Otto's Rebuild

[otto in norway]

Originally Posted by wwhalenc

All the 944 guys are stuck with Alusil. I've heard over there that JE has a coating availble that survives in an Alusil bore. Might be worth looking in to.

Yeah, that could have been a good idea.
But rather than going for a solution that may work, I opted for the much safer "no brainer" solution. I have heard so much tales of bad experiences with Alusil, that I choose to keep clear of it alltogether.
Besides, I've ordered the P&C set from Mahle (9,8:1), and sold the JE pistons.

[304065]

Originally Posted by otto in norway

That's what I thougt too..!
But my pal, who has opened a lot of engines, felt that this was a waste of time.
He said that since I have alomst no wear on these bearings, it means that the main shaft is nearly perfectly balanced and centered. So, if I keep these bearings, I will be sure this continues like that for the future. And a LONG time into the future as well! I choose to thrust his judgement; He does this for a living, and he has been spinning the spanner since he was 7 years old...

Otto,


There are a few ways to measure bearing wear: plastigage, a ball-tip micrometer, a bore gage on the assembled case halves, a comparator gauge set up on a stack of gage blocks to zero, then introduce the bearing to see the difference.

The eyeball is not an objective measuring device.

The specifications are in the factory specifications book for the bore diameter and shaft diameter, and the maximum allowable clearance. Wayne has thoughtfully reproduced these in the back of his book. A comparison could be made between the shell thickness of the worn bearing vs. the thickness of a new one. These dimensions are given in the hundredth of a millimeter.

A set of bearings is inexpensive enough that they can be replaced, even if the existing ones look fine.

[otto in norway]

Originally Posted by john_cramer

Otto,


There are a few ways to measure bearing wear: plastigage, a ball-tip micrometer, a bore gage on the assembled case halves, a comparator gauge set up on a stack of gage blocks to zero, then introduce the bearing to see the difference.

The eyeball is not an objective measuring device.

The specifications are in the factory specifications book for the bore diameter and shaft diameter, and the maximum allowable clearance. Wayne has thoughtfully reproduced these in the back of his book. A comparison could be made between the shell thickness of the worn bearing vs. the thickness of a new one. These dimensions are given in the hundredth of a millimeter.

A set of bearings is inexpensive enough that they can be replaced, even if the existing ones look fine.

Hmmm....
You make a lot of sense! Thanks for useful input!
I guess I'll just replace them then...
The expence is not a big deal, as you pointed out, so why bother measuring, if it's easily replacable as well...
I guess I should have taken into consideration that my pal has a habit of eyeballing things all the time. Allthough this in allmost every case works out, his work is hardly in the "feinschmecher" category.

Thanks again!

[otto in norway]

BAD news!
Got a phone from the guy overhauling the heads today; He announced that there is a crack in one of the cam housings!! He suggested buying a new one.
This is getting EXPENSIVE!
I'm way past the point of no return, so I guess I'm screwed..!
The only component not to be replaced is the crank/block...!
(Anyone up for a sponsor deal? )

[Aurel]

That is where the fun begins...
Get used ones. There are quite a bit for sale in the PParts classifieds:

http://forums.pelicanparts.com/search.php?searchid=1671164

Aurel

[sabeo.m]

Otto, you can also try www.partsheaven.com

I got a used OEM fog light switch from them.. I'm sure they will be able to help you out for a fair price. Good luck!

[otto in norway]

Update:
Got my parts from Pelican, finally. They were dealyed in customs over here.
But I forgot to order the o-ring for the #8 bearing. So I ordered that from a dealer here in Norway.
By next weekend, I'll be assembling like there is no tomorrow!!

Some pics:

[MBEngineering]

HI Otto
where is the crack and which cam housing??

"Got a phone from the guy overhauling the heads today; He announced that there is a crack in one of the cam housings!! He suggested buying a new one."

regards mike

[otto in norway]

MBEngineering:
I haven't seen the camhousings yet, because the shop isn't done with the heads yet.
But I've got a set of used housings on hand. So I'll probably go for those.

On the other hand, the guy at the shop said that I might be able to use my old ones, because the crach is small, and not all the way through...(?) -Maybe it's fixable..?
He tried expaining where the crack was, but I didn't quite get it. So I'll have to wait and see..!

[MBEngineering]

HI Otto
OK, long as you are sorted with parts.

regards mike

[toddu]

Otto,
Did you ever get any information with respect to the JE pistions and whether they would "work" with CIS (since the CIS pistions were designed with that type of injection in mind)?

With your posts and others to my related thread, I'm once again re-thinking the direction I will take. I'm thinking of NOT oversizing and initially leaving the CIS with leaving the door open for future carbs of maybe EFI. So, I'm wondering how best to decide on pistons... go with the CIS style to help initially, or would that hurt in the long run if switching to a different injection technology.

Cheers,
Todd

[911 tweaks]

I can summize it up for you in a short bit:
#1 define the personality you want for the engine i.e. hp, torque, trans gearing you plan to run and where in the rpm band you want performance.
THEN, the cam profile will be defined to accomplish such
THEN, piston size & dome shape, cyl displacement, crank stroke, head design, valve size, induction...
Good Luck !! If I were you, I would call one of the expert engine builders on this forum whom continually volunteer such info, like henry s., steve w., and any of the others on this forum that know what they are doing. Theu will spec ~ get you what you want... caution: you may not like the price of such an engine, but these guys are tops and you get what you pay for!!

JMO... Bob

[otto in norway]

toddu:
I think 911tweaks has some good points and pointers here...

I have read a "tech artichle" here on this web site, where a guy tells the story of his tuning experience. He used JE in the CIS system, and it worked well. I have also heard of others with the same result. BUT you cannot use JE with Alusil cylinders. You need Nikasil. Hopefully that's what you got. (I didn't)

[87 clubsport]

Hi Otto, actually you can replate your alusil cylinder with nikasil, and fit in the JE piston, I talk to EBS about this.

[otto in norway]

Yeah, I've heard that too...
But it's not cheap, so I went for a new set instead...

[87 clubsport]

Yes $150 per cylinder replate x 6 = $900 plus $1000 piston = $1900.

[otto in norway]

Those prices look allright in my book...!
Compared to apx. 4500 for a new set, that's a bargain!
Are you sure this includes machining to make the clearance within spec?

I've heard the cost is about $3000. (In belgium)


Small update:
I've started painting/refurbishing all the details/covers. MAN that takes up a lot of time!

[87 clubsport]

yes included, but if your car mainly street use you are in right direction, I also want some input about why alot of thread talking street use better go for Mahle, track car use JE , is that tear and wear issue?

[otto in norway]

I don't have any input on this.
Maybe you are right on the wear issue, but cost is probably a issue too...?

[otto in norway]

Update:
Assembled the cases, looks like it's sealed up good...







Also, I got the parts back from the shop: