Power & Heat Exchangers
 

Everyone seems to agree that upgrading to SSI's and sport mufflers or something called a pre-muffler willl give you a performance increase. So...........

Imagine this: Some shop (proclaimed Porsche expert) drills holes in your heat exchanges after your rear oil cooler fails. They claim they did it to let the oil drain out that got in there (how the heck could that happen anyway?).

So now you have heat exchangers with holes in them, and oh yea they take off your blower motor and hoses and don't replace them because you dont want to spend another $300.00. They cover some of the openings with "Aluminum foil" no kidding!

They say the exchangers will smoke a lot at first as the old oil burns off, they did their best to steam clean them. However they seem to smoke after heating up real nice and stoping for a while. Also you can see old oil in places, making you wonder how bad was it before?

After driving the car a couple of weekends you become increasing convinced that low end power is compromised, and the RPM needle just dosn't flick up to red line like it used to. Yea I took it back once, a three week wait, they re-did the ignition timing for some improvement. They did not touch the cam timing from chain tensioner upgrade they did.

Drum roll.......the question is: If finely engineered and installed heat exchangers give you a performance increase, then drilling holes and leaving holes open will degrade performance, right?

I kid you not, this is a true story.:(

The reason I am asking, is it will take more money and grief to figure out if the shop also screwed up the cam timing. I am hoping its only the damage they did to my old and leaky carbon monoxide belching heat exchangers for the performance degration.

Any theories out there?

PS: The mechanic that repairs my other non-Porsche car drove my 1977 911S 2.7L, before and after the other shop did the work. He said I have a claim, there is a definate loss of power. However there are so many details and variables to this story, that I want to exhaust all posiblities. I hate being wrong, I hate being the bad guy.

I hope they only drilled holes in the air shroud around the actual exhaust pipes - this is probably what they did. Stupid but not fatal. Your performance degradation is likely due to other causes. The exhaust doesn't go through the shroud, only air from the engine cooling fan. This will make little or no difference in engine performance nor should it increase the CO that one is getting in the cab. Of greater importance is what they've done to the air flow from the fan; the nozzles to the heat exchangers must not be left open as these become paths of less resistance and the cooling air will leak out there instead of blowing over the cylinder, heads and engine mounted oil cooler. They can be blocked off but not with aluminum foil. Get a new shop pronto. Jim

The holes they drilled must be in the outer jacket of the heat exchanger only, because it sounds the same.

The drop off of performance is not great, but it took a lot of the fun out of the car. Like I said, my regular mechanic drove it and noticed the difference right away. The guy who did the work, said this is a good as my year gets, he is happy with the way it is running. Well of course he is happy, anything less would cost him more time. They already had to correct the ignition timing once. I have zero confidence in any of the work they did. If I wanted it done wrong, I would of did it myself.

They could of did a bad job of adjusting the valves, or messed up the cam timing when doing the chain tensioner upgrade (or damaged the valves I have read) or even something when they removed the smog pump. Heck, they may of even put the wrong spark plugs in. They are screw ups, how they have a good rep, is beyond me. Never go to EuroTec of Ann Arbor.

At this point, the car is livable, but disapointing. Having a new shop check all the work of the old shop and getting a lawyer or small claims court (up to $3,000 in Michigan) is not how I want to spend my summer.

I am thinking of driving the car all summer (after I install a new shifter), and in the late fall getting the car re-timed (cam, valve and ignition) while I have it in for the heat exchangers. I don't need heat in the summer anyway and will have cash on hand to get the work done. I might even have the 2nd to 3rd gear syncro/sleeve replace while I am at it.

One thing at a time for now.

Sounds like some of the theories you have are not only detrimental to your butt-dyno but also to the engine. Incorrect plugs, bad timing, bad valve adjust, incorrectly blocked off air ducting, etc. could lead to significant engine damage.

If you are thinking about legal action it doesn't help your case to wait 4-5 months? How does anyone know that in the meantime another shop didn;t make some mistake and you are looking for Eurotec to correct the problem.

Personally I wouldn't drive it in that state of tune for fear of damage nor would I run the risk of a business not being around in 4-5 months to take legal action.

Now for your personal safety you need to fnd the hole in the exchanger and determine without a doubt that there is not CO dumping into your heating system.

Trivial maybe... Boil down basic theory is that the cooler the better for the air entering carbs or FI, and the exhaust the hotter the better.

