Engine rebuild - Leaky case already?

[garibaldi]

True, true. I dont have a pic of the plugs with crap on them, the plugs get ruined removing them anyway so there isnt much to photograph.

The thing that people should understand in respect to pulling out the plugs on the crank is this. If you have work done to the crank- like even a light micropolish, the grit that comes off the journals is hard material, and it comes off in fine particles, and will fly into the oil passages, Simply flushing the passages may not get it all out, and if it comes out during operation, it will imbedd itself into the bearings at best since it is material directly from the hard running surface of the crank. It woudl be like leaving grinding dust inside the motor, If you pull the plugs, run a pipe brish through it and flush it all out, you can clean every nook and cranny. But again, I rarely see plugs removed from cranks.

[Wayne 962]

My memory is not serving me well here, but you can clean the passages with a brush without removing the plugs, right? It's just harder to get to them. Or am I thinking of the Type-IV, or the 912/356 cranks? Can't recall off the top of my head...

-Wayne

[garibaldi]

Sure, you can run a brush through them, but I am always concerned about the spot the brush cant reach in the cross drilling up in the plug area. Thats where the stuff will get pushed up to

[viejopatron]

Christian, I’m not sure if I’ve been flamed or witness to a spontaneous combustion. While I yield the floor to the experience and expertise of yourself, Wayne, Chris Bennet, Fishcop, et.al., I do know firsthand that an interference plug insert job can be botched and the result is potential FOD aka Foreign Object Damage. Additionally, I also know that “The Devil is in the details.” Therefore, I felt that I had made an arguable, but informed, decision to leave the plugs in place. In my estimate, rebuilding an engine is a balance between cost, risk, time and sanity. At some juncture during a home garage rebuild, the issue at hand has to be pinched off. You’re correct, wrong decisions will be made, some even by me.

I come to this site to learn. I don’t like to hand off my parts and see them disappear into the back room anymore than the next guy. I am absolutely not a pro wrench and chose not to be one 35+ years ago (Yikes). It has been immensely valuable for me to read these threads, converse and learn from others. I will continue to do so.

[DonE]

Originally posted by viejopatron
In my estimate, rebuilding an engine is a balance between cost, risk, time and sanity.

Very well put.

I need to rebuild my 930 motor, but if I replaced everything that could be be replaced, I would go broke. If I replace everything that needs to be replaced, the rebuild cost will max my budget.

In many places, I drew a line to achieve a desired result, vs. risk.

For example, I will rebuild the motor vs. a professional - for sure, the weakest link in the project (I've done other rebuilds tho).

I opted for JE pistons rather than Mahle (OMG was this a religeous debate), but the cost savings is significant, and I get 8.0:1 CR.

I am trading my 930 crank for a 964 crank (completely refurbished), but I get low-end.

I am keeping the CIS - hey, it works for me (400rwhp as is, 12.5 AFR @6000 rpm)

I am going to refurbish my stock rods.

I am going to have Elgin cams regrind my SC cams into 964 cams.

I might use the original rockers and shafts (yes, I know I should get new rockers with a new cam, but its ANOTHER $350 on top of what I'm already spending).

And this is not to mention the machine work needed for a valve job, check the case, check the heads,.....

And on, and on, and on.

Now granted I will do what I can to clean and prepare the parts for reassembly, but I really can not afford to send these parts out, pay for the work and pay for the freight.

I wish OverHaulin would come to my house.....

[cstreit]

Christian and Wayne,

Your points are definitey understood...

Especially for high mileage motors... There is no "good enough" that is good enough here. I'm used to looking at race motors that don't have a ton of mileage and rarely see that much crud. Nor was I suggesting that this level of cleaning was "over the top", just playing Devils Advocate since this is rarely done.

Wayne, I'm with you on the leak guarantee. I get irritable when I hear people say "Oh, it's a 911 motor, it's gonna leak. Baloney! There's absolutely no reason it should leak if it's done right!

[Crowbob]

Gentlemen,

All this talk about pulling plugs, piston squirters, cleaning journals etc. in an effort to clean the case has gotten me to the point of asking how to do all these things. Can anyone point me in the right direction here?

