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cabinfourus
Samba Member
Joined: May 04, 2022
Posts: 11
Location: NC
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 Posted: Wed Jun 12, 2024 7:06 am Post subject: So confused... |
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A few years ago, I came across a rail buggy with a 1.7 type 4 engine. The seller also included a 2.0l type 4 engine that needs rebuilding. I came across a couple of Porsche 1.7l heads pretty cheap that are in great shape, but one head is missing an intake and exhaust valve. I was able to purchase the valves, but I am having a hard time finding the correct springs.
When I look them up on some sites, it says the 1.7 and 2.0 stock springs are the same, but I want to get some more opinions on this. I do have a spare set of 2.0 heads from a type 4 that I can use parts from. I will say, the intake valves are different, but the exhaust is the same. When I measure the springs, they are not the same.
Can someone verify if the 1.7 and 2.0 stock valve springs are the same? |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23111
Location: Oklahoma City
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| Posted: Wed Jun 12, 2024 11:55 am Post subject: Re: So confused... |
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A few years ago, I came across a rail buggy with a 1.7 type 4 engine. The seller also included a 2.0l type 4 engine that needs rebuilding. I came across a couple of Porsche 1.7l heads pretty cheap that are in great shape, but one head is missing an intake and exhaust valve. I was able to purchase the valves, but I am having a hard time finding the correct springs.
When I look them up on some sites, it says the 1.7 and 2.0 stock springs are the same, but I want to get some more opinions on this. I do have a spare set of 2.0 heads from a type 4 that I can use parts from. I will say, the intake valves are different, but the exhaust is the same. When I measure the springs, they are not the same.
Can someone verify if the 1.7 and 2.0 stock valve springs are the same? |
For 411/412 and Porsche 914 with the 1.7L the LATE engines all have the same spring. The part # is 021 109 623 E. That is for all of the engines except the early, Euro only (1968-1969) "V" letter code engines which use a valve spring part # 021 109 623 D.
The automobile atlanta website lists the late valve spring part # as 021 109 623 E for all 914 four cylinders.
Other sites like CIP1 also list 021 109 623 E - STOCK VALVE SPRING - 1.7L-2.0L - BUS 72-79 - VANAGON 80-83
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However, from what I understand (have read), the late buses that had HYDRAULIC lifters, had a stiffer valve spring so that would be bus 1.8L and Bus 2.0L....which are NOT the same engines as 411/412 and Porsche 914.
While all of the case castings and the 1,7L and 1.8L head castings are the same, a lot of little details like valve springs, camshafts and pistons vary.
So....what KIND of type 4 were the 2.0L heads that you have? Also....you really should not be using.....really "reusing" parts from a 2.0 or 1.8 head in a 1.7L head and vice versa.
You can pretty much get away with rocker shafts, arms and shims but the seats and valves are all different and reusing valves at this late date is a risky crapshoot.
Ray |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23111
Location: Oklahoma City
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| Posted: Thu Jun 13, 2024 8:39 am Post subject: Re: So confused... |
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As an added note.....
The Haynes manual for Porsche 914 lists the same valve spring for all three engines, 1.7L, 1.8L and 2.0L (914 specific).
That being said, they list a spring pressure that is 176 pounds at a loaded length of 1.18".
BU.... the without guesswork book for type 4 1.7 and 1.8 and type 2 bus (with type 4 engine) ....for all three engines 1.7, 1.8 and 2.0 (bus specific) as a range of 168 to 186 lbs.
This is probably where you get into differences in factory build levels. There is not any large difference between valve sizes and valve lift until you get into the Euro version of the Porsche 914 which had a different cam.
Also, the injection system used on 411/412 1.7L and Porsch 914 1.7L and 2.0L is what sets the rpm red line. It's the same for both engines. The spring pressures, height and diameter would likely be the same for both engines....1.7L and 914 2.0.
However, the bus 2.0 with hydraulic lifters also has fatter steel pushrods and 10mm adjusting screws instead of 8mm.... for a reason ....and likely uses the higher spring tension.
SGKent in the bus forums....going off memory here....has also pointed out that there is a different part # or spec on the type 2 bus 2.0L engines with hydraulic lifters.
This is why I am asking what 2.0 head you have.
What I would do is contact Len Hoffman at Hoffman Automotive machine (HAM inc.) and ask him what part number of Crower valve springs he uses for the type 4 heads he builds. He is the best in the business. The type 4 store also sells Crower springs in their kits and they are excellent.
In fact, I have been meaning to call him myself as I need a set as well. I may be able to get that info this afternoon. Ray |
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