Newbie engine teardown/rebuild - advice always welcome!

[kcheves]

Originally Posted by GT2BH

Thanks

On a different topic, here is a friends mint 1973 2.7 RS


and my other Porsche with its big brother, also owned by the same person

Wow, a GT1. Only one I've seen in person was at the Porsche Museum. Very rare and beautiful.

[fritzgator]

Looks like a combination of grinding marks and impact damage. As far as rebuild goes, post a callout to european pelicans for shop recommendations. If i could afford the rebuild i wanted, which is still fairly modest, i would do 3.2SS,with PMO carbs and whatever cam grind best suited for that setup. Maybe PMO's EFI setup if i had More knowledge on such things.

[GT2BH]

Originally Posted by fritzgator

Looks like a combination of grinding marks and impact damage. As far as rebuild goes, post a callout to european pelicans for shop recommendations. If i could afford the rebuild i wanted, which is still fairly modest, i would do 3.2SS,with PMO carbs and whatever cam grind best suited for that setup. Maybe PMO's EFI setup if i had More knowledge on such things.

Should I be concerned with the marks?

I am inclined to keep the CIS, don't want to go overboard.. especially that I'm spending quite a bit on new fuel lines, new oil lines and cooler (Elephant Racing), etc.. Maybe the next stage..

I'm going to start putting my shopping list together now.. If you had to set a budget for a new rebuild, what would you ideally be looking at?

[GT2BH]

Originally Posted by kcheves

Wow, a GT1. Only one I've seen in person was at the Porsche Museum. Very rare and beautiful.

The GT1 actually hit the track that day.. so did the 2.7.. and many others from their collection.. it was a great day.. I'll post more pictures when I'm home

[fritzgator]

Just check to make sure there aren't any burrs that could break loose later,other than that it looks ok to me. Search 3.2ss or ss3.2 for alot of info on variety of intake options. Did you even mention going 3.2 or is that me just projecting? If staying 3.0 i think cams, distributor recurve, CIS and headers(guessing you'll pass on heat exchangers) would be best $$ spent. Keep in mind that all my input info was garnered here on pelican, and there are many people here with actual experience with these matters. I'd Start a separate thread asking for options.

[GT2BH]

Originally Posted by fritzgator

Just check to make sure there aren't any burrs that could break loose later,other than that it looks ok to me. Search 3.2ss or ss3.2 for alot of info on variety of intake options. Did you even mention going 3.2 or is that me just projecting? If staying 3.0 i think cams, distributor recurve, CIS and headers(guessing you'll pass on heat exchangers) would be best $$ spent. Keep in mind that all my input info was garnered here on pelican, and there are many people here with actual experience with these matters. I'd Start a separate thread asking for options.

All options are open at the moment. I am looking a budget of $10k, give or take, and up for suggestions. Typically with any project, you start thinking one thing and slowly end up changing your mind I have been researching the 3.2 conversion and there is a lot of information, but my problem is I have no access to a good, reliable machine shop locally. I contacted the main machine shop and they said they don't have people available to disassemble, they will only do the machining.. I am not very comfortable with that.. yet I don't want to replace everything if my parts are fine or need minor machine work..

It's a bit of a mess but I'll get through it.. all guidance says I will need to replace my alusil cylinders so I'm looking at taking the leap to 3.2..

[RDM]

Originally Posted by GT2BH

It's a bit of a mess but I'll get through it.. all guidance says I will need to replace my alusil cylinders so I'm looking at taking the leap to 3.2..

I've seen a number of threads where members report success at reusing Alusil cylinders, including a very long thread that discusses DIY reconditioning. But if you're looking for a pretext, this will do!

Edit: Here it is: Re-ring Alusils?

[GT2BH]

Originally Posted by RDM

I've seen a number of threads where members report success at reusing Alusil cylinders, including a very long thread that discusses DIY reconditioning. But if you're looking for a pretext, this will do!

Edit: Here it is: Re-ring Alusils?

Thanks Dru - I'll go through it today.

Do you recommend any machine shops in Germany that I can ship my stuff to? I was in Dusseldorf a couple of months ago and visited a few places but I didn't take down any details

[KTL]

Looks like you had some cylinder leakage at cyl. #3, due to all the crud around that area of the case. Maybe when the studs were replaced, that cyl. was not sufficiently tight. If you have all steel studs, your engine has been serviced above the case at some point. The SC engine originally came with steel upper, dilavar lower studs.

Case looks REALLY clean inside which is nice to see. Bearings look to be in good condition from a far distance.