[garibaldi]

Yes a 911 motor should not leak if its done right. But define "Done right". 99% of the people out there having their motors rebuild, will take an old, higher mileage twisted up case, wash it, razor blade all of the sealant off, have some machine shop stroke through the main housing once or twice with a honing bar and gun it back together.

Heres the deal, mag or aluminum, these cases get so twisted up, that you can run a dial indicator around the case mating surfaces and main webs, and come up with .010 easily- yet you want to just slop on the sealant, and tighten it back together and bend the hell out of the case- which does what for seal housings, and housing bores for the mains???? Yeah, theyre round after that- and on top of all that, you wonder why is it leaking? Its like trying to make chicken salad out of chicken ****- yet you are asking why does it still taste like **** even after you tried to mask the problem with extra mayonaise.

Last week a customer brought in a mag case for me to check for him. He, like everyone is on a budget, but he wanted me to take a look at it, so we bolted it up. The case halves had been "Flattened" at a previous rebuild on what looks to have been a belt sander and there was some cross hatch honing marks here and there on the bores. When I measured the housing size perpendicularly to the parting line of the case, it came up about anywhere from minimum size to .003 under the minimum. When I rotated the gauge 90 degrees and measured near the parting line, it was about .006 over the max limit. Just to remind you, you woudl typically run around .0025 or bearing clearance on the mains- so you can imagine how installing your bearing shells into an egg shaped hole, and then cranking the case down will make your car run so great, and you will wonder why its leaking, or has crappy oil pressure no matter what you do, or only lasted about 10,000 miles, or your still getting your ass handed to you at track events by the other guys who has the excact same car.

So if you guys all are going to argue about budgets and time and leaving things out, and going to the "Extreme" on you rebuild, knock yourself out, why bother with doing any of it. But if you are going to do it right, then you shoudl budget accordingly, and at least have an understanding as to why you should do one thing over another and plan on confronting and approaching these issues with the motor while you have it apart.

[Shuie]

Christian, thanks very much for sharing some knowledge about this. This is the kind of stuff that scares the **** out of me when I read it for the first time and realize I never knew any better or even thought about it when I was tearing my engine down.

So is this something that can be taken care of effectively with a DIY rebuild? It sounds like removing the piston squirters and crank plugs for detail cleaning is a non trivial process better left to a pro with a full functional machine shop. Should this work be added to the machine shop request list, or will a shop only do this kind of thing for a customer who is giving them the business of a complete rebuild?

Nothing about these cars is cheap. I dont want to cut rebuild costs so much as I want to spread the necessary cost out over a period of time. DIY allows me to do this a little better than just writing a check.

[garibaldi]

I suppose that you can DIY, depending on what kind of tools and equipment, and skill you have. The consequences can be pretty severe if you mess up though, so even if it adds a few hundred dollars to the rebuild, at least it can be done and done presumably correctly depending on who does it.

If I had a customer bring me in a motor only to remove the plugs and clean the parts, I woudl do it, even if it wasnt me doing the rebuild. There are certain things that you can do yourself within the realistic realms of your home garage. I mean, you can go out and spend $7000.00 on gauges so you can mic your own crank, rods, measure your cylinders and line bore. You can go and buy bar stock to make your own plugs out of, and pick up a good toolroom lathe used for about $20,000 and make your own plugs. A properly equipped machine shop can easily have hundreds of thousands of dollars invested in machines, tooling, etc- so the work must be priced accordingly. Which is why I cant see how you can go on the internet, and get a exchange engine for a 911 for $3000- what do you think you get with that.

I can recondition a cylinder head for more than that depending what needs to be done, and there is places doing an entire motor for that amount? In this business- and this is the plain truth- YOU GET WHAT YOU PAY FOR.

So do you think if you get all of your motor parts back from machining and the bill was $2000 for doing the rods, case, crank and heads- do you think things like crank plugs are coming out?

To answer your question yes, these shoudl be added to the machine shop list. And they shoudl highly recommend doign that work even if you didnt know any better or suggested it on your own.

I look at it like this, there are those who argue that they cant afford it, or its only a beater, or a street motor, or im just going to sell it- well, there are machine shops and engine builders that fit their bill.

