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SkinnyG
SkinnyG Dork
2/12/17 7:24 p.m.

Well, gooder. Don't go ANY bigger than that one. It's ok to go a bit smaller too.

petegossett
petegossett GRM+ Memberand UltimaDork
2/12/17 7:59 p.m.

Day-62(2.5-hours):

After an afternoon break for errands, I decided to check lift on a couple other cylinders(the measurements earlier were from #2). I checked #1 & #3 this time, and was able to get 3 consistent readings from each valve, so my technique seems consistent...whether it's accurate or not though? Anyway, here's what I have:

1 Intake .463/Exhaust .442

3 Intake .476/Exhaust .415

Those values at least seem safe for the stock heads, but I still think I'll check out the other cams & post them here for everyone's input.

Frustrated with the engine, and without much else I can do with it at the moment, I started tackling the grime underhood.

There was a couple pounds by the time I said good enough.

And the finished(for now) result.

Though to be honest, the reason I started with the crossmember, well other than that it was the filthiest spot, is that I need a step to reach the underside of the hood.

BrokenYugo
BrokenYugo MegaDork
2/12/17 8:18 p.m.

Those numbers can't be right unless you got a cam different from advertised or something, have you checked lift at the lifter?

SkinnyG wrote: With those heads (look like 76cc) and those pistons (flat top), you're probably close to 9:1, assuming a THIN head gasket.

Those look like the default thick gaskets you get in gasket sets and rebuild kits.

Was the piston to head clearance checked? I don't think it's super critical but getting it down to 0.040" is supposed to be better (emissions, economy, power, detonation resistance).

SkinnyG
SkinnyG Dork
2/12/17 8:38 p.m.

1) Measure the lift off the pushrod, then multiply by 1.5 for lift at the valve. This takes actual valve travel limitations out of the picture.

2) thick head gaskets will drop the compression down almost a full point, last time I calculated. 10.0:1 (0.050 gasket) vs 10.9:1 (0.015 gasket) on my 350. With low compression and a big cam, it may not be that big an issue, but when you're compression is getting kinda sketchy, you want to be as close to 0.040 quench as you can.

petegossett
petegossett GRM+ Memberand UltimaDork
2/12/17 8:48 p.m.

In reply to BrokenYugo:

I haven't checked at the lifter - there's no way to get the dial indicator's probe square with the lifter. So I checked it at the top of the spring retainer.

Here are the other options I see on Rockauto, but if they're available cheaper elsewhere I'm all for that!

1.) ENGINETECH ES1014R - Stage 1 high performance .050" Duration-204/214; Cam Lift-.281/.296; Lobe Center -107/117. $43.79

2.) ENGINETECH ES179R - Stage 2 high performance .050" Duration-222/222; Cam Lift-.298/.298; Lobe Center -110/118. $50.79

3.) ENGINETECH ES1013R - Stage 2 high performance .050" Duration-214/224; Cam Lift-.295/.310; Lobe Center -107/117. $51.79

4.) ENGINETECH ES1151R - Stage 2 high performance .050" Duration-204/214; Cam Lift-.281/.296; Lobe Center -110/110. $64.79

5.) ENGINETECH ES186R - Stage 3 high performance .050" Duration-230/230; Cam Lift-.320/.320; Lobe Center -107/111. $58.79

I'm guessing #2, #3, or #4 would be good? I have no idea how to know which one would be best though? What I'd like is a wide flat torque curve, hopefully with 300+ hp and ~350 ft-lbs of torque.

petegossett
petegossett GRM+ Memberand UltimaDork
2/12/17 9:31 p.m.

In reply to SkinnyG:

Not sure I understand - I should go for a thinner head gasket than stock?

BrokenYugo
BrokenYugo MegaDork
2/12/17 10:25 p.m.

As I understand it you want the piston as close to the head as possible, so the charge gets squashed out of that flat area when the piston comes up and that turbulence better mixes up the charge in the combustion chamber. This works out to 0.040 inches being about as low as you can safely go once you account for rod stretch at 6000 rpm, the piston rocking in the bore, rod bearing clearance (the journal doesn't stay centered in the bearing), factory deck jobs not being perfectly level, etc. Go much wider and the effect disappears. Pre smog era GM did this from the factory with the pistons 0.025 in the hole and a 0.015 steel shim head gasket (which is still in production), if the engine is rebuilt and decked at that time you need a thicker gasket to bring the clearance back up.

