David S. Wallens Editorial Director
Oct. 12, 2011 12:59 p.m.

We're making progress: http://grassrootsmotorsports.com/project-cars/1984-porsche-911-carrera/starting-look-engine/

And have a question: What's the most difficult engine you have ever assembled?

Chas_H
Chas_H New Reader
Oct. 12, 2011 1:08 p.m.

Porsche 911 is right up there, along with Subaru. Old Bentley/RR 6 with the hollow crankshaft were also tedious.

Maroon92 SuperDork
Oct. 12, 2011 1:10 p.m.

Timing chains on the 911 are a 3 person job. I don't have enough hands!

bravenrace SuperDork
Oct. 12, 2011 1:34 p.m.

A Detroit Diesel 8V-71. It wasn't all that difficult, but it was the most difficult that I've worked on, due to having to pay much closer attention to clearances and such. I guess this would apply also to pretty much all the diesels I've worked on, but I've worked on 2 stroke Detroits the most. I don't know about the 911 engine, but my old bug flat 4 was a piece of cake.

Chas_H
Chas_H New Reader
Oct. 12, 2011 1:38 p.m.
Maroon92 wrote: Timing chains on the 911 are a 3 person job. I don't have enough hands!

I use a straight edge clamped to the engine case, leaves both hands free to hold the verier caliper. And I leave the crankshaft pully off, since it gets in the way.

Varkwso Reader
Oct. 12, 2011 2:04 p.m.

Twin cam 944S engine is a top contender for me.

92CelicaHalfTrac SuperDork
Oct. 12, 2011 2:10 p.m.

The Camry/Celica 2.2 5sfe isn't a whole lot of fun...

I'm sure it's much easier if you put the timing belt on BEFORE you drop the motor into the car, though.

a401cj Reader
Oct. 12, 2011 2:25 p.m.
bravenrace wrote: A Detroit Diesel 8V-71. It wasn't all that difficult, but it was the most difficult that I've worked on, due to having to pay much closer attention to clearances and such. I guess this would apply also to pretty much all the diesels I've worked on, but I've worked on 2 stroke Detroits the most. I don't know about the 911 engine, but my old bug flat 4 was a piece of cake.

you're speaking from experience and I'm not so you're one up on me but....this runs counter to everything I've ever heard about the big GM 2 stroke.

ProDarwin Dork
Oct. 12, 2011 2:32 p.m.

Don't know, but the Audi/VW motors scare the bejesus out of me:

v8

4cyl

Yo dawg, we heard you like timing chains so...

David S. Wallens Editorial Director
Oct. 12, 2011 2:38 p.m.

It has timing chains on its timing chains!

RossD SuperDork
Oct. 12, 2011 2:39 p.m.

Scariest thing I've torn into was taking the intake manifold and all of the assorted plumbing off of an Audi 2.7 Bi-turbo to get to the auxilary electric coolant pump. My dad and I took a lot of pictures...

ProDarwin Dork
Oct. 12, 2011 3:06 p.m.

Now I wish I was good at photoshop. I want to do an "escher" timing chain. I don't know why, but I think it would be quite funny.

mad_machine SuperDork
Oct. 12, 2011 3:45 p.m.

that v8 must have 1k in chain guides alone...

darkbuddha Reader
Oct. 12, 2011 4:39 p.m.

Okay, so take the two points as far apart as possible, and that is how close I'm ever gonna get to opening up one of those Audi/VW V8s. In fact, berkeley these hard engines, I'm sticking with 2.3 Limas, push rod V8s, and old DOHC 4 cyls.

docwyte Reader
Oct. 12, 2011 4:42 p.m.

The V8 in my Audi S4 has the chains mounted on the rear of the motor. That means the motor needs to get pulled to replace the guides, etc. It's a $3000 job.

bravenrace SuperDork
Oct. 12, 2011 5:34 p.m.
a401cj wrote:
bravenrace wrote: A Detroit Diesel 8V-71. It wasn't all that difficult, but it was the most difficult that I've worked on, due to having to pay much closer attention to clearances and such. I guess this would apply also to pretty much all the diesels I've worked on, but I've worked on 2 stroke Detroits the most. I don't know about the 911 engine, but my old bug flat 4 was a piece of cake.

you're speaking from experience and I'm not so you're one up on me but....this runs counter to everything I've ever heard about the big GM 2 stroke.

I'm not sure what you mean by that. I only meant that a normal engine rebuild on a heavy diesel is like blueprinting a gas engine. So it's more work, but I'm not saying it's more complex or anything like that. I've rebuilt a lot of engines (was a truck/diesel mechanic for a long time before going back to college), but nothing all that different, so this is the one that required the most amount of work and attention to detail. A big Cummins/Mack/Cat would be the same, only different.

JohnyHachi6 Reader
Oct. 12, 2011 5:49 p.m.

Definitely a rotary - shoooot, making sure all those little corner seals and apex seals stay in place as you assemble the housings...

Chas_H
Chas_H New Reader
Oct. 12, 2011 6:26 p.m.

