Stink Ten Two. The second Blazer.

[leegreen]

Pilot bearing failed and pieces of it lodged between the flywheel and clutch, then cut the clutch disk in half when running, in gear with foot on clutch?

Is the input shaft good enough to swap to a pilot bushing rather than bearing and run trans as is?

[HO455]

I like your theory on the failure. I haven't taken the time to mic the shaft but since I have no idea how many miles are on the transmission and now that it's on the floor I'd like to have it gone through for peace of mind.

Getting the bellhousing off turned into a bit of an ordeal. The bolt were torqued tight and LocTited and it was all I could do to get them loose with 30" 1/2" breaker bar. The 4 bolts on the top required a wobbly socket which I couldn't make work with the breaker bar so once again I had to use my 1/2" impact.

One of those 4 bolts just would not break free. After several tries that ended up with the wobbly socket blowing off the bolt and starting to round the hex off. I decided to drill a hole in the firewall so I could get on the bolt straight. Thirty minutes later after drilling pilots, using a step bit and a die grinder I got a socket on the bolt and broke it free. One more thing to fix during reassembly. Fortunately I have already bought new carpeting for the truck so cutting the old carpet wasn't traumatic and certainly expedited the process.

One upside of making a hole in the firewall was removing the gas pedal. Which I will post more on it later but I will give kudos to the PO for using NutSerts to mount the pedal assembly.

I believe I also have found the source of the annoying backfire I have had when coasting in gear, mostly in 4th from 50 mph down to 35 or so. I discovered a 3/16 to 1/8" hole in the exhaust pipe just downstream of the manifold. That, possibly in conjunction with the manifold havin one bolt missing and a 2nd bolt being very loose would let O2 in to the exhaust making conditions right for backfires.

[leegreen]

access hole for serviceability. Put a plate over and secure with pop rivets n goo, next guy will thank you.

there is always exhaust pressure if the engine is turning. those little holes may be letting some unburnt gasses out that pop off when they hit atmosphere, but I don't think any O2s are sneaking in.

[HO455]

Some guy named AI on the interweb said I had to remove the intake manifold to get the flywheel off. I'm starting to think he doesn't know what he's talking about.

[leegreen]

Did you have to for bellhousing bolt access?
Or did I miss the joke?

[HO455]

Oh no! It's my lame lead in to the rest of the work I've started. I was originally going to do it later this spring but since the truck the truck is down I've going ahead with the rest of the upgrades I've been collecting. Which has proved to be a good idea.

The new goodies are a new cam, a pair of Lloyd Elliot ported heads with a matched intake manifold. Going with all that a set of headers with wide band O2 sensors. I also have new upper and lower control arms. Most of it is bolt on parts but the headers will need some fabrication.

As of yesterday the heads are off and cam is out. It was a real benefit to have the transmission out of the truck when it came time to pull the cam out of the block. The core support has a center support that blocks the cam. By removing the drivers side motor mount bolt I was able to roll the engine up and over enough to get the cam to clear the core support. I'm not sure that would have worked with the transmission still in place.

[leegreen]

it was a good lead

[HO455]

Finally got some time for the Blazer today. I got the bellhousing cleaned up and I had some gouges that cleaned up with a flat file. There was no corresponding damage on the transmission front plate. It may have been from another transmission. I was told that the engine and transmission were out of a 1995 Camaro but the transmission guy has told me the transmission is a 1993. So who knows what may have happened.

On the upside is the transmission has been apart previously it had the new style carbon fiber synchronizers installed then. Plus all the bearings look good.

The down side is I will need to replace the 5-6 gear set on the main shaft due to worn splines. Which makes sense as sometimes when I shifted into 5th there was a slight vibration that would go away if I shifted down to 4th and immediately back to 5th gear. I will be replacing the first gear in order to get the later style (Viper?) larger synchro dogs for more strength. Just in case I want to bolt the slicks on the truck. The input shaft can be sleeved where the pilot bearing rides so I won't need a new one of those.

I got the remaining piece of the pilot bearing out the crankshaft but, the bearing pocket in the crankshaft is pretty rough as seen in this other thread I started on just that topic.

http://67-72chevytrucks.com/vboard/s...d.php?t=862823

The aftermarket Hurst shifter that is installed has a bad dust boot and that seems to be a part Hurst doesn’t sell. One more bit of imagineering to complete before this project is completed.

[HO455]

Before the clutch went south I had been hearing a chirping sound after start up on cool mornings. After a little bit of investigating I had determined the noise was coming from the front of the engine. Once the truck was warm the chirping would disappear. I assumed it was the alternator as the water pump is electric and nothing else is belt driven.

After pulling the alternator and inspecting I found that it seemed fine but the idler pulley bearing didn't spin freely. It felt rough and ready to be replaced. After several hours of searching for a replacement I came up empty handed. All the bolt-on idler pulleys (As opposed to one's with an integral mount) I found are larger in diameter than the one I have. The alternator mount has no name or part numbers on it and other than the bearing itself the idler has no numbers either. I'm guessing the PO used an ebay special when he put the truck together. So I decided to attempt to rebuild the idler by remove the bearings from the pulley. I found that they are common bearings easily sourced.

