84 Crossfire Corvette Second Round Of Mods

Crossfire Mike

Active Member
It's finally time to do the second round of engine mods to the Corvette. I've been daily driving it for over a month now after it's year long hibernation. It's running very good and all the previous mods were well worth the effort totally different car now than when it first came into my life. Time to take it to the next level. All the first stage mods can be found here http://garage.grumpysperformance.com/index.php?threads/new-to-me-84-corvette.15386/

The plan is to install the AFR 0916 cylinder heads and Renegade intake manifold do as much grinding and cleanup work on the stock exhaust manifolds to hopefully create a little more flow and have a 3" y-pipe made to help relieve the immediate back pressure right after the manifolds. This will complement the Crane Cams 114132 installed and all the first stage mods I already did. I will attempt to use a air/fuel ratio gauge to dial in fuel pressure and fuel injector size to give it the fuel it needs/wants. I've had good luck using an A/F gauge in the past with my turbo cars dialing them in so I'm hoping I can put one to good use on the Vette too.
Here a few pics of the car and the parts
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So I'm actually starting with some maintenance items beginning with replacing the oil pan gasket which I got off tonight. Block is all cleaned off and ready to accept the new gasket after I put some fresh paint on the pan tomorrow morning. I don't think anybody wants to see a picture of the pan, but I was very happy to see how clean it was on the inside and bottom. I can clearly see crosshatch in the bores still and the bottom end appears like previous owners never skipped an oil change.
I will make progress and post pics and info as I go along like specs on the head gaskets compression ratio expectations ect. Next series of pics will be with intake removed and heads coming off which I hope to get done this Saturday(or sooner) and I'll finally know what my actual piston height is at TDC.
 
the AFR heads and renegade intake will produce a noticeable boost in your seat of the pants acceleration,
but
while you have that oil pan off you might consider a much improved oil pan install.
durability is key in a good engine build, and proper lubrication and oil control helps a great deal.
several vendors have oil pans that are designed for road racing a 1984 corvette,
that feature a 6-7 quart baffled oil pan with much improved oil control
be sure you order the correct side dip stick oil pan and rear seal type,
if you go that route,
you could obviously add baffles and a larger sump to the existing oil pan,
if you have fabrication skills and a decent welder
,here as an option.

this link may help

http://garage.grumpysperformance.com/index.php?threads/building-a-custom-wet-sump-oil-pan.65/

http://garage.grumpysperformance.co...oil-pan-with-engine-running.11263/#post-50920

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this is a good but more expensive option:D and you can always just re-install the stock oil pan if you buy a second oil pan,
versus risking ruining the stock oil pan if your fabrication/welding skills..:rolleyes: are somewhat less than ideal....:eek:
but you will feel a sense of satisfaction if you modify the existing oil pan correctly :Dand gain new skills


https://www.summitracing.com/parts/ctr-15-240tblk
 
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Progress update I wrenched last night and did not stop till the stock cylinders heads were on the garage floor. IMG-3389.jpg IMG-3391.jpg IMG-3393.jpg IMG-3395.jpg IMG-3398.jpg IMG-3399.jpg
One thing that is concerning is on that last pic of the exhaust manifold, that's a quarter on top there for comparison. Those pipes are tiny I'm going to grind on them for sure but my wheels are really spinning for a real header solution. Plan is now to clean up the block and bolt down the heads possibly even tonight. I even bought a new electronic torque wrench this afternoon as I don't want to use/trust my 15yr old spinner type.

Thanks for the suggestion Grumpy and it's a great idea but the stock one is already installed. For my type of driving 99.9% on the street it should do fine. In the future if some time trial events come along then perhaps that's a good time to upgrade.

One last thing, I measured #1 piston and it is indeed .025 in the hole, so with my .020 gasket and the .025 I will have a .045 quench area. That should be good enough or I should say it'll have to do because it is what it is.
 
once it's back together I'd like to see you post something about your impression of the results in the car's feel responsiveness and performance.
 
I definitely will Grumpy I am looking forward to being completed. I'm making good progress now though as I thought that I would be removing the cylinders heads tonight I actually bolted the new ones on. I'm way ahead of schedule. I pick up a Proform pushrod length checker as I was not sure if between head gasket thickness, AFR cylinder head casting and valve stem length, 1.6 ratio rockers if the engine would need a different length pushrod. Well, it does that gap in the pic is .080 so need a little shorter one. I'm glad I checked.
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Got a lot done yesterday but not as far along as I want to be. I'm waiting for the shorter and chromoly pushrods as AFR says chromoly is needed with their guide plates. I also broke the coolant fan switch removing it from the old passenger side cylinder head. Nobody stocks it around here seems weird but whatever. I have one ordered and will be able to pick it up Monday. Still haven't fired up any air tools to grind on my exhaust but that will give me something to do while I wait for the pushrods to be delivered.

