Finally!

[Roadkill]

Quoting: Andy

DRE Race Conposites

Not to hijack but I've just emailed them about supplying me a 4" cowl hood . . . see what happens.

[Andy]

No worries dude, he may ask you for your current hood so he can makes mould for it.

[Roadkill]

Yeah, I guessed as much so have already offered it.

[Andy]

Finally got around to doing a leak down test on this engine to see what I really had bought.

After a little bit of head scratching and calibrating my gauge, I bunged it in cylinder 1 and immediately got a reading of a 110% compression. A little more head scratching revealed there was a Schrader valve in the quick connection spark plug lead that wasn't allowing any air to flow into the combustion chamber. This removed and retested, I ended up getting a more sensible reading of 10% loss in most cylinders with a couple only at 5%. I could also hear the air coming up from the oil gallery.



Spot the obvious mistake...



The only problem I came across was that cylinder 3 intake rocker never became loose when I was checking for TDC. The rocker arm stayed tight and I couldn't rotate the push rod at any point while turning over the engine. This I believe meant three possible things a) Lifter is stuck, b) Lifter is still full of oil c) The rocker arm is adjusted wrong.

I'm still not 100% sure how to tackle this, but everyone I've spoken to has said its a damn sight easy to work on an engine in a stand like this, than in a car, so might as well hook the intake off now and have a look at any possible issues. Only danger being I don't really want to remove the heads as I'm pretty happy with how they've checked out, and there is a high risk of me dropping stuff down the intake ports.

Moving on though, I drained the oil, disappointed to find the sump plug wasn't magnetic so got no clues from that, but with the pan off, no signs of any shiny bits or anything metallic in there. So fairly happy with that.







Rotated the engine to get a better look at the bottom end, healthy looking cam lobes with no signs of wear on them, the cylinders from what I could see seemed fairly decent nick, could still see some honing lines.









I left it there for the day as I had to be out, but next up will be removing some main bear caps to see what state the bearing material is in. May also get some plasti-gauge on there to see what sort of clearances I have on the bearing caps.  

I'm also trying to find out more about this intake. A few people have told me with the flow on these heads and the cam that a stock plenum intake manifold like this may not being up to the job. Again, this is all new to me, so I guess more reading up I need to do!

[Roadkill]

I'd guess the intake would be O.K for your heads . . . I still think it's the Cam that'll be the problem.

Go single plane to suit that cam but nothing much else will work the way you want.

[Andy]

I guess this is due an update...

I ended up making it to the penultimate RWYB challenge meet at the Pod. I had decided this was where it was do or die for me running a 15 this year. The weather that morning was a bit sketchy, didn't look fantastic when I left at 6am, but gradually got better getting nearer the Pod. The meet was a Saturday Night Special where they keep the track open til 8PM instead of shutting at the usual 5PM. This meant running into the darkness that was the top end, and also cooler air temps on a warmer track. If there was any chance of running that 15, this was it.

Turning up early at the RWYB sessions is pretty crucial to get some early 'hot laps' in before masses of others turn up, or any oil downs. Once opened I ended up trundling down the fire up road and being straight on the track. No burnout, shallow staged, fans off, gearbox in 1st. All set. I normally prefer racing silenced cars as I get a better chance of hearing if I've wheel spun off the line, this time and the first three other runs I drew up against a noisy as hell Toyota, however, all the launches felt good. I drove straight back down the return road and again was beckoned onto the track, must've only been about 5 cars running as the pair before had already gone through the top end. After this run though I stopped through the pits as one of my RWYB mates had hollered well done. Not really sure what he meant, he said I'd just ran a 15... a 15.90, backed up by a 15.91

More excited than anything I got back in the car and went straight back down the fire up road. The track was great, the air was great and obviously the weather was spot on too. The car seemed strong as well, launching hard yet not spinning up giving me some of the best 60′ times I'd ever run. I got back to the start line, now well practised in my procedure, avoid the water box, little hard launch to haze the tyres, drop it in first, fans off, prestage and then just light the stage bulb.

Came back to the pits, parked up and again my mate came over and said well done, unbeknown to me I'd just ran a 15.78, the fastest run the car has ever done and a perfect way to finish up the RWYB challenge for me. I did stay for the rest of the day, but the car went away with the heat and running into the night didn't prove to be worthy as it went into the mid 16s. I can only put that down possibly to the air quality.



This made my weekend for sure, I needed it after the previous night working on my 350 engine which I had hoped to drop in the car over the winter. I had bought it as a project, not expecting it to be much good, but more a way of learning how to build and engine and such. However when I did a leak down test and it proved to be in pretty good shape I actually thought I might get away with just dropping the engine straight in with a few simple changes to the drivetrain.