Then there are guys who say I want it done right, i want to try something different, I understand that it costs more and takes longer, but its worth it, its a race motor, its a street motor, i want it to last, i want more power, i want to know that it is all done as best that it can.

Well theres a machine shop and engine builder for them as well.

[jpnovak]

Christian, thank you for your honest information on this topic. I really appreciate your time to help us all learn the differences when it comes to the decision making and check writing.

[Wayne 962]

Originally posted by DonE
If I replace everything that needs to be replaced, the rebuild cost will max my budget.

Hmmm, if it needs to be replaced, then it *needs* to be replaced. If you're not going to do it right, then I would suggest simply not doing it at all. Wait until you can.

Originally posted by DonE
I might use the original rockers and shafts (yes, I know I should get new rockers with a new cam, but its ANOTHER $350 on top of what I'm already spending).

It's only $15 a rocker to get Walt at Competition Engineering to refinish them. To not do so will mean that you'll have old rockers on your new cam. This will cause you to ruin either your rockers or your cams, and have premature engine wear. This is not something Porsche-specific - it's a cardinal rule of all engine rebuilds. New on New, old on old.

-Wayne

[Wayne 962]

Originally posted by garibaldi
Yes a 911 motor should not leak if its done right. But define "Done right". 99% of the people out there having their motors rebuild, will take an old, higher mileage twisted up case, wash it, razor blade all of the sealant off, have some machine shop stroke through the main housing once or twice with a honing bar and gun it back together.

Agreed. However, hopefully the total number of people doing this is much less than 99% these days, primarily because I tell everyone in my book that these mag cases need to be 'remachined' to whole again when rebuilt.

Originally posted by garibaldi
So if you guys all are going to argue about budgets and time and leaving things out, and going to the "Extreme" on you rebuild, knock yourself out, why bother with doing any of it. But if you are going to do it right, then you shoudl budget accordingly, and at least have an understanding as to why you should do one thing over another and plan on confronting and approaching these issues with the motor while you have it apart.

I agree. I tell people not to bother rebuilding their engine if they are going to do it half-assed. However, as you know, it's an uphill battle. No matter how many times you tell people (based on the collective experience of many people), people will doubt you and attempt to take shortcuts. The forums archives are scattered with these tales - one should do a careful search before deciding which shortcut to take...

-Wayne

[DonE]

Wayne, I will be replacing everything that needs to be replaced. It will max my budget. However, if I replaced everything that should be replaced, then the cost would be prohibitive to me.

For the record, I am using your book as guidance on what to plan.

I find that I can talk to 10 different people and get 10 different opinions on how to complete this job. My local shop tells me to shuffle pin the case, but no need to pull plugs unless there was a catastrophic failure somewhere. Another shop in AZ told me to trash the factory heads in favor of his billet heads because of the miles on the motor (140,000). Another shop says check the rocker bushings with YOUR FINGURES to check if oblong, and you say its the cardinal rule to replace with rebuilt or new.

I went into this project with the intention of doing everything like Christian, but will probably end up doing it like Rube Goldberg. I did three months of research buying books and talking to many, many people.

What the hell do you guys want us to do? Who do we listen to? I'm ready to sell the whole damn thing...

[garibaldi]

Dont get all frustrated and give up. take a step back, take a deep breath and relax. You shoudl listen to people that you trust. Since you can either devote your life to learning about the dynamics of engines and building them, and trying things and making mistakes along with sucesses to make your own decisions, or you find people that have been there and done that and you value their input, and save yourself the time and expense.

Like I said, the market has been saturated with **** for a long time, and will continue to be, just full of people who are in it to make a quick buck and get out, and those people rely on volume, so they will spend the money on hype, smoke and mirrors and advertiseing, so thats all you see.

How many fast food commercials do you see on TV? Tons right, how many 5 star restaurant commercials do you see? None, yet if you want to go eat a kick ass meal, you dont take the family to Mc Donalds and splurge on the dollar menu do you?

Its not like an everyday project to rebuild the motor in your car, so why not take her out to eat at a good restaurant, instead of trying to fill her up on fast food. Its not like you need to go to the expensive place every night to eat, its once and a while, so it may be worth doing it right.

Take your time, educate your self, and dont be intimidated to ask questions.

