Engine Rebuild, 2.5L Six |
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Engine Rebuild, 2.5L Six |
jfort |
Oct 4 2017, 09:18 AM
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#1
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Senior Member Group: Members Posts: 1,135 Joined: 5-May 03 From: Findlay, OH Member No.: 652 Region Association: Upper MidWest |
I doubt that there will be anything earth shattering or even beyond common knowledge, but if only to document this project, here goes:
This is a big, first time project for me, an attorney and mechanic wannabe. My factory six with a 2.5L engine was missing. Turns out there was only 75% compression in #1 and it was leaking through the inlet valve. Auto Assets in Powell OH diagnosed and my friend and mechanic, Jay Kjoller confirmed. Thankfully, Jay, an experienced air cooled engine builder and racer who lives nearby agreed to take on the project and to let me help. I got the engine out and delivered it to Jay last week. We started the disassembly yesterday. Learned some things about the engine. It has an early aluminum case with Mahle 90mm pistons and Nikasil cylinders. Pretty sure they are 2.7L. It has a later 3-ribbed oil pump, which Jay says is sufficient for what I do. The pistons have been lightened, which Jay said was unusual. We expected to see something that would explain the problem with #1. Other than some carbon accumulation on the head where the valve closes there was nothing. But, having gone this far, we decided to go from top end rebuild to a full rebuild and we split the case. Considerations. I think the engine was built into a 2.5 in the early 70's given SCCA classes at the time, but it is just a guess. My prior owner was Jim Chambers in Oregon. He bought the car in 2001 from Werks 2 in in Burbank CA, which was started a long ago by Harry Bieker (Bieker Engineering) and continued by his son, Galen Bieker. I exchanged emails with Galen but he couldn't remember any details that would help us decide how far to go on the rebuild. But Jay said whoever built it did a good job and he can recognize the approximate build date from the materials used, e.g., paper gaskets and 3 thin copper seals at the bottom of the cylinders. What I would call the wear points, (bearings, cam lobes, valve tappets, etc.) looked to be in good shape. But I wanted to be sure. Jays says he has had good experience with something other than the existing E cam, a Solex cam? that is a little more aggressive. So, we are going to either source that or investigate grinding the E cam. Friday, I will wash all the oily parts. Heads, valves, piston rods go to the machine shop, which is nearby. What can go into a hot bath tank will go there. What can be powder coated will go there. The air shroud, which is green, needs something. Not sure what to do about that. |
JmuRiz |
Dec 7 2017, 09:27 AM
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#2
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914 Guru Group: Members Posts: 5,425 Joined: 30-December 02 From: NoVA Member No.: 50 Region Association: MidAtlantic Region |
Another in agreement with the two above....I'm going the replated cyls with new higher CR pistons running single plug on pump gas.
Twin plug is cool looking for you'd nee more than 9.5:1 CR to make it worthwhile. BUT those coil-on-plugs shown above are very interesting. For now, I'm just going with my good carbs and dizzy (will check the curve to see if it's close enough to 2.7RS spec or send out for recurving) and running like that for a while. If I get flush with $ (haha) I'll do EFI and crank-fire ignition. But I figure doing changes in stages works well to not change too much at a time and feel if an upgrade is worth the $$. |
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