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. |
Mark Henry |
Dec 7 2017, 06:09 AM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Since the OP is running carbs the MS box is another controller, just like in any other ignition only system.
But a debate on this is getting into hijack territory, if you want to argue this please start a new thread. after the Eric Shea/Jay Leno show, I started giving a twin spark ignition more thought. I was going to have to spend money to refurbish my OEM distributor and I was going to go to an optical trigger. more reliable, I think, but still a pain to get there being so close to the fire wall. long story short, we are going to do a crank fire and twin spark. Jay has the jig to drill the hole. (Anyone have a suggestion as to who, east of the Mississippi can drill it?) I figure it will be reliable and easier to tune and it's what Jay has on his race car. as for the cam, apparently there is one a little more aggressive than the Solex, an "S special" or something?, that Jay is going to look into. can't wait to start the rebuild after the turn of the year So now you're getting into the good ol' Slippery Slope (IMG:style_emoticons/default/biggrin.gif) There's absolutly no advantage in running twinplug ignition unless you are running high CR pistons. So you basically need a 10:1 to 11:1 CR So Mahle's are likely off the table mostly due to availability, If you do find a set it will be around the same price as nickies if new. The two other choices are JE pistons with replated stock cylinders, ballpark around $2400 or a set of nickies at $5500. And that's not the end of it, with Nickies (IMO replated stock/JE's as well) you also need $6-700. worth of head studs, the twinplug labour to the heads and lower covers, add the cams, ignition, etc. So you have now more than doubled (or tripled) your parts only bill. |
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