My long-term 94 caprice build...

This will be a long slow build thread (mainly so I can keep tabs on everything I do) of my 1994 caprice wagon. The first photo is a few weeks after I bought it. It had around 36k miles on the original 5.7 lt1/4l60, now has around 74k. Runs great, tows great,  the first upgrades I'm doing after owning it around 2 years is engine upgrades. I'm installing a LT4 hot cam kit, new timing set, oil pump, opti, 2600 stall, shift kit and 3.42 gears. A few other little things also. Not going crazy just want a fun daily driver. Next will be wheels/tires (leaning towards 17" torque thrusts) then some small body work and paint. Going to do some kind of hoodscoop but I don't want anything common, so I'm going to make a one-off out of steel, just not 100% set on the design yet. Later down the road will be a manual trans swap also.


Edit* apparently I can't add pics for another 6 days, so I will update it later.

Are you just doing a cosmetic hood scoop, or is it going to be functional? Do not forget to have your computer tuned for the upgrades.

If you are installing the hot cam, why not go for something that will really wake the car up. Are you doing your own body work? What gears do you have now? Look into the higher ratio rocker arms as well.

I usually buy the part I am going to rebuild from the local junk yard on "special price" days, then built it at my leisure, so I can just swap the parts for minimal down time. The cost of the part is minimal compared to the inconvenience of doing the work with the car out of commission. I paid $75 for complete rear, and $60 for a core transmission. I may be able to sell the 3.08 gears from the rear to recoup some of the cost.

Rebuild the trans with some beefier parts while you are doing the shift kit. With more HP, you want it to last a while.

You should put your zipcode in your information, so we know what part of the country you are from.

welcome.

The timing set doesn't really wear out on these cars at your mileage.  It's ok to replace it if you feel like doing it "while you're in there" but isn't completely necessary.
Do not cheap out on your torque converter.  It will make or break your combo.  You will hate driving your car if you get a shitty 12" restalled to 2600.  Yank, Edge and Vigilante make good units in 9.5 or 10.5".
Getting a new oil pump is probably not required.  Don't bother with a high volume pump. Recommend you get the gm white oil pump spring and an intermediate shaft from ARP (search on ISSF, I listed the part number, same username)
The LT4 cam is decent enough if you already bought it and it was cheap.  Check out amazon.com for the "used" crane 109821 (gm 845 cam). It's just a return.  There's one there for 200$. Probably better overall for a wagon.  Runs well with stock heads.  Should use upg. springs (like the hot cam).  People have had good success with the LT4 cam installed with 2deg advance.

If your opti is running well, keep it.  Either do a cap and rotor only, then loctite/reseal it or just loctite/reseal.  I do recommend you change the vent harness though.

Another very good brand of torque converter that is Circle D.

Advancing the cam will bias the power toward the lower end of the RPM range.

I picked up an unopened lt4 hot cam kit cheap, along with the converter and shift kit. The car presently has 2.93 gears and I'm going to 3.42 since I drive it daily (round trip to work and back is 60 miles a day). I should have gone with 3.73 but I already bought the 3.42s. The oil pump in it is good, but I figured while the motor is out I will replace it. Timing chain does seem to have some slack in it. I'm guessing it's because the car sat Unstarted for 2 years then started as a daily driver. Who knows, either way since the motor will be out To fix leaks and torque converter swap I'm going to freshen everything up. I'm looking for a local tuner so I can have the computer done while the car is running but I'm not having any luck so I'm going to have to send it out for a baseline tune I'm guessing.

Hoodscoop will be cosmetic. I'm going to find a spare hood to modify so mine isn't off while working on it. I will be doing my own paint and body. As a side business to keep myself busy I do restoration work on vintage cars and custom paint. When I'm able to post pics I will show some of my work.

There are some good mail order tuners.

If you feel compelled to change the oil pump (vs changing the intermidiate shaft and putting on a stiffer spring), I strongly recommend you do not install a high volume pump.

3.42 is a great gear for a dd. I do suggest you get the little offset bushing to advance your cam 2 degrees.

Why not a high volume? Haven't ordered it yet, but I was going to get the HV pump. Also, would you have a part number on the bushing to advance the cam? Thanks

If you are buying a new timing set, you can get one with multiple keyways for different amounts of advance. Then you do not need an adapter.

Tell us what brand TC and shift kit you got. Take Fred's advice. You really only want to drop and open the trans once. Everyone is on a budget, I get it, but the transmission and TC are not the place to try to save money. Do it right, do it once.

Lukey wrote:

Why not a high volume?

search a more performance oriented forum (impala ss forum, camaroz28.com, lt1 tech etc) or google for a detailed answer.  The short version is that with a stock pan, you can starve the pump.  There's zero benefit to running a HV pump.  You don't need it.  If you are DEAD SET on getting a new pump, buy a good quality standard volume pump and get a stiffer spring.   I have personally never had an issue with re-using the stock pump with the gm white spring and name brand intermediate shaft.

Fred Kiehl wrote:

If you are buying a new timing set, you can get one with multiple keyways for different amounts of advance. Then you do not need an adapter.

true.

