Corvette project car

[280Z Turbo]

Pretty much decided on a 60101 Lunati Voodoo cam, cast pistons, and stock intake for now. Looking for 9.5:1 compression so it will run good on premium gas. That will give me a dynamic compression ratio of about 8:1. With a mild cam that saves up the compression, I don't know if 10:1 is safe. Anybody know what DCR corresponds to which octane rating? I'm seeing different recommendations.

It's never had detonation issues before, but with all those grooves in the bores I can't imagine it really had 10:1 compression anymore.

Doesn't look like there's much to be gained by ditching the stock intake because I can't run a high rise manifold anyway.

[280Z Turbo]

Bringing the motor to the machine shop next Saturday. Everything is boxed up and ready to go now.

I was debating between a racing engine builder and a local hole-in-the-wall machine shop, but their shop looked like shit. They might be cheaper, but I didn't get good vibes.

This is the place I'm going with. Clean, organized, nice equipment:

http://peracingengines.com/

[280Z Turbo]

Finally got the motor over to the shop.

Decided it's not even worth it to recondition the old rods when I can buy these:

http://www.summitracing.com/parts/esp-5700bplw

Sounds like the crank will have to be rebalanced with new pistons and (now) new rods. I was thinking that the crank would be balanced independently regardless of piston/rod weights, but I guess not.

[hotrodalex]

How much $ is it looking like? Around $2k?

[280Z Turbo]

Probably more. I don't want to assemble the bottom end by myself.

[Eye of the Tiger]

I told you homeboy, you can't touch this.

[280Z Turbo]

I know it would be about the same cost to buy a crate engine, but this is more fun.

Also, this block is the same casting number as the original motor. It has the correct style oil fill tube crankcase ventilation system. I don't really care for the look of vented valve covers, the finned "Corvette" valve covers look way better than anything else.

[280Z Turbo]

The scratches are so deep in the bores that they barely came out with a .030 overbore. The builder says there are still some scratches at the very top of the bore but he thinks they would be OK. Debating on going to .040 over. If I do .040 over I probably can't rebuild it again. The block is the same casting number as original (just the wrong stamping)

Also, I can get .040 over pistons are way cheaper than .030 over pistons for some reason.

[Eye of the Tiger]

The scratches are not okay if the rings are expected to seal. Bore it to .040" over, unless you want a low compression oil burner.

[280Z Turbo]

I haven't seen it but it sounds like it may be above the ring. I need to see it for myself.

[hotrodalex]

.070" or nothing

[280Z Turbo]

.070" or nothing

Foil thin cylinder walls.

[GoCougs]

Has he said anything about overheating? Typically (or at least IIRC) anything more than 0.030" is usually a no-no for that reason.

[280Z Turbo]

Has he said anything about overheating? Typically (or at least IIRC) anything more than 0.030" is usually a no-no for that reason.

No. I think that may be a myth.

I've heard that .040 is the max for stock blocks. You can go to .060 over but then it can get flexy.

[hotrodalex]

Do all of the cylinders have scratches?

If it's just a few, you could think about sleeving them.

[280Z Turbo]

I guess in the future I could get a new style block and drill and tap the rear of the block for a PCV valve for a stock breather less valve cover look.

[280Z Turbo]

Just racked up a $1000 tab with Summit Racing. New rods, pistons, valve springs, cam, fuel pump, oil pump, etc.

[Gotta-Qik-C7]

Just racked up a $1000 tab with Summit Racing. New rods, pistons, valve springs, cam, fuel pump, oil pump, etc.

I'm late to this tread but is this a numbers matching Corvette?

[280Z Turbo]

I'm late to this tread but is this a numbers matching Corvette?

Thank God no

[Gotta-Qik-C7]

WHEW! LOL!!

[280Z Turbo]

Numbers matching Corvettes are for grumpy old farts with straw hats and jorts.

[280Z Turbo]

I opted not to do hardened valve seats in the head. The machine shop wanted $200 to install them and I don't really want to invest a lot of money in old double hump heads. After 50 years there was no recession of the valves, so I couldn't justify the cost.

[280Z Turbo]

Had to replace the block. The shop found a crack at the main bolts prior to assembly. They felt bad about missing the crack after magnaflux so they gave me a nearly identical block that was at .030 over and bored it to .040 over.

They called me today to let me know I bought the wrong rods. I got large journal rods instead of small journal rods. Hopefully I can exchange them with Summit. They didn't assemble them yet.

Got the front control arms assembled. Tried to replace the tie rod ends (all 4) but one of the ends was rust-welded to the sleeve. I think I'll replace the thin hollow tubes and clamps with modern coupler and jamb nut style:

http://www.summitracing.com/parts/gls-adj-4

[280Z Turbo]

I thought that the passenger side was the more screwed up side, but that side's lower control arm bump stop fits perfectly into the hump of the frame.

The driver's side misses the bump stop indentation entirely. It's too far forward. I'm a little bit afraid to fuck with anymore fuckery on this car since it still drove OK. However, I think just hogging out the LCA mounting holes and welding this retainer plate to the frame might make it better:

[Secret Chimp]

Honestly this thing sounds like it might be better off with a good wait while you save for an entire new frame.

[280Z Turbo]

It's been fucked up for years. There's no rush.

[280Z Turbo]

http://chicago.craigslist.org/wcl/pts/5080728249.html

[280Z Turbo]

Bringing the motor to the machine shop next Saturday. Everything is boxed up and ready to go now.

I was debating between a racing engine builder and a local hole-in-the-wall machine shop, but their shop looked like shit. They might be cheaper, but I didn't get good vibes.

This is the place I'm going with. Clean, organized, nice equipment:

http://peracingengines.com/

Just picked up the motor today. The shop was really good to me and gave me a new block for free since my old one was cracked at one of the main caps.

One of the guys there was telling my dad that they get a lot of customers from that hole-in-the-wall local shop that I looked at. Cheap is rarely good and good is rarely cheap so I'm glad I went with the nicer shop.

[280Z Turbo]

I started working on the car again this weekend. I adjusted the valves. Kinda weird. No set clearance, just kinda tighten the rockers until you feel resistance on the pushrod, then turn another 180 degrees. I hate qualitative work instructions like that. Bah.

There's a lot of debate on the exhaust crossover in the intake manifold. Throughout all of the name-calling and "don't you know who I am's?" I was able to gather this much:

1.) The "hot slot" design of the late 60's was suppose to expose the carburetor to exhaust heat through a stainless steel metal shim. It was still way too hot and caused a recall, from what I understand. I picked up a 1/4" NPT tap and shoved some old core plugs from the block in the hot slot holes to keep out the exhaust.



2.) The crossover is not needed on aluminum intakes because aluminum transfers heat better. It is needed on my cast iron intake because it doesn't transfer heat well and I have a divorced choke. Still, I installed some stainless steel crossover restrictors included with the gasket set to reduce the amount of heat.

3.) I need to reinstall the crossover heat shield or else it will leave a pile of burnt shit in the valley.

[CaminoRacer]

Wait, why would you want to heat up the carb?

Might be beneficial on cold mornings, but terrible for normal driving.