Top End Rebuild - can it be done in time?
 

After owning my 87 for a little over a year I decided it was time to take care of the oil consumption and compression issue. The car is burning about a quart of oil every 200 miles and has 114k on the clock so it was time to freshen it up. A local Pelican, Donnie Weymer (Dwymer), offered to host this endeavor at his house since he had recently rebuilt his 2.7. Since I am a rookie having only completed projects like valve adjustments, brake pads, etc, I was excited to have knowledgeable help with the process. There is only one caveat... Donnie is moving in two weeks. That means that everything has to be completed by then, including sourcing parts, shipping heads to and fro, as well as all the actual labor. Are we being aggressive? Will it be complete? Will I get my car dropped off in my front yard in a pile of parts? Only one way to find out - follow this thread!

Initial thoughts are to pull the engine, send the heads off to Bob at Anchor Atlantic for a rebuild, and then assess the cylinders and possibly re-ring. At the same time, examine the rest of the engine and compartment for wear and replacement of various parts.

Monday: T - 8 BD. We pulled the engine and got it on the stand. I broke the throttle linkage extension rod trying to pry it off the ball under the tranny. Add it to the list of parts. Apparently it has a three day lead before it gets shipped off. Not good. Also found a leaky fuel hose that runs from the fuel pressure regulator to the fuel rail. Its about four inches long and costs more than you would imagine. Also not good. (Does anyone have an extra)? The three wiring clips (CHT sensor, etc) are all very brittle and one crushed when removing. Not sure if they make replacements for those, but I'll have to figure that one out later, don't have time now.

Tuesday: T-7 BD. We got the heads off. No broken studs. Only had to cut one exhaust nut off. Overall a smoother day.

Wednesday: T-6 BD. The heads go out today - overnighted. I can't even imagine what that will cost. Also placing first big order from our host for parts.

Here are some photos including the obligatory standing in engine compartment. Also, is the picture of the leaky hose. Please let me know if you have one lying around! More photos to come.

John


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Don't do it. Unless you pay a machine shop a lot of money, they are not interested in giving your heads back in a short amount of time. THen there is always the while-in-there syndrome to worry about. 2 weeks is not enough for me.

I love it. Bob did my heads about a month ago, I believe he WILL perform. Shipping will NOT be cheap, but imagine that you are the Factory, getting ready for Le Mans!

A few more photos
 

Here are a few more photos. Notice the build-up in the exhaust port of the head. Looks like stalagtites. Anyone care to chime in about what that is? I'm guessing its carbon buildup, but its looks really bad. It has to restrict flow.

I just got off the phone with Bob from Anchor Atlantic. What a nice, helpful guy. He's going to turn the heads around quickly to help out the time constraint.

I like the racing number magnets on the side of the car. I'll have to get myself a set. Maybe tonight I'll make the car a 993 - nah.

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Fun! White carbon?

Wow, that is an agressive time schedule. It took my shop two weeks, and they have an in-house machine shop. How are you going to clean the cam towers and the other bits that are not going to the machine shop? Are you only doing a top end or splitting the case?

Good luck... Keep us posted.

Mine looked similiar - although not quite that bad.

2 weeks is pretty darn aggressive - now would be a good time to change the carrera gas line and reference and speed sensors - cht for that matter - much easier to get to when the engine is in this stage.

Two weeks! God bless you if you can do it. You might want to keep a trailer and tow vehicle on standby:) A hydraulic hose shop might be able to remake the fuel line for you, that hose clamp doesn't look factory though.

Good Luck!

edit - Curiosity got the better of me and I checked my car. The hose clamp is factory!

May I suggest that you start looking for a friend with a trailer.

Make sure you have everything ready to go back. Make a list of items you have here and maybe we can help fill in the blanks.

For the fuel line I would just get some good injection rated line and use hose clamps to get the thing up and running. Though not easy it can be replaced later.

I would for sure do the two referrence sensors. Also check all the vacuum lines. The size adapter hose to the brake vacuum, the size adapter hose for the PCV, the two large hoses from the oil tank to the engine.

There is no replacement for the car side of the O2 sensor. Just cut it off, strip back into the wireing a bit and solder on a three wire connector of some sort. The replacement O2 sensor should have 3 wires, 1 for the sensor and 2 for a sensor heater.

Did I mention a trailer.

Also supply items like anti-sieze, anaerobic gasket maker for the cam tower to head seal. JB weld to re-seal the various molding plugs. Thread locker - red and blue.

