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: 1,134 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. |
jfort |
Feb 25 2018, 07:54 AM
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#2
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Senior Member Group: Members Posts: 1,134 Joined: 5-May 03 From: Findlay, OH Member No.: 652 Region Association: Upper MidWest |
Did volume of combustion chamber measurement with new JE. Pistons and fresh from the shop heads. 10.78:1. Happy with that. Cams back, too. Described as Solex+. To attain proper piston to head clearance we had to add a couple of copper gaskets at the bootom of the jugs. Still, after a couple of “squeeze the solder” tests, where the curved crown of the piston meets the side of the head it was too tight. So, back to the machine shop to shave a little off the curved top of the piston. What will be gain in volume by that will hopefully made up be being able to use one less copper gasket at the bottom.
Also, the new pistons and rings with my otherwise OK jugs don’t yield the right clearance. So, they are off to Wisconsin for what I would describe as a new layer of Nikosil and some machining. Back at my end, I completed the refinishing of the bottom of the car. Clean, primer and rubber undercoating. Looks good. Got new Hawk HPS pads and fluid. Rotors are good. Bleed the brakes hopefully next weekend. Then off to Track First in Richfield OH where new race seats and harnesses will be installed. |
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