Is it possible that by venting your heat exchangers that your exhaust temp dropped off?

Maybe a dumb thought, but I haven't seen the holes! Take some JB weld and close them up, see if it makes a difference....

Just a rambling thought from a 912 guy...

Best,
Morrie in Texas

Whoa!!! First what did the wrench do to the car besides drill holes in the tin surrounding the exhaust pipe?

The holes in the tin alone will not degrade performance on the car. I don't imagine they are big holes, but it is still not desirable. I would make the shop replace it. Claim potential CO poisoning and a large medical bill or property damage or human injury should you pass out at the wheel. That will scare them. There is no reason they should have drilled into the tin. Esp. if they had the headers/HE's off the car! A good used replacement would be adequate...

What else did they do while the car was in the shop? You mentioned changing the cam timing...why? Did the shop break the engine down?

You need to provide more history if you expect good advice/opinion.

http://forums.pelicanparts.com/uploa...1081274208.jpg http://forums.pelicanparts.com/uploa...1081274242.jpg

WOW you had a lot done. Looks like you got some pretty good labor time quotes. Especially .50 hrs for the pedal bushing replacement. The clutch cable one is a little questionable at 1.3 hrs since they had it removed anyway. Parts prices aren't that bad either considering you went through a shop. Was your oil cooler leaking? That's the most painful part of the whole bill. No new clutch either. Interesting.

Isn't it crazy how the "while you are in there" bill can grow so fast?

So the suspected timing miss is from the tensioner upgrade.

It is hard to see, but what is with the 8 exhaust gaskets, and 3 different types? I could see 8 gaskets but only two types. So did they remove your HE's? If they charged you for gaskets they would be just a little hard to install with out removing the HE's, so it seems as though the holes drilled were useless.

About CO: the turbulant air under the car will allow some exhaust gases in the holes if there is neg. pres. in the HE's. But I see in the notes that they state the HE's are rusted out, so that makes the holes irrelavent (as long as the rusted out bit is the surrounding metal of the heat exchangers).

Let me know if you ever find a good shop in MI, I sure haven't yet.

-Jeremy

I don't think that's a good invoice, but I'm a cheap bastard....

Where they saved him some time, they screwed him on others....90+ dollars for a pop-off valve! 1200+ for an oil cooler! 300+ for plug wires!

2 hours to check his clutch action?!?!?!?!

Mind you that some of that work was done with the engine on a stand! I hope they used a stand...

...some of the shop owners can speak up, but the invoice total is what I would pay for a good (almost excellent) '77!

Sorry "kack," but that's my honest opinion....you did wanted honest right?

I'll never make money for a shop as a service writer....

On topic...it doesn't look like they dug into the engine internal, so it is likely a poorly tuned CIS/ignition that is making the car seem different.

"3 different types"; the 2.7 liter engines have a third type of exhaust joint (has three bolt holes) between the thermal reactors (or three to ones) and the heater boxes. This joint uses a triangular shaped gasket different from the others. However, if the exhaust system was off, the count should be ten gaskets unless they reused a couple of them. It should be understand that the heater boxes or heat exchanger sheetmtal shroud is not gas tight even when new; if fits closely but still has enough of a gap to allow air and gases to leak in and out. Afar bigger source of CO is when the car is idling and the wind drift is unfavorable. The exhaust can be pulled right up into the back hatch intake grill and pushed in the the cab by the engine cooling fan. Jim

Souk, I am like you...a cheap bastard and a total DIY when required. But we have the space, time, competancy, and the interest level that others may not.

This BBS is great for people who are about to have work done. It's a wake up call for those who have already had it done and paid more than they could have (again assuming the four points above). I am a softy for the people having the wake up call.

-Chris

FOUR HOURS to replace oil return tubes?!!!!

They sold you the collapsable ones. With those this is a 30 minute job, especially since they had the heat exchangers off already.

It really looks to me like they charged you the book rate for everything, even if the labor for somethign had to be done for another line item. THese might be the book rate for the standard ones, but NOT collapseable!

Not everything was outrageous, but on this one dude, you got hammered. I would call them to task on that one. Hell, if you want, I'LL call them and ask!

If they changed you tensioners they might have mistimed your cams, that would decrease power and possible ruin your valves.
They could also have bend your valves while timing, have a leakdown check performed.
If they had your HE's off, why didn't they just steamclean them?
Sounds like a bad shop.