SkinnyG
SkinnyG Dork
2/12/17 11:12 p.m.

1 or #4 would be good; certainly better than stock. Nice idle, good vacuum, good torque. Looks like #1 is advanced 3°, which would give better torque.

3 may start to have some lope in the idle, but still run well. Probably as big as you want to go with a stock torque converter. A rumpity-rump cam with a stock converter is a dog, and sketchy at traffic lights when it's trying to stall in gear.

2 is too big. Leave it alone. 222°@050 is pushing what the stock converter will like.

5 would sound w-i-c-k-e-d, and is a tick milder than what I have in my daily driver truck (at 10mpg, and lots of other stuff to make that cam work).

petegossett
petegossett GRM+ Memberand UltimaDork
2/13/17 12:31 a.m.

In reply to SkinnyG:

It looks like the only difference between 1 & 4 is the lobe center? If 1 offers more(I presume low-RPM?) torque, does 4 trade that for a higher RPM?

SkinnyG
SkinnyG Dork
2/13/17 10:33 a.m.

It ~looks~ that way, but there is a price difference, so there might be more to the lobe shape than what I see in the limited specs. I'm not seeing a lot of information through Google on those cams. Any chance you can contact the manufacturer?

petegossett
petegossett GRM+ Memberand UltimaDork
2/13/17 11:13 a.m.

In reply to SkinnyG:

Checking the specs on Enginetech's site, it appears the Rockauto catalog is slightly wrong. I've updated the full list below with the updates in bold. I've also added total valve list.

1.) ENGINETECH ES1014R - Stage 1 high performance .050" Duration-204/214; Cam Lift-.280/.295; Lobe Center -107/117. $43.79; valve lift .420/.443

2.) ENGINETECH ES179R - Stage 2 high performance .050" Duration-223/223; Cam Lift-.298/.298; Lobe Center -110/118. $50.79; valve lift .447/.447

3.) ENGINETECH ES1013R - Stage 2 high performance .050" Duration-214/224; Cam Lift-.295/.310; Lobe Center -107/117. $51.79; valve lift .443/.465

4.) ENGINETECH ES1151R - Stage 2 high performance .050" Duration-204/214; Cam Lift-.280/.295; Lobe Center -110/110. $64.79; valve lift .420/.443

5.) ENGINETECH ES186R - Stage 3 high performance .050" Duration-230/230; Cam Lift-.320/.320; Lobe Center -107/111. $58.79; valve lift .480/.480

I just called - they're B2B wholesaler, but I left a message for their high-performance tech guy. Hopefully he'll have a few minutes to return my call.

petegossett
petegossett GRM+ Memberand UltimaDork
2/13/17 7:38 p.m.

Day-63(30-min...unless you count travel time):

I heard back from the seller of the Vettes, he agreed to sell me the top($250) and pair of seat rails($50). That's a bit more than I wanted to pay for a top, but I'll be using the existing cracked/repaired one for the Challenge. Not sure if I'll use one of the seat rail sets for the driver's seat, or fab something up...that'll probably depend on where I end up budget-wise.

I did go ahead & install the driver's seat so I could sit in it and make "vroom-vroom" sounds though. It also got it out of the way.

petegossett
petegossett GRM+ Memberand UltimaDork
2/15/17 7:54 a.m.

Day-64(2-hours):

I cleaned up the a/c bracket and temporarily hung it on the engine.

I'm not sure whether to blame an engineer or accountant for this "feature" though...

This bolt need to attach the compressor from the rear, but it doesn't fit while the bracket is mounted. I'm tempted to replace it with threaded rod...or drill out the front of the mount and run a longer bolt all the way through to a nut on the rear of the bracket.

I also cleaned up underhood a bit more, but nothing worth photographing.

Dusterbd13
Dusterbd13 PowerDork
2/15/17 8:29 a.m.

Drill bigger. Add nut.

sixt9stang
sixt9stang New Reader
2/15/17 9:16 a.m.
Dusterbd13 wrote: Drill bigger. Add nut.