TC is a B&M TorqueMaster #70418  (2400-2600rpm) I've run B&M in numerous vehicles for all purposes and never had a problem, that's why I chose it.  I've run 3k stalls before and hated them in traffic, my driving is 20 miles country roads then 6-7 miles start/stop traffic. That's why I'm not going higher.  

Shift kit is an ATP-SK3...I'm not 100% sure I'm using the shift kit, I may just have trans pressures readjust when the computer is tuned.

The timing set I bought I just checked out, it has multiple key ways, so I'm good there:)

I'm not building an all out toy, it's a daily driver that may hit the track once or twice a year, and I use it to occasionally tow a car trailer...not near as much as I used to, I finally got my truck finished.  

I finally got the engine pulled & upart today...74k miles on it now (had 36k when I bought it) the previous owner only ran penzoil in it, I've always just used Oriellys special and fram filters,  but after seeing the sludge build up, its back to valvoline only and WIX filters only!  I'm getting the block hot tanked and replacing all bearings and rings. Bore is perfect and still has a nice cross hatch in it so I'm not boring it.

I'm hoping it all performs as expected when done...now is the time to make changes if needed, before putting it back together.  Thanks all!

did you buy the complete hot cam kit with the rockers and valvesprings ? You will realistically need at the very least new valvesprings. Amazon has the steel head crane springs 10309-1 showing up as used (they're still new, but someone returned them).

The new cam going through a 12" converter is going to put more stress on the tranny. Maybe consider getting some upgraded parts and a different shift kit if/when you need a rebuild. A lot of guys like the transgo HD2-C or the new Sonnax 4L60e HP kit. Having used both, I prefer the latter. For what it's worth, the better (i.e. more expensive) torque converters drive almost like stock at part throttle even with high stall rpm. I agree with you, a crappy TC will make the car unpleasant to drive.

While the engine is out, do plugs, wires, reseal the opti and IMO do headers. I would do headers before cam myself.

You should still run a hone through the cylinders to allow the new rings to seat properly.

Definitely honing it. I picked up a reconditioned set of aluminum heads from a 95 camaro. Done at a very reputable shop (very familiar with LT1s). They have upgraded springs so the cam will be fine. Using the 1.6 rockers that came with the cam too. The opti I picked up is an ac/delco. One thing I can't seem to get a straight answer on tho, will I need an LT4 knock module?

Lukey wrote:

Definitely honing it. I picked up a reconditioned set of aluminum heads from a 95 camaro.  Done at a very reputable shop (very familiar with LT1s). They have upgraded springs so the cam will be fine. Using the 1.6 rockers that came with the cam too. The opti I picked up is an ac/delco.  One thing I can't seem to get a straight answer on tho, will I need an LT4 knock module?

You don't need the LT4 KM. They are super expensive now. If you have one lying around, go for it. If not, a good tuner can net you almost the same results. Don't pay 350$ for one.

Use the Mr Gasket 5716 or equivalent Head Gasket (.026") vice the F-body head gasket (.039 IIRC). You'll want to run premium. Tune for 91 (or whatever your premium is).

Take apart the opti with an E4 reverse torx socket. Put red loctite on the 2 small screws inside. Put a small bead of black gasket maker on the lip of the case and re-seal. Should be good for a LOOOONG time.

or in lieu of the E4, use one of the screws from the throttle body cover...

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Here it is shortly after buying it. Thing tows like a dream!

Looking good!

Dropped the block off for hottank, hone and new cam bearings today. Ordered new stock oil pump and GM white spring (#3848911), sold off my shift kit. Now I need to send my computer off for a tune and get this thing back together!

I really like that towing picture.

Ok, got the block and crank back from the machine shop, got it all together and then realized for some reason the dowel pin in the cam that drives the opti was pushed in to .300", not the .600" it should be. After fighting trying to get it out, I finally pulled the cam and took it to the machine shop and had him get it out. Waiting on a new dowel pin then will get the motor finished and reinstalled. Picked up Hedman headers (HED-68609) from summit. Description says they will fit my car, if they don't I will return them and figure something else out. Picked up a new stock replacement oil pump and the GM white spring for it. Gonna ship my computer out later this week to lt1pcmtuning and have it set up. Once it's up & running I'm going to save up for trans upgrades then a better posi for the rear. Getting close!

There is a $50 rebate on the Detroit TrueTracs (913A481), and JEGS will price match. I found one on ebay for $429, they price matched, and I still got my rebate. After the fact, I found someone selling them for $425. Do not buy one on ebay, because the rebate is not good for ebay purchases. Get a copy of the rebate on the JEGS site, and read it before you buy. It is only good until March 31. You need different carrier bearings for the TrueTrac, so plan on getting them as well. I bought the races (expensive part) on ebay for under $25 for the pair (http://www.ebay.com/itm/302020868765?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT). I asked, and the seller even refunded the shipping for the second race. Most places are about $25 each. Timkin is the brand you want.