[Crowbob]

Chris,

Your words are true and correct. The problem is not philosophical, however. This problem we are discussing is emotional. People WANT these cars, nobody needs these cars. It's irrational and predictable: A guy wants a Porsche...he gets a Porsche, then he wants to fix it up and finds out the true cost when it's too late...he's sunk money into the inital purchase and can't give up, good money goes after bad. Then you see the add: "Decent Porsche, needs work. Good project car." What the guy is really selling is his dream. It is my worthless opinion that there are many, many more guys out there with too little money than thee are with too much. It's not so simple as deciding where to eat dinner. It's frustration, impatience and the good ole' American rat race. My project has taught me very painfully about patience and how utterly, absurdly materialistic I am and how utterly, absurdley materialistic we all are...Oops, are my 50 minutes up already, doctor?.

[Doug Steinel]

Christian,

I think the problem is basically an economic one. It costs plenty to do things 100% and if most of the people on this board went that 100% that you are speaking of, they couldn't afford it; they would have to give up their Porsche and that they don't want to do. So they do the best they can within their budget and for many of us, we do OK. Some will not. Believe me I know from experience... bit by the Porsche bug while in graduate school. I rebuilt the motor with the only p/c I could afford, and (they were out of spec) and failed. Burned oil like a drunk drinks whiskey. Fouled the plugs every 200 miles. I gambled and lost and now I am more careful, but still feel some econmic restraint.

[Wayne 962]

Originally posted by DonE
What the hell do you guys want us to do? Who do we listen to? I'm ready to sell the whole damn thing...

Well, at the risk of sounding like an egotist, you should listen to me! Seriously, the book has been compiled from many different engine builder's opinions around the country (Walt, Bruce, Jerry, Tom W., etc.) and compiled into a format that combines all of that information. It sounds like Christian and I are in complete agreement (I'm still nervous about recommending the pulling of the plugs, because I feel there's room for error from the shop) on just about everything.

Shufflepin = no on the aluminum cases. The guy who told you that doesn't really know. In fact, Jerry Woods told me that if you shufflepin them, then they may be too stiff and actually break main bearing ribs under huge loads.

The guy trying to sell you his heads - well, I'll let you figure that one out for yourself.

Be aware of the small shop mechanic - he is your best and worst friend. Ask him some of the questions covered in the book, and see if he really knows what he's talking about.

As for the rockers - I would definitely have them redone. Ask Webcam or Elgin for advice, I'm sure they'll say the same thing. They might not even warranty their camshaft for you if you don't.

-Wayne

[David Goodman]

Wayne,
I think part of the frustration is that the experts don't always agree. I doubt very much that you would see garibaldi within 1000 feet of one of his motors with a tube of RTV, but your book recommends it for the through bolts. I can see folks out there trying to do the best job they can, driving themselves nuts resolving the inconsistencies.
Dave

[cstreit]

Christian sez Its like trying to make chicken salad out of chicken ****- yet you are asking why does it still taste like **** even after you tried to mask the problem with extra mayonaise.

Now there's a quote we all can understand.


Christian, Wayne, Steve Weiner, and any other experienced guy out there, you should definitely hear what DonE said

I find that I can talk to 10 different people and get 10 different opinions on how to complete this job

You guys probably don't talk to a lot of sources these days when it comes to builds, suspension, etc.. but let me relate my experiences to you...

DonE is 100% on this. When I was setting up my suspension, I talked to ALL the "Porsche Racing experts." Not your half-baked parts suppliers, but the guys who race pro and names are everywhere. EVERY SINGLE ONE told me something different, often completely conflicting information. I finally got so fed up I went and bought several suspension theory books and learned for myself.

Motor builds are the same thing. Everyones got an opinion out there, and for the new builder/home mechanic, it's all very confusing and often brings people into a total deadlock situation. "Analysis Paralysis"

I spent 3-4 weeks researching valve angle grinds alone when building my race motor. No one tells you the same story or the same results twice... Again, got fed up, learned for myself.

What an I getting at? Whether it's case cleaning, setup, etc.. etc.. there are so many opinions that it's hard for new guys to seperate the good stuff from the Bull***

Hmmm... that really didn't help this thread at all, but I guess it's a rant of my own.