It took me about 2 days to put the engine back togeather and get it in the car. And by two days I mean about 20 hours. I don't even want to think how many hours I had cleaning parts and I am not that picky.

If you are working at a real fast pace make a list of must do items and check them off. Have all your parts sorted into plastic bags by item so that when new parts come you can compare to the old parts and make sure that you have everything you need.

Those are the plugs that disintegrated when touched.
I have the "shop supplies" needed, and I also have a trailer if needed! I even told John I would take the car to NC and finish it if we don't.

D

cleaning
 

So far the progress seems good, considering we began to tackle this on a monday of a work week.

With the heads sent off to Bob, it was time to do some cleaning while we waited for their return as well as the parts from Pelican. Last night we cleaned half the engine case and the majority of the bolt-on parts. Tonight we clean the transmission, finish up the case, and any other misc parts.

I ordered new return tubes, a gasket set, a new CHT, a sound mat and a few other misc items. I'm debating adding new reference and speed sensors to the list while i'm at it. Are they just one sensor or are they two seperate sensors? They look identical and are hooked together.

Still working on sourcing the fuel line and linkage extension as the shipping delay from pelican puts it out of our rebuild window. I spoke with Sid at Troysport last night and he thought it wouldn't be a problem to find a solution for the throttle extension. Either use his supplier to find a new one or fabricate one. The fuel line will be another story, as it is hard to find. I spoke with a hydraulic shop yesterday and they said they should be able to fabricate it for me. Keeping my fingers crossed.

John

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There are two referrence sensors that go into one bracket. They are identical. They are removed by taking out the allen bolt. Do not remove the bracket or you will have to re-position. Not that hard out of the car but still no need. The rubber goes bad and exposes the shield wire. They are expensive but are one cause of intermitent problems.

Very easy to do out of the car. Very hard to do in the car.

Here's a great bar bet: Bet someone they can't eat one of those small bags of Planters Peanuts in a minute. Sounds easy, but it's nearly impossible. Here's the reason I mention this peanut thing: If the person does not put all the peanuts in their mouth in the first fifteen seconds, they will fail. You need to remove and disassemble everything very quickly. Get them soaking in a parts washer. Predict you will want to at least see the condition of the rings and when you do, you'll make a decision to "freshen" that too. This means decisions about cylinders and pistons. There is enough information about that decision here on Pelican that you would need at least two weeks to read it all. I re-ringed my Alusils and it has worked fine. You will consider splitting the case. If you do split the case, you will find a worn layshaft bearing and a fairly worn flywheel end main bearing. It will be fun to be at this point, because the guts of an engine are pretty simple. WAY more simple than all the bolt-on components you are dealing with now. In your shoes, I would consider balancing the crank and rods.

I hope you won't need a trailer, but I think you will.

If you think another set of hands will help you make it in time, pm me for my tel no., and I can help.

And looking at the pic-that fuel line is a dealership item. They will order it for you. It a dealer only item.

Regards,

Amazon hose in tampa will do the fuel line * both parts - they did mine...

Just had the hose made by a local hydraulic shop. Thanks Andrew for that suggestion. A place called royal brass and hose here in Orlando did it for $10. I may take off the big expensive fuel hose Jeremy was referring to and see if they can replicate it as well.

Bernard, thanks for the offer, we could probably use your help later next week when parts start ariving (hopefully).

Superman, you gave me some interesting things to think about. I'm not sure if I can eat a whole bag of peanuts.

disfin, I freshened my engine at about 183k miles. It was not burning oil and it was running great, but had a broken head stud problem. BTW, you really should remove those exhaust-side studs and replace with cheap, plain steel ones like those on the intake side. Used ones work fine, but the Dilivar units are a time bomb. What's worse than the expense and time of a Porsche engine rebuild? Two Porsche engine rebuilds.

I digress. When I disassembled my engine, I found the rings were at the edge of factory spec. The ring gap was fairly wide. I also found that the ring lands on the pistons were not worn, and that the cylinders were basically not worn (.0015" is the most wear I could find on any cylinder!!!). I also found the exhaust valve stems were worn. So, the engine got new valves and new rings. And new bearings. It is unlikely I will ever disassemble this engine again. It is unlikely I will have any reason.

I was thinking that the rings might be an issue as well... If you were using that much oil, I would think it was getting past the rings (unless you were dripping one quart every 200 miles).

My manifold gaskets were brittle and had fine cracks that would have only gotten worse over time. So they were changed too.

With Donnie taking a load up to NC, we had Friday - Today away from the car, so no progress has been made. However it looks like we are still tight, but barely on schedule - knock on wood.