Just using my arbor press and some heat on the outside of the the pulley I was able to remove the bearings and then I pressed the inner spacer out of the bearings. It went pretty smoothly and other than the condition of the inner spacer it should reassemble without issues.

The scoring on outside of the inner spacer must have been present when it was assembled. That spacer pressed out too easy to cause any scoring. Once separated I noticed that both bearings are rough when I spin them. It seems odd that both would fail in simultaneously in relatively light duty usage. The bearings are rated for 10500 rpm and static load of 980 psi each.

It's possible with the outer races pressed into the pulley together and the inner races being pressed together on the spacer the ball bearings may have been side loaded somehow against their races and that may be why both bearings failed. That being said I'm not sure how to prevent that when I reassemble the idler pulley.

The last photo shows the alternator mount. The yellow arrow points to where the idler mounts and the purple line represents the drive belt.

[HO455]

More progress today! I installed the bellhousing, flywheel and the front plate of the transmission so I could check the bellhousing alignment. To do this installed the crankshaft adapter (Photo #1) we made with the long post for the dial indicator to the crankshaft (Photo #2).

Then after bolting the front plate to the bellhousing I found a combination of pieces that allowed me to measure how out of true the bellhousing is to the crankshaft. (Photo #3) Grrrr! It's now, Pet Peave time! Why does every manufacturer of dial indicators and their associated adapters have to have its own special size of rods and clamps. SO FRUSTRATING!

I asked my wonderful wife to come out and turn the engine for me, so I could watch the dial indicator and record the readings. After rotating the crankshaft twice I found the closest reading and then zeroed the indicator and after several more rotations I was confident that the highest reading was .004 TIR or .002 of misalignment. I used these tolerances I got from the thread linked below.

Bellhousing Alignment Specs:
Parallel Specs are: +/-.001" or .002" TIR
Concentric Specs are: +/-.005" or .010" TIR
That I got from the thread linked below.

Fortunately things were well within specifications and I did not have to replace the index dowels with offset ones. As part of the set up the bellhousing and front plate were torqued to 35 ft-lbs. I had also cleaned all the surfaces and dressed a couple spots between the bellhousing and the front plate with a file to get a accurate fit.

This was one of those jobs that took much more time to prepare for than to actually do. Mostly due to the fact I didn't have to mess around with replacing the dowels with offset ones.

Also once I determined there was only .002 of offset I felt confident that the parallel specifications were good. If I had found the concentric measurements to be out of tolerance I would have checked and corrected any parallel out of tolerance measurements before attempting to address the concentric part.

https://www.pro-touring.com/threads/...56+bellhousing

Next up unbolting it all and do a final cleaning before installing a new pilot bearing. I'm on the fence as to go with a bearing or a bushing. From what I have found Tremec wants me to use only a bearing, not a bushing. However a majority of the interweb says bushings are the way to go. I do know that the factory bearing looks dainty and when GM went to the LS motors they changed the end of the crankshaft and switched to a more beefy bearing. Those engineers knew something and went with what looks to be a more expensive design.

[connorm]

Good work! I really like the 2 door blazer and was looking for one around me for awhile. All of them around me were all rusty, trashed, or expensive. The 2 door 2wd 1st gen blazers are one of the more under rated platforms in mind. Plus the SBC and T56 make it a good little sleeper!

[HO455]

Thank you for the kind words. I looked for quite awhile before this one popped up on Craigslist. I'm certainly happy I was able buy it. It's my second first gen S10 Blazer.

[HO455]

Made some progress over the weekend. I got the new cam degreed and installed. It came in at 107.5 for a recommended 108 degree lobe centerline with the timing chain set that was installed. The engine has about 8k miles on the rebuild. The chain and gears looked like new.

The crankgear markings were a bit odd in that the triangle mark retarded the timing and the rectangle mark advanced the timing. The gear set looked like a Cloyes set so I don't know what the story is with the markings.

The timing cover shows signs that the chain has rubbed the cover. (Photo 1 see arrow ) The chain shows no indication that it has touched the cover so maybe it was from before the rebuild.

The oil pump drive gear is definitely due for replacement. (Photo #2) I have no idea if it was replaced as part of the rebuild. The camshaft I removed was a factory cam and it may have been the original camshaft. The new cam is an Erson grind of a Lingenfelter design meant for improved horsepower and still pass emissions. I need to call Erson tomorrow for their recommendation on what style of drive gear to install.

[HO455]

I also got a new oil pan gasket installed and the timing cover installed. Still a lot of moves left to go but things are headed in the right direction.

A couple of glamor shots of the newly rebuilt heads with complete with Lloyd Elliot porting. Woo Hoo!