I wouldn't bother taking apart the cam towers down to the bear minimum. Only need to remove the rockers & shafts and the camshafts for a thorough inspection & cleaning. For peace of mind you can pull out the aluminum end plugs and run a nylon brush thru the spray bars to clean out any crud in there. Also inspect the oiling holes by fishing some stiff wire thru each hole. NO reason to fully remove the spraybar if you do not truly need to do that.

[GT2BH]

Originally Posted by KTL

Looks like you had some cylinder leakage at cyl. #3, due to all the crud around that area of the case. Maybe when the studs were replaced, that cyl. was not sufficiently tight. If you have all steel studs, your engine has been serviced above the case at some point. The SC engine originally came with steel upper, dilavar lower studs.

Case looks REALLY clean inside which is nice to see. Bearings look to be in good condition from a far distance.

I wouldn't bother taking apart the cam towers down to the bear minimum. Only need to remove the rockers & shafts and the camshafts for a thorough inspection & cleaning. For peace of mind you can pull out the aluminum end plugs and run a nylon brush thru the spray bars to clean out any crud in there. Also inspect the oiling holes by fishing some stiff wire thru each hole. NO reason to fully remove the spraybar if you do not truly need to do that.

Yeah the crud looked like it was concentrated around cyl 3, and as I mentioned earlier some studs were really easy to remove. Whoever did it before was probably sloppy. The case opened up real quick like there wasn't any sealant applied before.

So you don't think I should consider replacing the valve springs, etc? I'm considering sending my heads for proper inspection and machine work to the US but it'll cost me dearly, so I want to make sure I get full benefit

[KTL]

Porsche original valve springs are really good but nothing lasts forever. They had some problems with broken valve springs in a small number of SCs but otherwise they have been great. So, no, I don't think replacing the springs is an absolute must. Especially not on a stock engine refresh.

Well the case should take some effort to pop it open. I don't see much of any orange Loctite 574 sealant on either of your case halves. Did you already clean the residue off or is it pictured exactly how it came apart? If there's no signs of orange sealant, someone has previously opened the engine case. And those marks inside the case would lead me to believe someone has been inside it before.

If you send them to G2 Performance in Michigan (cgarr here on the forums) he can do all the assembly work on the heads. So you don't need to disassemble them.

[GT2BH]

Originally Posted by KTL

Porsche original valve springs are really good but nothing lasts forever. They had some problems with broken valve springs in a small number of SCs but otherwise they have been great. So, no, I don't think replacing the springs is an absolute must. Especially not on a stock engine refresh.

Well the case should take some effort to pop it open. I don't see much of any orange Loctite 574 sealant on either of your case halves. Did you already clean the residue off or is it pictured exactly how it came apart? If there's no signs of orange sealant, someone has previously opened the engine case. And those marks inside the case would lead me to believe someone has been inside it before.

If you send them to G2 Performance in Michigan (cgarr here on the forums) he can do all the assembly work on the heads. So you don't need to disassemble them.

That picture of the case is 5 seconds after I opened it. I am sure this engine was messed around with before since I noticed alot of irregular bolt and nut sizes. There is no sealant as you can see. This is why I don't want to take a chance on the heads or the springs since I really don't know what the engine has been through.

I got some stuff in the mail.. it seems the cart arrived before the horse

[KTL]

Understood on the history. But if there was no sealant used, the case parting line would be extremely leaky. I don't know what was used to seal it, but it must have been VERY thin!

If you want to get new valve springs, that's understandable. Porsche factory valve springs are really good springs so do not hesitate to get new OEM Porsche springs.

What is the black Permatex sealant going to be used for? I would recommend against using it to seal the case thru bolts like shown in the 911 Engine Rebuild book. That is a very messy/sloppy way to seal the thru-bolt o-rings and captive washers.

The best way to ensure the o-rings seal is to make sure the o-rings have enough room under the captive washer and are not crushed by it when the bolt is tightened. There is a massive debate that went on not long ago about how to seal the thru-bolts properly.

Your opinion wanted. Green bolt through viton o-rings with rtv

I'm of the opinion that the correct o-ring (green type) lubricated with special grease, oil, DowCorning 112 paste (or similar silicone paste) or whatever lubricant you choose, and a slight countersink in the case thru-bolt holes is the right way to make sure those o-rings are not damaged and seal properly

[GT2BH]

Originally Posted by KTL

Understood on the history. But if there was no sealant used, the case parting line would be extremely leaky. I don't know what was used to seal it, but it must have been VERY thin!