I agree. Always try to make it easier for future you working on the engine.

petegossett
petegossett GRM+ Memberand UltimaDork
2/15/17 11:08 a.m.

Thanks! I'll raid the hardware bins & see if I can turn something up.

jfryjfry
jfryjfry Reader
2/15/17 11:55 a.m.

Will the pulley and other parts of the compressor allow a long enough bolt to go in from the front?

Jerry From LA
Jerry From LA SuperDork
2/15/17 2:52 p.m.

Preload the bracket with the long bolts, then attach to the block.

petegossett
petegossett GRM+ Memberand UltimaDork
2/15/17 8:36 p.m.

In reply to jfryjfry:

You know, that's a good question...

petegossett
petegossett GRM+ Memberand UltimaDork
2/15/17 8:40 p.m.

Day-65(1-hour):

I cleaned up the air pump bracket and painted it(it's steel), and since the bolts were skanky and mount up on top of the engine I also gave them a coat of paint. Then I cleaned up the alternator-to-air pump bracket...though I'm not actually sure I'll end up using either of them. Though I think I will.

petegossett
petegossett GRM+ Memberand UltimaDork
2/16/17 1:03 p.m.

I've been researching cams and gearing quite a bit. I also found some more details on the Elgin site for these two cams:

1.) ENGINETECH ES1014R - Stage 1 high performance .050" Duration-204/214; Cam Lift-.280/.295; Lobe Center -107/117. $43.79; valve lift .420/.443 RPM range 1500-4000

3.) ENGINETECH ES1013R - Stage 2 high performance .050" Duration-214/224; Cam Lift-.295/.310; Lobe Center -107/117. $51.79; valve lift .443/.465 RPM range 2000-4800

So I pulled up my gear ratios and ran them through a calculator. 1500rpm in 1st is 12mph, while 2000rpm is 17mph. I've certainly run autocrosses where we slowed at least that much (Chicago box/garage), but those seem pretty infrequent now.

However, I also discovered the 84-86 Vettes have a 2046rpm stall converter from the factory. So would it make any difference at all if the cam comes on at 1500rpm vs. 2000rpm???

pres589
pres589 PowerDork
2/16/17 1:16 p.m.

That stall speed is computed with the brakes on and max torque input from the engine. Low/no throttle operation will have the converter trying to come out of stall at lower engine speeds. The truck-ish engines that were in Corvettes in those years did not need to be taken to 2k RPM to move off the line from a dead stop.

Assuming your car has the optional 3.07:1 rear gear, and a 25" tall tire (has to be close) 2000 RPM is 69 mph. Standard 2.73:1 gear has the car at 78 mph at 2k. If the quoted power band is to be taken literally, the engine is probably not going to be operating very efficiently at the engine speeds you'd see on the highway. My two cents; the "Stage 1" cam is probably what you're wanting for this application.

petegossett
petegossett GRM+ Memberand UltimaDork
2/16/17 1:33 p.m.

In reply to pres589:

You are correct! The rear is a 3.07 and stock size tires are 26". I'm not really concerned with highway use though. It'll get some around-town use, but other than possibly driving to some events later on after the bugs are worked out, I don't expect to be on the highway with it much/at all.

I'm ok with their "stage-1" if that's the best choice for autocross with the stock heads. It does need to be driveable on the street too...though I don't expect it to be particularly comfortable.

Using the gear calculator, with the first cam I'd hit 62mph at the top of 2nd gear. That's probably fine for most courses anyway. Though the other cam would increase it to 75mph which would give me plenty of room. Of course, being an automatic a shift into 3rd and back down isn't the end of the world either.

Jerry From LA
Jerry From LA SuperDork
2/16/17 1:37 p.m.

Too little cam beats the living snot out of too much cam on the street. Probably goes the same way for autocross as well.

petegossett
petegossett GRM+ Memberand UltimaDork
2/17/17 7:15 p.m.

I've been slacking a bit on updates. I did spend about 40-minutes cleaning the engine bay last night, but nothing exiting or photogenic enough to document. I'm going to be out of town next week, but I'm doing my best to keep up momentum.

I'm also bringing the valve covers, so hopefully I'll have time to sand & paint them, and the Haynes manual so I can study the wiring diagrams a bit.

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