First rebuild - To split or not to split?

[PrimeMvr]

I'm doing my first build on a 3.0 from a '83 SC and I'm at the decision point of opening the case. It's gone smoothly to this point, but I am paranoid about disturbing the internals if I don't have to. I feel like I've hit the limit of my DIY comfort level at the case. Here are the facts, what would the experts do in my position?

1. 105k miles. Lots of leaks, but none from the case seam or main seals.
2. Engine ran very well, started right up, smoked at start up and down shifts.
3. Valve guides worn, I replaced along with seals
4. One broken head stud, no visible mating surface damage, lower studs replaced
5. Leak down good at 1-3%
6. P&C, rings, rockers and cams all look very good

I listed the top end info as a sign that this engine seemed to be taken care of, but I have little service history on it.

Is it a given that the IS bearings are shot, and should I just keep going? I don't want to drop a lot of money refreshing everything for the sake of refreshing, but I will gladly replace what needs it.

All advice is welcome!

Thanks,
Steve

[Flat6pac]

The center line seal is about 29 years old. IS bearings are about $20, center case gasket set is about $50, new chain rails because the old ones are brittle. You get to look at the main bearings, clean the case reseal with yamabond4 and when you drive down the road you know exactly whats there.
Grease each O ring on the case cross bolts. Dont forget the cross bolt inside left chain area, nuts and seals behind the oil cooler, test the oil cooler for pressure,
and the experience is priceless.
Bruce

[PrimeMvr]

Thanks for the reply Bruce, I've read many of your posts and your opinion means a lot to me. You make it sound so easy

Any gotchas on the main bearings? My bigest fear is not installing them right when putting everything back together and trashing a perfectly good lower end.

[KTL]

The biggest job of splitting the case IMO is the cleaning. The rest is very simple if you're just refreshing bearings/seals and throwing it back together.

The bearings don't get any easier to install. You place them on the case saddles and the notches self-align them. Rod bearings are easy too. The critical part of the rod bearings is your rod bolts- proper torque and stock bolts cannot be reused.

In terms of reassembly of the bottom end, you need to do some trial assembly to make sure you have everything in order when it comes time to actually seal it up. A practice run of organizing all your nuts & bolts & seals and parts (don't forget the chains on the intermediate shaft and the o-ring on the #8 nose bearing......) is well worth it to make sure you don't have to crack open your freshly sealed case and do it all over again.

[nick_911]

If you are worried about splitting the case yourself , why not get your machine shop to disassemble , check that everything is in spec and get them to re - seal it.
Shouldn't cost too much extra in labour.
All the parts needed are probably $700 worth and labour shouldn't be too much.
Small price to pay for a lot of piece of mind and you will basically have a new engine throughout.

Cheers
Nick

[kenikh]

SC cases don't warp (like mag cases), so splitting them is a very good idea, with no appreciable additional costs assocaited with machining out warpage.

Split it, clean it, put in new bearings, be happy and secure that all is well afterward.

[Dr J]

I went through this process a little over a year ago. I decided to send it to a pro to split the case and give me the long block sealed again. They found the innards in good shape, but the conn rods were out of spec. They got refurbished, the oil pump was checked, and although the bearings were in good shape, they were replaced along with the chain. It was a tough call, but now I know the condition of my engine, and all of the work was well done.

[Richey]

Hi Steve ,
I think it depends a little bit on how you drive . If you aproach the red line often , I think new IS bearings and reconditioned rods are a good idea . Rich

[al lkosmal]

Do it! The engine is out....time to do it right.

regards,
al

[KTL]

Most engines show significant wear on the IS bearings, even with low miles or even when opened up after a recent rebuild. It's just a mild shortcoming of the engine structure. That said, IS bearings really don't fail that often, if at all. Main bearings are often reusable. Rod bearings should be replaced since they take a TON of abuse. C-C length of the rods should be checked and the big end bore. Rod bolts are simply replaced with new OEM or aftermarket reusables like ARP. Rod inspection can be done with a bore gauge and quality set of calipers and micrometer. Any competent machine shop can check the rods against specs and magnaflux.

I find it odd that people think the top end is the easier of the two, top end vs. bottom end. Bottom end can be opened, visually inspected, and put back together with little worry of how it well will function when reassembled (assuming proper assembly of rods and sealing of case). Everything just drops in there and you seal it up. There are some tricks, such as case thru-bolt o-rings and ensuring the #8 bearing seals properly. But on the whole the bottom end assembly is pretty straightforward aside from the rod inspection. Crank inspection is visual, a simple check with a 1"-2" micrometer and any machine shop can magnaflux it for you.