$117.90 for spark plugs? I know of a shop in Ann Arbor, MI that I won't be going to for any work on my car!

i think your board name fits, because you are definately stuck in a tough place. maybe it is time to buy some book and some tools and go for it your self. i think most of the stuff on the reciepts may seem scary, but in reality, is a piece of cake. how about driving it for the summer to get some damn enjoyment out of the car first. when i drop my exhaust to change into some SSI, you figure out if our exhaust are compatable, and you pay for shipping to the shop of your choice. nothing else. no holes in mine...

You hit the nail on the head, this is why I am putting all the cards on the table with a new shop - still looking. I don't trust EuroTech to correct their own mistakes (they had a shot at it already).

My first concern is: was the cam timing messed with inadvertantly while upgrading the tensioners. That would be neglect, verses abuse if they bent valves in the procedure. Either way, I need another shop to verify my fears, or tell me relax they only put the wrong kind of plug in, or other stupid goof.

Now I remember why I used to make car payments and pay through the nose for insurance. New cars don't make you deal with frauds as much- they have a warrenty.

No no "kack".... this incident should not be a deterant. Owning an air-cooled 911 can be a lot more joy than pain. You just ran into the wrong service guys...

You will learn a lot here and on GruppeB ( www.gruppeb.org .... bring your '77 to the Dark Side). In a few months, you will be helping others and driving your car on the track..and wishing you had not tried the "track crack."


I and a lot of guys here and on GruppeB have spent a lot of money on our cars, and we continue to do so...happy as a blind pig in a bowl of *****

But! I bet most of us would turn away from a car payment for our beloved 911's. As much money as I spend on my car, it's elective. If I didn't own my 911, I'd have bought some hot sports car and be making payments on it...not so elective sometimes.

And warranty work is not guaranteed to be good work either....you still have to find a trusted mechanic.

I'll agree with Souk, You just ran into wrong shop.
On the other hand, these cars can be expensive to get up to good standard if they have been neglected. And when you finally get a good car, there's allways something to improve.
Like a well without buttom.
But I guess that's called customizing and thats also expensive for newer cars.
My P-car is possibly more expensive to run compared to to my everyday/winter car, but I enjoy very second in it. And as a hoppy you spend whatever is needed. I'm on a budget, but my hoppy gets high priority.

Hey Kach, Next time you need work done, give me a shout, I'll work for half that price!!

Changing tensioners shouldn't do anything to the cam timing. As long as you keep the chain tight on the cam sprocket, (I used zip ties) there is no reason to even look at it.

The invoice says "adjust cam timing", why did they do this, and what exactly did they do? Changing the cam timing can alter the power curve of the engine, advancing the timing helps for low RPMs, retarding it helps for high RPMs. Here is a hare-brained theory: Timing chains stretch over time, which would have the effect of retarding the cam timing. If they returned it to stock you could lose some top end. Whether you could tell the difference without a dyno, I don't know. I would think it would have to stretch a lot for it to be noticable though.

I don't see chain ramps on the invoice, which is suprising. Holy ****, $127 for spark plugs?

chrisp, there is a "clutch kit" listed on the invoice.

Tom

kach22i-

I'm in Battle Creek, if you are ever in the need of space to do some DIY my lift and shop are always available!!

Monday I will be taking my car into P.A.T., to see if the Cam timing is correct (another $220). I can not go on driving without knowing for sure.

If my cam timing on #1 and #4 is alright (I think that's what Mike said), then it's the end of my main concern, which is potential engine damage due to poor cam timing.

Checking this is something EuroTech (Tim Pott) has refused to. A responsible person double checks their work.

I can live with less than stellar performance due to other causes and figure out what they did wrong later.

When it comes time to do the heat exchangers, I might take up one of the generous offers made. Thanks, you guys are the best.

You can check if valves are bend by doing a leakdown test.
Piston a top dead center of compression stroke and add compressed air through the ign.plug hole, with an adapter, a bend valve will show by hissing noise in either exhaust or inlet (or oil breather hose if a piston worn)
Take care when holding the crankshaft dead center as compressed air will try do turn/crank the engine.
Same thing is done to small aircraft piston engines on regular basis.
With 2 pressgauges, one for inlet press, one for actual press in cylinder you know the leakage. I do not recall the procentage allowed.

palle7688, thank you for the information.

