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maschinenbau
maschinenbau Reader
1/21/16 8:45 a.m.

In reply to jmk015:

That's why I'm sticking to the S10 V6 converter. Enough stall to help launch a 4,400lb missile, not too much for the autocross, and junkyard cheap.

Risky, yes, but 4l60E's aren't exactly rare either.

jmk015
jmk015 New Reader
1/21/16 9:06 a.m.
maschinenbau wrote: In reply to jmk015: That's why I'm sticking to the S10 V6 converter. Enough stall to help launch a 4,400lb missile, not too much for the autocross, and junkyard cheap. Risky, yes, but 4l60E's aren't exactly rare either.

Do you know how much power the S10 converter is rated for? There seems to be controversy on the other forums as to how much abuse it will handle behind an LT1. From what I've read the S10 converter will give you about a 2,200 rpm stall behind a v8. I like the low price and easy availability of the s10 unit though. I'm just worried about blowing an S10 converter or a used/abused one when launching at the strip. we'll be running 295 DOT approved 'slicks' on the back, so I'm expecting to hook up pretty well and we don't want to grenade a converter when launching...

Your local parts store can probably get you a new or remanufactured S10 converter for ~$100. That's more than junkyard price, but its still not very expensive.

Summit has the FTI Performance SB Series Torque Converters SB2400LT30, which is a locking 2,400 stall for $199 new. That's a pretty good chunk of the budget, but we're still considering it. A converter failure would end our day/weekend at the races...

Basically, I've never raced an auto before and I don't know what (if any) balance exists between a higher stall for better drag times, while still maintaining throttle response and drivability for autocross.

I'm about 45 minutes away from Summit Point, and we'll probably use this car for some HPDE events too, so we can't go full drag race on the converter... or can we as long as its a locker??

Thanks again for your input!

tuna55
tuna55 MegaDork
1/21/16 9:24 a.m.

A locking converter locks up at high speeds to allow for better highway mpg based on lower slippage between the engine and transmission. If you're doing lots of highway driving, it's great, it's almost like another gear.

If you're not, it's added complexity and added weight. Skip it for a race car unless you also plan to commute with it.

maschinenbau
maschinenbau Reader
1/21/16 9:51 a.m.

In reply to jmk015:

With your OBD1 tuner, you can program at what speed and in which gears the converter locks up, along with shift points depending on throttle position. Seems like most people do a converter lock during the 3rd gear shift for a higher trap speed.

As for the price, local PAP has them for $25 plus core. All 96+ Blazers will have the V6 too. As with all drivetrain parts, look for the vehicle with the lowest miles and most body damage. Just check the 4-letter code on the side from the links above.

That's my plan at least. I still have over a grand in the budget after the engine rebuild. I'm just cheap.

jmk015
jmk015 New Reader
1/21/16 11:55 a.m.
maschinenbau wrote: In reply to jmk015: With your OBD1 tuner, you can program at what speed and in which gears the converter locks up, along with shift points depending on throttle position. Seems like most people do a converter lock during the 3rd gear shift for a higher trap speed.

Thanks for the info and tuning tips. I really need to get an OBDI tuner and start learning how to use it.

jmk015
jmk015 New Reader
1/22/16 8:48 a.m.

I went up to York PA yesterday and met Wheels777 and got to tour is AWESOME shop. Thanks for the parts, the tour, and the advice!!

I picked up a complete 9C1 motor, LT1 short block, 2 sets of aluminum LT1 heads, a stock LT1 intake, a GM performance cam, 2 ECM's, and a wiring harness for $400.

Our plan is to tear down the 9C1, pick the best short block, refurbish the best set of aluminum heads, and build a motor for our car. We'll probably be selling off everything we don't use to recoup some of the budget.

Here'sour old block, stripped down and ready to be removed from the K-member:

Here's the stash of parts I picked up from Wheels:

java230
java230 HalfDork
1/22/16 9:48 a.m.

Nice haul! And I like your jack stands/blocks

jmk015
jmk015 New Reader
1/22/16 3:56 p.m.

Its nice to have a snow day and new motor parts to play with... until you realize that the gasket set you ordered has the wrong gaskets in it!!!!!!

Warning to any LT1 owners who order SUM-G2602 from Summit racing. This is supposed to be a complete gen II / LT1 350 gasket set. The only problem is that the head and intake gaskets in the kit are actually for a gen 1 small block Chevy!! ARGH!!