However I pulled off the main caps bearings and gave them a once over, the results were not fantastic. Nearly everyone was scored through the white metal, suggesting at some point this engine has suffered from oil starvation. I do however reckon it might be more down to the quality of the oil, which on removing was very thin and smelt strongly of petrol.





With the mains in such a bad way, I really had to check out the big ends and at this point I might as well pull the heads, take out the pistons and give the crank a proper go over. Just like the mains, the big ends appear to have suffered a lack of quality oil too, so these will need replacing as well. With the engine in bits, my plan is now to upgrade what I can and take my time with the rebuild process. I don't really see a need to have it fitted before next year, so I won't be rushing to complete it, but I would like it to be the best engine I can build and one that gives me performance on the street and on the strip.

Stripping the water pump and front pulley, starting to pull the harmonic balancer:


Dizzy out:


Manifold off, some nice ARP hardware used on this engine:


Push rods cleaned and checked, all seem ok:


Heads off, noticed the gasket seems to be pooling water on the return side of the head:


Pulling pistons


Lifters in order, everything is laid out as though you're looking at the engine from the front:


Bores that I need advice on:


Everything laid out:


Heads awaiting cleaning and de-coking:

[Andy]

I had planned for this winter being one of engine swapping, but having thought long and hard about it, and the possible financial circumstances that might involve, for the time being my winter plans for the car no longer involve getting the 350 in. I shall save that for later in the year.

Instead I have drawn up this list

- Get the rear end sorted out, LSD installed, gears changes 3.08 -> 3.73, Detroit TrueTrac installed.
- Get Subframe connectors welded in.
- At least have Fibreglass hood close to being fitted or installed, not worried if painted or not.
- Sort out weather stripping and leaks in the car.
- Oil and filter change
- Coolant change
- Remove the remains of the AC system.
- Fit front fog lights.

All but the rear end I have waiting to install or fit. Its just a case of getting the time or enthusiasm to do it. Hopefully though all that will be somewhere close to being done by the RWYB season next year.

[Roadkill]

A much more sensible approach, IMHO.  

[Andy]

Hmm, an interesting update this, and one that could either make it or break it.

Decided that as I wasn't going to do too much with the engine until next year, I might as well clean stuff, so assembly is more a case of just carefully putting nice clean parts together.

First up with cleaning down the block. All the gasket surfaces got the scraper treatment and I still need to carefully go over the head mounting surfaces as I didn't remove the ARP studs. I have every intention of going with a traditional GM Orange colour for the block, but will see where I can get the thing washed first.

Next up was cleaning off the ridiculous amounts of carbon build up on the pistons. I knew the guy had used gas at the track, as he told me, and he always over fuelled it to be on the safe side. But this is to another level.

Anyway, I tried to get it off with a rag and ended up resorting to carefully scraping the carbon off with a scraper, making sure not to damage the ally. Then, something appeared out of the deposits... oh shit.



Yep, this block has reached maximum capacity.



There in the middle is stamped .060" and measuring up a piston, sure enough about .002" on 4.060". So that now means I hope when I crack test this, it comes up ok, otherwise I have myself a rather fancy table.

I ended up finding the best approach to cleaning these was a decent soak in Jizer, bit of a rub with a scotch pad and finished off on a brass wire wheel, to get into the valve reliefs.





All the pistons look to be in good shape, one of two have slight nicks in them, but nothing that would cause any issues. The big end shells on these will need replacing, thankfully they're not as far gone as the mains bearings, but still a couple show some quite considerable wear.

Not entirely sure what to do about the rings, whether to replace of keep the old ones. I'm getting mixed messages from various people as to what to do there. The leak down test seemed to show they were good of holding pressure, but whether disturbing them like this will cause issues I don't know.

My crank is still in the block and I'm waiting time to go up and remove the timing chain and take it out for measuring and redressing. I did a newbie error and appear to have left a slight witness mark on the journal from removing a rod, nothing that I don't think won't polish out, again, this all needs finalising once I've put a mic over it.

I've ordered a 3 stone hone and intend on deglazing the bores. This again is something I'm getting mixed messages about. I can see cross hatchings down the bores, but they look very shiny and as though they are varnished over. A tell tale sign of bore glazing. Having put a bore gauge down the bores I'm finding at worst, .002" of ovality on the thrust sides. I need to find out if this is good or not.

[Roadkill]

Doesn't look too bad.

+60 thou ain't a great start, though, on a Chevy.  That said it should last you "long enough".

It'd be inclined to swap out the rings myself - they're not a major expense - but that's me.

2 thou ovality sounds O.K to me but I never even checked the LT1 before I put it in the Camaro.  