The rotary definitely needs a few tricks for assembly. I glued all the seals in place with "Vaseline" and used the outer rotor housing o-ring doubled up as a big rubber band to hold in the apex seals.

a401cj Reader
Oct. 12, 2011 8:51 p.m.
bravenrace wrote:
a401cj wrote:
bravenrace wrote: A Detroit Diesel 8V-71. It wasn't all that difficult, but it was the most difficult that I've worked on, due to having to pay much closer attention to clearances and such. I guess this would apply also to pretty much all the diesels I've worked on, but I've worked on 2 stroke Detroits the most. I don't know about the 911 engine, but my old bug flat 4 was a piece of cake.

you're speaking from experience and I'm not so you're one up on me but....this runs counter to everything I've ever heard about the big GM 2 stroke.

I'm not sure what you mean by that. I only meant that a normal engine rebuild on a heavy diesel is like blueprinting a gas engine. So it's more work, but I'm not saying it's more complex or anything like that. I've rebuilt a lot of engines (was a truck/diesel mechanic for a long time before going back to college), but nothing all that different, so this is the one that required the most amount of work and attention to detail. A big Cummins/Mack/Cat would be the same, only different.

I had just always heard that they were super simple and I equated that (perhaps wrongly) with being being easy to work on

Oct. 12, 2011 9:51 p.m.

I've got a 4 cam Mustang apart just now. The engine itself is fairly straightforward, but accessory drives and manifolds and plumbing and wiring, oh my.

Ian F SuperDork
Oct. 13, 2011 9:00 a.m.
a401cj wrote: I'm not sure what you mean by that. I only meant that a normal engine rebuild on a heavy diesel is like blueprinting a gas engine. So it's more work, but I'm not saying it's more complex or anything like that. I've rebuilt a lot of engines (was a truck/diesel mechanic for a long time before going back to college), but nothing all that different, so this is the one that required the most amount of work and attention to detail. A big Cummins/Mack/Cat would be the same, only different.

I had just always heard that they were super simple and I equated that (perhaps wrongly) with being being easy to work on

I think what he means is that it's not the actual tasks, but the knowledge and attention required to do those tasks. When he says, "like blueprinting a gas engine", I'm guess it means you have to really check and triple-check that tolerances are within spec, which usually requires time and very good ($$$$) measuring tools.

Personally, I tend to like modern engines. They are designed to be assembled quickly on a production line, so many things like tensioners and what-not are self-adjusting and don't require a lot of old-school voodoo knowledge. If I had a good service manual, that Audi V8 wouldn't really scare me. That said, I would also expect to drop a fair amount of coin on the various holding tools required to keep everything in place during the job.

bravenrace SuperDork
Oct. 13, 2011 9:29 a.m.

In reply to Ian F:

Yes, that is what I meant. Heavy diesels are built with very tight and precise tolerances, which is one of the reasons they are so durable. I worked on these engines when they weren't old, and like I said before, they are just the one particular type of engine that I have rebuilt that took the most work. I have worked on engines that were harder to work on, but David asked what engine was the most work to assemble, so that's my answer. I know there are many engines that are much more complex and harder to assemble, but I just haven't assembled any of them. Other than heavy diesels and small engines, I've rebuilt mostly american V-8, V-6, inline 6 and 4's, and Honda 4 cylinder engines. I have rebuilt a couple VW flat 4's also, but nothing all that complex.

motomoron HalfDork
Oct. 13, 2011 9:30 a.m.

This is the stuff that drives our (us, the GRM community) car decisions vs. the general population. And that's both awesome and sad.

GenPop: "Dude, Audi S4s are sweet, and they're getting cheap"

GRM: "Dude, there's an S4 Avant V8 6 speed on craigslist, but the timing chain job would break me as a man. Sad"

ahaidet New Reader
Oct. 13, 2011 9:40 a.m.

Ive rebuilt a 4G63T Mitsu motor, a few Kawi 600cc bike motors, been most of the way through a 4AGE Toyota and by far the most difficult for me is the EJ205 in my Saabaru. Like was mentioned earlier a GOOD factory manual is a MUST. (Can't stress GOOD enough!)

I just had the motor in and ready to start on Saturday afternoon. Found out it wasnt getting oil pressure. Traced it down to the rear main seal being pressed in too far. Factory service manual makes no mention of how far it should go in.. (if you press it all the way in there is just about enough room for another one on top of it) Well every engine I have worked on so far you press it in until it seats to make sure it is square to the crank. Turns out if you press it in that far you block an oil drain at the bottom of the seal bore. WHY they make no mention of this in the manual is beyond me! They just say use SST to seat rear main seal.. I would guess that this tool has some recess that only allows it to press the seal in a certain depth. Why they don't make some "stops" or a lip for the seal to seat on is beyond me.

So I spent the better part of my Sunday, Monday and Tuesday nights removing the trans, clutch and flywheel. Using my homemade SST (drywall screw) to pull seal and install a new one. Then reinstalling everything. Heres hoping for oil pressure tonight when I finally try it again.

Ian F SuperDork
Oct. 13, 2011 10:02 a.m.
ahaidet wrote: They just say use SST to seat rear main seal.. I would guess that this tool has some recess that only allows it to press the seal in a certain depth. Why they don't make some "stops" or a lip for the seal to seat on is beyond me.

I think you sort of answered your own question: they use a special tool that inserts the seal at the correct depth, thus negating the need for a stop or lip, which would add to production costs. Asking "but how much could it add???" misses the point, manufacturers look to shave every bit of cost they can from a car. A nickle here... a dollar there... it adds up.

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