I had been thinking about doing the rings so I went ahead and ordered the rings and gaskets. They should be here tomorrow along with all the other items ordered from PP.

Bob completed the heads. New exhaust valves, guides, regrind etc. They should arrive in orlando on Thursday. Thanks to Bob for expediting it!

The goal will be to do any work that can be done without the heads prior to thursday. That means changing misc gaskets and parts as well as re-ringing. That will leave thursday-saturday to put it together, set timing, re-install and head off any of the unanticipated issues. Did I mention that Thurs and Fri will be very long, hectic days at work? Oh, and we get to load up another moving truck load for donnie on Saturday as well.

John Meyers
Orlando, FL

Ordered rings?
Did I miss something here?
What type P/C's did you find? Alusil? Nikasil?
Each require different rings and Alusil is a gamble.
Re-ringing requires some cylinder preps, what is the plan?
Is the first land on the piston still in spec?

First rule of Engineering: It always takes longer and costs more than the estimate, especially if you are in a hurry.

An engine rebuild is only fun if you take your time and do it right.
Things are missed when in a rush.
For the bottom: Do not use new chains on old chain sprockets (I-shaft)

http://forums.pelicanparts.com/porsche-911-technical-forum/200267-new-chains-without-new-sprockets-read.html

I just read this thread. Great pics! I have a few questions though: with the car tipped at that crazy angle, why is that man smiling? Is Diet Mt. Dew as good as regular Mt. Dew? Oh, and do I understand this right, the plan is to machine the heads, but not replace the cylinders, and maybe the rings? Did anyone check the pistons for wear too? Was a leakdown test performed to try to pinpoint the source of the oil consumption? Is it too late to scrap the original plan and just do a full engine rebuild?

Diet mt dew is better than regular mt dew. And diet vault is actually better than diet mt dew.

Scrap the plan and do a full engine rebuild...bite your tongue young man! p&c's will be carefully measured and hopefully be in spec. Haven't had the chance to do the measurements, but they will be done in the next day or so. Initial visual exam showed no scratching, grooves, or general funny business. The leakdown showed only cyl 3 with >5% loss, which, when conducted sounded as though it was coming past the rings. Unfortunately, a leakdown doesn't show valve guide wear, which I knew the car had. So all initial indications pointed to rebuilding heads and checking/replacing rings. We'll know more once we start taking off the barrels and measuring.

Dude,

I just saw your signature. "77 Wife, stock".. Too funny. That's awesome.

Anyway, back on topic now, good luck with your rebuild!!

So, what type P/C's do you have?
Alusil?
Nikasil?
And what is the plan for prepping the P/C's?

The cylinders are Nikasil, and once checked for spec will be de-glazed with a scotch-brite wrapped around a hone, as recommended here by someone I trust.

There is a lengthy debate in the rebuild archives about this prep as well.

I could see how a compression test wouldn't show leaking cylinders, but a leakdown test would have air coming out of the intake. worn rings result in air coming out of the tailpipe. All of this is academic now that you have the engine apart though. Now you can and should actually measure the wear physically. Dont forget to measure the amount of wear in the piston grooves, from the rings moving back and forth. Too much wear will result in a new ring breaking off.

You are right about the ring grooves, and they will be measured. I don't want any rings failing to seat, breaking or being generally disagreeable. I was told a good coating of gorilla glue will help hold them in place.

As for the leakdown test - it is my understanding that leaky rings will allow air to enter the crankcase, leaky exhaust valves will have air coming out through the tailpipe, and leaky intake valves air through the intake. However, if the valve guides are worn but the valves are still seating well, the leakdown won't show a loss in pressure as the cylinder can still be sealed. However this same engine can still burn oil as oil will drip down past the valve guides, past the valves and into the cylinders when the valve is open. The common diagnosis to a 3.2 with approx 100k mi (no top end rebuild), oil consumption, decent results on a compression and leakdown test would be worn valve guides. Which in my particular case, worn sloppy guides were confirmed by Anchor Atlantic. Of course this doesn't mean its only the valve guides 100% of the time. And in my case it may also be p&c's or rings or all of the above. Should know by tomorrow. Also smoke on decel vs. accelleration shows guide wear vs ring wear.

Yes, disfin. Your post directly above suggests to me that you know what you are doing.

Some folks have removed cylinders with the pistons still in them, but I don't recommend that. Again, my rings were among the few parts in my engine that were worn. The pistons and cylinders were NOT worn. The valves were worn. And the bearings were worn. And again, the closer you get to the bottom end, the simpler it gets. The head job will cost you a pretty penny. The rest of a good freshening job (rings and bearings) is pocket change.

I wish I had balanced my crank and rods, for peace of mind. I am currently replacing the flywheel and hoping the engine vibration goes away. I also wish I had rebushed the rods. I may have a tiny bit of wrist pin slap.

I kinda wish I had replaced my rocker shafts, but that's not critical. I am GLAD I installed the little o-ring thingies that help the rocker shafts not leak. They don't.

I don't know how much I'd hone the cylinders. Not much, if at all. I would wash and clean them within an inch of their lives, and I would use very little oil on them during assembly.

Good luck to you!

Don't forget to put the air deflector tin on the engine BEFORE you install the heads.

disfin, you are right, I got a little brain freeze there.

Superman, what is the reason for very little oil during assembly?

Man! I can't believe I've been missing this thread!

If I had joined in before you started I would have asked if you had a detailed project plan with time lines and some built in float. I love projects with aggressive time lines. Very challenging!

This sounds like the kind of project I would have done on my first car, a '70 Bug. Parts were cheap and easy to find and I could afford to be a little reckless.

If I were closer and not in the middle of race week, I'd offer to help.

Sage wisdom from Gen. Eisenhower.... "Plans are worthless, Planning is essential." In other words, nothing goes as planned but, if you have thought about contingencies and are prepared to act you have a better chance of success. Sounds like you gave this some thought and will come close to your goal but I wouldn't bet on the margin. :eek:

Once its running, plan on bringing it to Deland for an autocross. I need another 911 to run with.

For an engine that has never been apart:
Instead of using new rocker shafts, I turned them exactly 180 deg.
One can actually see the slight wear pattern from having pressure on the same area. Centering the shafts is critical to get the right torque and prevent leaks.
I recommend doing the rods professionally.
The shop will shave a few thou off the shoulder, then mount the lower half with the OLD bolts and bore out for the large bearings.
The small bushings are replaced and the rods are peened.
Give them the rods with the new wrist pin and the old bolts.
If the crank, after polishing, is standard, the new bearings can be standard.
I like ARP bolts.

I still think doing an engine in a hurry is asking for trouble.
Doing things right takes a certain amount of time.
Watch the clips for the wrist pins; they want to zoom off into the void. (Or disappear into the case)
Hope it works out without disappointments.

We are not splitting the case, never planned on doing so.
The pistons and ring groves are well in spec.
Cylinders will be measured today.

Have a safe holiday!

I see most don't have faith in d but I assure you he knows what he is doing much more then most of us.. so be patient and watch

Thanks Ben.

Cylinders all in spec for wear and ovality. New rings are in(John only dropped one circlip in the case!) Heads should be here tomorrow.

For the record, I have faith in Donnie and John as well. It is the stuff they can't control that I would be concerned about. A tight time line doesn't allow room for unexpected problems.

Glenn, this cracks me up:
"Some people are like Slinkies, they are not good for anything, but they still bring a smile to your face when you push them down a flight of stairs." Great stuff!

We are still on track with out timeline. P&Cs were reinstalled yesterday with their new rings and gaskets. Also did a couple of other things such as breather cover gasket, oil themostat gasket, engine sound pad, new oil light switch and more cleaning.

HEADS SHOULD BE HERE TODAY! I'll finally get around to downloading some of the pictures and hopefully post some tonight.

and slid a brake job on my truck in yesterday as well

I'm jealous. I wish I could spend some significant time turning wrenches on my car.

subscribed. When are you starting to put the motor back together?

So, today the heads came in from Bob at Anchor Atlantic. I think he made a mistake and gave me brand new head as there is no possible way these are mine! They are gorgeous! I wish I had the time to have all my engine parts cleaned in his ultrasonic cleaner. To top it off, he threw in a cool little pocket knife with his company logo on it. So, thank you to Bob for a timely turnaround, and a job well done. Oh and his packaging was superb - no broken or bent studs.

So, tonight after work we installed the heads, cam towers, cams and began the cam timing process. We will finish the timing tomorrow, install the remaining rockers, install exhaust, intake etc. Oh and we get to load up Donnies moving truck again.

Hats off to Donnie for having the patience to answer all my questions. I've learned alot from this process as you could imagine and I couln't have done it without him and his garage full of tools. North Carolina is gaining a great porshe resource.

Here are a few more pictures. Notice the change in appearance of the tranny. Its far from concours, but at least you can see the metal now. And check out those heads.

Good night.

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