging purposes...like they used to do for the Hot Rods to increase the flow characteristics. Maybe a project for later...but I found that the steel stock exhaust was better and that because the SSI's stress relieve at different rates....a property of SSI...had a tendency to crack and were absolutely hell to take off and reinstall if needed because of it. My "Worldly" thoughts. NZ is east of us in north antarctica. its a dangerous place full of active volcanoes. but you definitely should try and make it there. i have a lot of kiwi friends - great people. i haven't been there for 30 years but still remember going there fondly. all jokes aside regarding the contortions of 75 log manifolds, which is sort of half true, i honestly think the VW mufflers on 70-74 1.7 and 1.8 cars were no great shakes. i always admire the beautiful curving heat exchanger pipe set up on my 1.8 but the beauty ends abruptly in the section of tree trunk VW called a bus muffler. Those VW mufflers were a product of german TUV noise regulations more than anything else. poor old VWs (and also porsches) concentrated engine noise (in the VW case noise is perhaps flattery and clatter is a better term) and the exhaust outlet in one distinct peak as the test car went past the certifying microphone. this may have been slightly less of a problem in the 914 as the engine and exhaust outlet were just that little bit further apart to get two peaks on the microphone. the rear engined cars had the real problem and set the parameters for the muffler design. or to say it in fewer words the VW muffler is all about noise reduction not exhaust flow. the 75 and 76 cars were no longer bound by having to use an off the shelf VW part. they got their own exhaust system with the cat etc. its entirely possible that despite the contortions involved in all the 75/76 pipework that the mufflers themselves are actually better for exhaust flow than the old standard pre 75 mufflers. i think somehow the 75 mufflers made up for the log manifold and u turn pipe and the playing field levelled enough for a 75 1.8 to pretty much not lose any of its precious few horses. i am not sure but there might be a separate reason for the 75 2.0 L losing power over the earlier 2.0s. don't know enough about them. but perhaps still running D jet meant that they could not be made to meet emissions the same way the smaller cars could - L jet might have helped the smaller cars. it is interesting that porsche chose to adapt L jet for the 2.0L 912e that used up the remaining stock of 2.0L engine short blocks. those 912e cars had to meet calendar year 76 emissions for california and USA. using L jet would seem to suggest that D jet could not be made to pass emissions without some serious compromising of power. porsche and VW used a trick in USA emission laws to sneak the last of the D jet cars through in 76 MY. basically they had to stop making them by the end of 1975. they could qualify as 75 emissions cars that way. |
brant |
Oct 6 2023, 05:51 PM
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#19
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914 Wizard Group: Members Posts: 11,632 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Why fab
It’s hard and time consuming Especially when there is already a great product that bolts on Fits tin work And fits the car already |
Gatornapper |
Oct 6 2023, 07:33 PM
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#20
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Senior Member Group: Members Posts: 1,235 Joined: 22-September 17 From: Woods west of Richmond, VA Member No.: 21,449 Region Association: South East States |
Because of the angles involved on the headers for studs, etc., I don't think you could flip them. But maybe someone else knows....
Brant - what is the product now on the market? TIA, GN Why fab It’s hard and time consuming Especially when there is already a great product that bolts on Fits tin work And fits the car already |
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