I might pay for an extra hour of shop time just to have peace of mind that my top end has not already been damaged. Then again if the cam timing is not off, the valves still could of been damaged during the chain tensioer installation. I better have both checked.

In for a dime, in for a dollar.

If the top end is damaged, I would think you would know it. Pistons hitting valves is not a quiet event.

Quote:

Then again if the cam timing is not off, the valves still could of been damaged during the chain tensioer installation. I better have both checked.

No they couldn't. I am not trying to be an dick here, but it really sounds like you don't understand what the tensioners do. Each timing chain is on 2 sprockets, one on the layshaft, one on the cam. All the tensioner does is pushed against a third sprocket to keep the chain tight. When you change the tensioner, all you need to do is keep the chain snug by some other method (like zip ties) so it stays on the same teeth on the cam/layshaft sprockets. As long as the chain doesn't slip a tooth, it is impossible to damage the engine by changing tensioners.

Even if it does slip a tooth, the only way to damage the engine is by starting it.

Timing the cams is not required, because there is no reason to even touch the cam bolt (or nut depending on year). For more info on what is involved in this job, check out the tech article.

Call the shop and ask "I see on my invoice you adjusted my cam timing. Can you tell me why you did this? Where were they set before? What did you set it to?"

Tom

George:

Your story sounds very frustrating and I must admit that the prices for spark plugs ($117) and ignition wires set ($334.00) are harsh. I bought a set of Magnecor reds - the best - for $120. Also, the stock oil cooler is expensive at $1200+ Not Eurotech's fault, but you can pick these up used for $250 all day long.

That said, I must relay my positive experiences with Tim Pott. I cannot believe that he condones shoddy work or cannot/ will not make it right. Maybe he has a new employee or some other explaination.

I used to own a rustproofing and quick oil change shop in Ann Arbor (State & Ellsworth area - sold in 1996 - now called Choice q Lube) and owned a 1987 944S at the time. I knew Tim Pott and had a professional relationship with him, in fact, we discusssed me doing his customers Porsche oil changes so did not back up his shop - I declined, because 911's cannot be done in 10 minutes and I did not want the liability. Anyway, when I bought my 1987 944S in 1996, somebody else did the PPI and then I took it to Tim to install Yellow Koni's up front and do the whole timing chain/ balance shafts thing that 944's require. Tim blew me away with his Porsche knowledge and sold me the Koni's at no mark up (professional courtesy). He found a dozen important items that the PPI missed. He did the most through inspection of the car I have ever encountered - even found a shoddy repair on one of the wheels where the lug nut goes and went over his findings in detail with me.

Then Tim really saved me. In 1997, my engine was making some strange noise and I had it towed from Royal Oak all the way to Ann Arbor so Tim could look into it. He found that the timing chain tensioner had failed and ground off the teeth to my 2 cams and the repair bill was like $4,500! I questioned his findings (did not want to believe) and he gladly showed me the car - it was just as he had described - ruined cams and a lot of work. I was very lucky it didn't jump timing! I had just gotten out of grad school and couldn't afford to fix it, so Tim told me where to located used parts. He put these in for me and got me back on the road for like $2,900.

Tim encouraged me not to fear these cars and I subsequently learned to work on my own Porsche, replacing the rear shocks, power steering rack (twice!) front control arms, muffler and other items. I sold that car and bought my 1972T in 2000. This car is not my daily driver, like the 944 was, but I'm proud to say that it has never been to a mechanic, save for alignment. I have replaced brakes, door stays, ignition, spark plugs, adjusted valves, installed sway bars/strut braces, rebuilt Weber carbs, installed updated seats & seat belts, sterring wheel. The list goes on and on. The point is, if you have the time, old 911's are really simple cars and there is not much that you cannot do yourself with the guidance of this board and wayne's two books (101 projects and the engine rebuilding book).

However, if you take your car to a wrench in the A2 area, Tim Pott and Eurotech would be my first choice, hands down. I knew all the A2 shops (in 1993-1997 anyway) and PAT had a good reputation. There were a lot of good shops in that area, but only PAT & Eurotech for Porsche's.

I have not talked to Tim in seven years, but a guy generally doesn't go from knowledgable & honest to ignorant and devious.

Good luck with your car and I wish you the best.

Jim Chatfield
1972 911T

Jim, you are not the only loyal customer of Tim's willing to speak up for him. A guy named Will over at RennList feels the same way. I told Will he was free to call Tim and fill him in. He did!