Top end is more critical IMO when you consider the machine work needed for your heads and the concern of new rings sealing well if you're reusing your pistons and cylinders. Also need to measure piston ring clearances to ensure the ring lands are not worn. There's new parts often needed on the heads like new valves and certainly need new guides. Then there's the head assembly (setting proper spring height) and cam timing. Let's not forget rocker arm bushings, rocker shafts, rocker shaft bores in the cam housing....... There's a lot more pitfalls in the top end IMO.

[88911coupe]

I went through the same dilema...ended up going all in just because I wanted to check all the bearings and did not want to get that far and stop. I do have a couple of small leaks though that are really annoying that I hope I can fix with a second drop and not have to take it apart again. Sealing all back up is critical. I think mine is the RMS but won't know till drop #2. Still glad I did it b/c now have all new wear surfaces inside. Although things were actually in extremely good condition and could have gone substantially further without issue.

[PrimeMvr]

Excellent feedback guys, thank you! I'm going for it.

[911pcars]

Do you guys throw in new bearings (or other new parts) without confirming proper oil clearance?

If not, add some time to confirm.

Sherwood

[500_19B]

FWIW I have a 3.2 Carrera with almost identical mileage (allegedly anyway) and decided to split the case. I am:

1) Replacing all the bearings (including the #8), even though they look good (with the exception of the intermediate shaft ones).

2) Had the connecting rods re-sized and re-bushed.

3) Upgraded the con-rod bolts to ARP (I understand that for SC's the stock bolts are fine, but they are bit of a weak link for the 3.2/3.3 motors).

4) Had the crank checked and magnafluxed and found that one throw had some the hardness come off and needed to be hard chromed and ground to standard size on that throw only.

So, even though the bottom end was in relatively good shape (and would have been OK for many more miles), there still turned out to be enough things to "fix"...

[88911coupe]

Just to clarify, I sent all parts out to a local independent Porsche Shop to make sure everything was in spec as far as wear.

[AlfonsoR]

KTL, what's the recommended brand for main bearings? I also am planning a rebuild and will use the Smart racing - calico coated rod bearings, but unless I missed something, I did not see any main bearings on their website.

Actually I just tried to go to the Smart Racing website and it seems to have been unplugged??

PrimeMvr, if I am highjacking please say so and I will get off.

[KTL]

The OEM Glyco bearings seem sufficient for our use. Apparently there's been some QC issues with them in recent past and the pro builders have resorted to sourcing the bearings from Porsche dealer directly. That said, I recently received some OEM Glycos from Pelican and they seem OK to my inexperienced eye.

For SC rod bearings I went with the 996.103.121.94 GT3 rod bearings. If those can spin to 8000+, they're good enough for my mild 3.2 engine.

Yep I noticed the SmartRacing shutdown too. I heard that Flying Lizards took over the SRP operation sometime in 2010 or 2011? Dunno what that means for the future but it doesn't look good so far, considering the website's been shut down. I have to think the Jerry Woods end of things is still doing his thing, as he is/was the source of SRP's engine part offerings. Their addresses are in the same building complex. Try giving Jerry Woods a call?

[Flieger]

Well, it is my understanding that Craig Watkins started or ran Smart Racing, so it makes sense that he would like to bring it all together under one roof in Flying Lizard Motorsports.

[KTL]

That's correct about Craig. But he's just the Flying Lizard's chief engineer. He doesn't own Flying Lizard, nor is he even mentioned as part of the team..

The only thing SmartRacing I see at Flying Lizard is the SmartStrings

Car Racing Apparel, Porsche Apparel, Merchandise | Flying Lizard Motorsports

That's a shame, because SRP provided a lot of nice stuff for the older cars.

[El_Mecanico]

I was in the same dilemma...my had 115k miles. If you believe your engine indeed has 105k its all good inside with the exception of the IMS. That said I would stick with the top end only. My cylinders and pistons were like new. Also the bearings were like new to. It will add up fast. I spent $500.00 in lock tight the case gaskets flywheel bolts, stock rod bolts, oil relief pistons with springs and a pilot bearing. I still haven't order the bearings and chains and guides...thats going to be anothere grand. If you have the money and want to learn how to rebuild the engine and have plenty of time then I would say go for it. If you want to spend minimal money then send the heads out and buy othere things like rear shocks and bushings and maybe overhaul your CV joints while your there. Just my opinion. Personally if the cylinders and pistons look good I would stop theree. With 1-3 percent leak down thats hoe mine was to. By the way the inside of my case was crystal clean. Totally new. Number 8 bearing is around $200.00.

NOTE: These are one of the most expensive engines I ever worked on. I'm sorry it is the most expensive engine I worked on.

Good Luck