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I still haven't tried to close the hood yet also... I'll install the air cleaner assembly today for test fitting and slowly lower the hood. I'm not expecting any issues but you know aftermarket parts. The Renegade was a mostly good install just a few places where things were just a bit off took some thinking about it but nothing that held up the installation for long.
 
well at least your making steady progress and posting clear pictures,
so your most likely going to be fine
 
Well installing exhaust now. I got a little grinding happy opening up the flanges and actually broke through a couple places. I visited my friend at his shop and he filled them up with some welds for me. I also had him weld on my O2 sensor bung on the test pipe since the welder was fired up. You can't really tell since I painted them but I did remove a lot of material. I also cleaned up the exit side not much you can do there but I did remove a bunch of welding slag that was clinging all around. They'll have to do for now and all in all their not the worst stock manifolds I've seen they will probably flow pretty alright.

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Finally recieved my push rods Friday afternoon and was able to get my rockers on valves adjusted and valve covers put on. I finished up on everything and actually have a running and driving Corvette now.
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I installed my A/F ratio gauge but did a quick install and signal reference it from the drivers side o2 sensor, so it's only half the story but gives me a good idea how things are going fuel wise for now.(It's not how I thought it would be) I'll get the better signal this week from the test pipe where both banks are flowing through.
 
Here is the final basic mods list done to the car. This of course does not include everything done to the Corvette.

Renegade Intake Manifold
Crane Cam #114132 with my 1.6 ration RR's my effective specs are .469/.484 lift 210/216 Duration. (perhaps little more because of the 1.6 ratio)
AFR 0916 Cylinder heads
Stock exhaust manifolds opened up to match cylinder head ports
Fuel pressure currently set @18psi (which is looking like a little too much right now)

I finally settled on the MR. Gasket copper head gasket set #1052G it was larger than I wanted but it worked best with the combustion chamber size of the cylinder heads and required minimal modification and other than that fit my needs very well.
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So my final combo is engine #3 the most important data from the spreadsheet to me is, 9.76 static CR, 8.25 Dynamic CR and .046 quench. I'm pretty sure this may not be exact but is close enough for me. I have the timing set conservatively at 8 degrees as I wasn't sure what to expect. I do plan to bump it 2 degrees at a time to see how it reacts and if all goes well will probably settle for 12 degrees or so. Fuel pressure is set high for these cars(18psi) I guess and I am running basically new stock size injectors. The old combo seemed to like this pressure best although I did not really know what the A/F ratio's were back then but now it seems its running slightly on the rich side as I'm seeing high 11's to low twelves at full throttle. I'll leave it for now as I still have the timing to mess around with and it's safe with no lean conditions exhibiting right now. Stock throttle body size may be good enough for 350ci too. With all this said I'll get onto my impressions I took my wife for a ride and she was all giggles and said the car feels way faster.

The car is absolutely faster now has a different tone at speed and pulls very cleanly and HARD. Under regular/normal driving it feels very much as before, perhaps slightly less torque off the line but nothing that has me concerned and this may change when I start adjusting the timing. I think I can sense the weight reduction from the front end and to me the car feels better balanced. The top end pull through each gear like from 4500-5800rpm where I have my rev limit set is awesome to me. Bottom line is the car now rips and performs how a Corvette should in my mind. I'm positive that it's still not the fastest car out there but it will no longer be the butt of Crossfire injection jokes thats for sure. This 36yr old Corvette is going to surprise some unsuspecting newer cars. I believe that with more fine tuning and some key area exhaust work that there is a little more in it too. As of right now it runs good nothing has broken and there may be more potential in it, I'm happy and feel it was money well spent.
 