[Andy]

Even though I've said I'm not going to be installing this anytime soon, I know I've now given it more attention than the car... thats mainly due to me not wanting to face the bill for the rear end anytime soon! It will happen

Anyway, yesterday I got round to completely gutting the block, I wasn't terribly keen on doing it, but I have to hone it, clean it and I want to repaint it, so it all needs to come out.



First thing I did was get some decent photos of the timing setup. I know it sounds bad, but ever since hearing a car running timing gears, I've always wanted a set... now I genuinely have the opportunity to do it, I'm not sure whether it'll be a bit too much noise to live with. That said, just like the rods and crank, this is all stock GM parts, so I'm tempted to get something a bit smarter.



Pulled the Cam as I wanted to 100% confirm the grind of the cam before I commit to purchase stuff that'll make it run. Sure enough comes back as a Comp Cams 280H. The actual lift at .050" is 230* of duration, not quite as bad as 280* that it is marketed as. Still recommends gears and a higher speed t/c which was on the list anyway.







With the cam out, the last thing to pull was the crank. I intend on taking this to work and seeing if I can put some crocus paper on the bearing surfaces and see if I can't bring it up a bit better. As it stands, it doesn't feel too bad, no major scores or marks anywhere. Its just visible that you can see them.



The engine side bearings seem worn, but nothing like as bad as the cap bearings. I'm definitely going to go over the oiling system before this all gets buttoned back together.

[Andy]

Bit of an update to proceedings.

I decided to get the engine honed by a machine shop rather than risk buggering it up myself. Also part of that will be it getting put through a washer and degreaser. Seeing as I want to paint this engine, I decided it would be a good idea to get all the remains of the paint off before hand... messy job with an angle grinder!




... impossible to read casting number...


... Engine and car VIN over punched with some other numbers...



... chasing out the millions of oil pan and timing cover thread...


You'll also noticed I removed all the ARP head studs which had been in place. These all got a good cleaning in the jizer and then in the ultrasonic cleaner... which as far as I can tell does nothing!



The engine is now at a local engine machine shop, getting professionally honed and washed. I also dropped the crank off there to be polished. There was only so much I could do myself on the lathes here. That will also be getting a thorough wash through as well.

With those now out for work, I turned my attention to getting all the other little bits that I have cleaned and ready for reassembly. That's when I saw this and wondered if it matters or not...


... Intake manifold, notice the front and middle coolant passages...


My cylinder heads have coolant passages at the front and at the back, not in the middle, will this cause the back cylinders to run hotter?





So if anyone knows, I sure would appreciate any input

[Andy]

Oh and I decoded the VIN for this engine.

T = Tonawanda
08 = August
07 = 7th day
TDA = 1980 350 V8 in a C10 or C15 Truck

[Roadkill]

Quoting: Andy

Engine and car VIN over punched with some other numbers...

You may find that's a reference to a builder who's rebuilt it at some point in its life . . .

If you're worried about the intake coolant passages, Google some images for comparison . . . I don't recall what's the norm, TBH . . . does seem odd, though, that the back passage (oo-er) isn't utilised.

[Big Mouse]

Quoting: Roadkill

Not to hijack but I've just emailed them about supplying me a 4" cowl hood . . . see what happens.

Dale altered my 4" cowl when we noticed it had no clearance over the carb once the nitrous plate was fitted - I didn't like the end shape but the quality of his work is good

[Roadkill]

He got back to me and said he can do 3" but to call him.   I haven't actually seen the Camaro since then so haven't called him back.

I don't think I can get away with a 3" without using a smaller air filter (and I love my air filter ) . . so we'll see.

I'll give him a call when I get a day off !  

Hi-Jack (again) over.  

[Andy]

Time for another bit of an update...

Sent the block off to be honed professionally and have the cranks polished. It came back looking schweet! Also can both of them a thorough wash through, and now just need me to get around to painting. Going to be painted GM Orange... will be interesting to see how that works out









Along with this was my first order of 'bits' from Real Steel. At this point I hadn't got the crank back so couldn't order the shells. Those will be in the next order, along with intake and manifold gaskets, timing cover gaskets, seals etc.



Moving away from the engine, focus shifts to the other end of the car. For ages I've been looking at getting an LSD sorted, and at one point buying a 4th gen Auburn unit. After talking a while to some various axle builders and friends, I was swayed towards the Eaton TruTrac carrier. This doesn't have clutch material or wearable parts and instead uses helix gears across the perimeter of either sides half shafts... if that makes sense. Sod it, I'll copy the video:



Anyway, I've got that now, along with a set of 3.73 gears and a full rebuild kit. I intend on doing the work myself... although I'll see how I get on with setting it up, as I know setting one of these up can be incredibly time consuming and hard.

[Roadkill]

RK approves of these shiny things.  

