connecting rod Help

Hoffman911 · 10-28-2008, 03:16 PM

Can someone give me advice or a thread reference on removing / replacing the connecting rods from the crank WITH OUT splitting the case? Looks like getting the nuts off the bolts is easy, but how do you hold the lower half of the rod, bearing, and bolts when securing the long half of the con. rod??? Help!
The engine is a 2.7 ltr. mag. case.

relayswitcher · 10-28-2008, 06:56 PM

First of all, why is the engine out of the car? What is wrong that you are down to the bottom end and removing rods?.
My educated guess and experience tells me to tell you the 2.7, though running, was removed because it developed head shattering noise. What I learned as many others have, is this engine was in 1974-77 model years. The time when states started requiring smog equipment on automobiles. This was a quick fix by Porsche from Germany's point of view. The equipment involved a pair of "thermal reactors" on both sides of the engine just under each bank of heads where the heat exchanges and headers meet the 3 heads on each side. Thermal reactor heat was so severe the case softened where the head studs would pull away from the engine case especially the lower 12 on both sides. This pulling away or loosening let the heads leak air and lower compression. Most people think it's an exhaust leak when they hear this "shattering noise" and several $$ later they find it's head shatter not exhaust leaks.
Porsches have to be driven or at least warmed up on a regualar basis. Rubber seals and gaskets like in the oil cooler and oil pump can hardened and crack with time if not used regularly.

1st FIX is remove the head studs from the case and have a Porsche Machine shop insert course STEEL threads into the engine case.
2nd... remove the thermal reactors if you can get away without smogging.... In California you don't have to smog a car up to and through 1975. 1976 and newer you have to smog.
3rd.... install and exterior oil cooler at the front of the car ....usually inside the front wheel weld.
4th.... Also, go through all the gasoline involved components and clean out completely especially the fuel injectors.
Without knowing exactly what's wrong it's hard to advise you.
As to removing the rods without splitting the case? Why not? You have just done 85% of the teardown for a rebuild, why not spit and have piece of mind and a fresh 250k to put on the motor?
You CAN remove the rod nuts and back ends with 2 LBS. telescoping magnet from any Auto Zone but why risk blowing the engine early because you didn't bother "going all the way" down to the crank? Again without know why the engine is out..... there is plenty inside to easily replace. Besides you will have to split the case and remove the the studs anyway in order for a Porsche knowledgable Machine Shop to place the steel thread inserts precisionly. "Do not put a 2.7 back together with out doing this to the case " .... or you will only get about 50-70k out of it.
Let me know what's wrong with the engine and maybe I can suggest what's best for you.. ( my opinion of course.) BUt to try and save money just not to split the case is unwise, though you may not see why. Regards, Josh
Rebuild it and have no worries.
Relayswitcher / JOSH

Hoffman911 · 10-28-2008, 07:13 PM

Josh,
Thanks for your reply. I was a bit brief on "Why". This is a race motor. All that you mentioned has been done. What caused the engine to be out of the car...it jumped timing due to a jammed chain tensioner sprocket. top end was opened up to inspect valves and pistons..which have to be replaced. while we are in there, we thought we'd put new bearings on rods after inspection, and install ARP hardware. So, again, I ask how do you stabalize the rod ends with bolts. Can you access the end from the opposite side of the motor, or can you access them from the sump plate on the bottom of the case? Thanks for any help. Larry

relayswitcher · 10-28-2008, 10:06 PM

I spun #5 rod bearing on my stock 81 SC 3.O. Before I split the case I did take the #5 bearing out to see just how bad it was. LIke I said in my last post ( stock rods) I undid the nuts and the rod stayed together because of the bolts. The bolts stay in place really well as you place a magnet on the small cap end and pull the rod arm away. Once I place the rod on the table I gently swung the small cap end around and remove it with the magnet and 2 fingers. I don't know if it works that way with any race ware rods you may have.
Putting them back in with new bearings in place would be the opposite I suppose.... never put rods back on that way you understand.
RelaySwitcher / Josh

JohnJL · 10-29-2008, 02:55 AM

Hoff,
Just my 0.02 and understand you are just doing a "while you are in there" replace so dont want to spend too much time and money but you might as well split it...you'll probably save time and of course you can do other "while you are in theres." Carrera or SC oil pump and a good thorough cleaning for example. At least you'll know everything is 100%.

Hoffman911 · 10-29-2008, 11:00 AM

Thanks to all for your help. We removed the rods this afternoon w/o any problems.
The install should be just as uneventful.
Thanks again.
Larry

relayswitcher · 10-29-2008, 11:17 AM

Larry, Did you use the magnet method? It's pretty easy.

Hoffman911 · 10-29-2008, 12:09 PM

Josh,
Actually, after loosening up the two nuts on the rod bolts, my buddy stabalized the little half of the rod with a long screw driver, I was able to withdraw the long end of the rod, and then rotate the little end with the two bolts 180* on the crank and extract it through the case! It couldn't be any easier. the rod bolts were snug in the little half of the rod the the entire structure just rotated around the crank! I presume the magnet method would work just as well, but the long screw driver was handy, and when it worked....well..we just continued using it. Thanks again for the info.
Larry