While you have the rear apart, check the right axle for wear. You can usually find good axles on the driver's side in the junk yard if yours is worn. The passenger's side gets almost all of the wear because of the dynamics of the rear.

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Maybe have this sucker ready to drive in a week or so!

Now that I'm close to having it done, I'm short on funds...
The stock exhaust is in great shape so I'm considering running stock exhaust manifolds. Less burnt plug wires, less underhood heat, etc. My left manifold has a broken bolt (not a hard fix) and I can't get the EGR fitting out of it. I'm considering just replacing both manifolds. any idea where to get a new replacement. I found a brand new right side for less than $50. I read the 94 left is different than the 95/96, what's different? Is it just the size of the EGR port?
I bought hedman headers (p/n 68609) but can't trial fit without removing the headpipes, and prefer not to do that just yet. Summit says they fit my car but I can't find anybody running them to verify no issues with the air conditioning.

Also, I'm removing the A.I.R. system. Anybody know what serp belt I will need?

It is my experience that any header that isn't a tri y is going to have AC lines clearance issues.

Got it back together last week. Got my computer back from getting tuned, and the crazy thing floods itself instantly when it first started. Was told to put new o2 sensors in from the guy that did my computer, which I haven't done. I found a broken wire in one sensor and a bad IAC valve. New acdelco parts are ordered, should be here tomorrow, so I hope that fixes it. It will start now, but it won't idle (have to hold it around 1500rpm, and it dies as soon as I let off the gas). I've verified no vacuum leaks and no exhaust leaks. Coolant temp sensor in waterpump is new also. The o2s are preheated to im hopingvthe broken wire is the trouble.

Check to make sure your PCV valve is working properly.

The O2 sensors are only used to trim the air/fuel ratio. Even totally failed they will not affect the injector duty cycle to where the engine won't idle or run. When the engine is started cold, it relies on the injector duty cycle the PCM has in memory. Several parameters have to show the engine is warm and under load before the PCM even looks at the O2 sensors (closed loop).

The dead IAC valve will certainly keep the engine from idling. You might want to check fuel rail pressure as well.

Check the passage to the IAC valve as well. If it is clogged, the IAC can not function.

I realize that the LO5 is not the same as the LT1, but I found a ground that was not making contact, and it caused similar symptoms. It was the ground for the computer, and a couple of other things.

Done with this one...

Oh no! What happened to it?

I'm guessing electrical. Started under dash and spread to front seat. I had a box of papers in passenger floor board which didn't help. Brand new motor, aluminum heads, lt4 cam, 1.6 rr, 2400 stall plus a bunch of small stuff. Insurance is coming to look Friday. I'm guessing it will be a total. Rust free 74k mile body. Not a dent anywhere...only car I've really liked other than my 58 Ford...luckily I have full coverage on it and all my receipts.

Lukey wrote:

I'm guessing electrical. Started under dash and spread to front seat. I had a box of papers in passenger floor board which didn't help.  Brand new motor, aluminum heads, lt4 cam, 1.6 rr, 2400 stall plus a bunch  of small stuff. Insurance is coming to look Friday. I'm guessing it will be a total. Rust free 74k mile body. Not a dent anywhere...only car I've really liked other than my 58 Ford...luckily I have full coverage on it and all my receipts.

Man, that sucks. Sorry about what happened to it. Hopefully insurance is able to fix it.

Ouch man! That sucks...BAD! There are guys in the forum,with the skills to bring this back to life. Maybe it will rise again,after all it is the Easter season.

Lukey wrote:

I'm guessing electrical. Started under dash and spread to front seat. I had a box of papers in passenger floor board which didn't help.  Brand new motor, aluminum heads, lt4 cam, 1.6 rr, 2400 stall plus a bunch  of small stuff. Insurance is coming to look Friday. I'm guessing it will be a total. Rust free 74k mile body. Not a dent anywhere...only car I've really liked other than my 58 Ford...luckily I have full coverage on it and all my receipts.

Well at least the receipts weren't in the box of papers.

https://www.youtube.com/watch?v=sft3VHxru2s

oh man that stinks. Hopefully, if they total it, you can buy it back. then get one with a rusty frame and swap in a new interior and wiring harness, etc...or at least save the motor for another project.

Talked with insurance today. Totaled...
Can't buy it back due to the fact it was a fire. Liability reasons. Can't keep any of my parts, not even my new tires. Luckily since I have my receipts for everything I will n getting paid for everything I've done to it. Will try to settle on value Monday they said. Hopefully have a Check by Friday of next week so I can get another car.

Lukey wrote:

Can't keep any of my parts, not even my new tires.

Wow that's a load of crap... why won't they let you keep your new parts?

Lukey wrote:

Talked with insurance today. Totaled...
Can't buy it back due to the fact it was a fire. Liability reasons. Can't keep any of my parts, not even my new tires. Luckily since I have my receipts for everything I will n getting paid for everything I've done to it. Will try to settle on value Monday they said. Hopefully have a Check by Friday of next week so I can get another car.

Now,tell me how to do this ,again... Im asking for a friend...