(Glad you went with a double-roller instead of a timing gear set up, too)

[Andy]

Have a free weekend and was hoping to get some way in to building the motor back up but my order from Real Steel is being delayed as some parts are waiting in customs.

Now waiting for the main cap bearings and the big end bearings, as well as some replacement parts for the oil system. Not taking any chances with the old oil system parts, just replacing them all. New stock sump pan as well, with pickup, which when I go to fit will be checked over for clearances.

[Andy]

Was a bit of a delay on getting the work started on my axle, had to wait for the workshop to become free, but finally got it out and back to my work (have far more tools and machines + it is heated.)



Cover off, 3.08 gears and open carrier:



Carrier, pinion and all bearing races removed. Thoroughly cleaned with brake cleaner. Also removed the fairly large burr from where the axle tube bore had been machined into the centre pumpkin casting. Nice GM quality control there!



Carrier, both shims were measured and marked, along with the carrier bearing clamps.



In removing the drum brake backing plates from the axle, I had to muller the huge bolt that anchors the drum brake springs. Turns out these are out of production and no longer able to be purchased, guess I'll have to make my own!





Next problem was to suss out how to remove the pinion bearing for setting the pinion depth. Would need to be able to remove the bearing several times without destroying it. Would be nice to get my hands on the Yukon clamshell design thing, but unfortunately they cost a fortune, so again, time to make up my own!















Now the pinion and bearing are apart, I've measured up the shim, turns out to be .031".

Now waiting for the Axle casing to come back from the shot blasters and being powder coated. Then the rebuild can begin!

[Cunning Plan]

Lovely bit of fabrication work

[Andy]

GM 10 Bolt Torque and Preload specs:

Ring Gear bolt torque: 65ft lbs (Left hand thread, use locktite.)
Carrier Cap bolts: 55ft - 60ft lbs
Pinion Preload: 20" lbs (using swing bar to set and rotational torque not break away.)
Ring and Pinion Backlash: .006" - .010" on edge of ring gear tooth
Carrier Preload: Test installation should be a snug push fit, final installation with a brass mallet


Prepping the ring gear for installation, using a set of Motive 3.73:1 gears designed for a series 3 carrier:



Installing the ring gear on the Eaton TruTrac series 3 carrier:



Installtion process goes like this:

Install inner pinion bearing on pinion gear with 'stock' (shim you removed from original install) underneath. Oil up bearings as installing. Fit outer pinion bearing and yoke, do not install crush sleeve at this time. Using the old pinion nut and washer, tighten down bearings until 20" lbs of rotational torque is made.

Now time to install the carrier into the casing. Working from the ring gear side, install shim(s) until the ring gear seems to be in tight contact with the pinion. Shim out opposite side until snug fit is achieved with installing the carrier.

Using a DTI (Clock) check for backlash of the pinion and ring gear engagement. Aiming for between .006" - .010". Decrease the shim amount on the ring gear side to increase backlash, increase the amount of shim on the ring gear side to decrease backlash. Whatever shim you add or remove from the ring gear side, it must be replaced on the other side to maintain the carrier preload.

Once the correct backlash has been achieved, time to get the gear marking compound out to see what gear contact pattern is being formed.

First pattern ran at .006" of backlash with .032" shim...

Coast side:


Drive side:


On inspection, this appeared to show the pinion shim being too large as the pattern was very deep within the ring gear. Recommend that I remove the pinion shim for .002" less.

Second pattern formed with .006" of backlash and a .030" shim under the pinion bearing...

Coast side:


Drive side:


Here you can see the Coast side gear patter is nicely centralised in the gear tooth, and has a round appearance. However on the drive side, the pattern is similar but has moved out towards the heel (outside) of the ring gear.

An idea gear contact pattern is one with an oval round appearance, that sits in the middle of the tooth favouring the toe (inside edge) of the ring gear on both sides.

[Roadkill]

Quoting: Andy

However on the drive side, the pattern is similar but has moved out towards the heel (outside) of the ring gear.

Have you re-shimmed again, yet ?

I can't believe 2 thou would make that much difference.  

[Andy]

The consensus from my american friend 'Big Gear Head' is that he prefered the .032" shim, and that perhaps I should've shot for more backlash. Greater backlash will also make the pattern edge towards the heel of the tooth. He liked either pattern but prefered both being centralised.

It's recommemded making .003" shim changes to the pinion at a time to get a noticeable change. Thankfully my bearing puller is working like a charm!

I'm currently waiting on a new outer bearing to arrive before I make any more changes. First thing I shall do is try rerunning the pattern with a greater backlash allowance.

[Roadkill]

Quoting: Andy

He liked either pattern but prefered both being centralised.

Makes sense to me.  It's like so many things . . . once you've done it a thousand times, you know what you can realistically get away with.