I noticed that the these gaskets didn't look right in the photo on the website before ordering, but I figured it was just a stock photo and ordered anyway, after calling and asking if these really were gen II / LT1 gaskets. Guess what? Its the actual photo, and the gaskets really are wrong. Summit customer service rocks, and they shipped me out the right LT1 head and intake gaskets free of charge... but now we can't put our motor together this weekend. Bummer.

Here's our two options for short blocks:

I have a noob question about Challenge budget rules:

We bought the C4 wheels to put on the Camaro for the Challenge. I want to keep the Z28 wheels for a future project. Since the z28 wheels will be removed from the car, can I subtract their fair market value (~$100 ??) from our Chalenge budget? I'm sure I could get $100 for the wheels if I posted them on Craigslist, but I'd like to keep them for another project...

jmk015
jmk015 New Reader
1/25/16 4:33 p.m.

I picked out what I thought was the best set of aluminum heads and lapped the valves, replaced the valve stem seals, and upgraded the springs. I only got one head done today, hand lapping all the valves takes forever!

Look at that nice seal!

Finished! It doesn't look much different from when I started, but its much better now.

Robbie
Robbie SuperDork
1/26/16 10:46 a.m.
jmk015 wrote: I have a noob question about Challenge budget rules: We bought the C4 wheels to put on the Camaro for the Challenge. I want to keep the Z28 wheels for a future project. Since the z28 wheels will be removed from the car, can I subtract their fair market value (~$100 ??) from our Chalenge budget? I'm sure I could get $100 for the wheels if I posted them on Craigslist, but I'd like to keep them for another project...

Yes, that should be fine. It does count toward your recoup limits, and of course, if you use it in a questionable manner you should expect it to be questioned.

Jerry From LA
Jerry From LA Dork
1/26/16 12:15 p.m.
Robbie wrote:
jmk015 wrote: I have a noob question about Challenge budget rules: We bought the C4 wheels to put on the Camaro for the Challenge. I want to keep the Z28 wheels for a future project. Since the z28 wheels will be removed from the car, can I subtract their fair market value (~$100 ??) from our Chalenge budget? I'm sure I could get $100 for the wheels if I posted them on Craigslist, but I'd like to keep them for another project...

Yes, that should be fine. It does count toward your recoup limits, and of course, if you use it in a questionable manner you should expect it to be questioned.

I think you can add to your budget if you sell them. I'm not sure you can add if you keep them.

jmk015
jmk015 New Reader
2/8/16 8:25 a.m.

We got our 'good' motor assembled this weekend. We picked up a Comp Cams 503 grind, a set of Trick Flow Hardened pushrods, and a new timing chain off of Craigslist for $200. It was all new and un-opened, so we thought it was a pretty good deal. A $50 set of valve springs and an $85 dollar gasket set from Summit Racing completed our engine build.

We cleaned up most of the 'extra' motor parts and posted some of them on Craigslist. Its time to start selling off our extra parts to see how much of the budget we have left for suspension, brakes, and a torque converter.

We were debating whether or not to replace the oil pan gasket on the motor we're using, and decided to go for it to take a look in the bottom end and because our gasket set came with one anyway.

We found a broken off main bearing cap bolt!!!

This is how we found it when we pulled the oil pan. It was broken off ~1/2'' up from the bottom, and the top part of the bolt had backed itself out. The oil pan was keeping the bolt from falling out of the hole. The bottom 1/2'' was still threaded into the block. Weird.

Luckily, it was the farthest rear main bearing cap, so the oil pan kept the broken off bolt from falling into the motor and going boom. Also luckily, the bearing with the loose bolt looks ok. We checked the torque on the other main bolts, and they were all tight. What's ever weirder is that the bolt was broken off in the threads, ~1/2'' up from the bottom. The top part of the bolt backed itself out, but the broken piece was still threaded in.

I've never seen a failure like this before... how the hell does this happen?

jmk015
jmk015 New Reader
2/8/16 12:03 p.m.

Here are pics of the crank and bearing where the broken bolt was located: Even though you can see some marks on the bearing and the crank, you can't feel any of them with your fingernail. We grabbed another bolt out of a donor engine and put the main cap back on with lots of assembly lube and torqued them to 77 ft lbs (in 3 stages): The actual bolt that failed: I'm a little worried about the main cap bearing one back from this one - we didn't check it. Would it be worth our time to do so?

maschinenbau
maschinenbau Reader
2/8/16 12:12 p.m.

I would pull every bearing cap (mains and rods), inspect, and check with plastigage, regardless of finding a broken bolt. Replace worn bearings as necessary. One of those "while the engine's out" things. Plus then you can take the pistons out, inspect ring surfaces, maybe replace rings, and re-hone the cylinders.

