Several new questions

[andreic]

Hopefully one of these days I'll stop with my questions, the car goes into storage for the winter on Saturday... But here is the new bucket list of questions, if anyone can help.

a) I changed the oil a couple of days ago, and in the process washed the bottom of the engine trying to figure out where the oil leaks come from. The two places that were wet after driving the car back from the wash were: 1) the two pushrod tubes that were not replaced (6 were replaced recently, long story why the other two were not); and 2) the pressure relief valve on the bottom of the engine, near the oil filter. I know that the pushrod tubes leak. But I have not yet heard anyone say that there could be a leak at the pressure relief valve. Is this a common place where these engines leak? Or could it be leaking somewhere else, and dripping down to the relief valve? A mechanic said to check the the oil filter hanger and the oil pressure switch at the top of the car, but none of them seemed obvious sources of leaks.

b) My muffler makes a squeaking sound at low RPM, or when going over even the smallest of bumps. Inspecting the exhaust system, it appears that someone has replaced the original muffler and heat exchangers/headers with a mix of parts. The car is a 1975 1.8L. I think the original system on the car had the straight pipes for the heat exchangers, while the ones I have now are curving down (as they come from the engine), then they curve up to get to the muffler -- like the earlier 1.7L & 1.8L ones. They are stainless steel (the exchangers themselves) -- I guess. More precisely the pipes themselves are rusty colored (deep red), while the heat exchanger covers are shiny, like stainless steel or aluminum.

The fit is not very good: first off, the bolts holding the mounting bracket to the transmission are not screwed all the way in, but rather are unscrewed about 1/2"; it looks as if the heat exchanger pipes are about 1/2" too long. Second, the muffler appears to be an original 2.0L Leistritz muffler, very similar to this one:

914World.com - The fastest growing online 914 community!

But the way it is mounted now it is pushed up right against the bumper, and that is what makes the squeaking sounds. How should I fix this? The part that seems to be wrong is the heat exchangers (too long), but that seems weird, since the distance between the motor mounting point and the end of the tranny never changed in the 1970-1976 years (I guess). Should I find a muffler shop to cut out a piece of the heat exchanger pipes and re-weld them to make them shorter? Or replace the muffler with a narrower one? Or ...?

c) I am in the process of rebuilding a new 1.8L engine. The crankcase was cleaned and miked. It turns out the main crankshaft bearings are out of spec, between -0.001 and +0.002. The shop I was originally working with said "out of bounds is out of bounds, the case needs to be line bored to next size up," but they don't have the tooling to do this.

The other Porsche shop in town said that they've seen this many times, and that these cases are extremely sturdy, and very rarely need to be line bored. What I should actually do is measure the crankshaft journals, put the bearings in the case, and measure the actual inside bearing measurement. If the clearance with the crankshaft is OK, I should just go ahead with the build. Is this kosher? Or should I ship my case to California to get it line bored to next oversize? If yes, anyone know of a source of oversize bearings?

d) My transmission shifts great between 2nd and 5th, but sometimes when the car is stopped completely it refuses to go into reverse or into 1st. (If the car is moving the least bit, it always goes into 1st very smoothly.) I need to double clutch, and then it goes in smoothly. Does that mean that some parts in the 1st/reverse sections need to be replaced? Or is this an adjustment that needs to be done (clutch, or shifter linkage alignment)?

Thanks a lot for all the help so far.

[Dave at Pelican Parts]

a - The seals on the other two tubes can be changed if you pull the tube halfway out of the head. That gives you room to replace the seals, without needing to pull the tube all the way out.

The pressure control valve rarely leaks, the more common ones are where your mechanic said--the oil filter or the oil pressure switch. Sometimes the seals between the oil cooler and the case also leak. (But "rarely leaks" does not mean "it cannot leak"...)

b - Pics would help a lot. The stock 75-76 exchangers have pipes that come out of the head and point forward. Those attach to the exchangers, which make a tight 180 and go to the back of the car. The muffler assembly bolts on there. The exchangers have only one pipe in each side, while the earlier style ones have two pipes inside each exchanger.

Here is one of the pics I was looking for, courtesy of Jeff Bowlsby. These are of the 70-74 style exhaust:



c - Sounds like the first shop measured the journals for the mains? If they did that while the case was torqued, then it's out and needs line boring. The Type IV case is pretty stout, and for many years we used to tell people that a case that needed line-boring was trash, but it's been enough years (and miles and heat cycles) that they are now worth boring. Don't know where to get oversize bearings, though. Try talking to Glenn or Bruce Stone in our Parts department, they should know where to get them.

Also have the spigots where the cylinders go measured. They can evidently start to collapse inward in the middle, and if they do you really need to find a new case at that point.

d - Tighten the clutch and see if that helps. If so, then keep an eye on it. If it gets worse again, you either have a clutch cable that is breaking, or a clutch tube that has broken loose, or you haven't used two nuts on the end of the cable and the single nut is backing off.

--DD

[andreic]

Thanks for the detailed reply, Dave.

a) I'll probably replace the seals on the other two tubes after I take the car out of storage. I was thinking of actually keeping the transmission attached to the car, and to lower the motor an inch or two by disconnecting the support bar from the car. That way I may be able to clear out the obstruction that did not allow me to replace the remaining two tubes.

b) I have the heat exchangers that in your picture are labeled 1.7/1.8, which I figure are the earlier style. I think these are a bit longer (by about 1/2") than what I originally had, and that is causing the problem with the mounting bracket and the muffler. From what I saw in other pictures the bracket that came with the style I have is slightly curved toward the back of the car, precisely to accommodate this slightly longer length.

At this point I have three options:

1) Replace the muffler and the bracket with the older style 1.7/1.8 ones (cost about $250-350 used).
2) Replace the heat exchangers (cost about $700 used).
3) Have a good quality muffler shop cut out about 3/4" of the sloped length of my current heat exchangers to bring dimensions in line with the rest of the stuff in my car.

What do you guys think I should do?

c) I am checking now with Rimco to see if they can get oversize bearings to line bore my case.

d) I adjusted the clutch. It actually seems that **loosening** it by about 1/4" has helped, but I need to drive it a bit more to see if this is indeed the case. My clutch cable is a bit frayed, so I will need to replace it at some point. (Again, most likely in the spring.)

Thanks,
Andrei.

[beatnavy]

With regard to the clutch, it's interesting that "loosening" it helped. I agree with Dave - there's a couple of things that could be going on:

1. Clutch needs tightening (as mentioned) - the normal fix for 1st/reverse grinding

2. Clutch cable stretched and ready to break - may be worth ordering new cable, clevis, etc. based on your description of the condition.

3. Clutch tube has broken its welds at one or two of the three (three?) points. IIRC it is welded in the tube in front of the gear shift, in the tube past the gear shift, and at the firewall where it comes out. If you're down to one weld point, the last one may be ready to give (as it takes all the stress). When it goes, you will lose all clutch and pretty much be stuck, so best to check before that happens. Check by removing carpet and removing the access plate between the seats. Find the clutch tube (there's also an accelerator tube), and see if it moves while you push the clutch. Also inspect weld point at firewall. This normally requires welding to fix. There are some good threads out there about different ways to fix.

[Dave at Pelican Parts]

I would pick up the 1.7/early 1.8 muffler and muffler hanger, rather than chop up the exchangers to hopefully fit whatever it is you have.

You don't have to drop the engine, or even lower it down, to replace the pushrod tube seals. Just slide the tube halfway out of the head, so it's hanging by the middle of the tube. That's enough to replace the seals.

--DD