Tim called me on 4/8/04 and offered to check the cam timing. I accepted and droped off the car at 5:00PM.

He asked me if I have had any problem with my projects as an architect, and I said yes. What do I do about them? I take car of the probem if given the chance.

It's funny he called me when he did, I was in the middle of the biggest problem I have had to deal with in a while. I am usualy so on top of things that I just dont have any problems, just small fires to put out. This one however was due to a client changing their mind on the type of window, and the builder resizing per new window type on this own (casements and single hungs don't come in the same sizes). They were too small, 2" to narrow, and almost 5" to short. Its not much of a sunroom if its more wall than window - so we are taking them out and upgrading them at no extra charge.

The clients problem, is my problem even if the people I work with keep me out of the loop. We work together to fix problems before they are real problems all the time. That's my dirty laundry, we all have some.

squeaky wheel gets the grease. squeaky wheel telling other potentially squeaky wheels, about a bad grease supply....? crap i lost my train of thought, good luck.

UPDATE
 

UPDATE:
True to his word, Tim Pott/EuroTec checked all of his work again. In addition he replaced the points and tweeked the ignition timing. Oh what a difference!

It's nice to see someone stand by their work and not give up, perhaps next time it will go more smoothly.

I only drove the car a little while, from the shop to my house, a ten minute drive (with side trip into an industrial park-low traffic area). However I can tell that the car moves like it lost 500lbs (like it used to). Now it takes off when you hit the gas, and not just thinks about it for a half second.

The low end seems to be back, and the top end too. The mid band has more meat in it.

The car has pep to it and is more fun to drive.

It was sad to have my old Geo Tracker more respondsive than the Porsche, now nature is back in equaliberium.

On the invoice (no charge) there is documentation (good sized paragraph) all about the oil leaks. There is much debate on-line about switching an old car to synthetic oil, but eventually I will need a re-seal job and some tranny work. It leaks too much the way it is for my taste, after warming up it leaks pretty bad on to both heat exchangers (been told it's not the new valve covers)- not something it was doing last fall. Thinking about changing the oil back to regular and seeing what happens.

PS: The cam timing is within spec's, that was not the problem afterall.

I am glad things worked out for you!!

congratulations!
 

I'm glad it all worked out for you and I'm happy to see Eurotech get a clean bill of health. Pay attention to his notes about the leaks. My notes were always spot on and revealed what some current problems were. There are usually various solutions (low $ up to high $, owner fixes vs. hired wrench fixes) so ask Tim and describe the leaks to this board as well and I'm sure you will get a ton of helpful suggestions and insights. Leaks are a pain, but sometimes not too harmful, othertimes maybe a fire risk. Also depends how much cabin smoke you are willing to deal with! Check out wayne's book on "common oil leaks" and hope yours is one of these, which you can fix with some help from the book and this board.

Most of all, enjoy your car! There are some awesome drives our your way. Try Huron river Drive out towards Dexter.

Glad to hear it all worked out for you Kach22i. I grew up in Ann Arbor (3rd grade thru college and beyond, 22 years in total) and plan to move back to the area in a couple years. I'll actually be living in Hell, MI. I would have been back this year but fate brought me a job I couldn't turn down. I had planned on showing my SC at "Porsches To Pinckney" this year but I'll just have to be a spectator (if I can return for a vacation at all). I look forward to meeting all the SE Michigan Pelicanites one day soon.

Re: UPDATE
 

Save yourself future headaches:
http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_911REC_pg19.htm#item

Tom

So your power issue was points related....correct?

Change the oil back to dino oil...the leaks will improve. There is no need to run Synthetic unless you don't plan to change your oil every 10K+ miles...or if you are really running hot. In that case, get an external cooler, and then use dino oil, the money you save buying dyno oil will pay for the cooler.

Re: Re: UPDATE
 

I saw that in the Tweeks catalog too. Does it work? I will go that rout if the distributor stem "O" Ring ever goes, or if performance slips on it's own.

The points were replaced and the ignition timing redone, I suspect right back where it used to be, probably out of original spec. What ever works, you go with, right?

I know already this old car is a handful for anyone. If I save another $15,000 and sell her maybe I'll get a Boxster (just kidding).:D

kach22i,

I'm glad things worked out for you! I hope we can meet some time as I'm in Wyandotte, MI Try to get to Pinckney the last weekend in July for the "Porsches to Pinckney" event, it's alot of fun! Take care!