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congrats on building what I'm sure will be a very nice combo for a daily driver,
with much-improved performance over the cars original power levels
youve most likely added over 120 hp or more vs stock.
,

yes you could rather obviously gain more peak hp in the upper rpm range,
with a bit more cam lift/duration,
but at the cost of some of the current combos nearly instant responsiveness,
and the loss of some lower rpm drivability

these links may help

cooler denser air

Im always rather amazed at the guys that don't stop and think about the total process of making power and the failure of so many guys to think thru how each step can be improved. it really doesn't matter if you have a single carb, dual quads or efi, cooler denser air will result in a more...
garage.grumpysperformance.com

cooling off that c4 corvette

your stock corvette http://garage.grumpysperformance.com/index.php?threads/thoughts-on-cooling.149/page-3#post-107697 has a rather marginal cooling system if your engines been modified for significantly higher hp levels, that cooling system can be significantly improved upon.I run into this...
garage.grumpysperformance.com

Mounting An Effective Trans Cooler On A C4 Corvette

now I know few cars with less room to mount an efficient oil cooler with a fan than a c4 corvette, and after I installed a 3200 rpm stall converter in my corvette it became obvious I needed an aux trans fluid cooler. theres very little under the hood room and ground clearance is already minimal...
garage.grumpysperformance.com

www.digitalcorvettes.com

Crossfire conversion question

I have been restomodding an 84 Vette that had already been converted if you could call it that. If you want the more detailed story of my experience so far,read my community introduction post. What I am stumped by and confused about are two things. First I should say i have read hundreds of...
www.digitalcorvettes.com
www.digitalcorvettes.com

Unwanted engine bay heat.

I have an 84 Trans Am. As you might know, these cars have tight engine compartments, no front grilles, and lower hood lines than Camaros. When I finally get the 334 re-installed, my Turbo "bulge" hood should just close - I hope. The intake manifold is a Weiand 8000, Edelbrock 1904 Quadrajet...
garage.grumpysperformance.com
 
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Thanks Grumpy you have helped me more than you know with all the knowledge you give and make available. You have peaked my interest though with the bit more cam comment. I thought I installed the most cam that would work well with the stock computer. Couple questions, how much more lift/duration do you think I could go? Could stepping up to a 1.7 ratio roller rocker be a good way to get some more lift or best to save up for a new cam perhaps even a roller conversion?
 
yes a hydraulic roller cam would be the route to take, when and if you go the larger cam lift & duration route,
the hydraulic rollers and ramp profile and lower wear potential all could benefit the engine combo.
(theres no free lunch, other changes must match to make the combo work correctly)
(for anyone reading this remember if its a AUTO TRANSMISSION, a more aggressive cam profile than what he has now, will most likely require a higher stall speed torque converter)
AND
(a more aggressive cam would benefit with a rear gear upgrade and a full length 3" exhaust low restriction mufflers and headers and probably an increase in throttle body injector flow rates)
http://garage.grumpysperformance.co...-the-extra-cost-vs-a-flat-tappet-design.3802/
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if you were to want to get more performance, and while swapping to 1.7:1 ratio rockers sounds like its something that might work,
the potential "gains" would be minimal if you gained anything while the potential loss of valve train durability,
and valve train wear , and loss of valve control at peak rpms with the flat tappet valve train would take a very noticeable potential loss,
Id bet you would have cam lobe and lifter wear issues inside of a year or so and in under 20K miles if you went the 1.7:1 rocker ratio route with that cam.
your cars efi software can be upgraded, but your current rear gear ratio,is one factor limiting the cam compatibility choices, and keep in mind the valve spring load rates and clearances , push rod length, would change with a new hydraulic roller cam swap.
I would suggest you just play with the current combo, MAXIMIZE THE TUNE, a/f RATIO, IGNITION TIMING ETC, and EVENTUALLY, add a full length 3" exhaust and full length headers and perhaps a 3.53:1 or 3.73:1 rear gear ratio before you go looking at a cam upgrade/as that would provide a nice seat of the pants boost in acceleration and also boost performance further in both the current combo, and help if you eventually go to a more aggressive hydraulic roller cam.
 
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I would suggest you just play with the current combo, MAXIMIZE THE TUNE, a/f RATIO, IGNITION TIMING ETC, and EVENTUALLY, add a full length 3" exhaust and full length headers and perhaps a 3.53:1 or 3.73:1 rear gear ratio before you go looking at a cam upgrade/as that would provide a nice seat of the pants boost in acceleration and also boost performance further in both the current combo, and help if you eventually go to a more aggressive hydraulic roller cam.

This is good advise and I will follow. I have advanced the timing to 10 degrees and on my short drive to work the car ran great and feels very good off idle. I will continue to play with the current set up and move my A/F ratio gauge signal to the test pipe so I can fine tune the fueling. So far so good!
 
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