If you want to get new valve springs, that's understandable. Porsche factory valve springs are really good springs so do not hesitate to get new OEM Porsche springs.

What is the black Permatex sealant going to be used for? I would recommend against using it to seal the case thru bolts like shown in the 911 Engine Rebuild book. That is a very messy/sloppy way to seal the thru-bolt o-rings and captive washers.

The best way to ensure the o-rings seal is to make sure the o-rings have enough room under the captive washer and are not crushed by it when the bolt is tightened. There is a massive debate that went on not long ago about how to seal the thru-bolts properly.

Your opinion wanted. Green bolt through viton o-rings with rtv

I'm of the opinion that the correct o-ring (green type) lubricated with special grease, oil, DowCorning 112 paste (or similar silicone paste) or whatever lubricant you choose, and a slight countersink in the case thru-bolt holes is the right way to make sure those o-rings are not damaged and seal properly

The case was pretty leaky, that is a primary reason why I decided to do a full teardown.

I bought all the items on the shopping list as per Engine Rebuild book. I will go through that thread and make sure to do it in the best way possible, thanks for pointing me in the right direction!

I dropped a PM to cgarr and he came back to me with some good advice. I will know more this weekend once I remove the rockers, shafts and camshafts for inspection. Will post more pictures soon.

[GT2BH]

OK - rockers removed, heads separated, camshafts out, and rods removed.

Now, lets play "Normal or Not", starting with the obvious one



Not sure where that piece of plastic came from!


Now, rod bearings




Camshaft

[GT2BH]

Heads



For the Cyl 4,5,6 heads, one of each exhaust stud has white material on it


Despite the rod bearings, the crankshaft looked OK

[GT2BH]

and one thing I found strange. While all the rocker bolts I removed were lubricated, the cyl 4 intake side bolt was rusted and dry

[GT2BH]

Just weighed my rods, they were (in grams), 745, 745, 740, 744, 745, 744. 5 grams off the 3rd one, which had the worst bearing pictures above. Should I be concerned?

[KTL]

Those rod bearings are a mess. The crankshaft may look good by eye but run your fingernail across the surfaces. If you can feel ridges with your fingernail, the crank needs to be polished.

The rocker shaft bolts were lubricated because the rocker shafts were not sealing well in the cam housing. They all should be dry.

The camshafts are pitted likely from using oil with not enough extreme pressure additives (zinc/ZDDP) but luckily they can be reground. Dougherty Racing in CA can regrind them for you to stock SC or 964 specs. 964 is a very good choice for rebuilding an SC engine.

No surprises really in the combustion chambers or ports. Pretty common for valve guides needing replacement. They don't look bad so they might have been replaced previously, as evidenced by the head studs being all steel instead of half being dilavar.

The weights of your rods are OK. The Porsche specs says the max variation in a set should be no more than 8 or 9 grams (going by memory here) so you're OK.

[GT2BH]

Originally Posted by KTL

Those rod bearings are a mess. The crankshaft may look good by eye but run your fingernail across the surfaces. If you can feel ridges with your fingernail, the crank needs to be polished.

The rocker shaft bolts were lubricated because the rocker shafts were not sealing well in the cam housing. They all should be dry.

The camshafts are pitted likely from using oil with not enough extreme pressure additives (zinc/ZDDP) but luckily they can be reground. Dougherty Racing in CA can regrind them for you to stock SC or 964 specs. 964 is a very good choice for rebuilding an SC engine.

No surprises really in the combustion chambers or ports. Pretty common for valve guides needing replacement. They don't look bad so they might have been replaced previously, as evidenced by the head studs being all steel instead of half being dilavar.

The weights of your rods are OK. The Porsche specs says the max variation in a set should be no more than 8 or 9 grams (going by memory here) so you're OK.

Thanks Kevin - what do you think caused the damage to the rod bearings? does crankshaft polishing have to be done professionally? That'll mean I will also need to ship it out

I spoke to Dougherty and will hopefully get the cams reground to 964 specs. If shipping isn't reasonable then I'll just buy a new set.

Strange about the rocker bolts.. instead of 1 being the problem, it turns out all were the problem except 1.. I'm sending the rockers out for inspection as well..

So, now that everything is apart, what should I have done to all these parts to make sure I have many happy miles? Plan is to send the heads and rockers to a reputed machine shop, camshafts to Dougherty (maybe), and keeping my rods but ordering new rod bolts.