Or at least that's the plan for my LT1 Challenge rebuild.

BradyD
BradyD New Reader
2/9/16 2:32 p.m.
maschinenbau wrote: I would pull every bearing cap (mains and rods), inspect, and check with plastigage, regardless of finding a broken bolt. Replace worn bearings as necessary. One of those "while the engine's out" things. Plus then you can take the pistons out, inspect ring surfaces, maybe replace rings, and re-hone the cylinders. Or at least that's the plan for my LT1 Challenge rebuild.

We're planning to check all the main and rod bearings Friday night along with the crank end play. Don't think we're going to be taking any pistons or rods out - we've already got the whole engine buttoned up. Just going to check the bearings for peace of mind.

BTW, I'm Brady - the other half of this build. Howdy!

4cylndrfury
4cylndrfury MegaDork
2/9/16 2:48 p.m.

Really loving this build. That is all.

jmk015
jmk015 New Reader
2/17/16 11:33 a.m.

We put the 'new' motor into the K-member and started to swap over all of the brackets and accessories:

Once we get our hands on a better torque converter we can bolt up the tranny, install the headers, and put the powertrain back into the car!

Correction to an earlier post: our car actually has 2.73 gears with a Posi, despite being told by the previous owner that it had 3.55's.

We're debating going with a ~2,400 RPM torque converter with 4.10 gears, or keeping the 2.73's and getting a ~3,800 RPM converter. There seems to be two different schools of thought on this... and we're tiring to figure out what's going to give us the best 1/4 mile time.

BradyD
BradyD New Reader
3/3/16 8:08 a.m.

We're back and still making progress. We got our 3600 stall torque converter from FTI. Probably the only new part on the entire car...couldn't pass up the 1 year warranty and free restall.

I don't have a pic of it, but we've got the engine on the trans and it's all on dolleys. Gotta put the engine and trans in Saturday and maybe even try to fire it up. Making progress!

We're also on the lookout for a cheap rear axle assembly - our 2.73s are absolute crap. Hoping we can find a whole assembly with 3.23 or 3.42 gears (a whole axle is $100 in a local junkyard chain).

MODS - Is there any way we can change the title of this thread to have "'94 Camaro Z28" in it also?

patgizz
patgizz UltimaDork
3/3/16 10:01 a.m.

look for a v6 car with manual trans for the rear axle. if you don't have a list already look up the GM RPO codes for axle ratios so you can check the SPID label in the glovebox/console.

BradyD
BradyD New Reader
3/3/16 12:27 p.m.
patgizz wrote: look for a v6 car with manual trans for the rear axle. if you don't have a list already look up the GM RPO codes for axle ratios so you can check the SPID label in the glovebox/console.

That is an option, but it will have to be a V6 car with the Y87 option - otherwise it won't be a posi rear. Basically if we can find a V6 car with rear disc brakes, that means it's a 3.23+ gear with posi. Hopefully we'll find something, but we've got time.

patgizz
patgizz UltimaDork
3/3/16 3:35 p.m.

could always just swap out gears if your differential is still a functional posi. and if that's the case it opens you up to a whole new world where 3.73's are available - s10

BradyD
BradyD New Reader
3/3/16 4:46 p.m.
patgizz wrote: could always just swap out gears if your differential is still a functional posi. and if that's the case it opens you up to a whole new world where 3.73's are available - s10

That also won't work, unfortunately. GM decided to use different carriers, so basically nothing worth having will both to the carrier we have.

maschinenbau
maschinenbau Reader
3/4/16 7:28 a.m.

They make an adaptor spacer that lets you put Series-III gears on a Series-II carrier. However, I think that only works for the larger 8.5 rears (yours is a 7.5 I believe). My Roadmaster came with a 2.56 peg-leg Series-II, but I pulled a 2.93 Series-III posi out of a junkyard cop car, then found 3.42 gears on craigslist.

patgizz
patgizz UltimaDork
3/4/16 8:31 a.m.

they do make ring gear spacers to put the 3 series gears on the 2 series carrier, and they're pretty cheap.

BradyD
BradyD New Reader
3/4/16 9:16 a.m.
patgizz wrote: they do make ring gear spacers to put the 3 series gears on the 2 series carrier, and they're pretty cheap.

I didn't know that. Will definitely be looking into that now!

I also have a lead on craigslist for an entire rear with 3.42 gears and posi. Unfortunately the guy isn't responding. Craigslist people can be frustrating - why list something and not respond?

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