Inliners International Forums General Discussion Engines My 230/250 Build

Haha, I like that one!

New starter from summit on order ready for exchange.

I took the car in for alignment (new springs). The drive home was mid-70's, partial sun, 50 minutes of nearly idle crushing rush hour traffic. Before the overhaul, the engine would be getting hot, hot, hot. I'll try to get a picture of the plugs just to see how she's running.

The electric fan cycled on and off. Not once did the temp light come on!

Yeah!

Ok, back from being away from my PC for two weeks. Sway bars on front, proper sub-frame alignment and some trim modifications and the wheels no longer appear to hit the fenders. Yeah!
Main jets: 52
Accelerator nozzle: 35
Power valve: 8.5
Secondary jet: 59
Secondary spring: one stronger than middle

Plugs are getting a touch of color versus pure white before. We're getting close.



She still has a significant stall coming off the line. I'm thinking about my 53 main jet on the bench and power valve 9.5 to try out tomorrow. I'm afraid that it is indeed the distributor and it needs trimming or whatever was suggested. I'm not ready yet to get the exhaust work done, where I'll have them put an O2 sensor in, so just doing some shotgun of parts for now with parts on the bench.

Big progress today. Main jets were 54's (forgotten i put those in). Put in the 9.5 power valve, seemed to help slightly. Went to the machine shop, guys came out with timing lights and help. Timing is 8BTDC with premium gas. Max timing is 40BTDC. Smoother, but still sluggish in lower RPM. Discovered exhaust leak, shop put it up and found one nut disappeared! The replaced it, tightened it all up with air wrench and amazingly, it's not nearly as sluggish as it was. Wow, not having proper back-pressure really surprised me as to the effect.

Another problem though. I had used some sort of sealer (liquid metal?) on the intake header to seal up the Offenhauser water plugs. Those are ever so slighly leaking.

Now that the intake is on the car and I'm reluctant to remove, what are your recommendations to repair? Guys tell me to pop out the plug, thread it for pipe threads and put in a plug. Just looks super hard for the front plug, just really hard for the back plug. Suggestions?

Thanks!

I always recommend welding those ports closed. The metal is too thin to thread and tap.
Any chemical you use to seal it is a bandaid.

I used a 2-part liquid epoxy to seal mine and haven't had a leak in 3 years.

I think those casting plugs are only good for sealing exhaust and not water.

Barely adequate for that!

That said epoxy does work if done properly.

I also agree on the staked in plugs they come with. Removing the staked in plugs and welding a cover over the hole is the only permanent fix that will stand up over time and heat cool cycles that these intakes will see. You also have to remember the antifreeze behind the plug can have more than 16lbs of pressure.
I also don't like to hear stories from guy's on how they have to tear the intake back off to repair at a later date. Hence , I try to give the best advice possible.

I'm trying to remember why I took the route of epoxy, had something to do with the rush decision to have the machinist install the intake and headers. Coulda, woulda, shoulda...

Thanks for the tips, it looks like I'll be taking it apart this fall once the rainy season starts.

More progress. Put in 10.5 PV and the hesitation is all but gone, only is a few scenarios. Woohoo! Main jets could probably go one setting higher. I've got that and some how I ordered two 10.5 PVs on the bench, but I'm sticking with what I've got so far.

To recap again:
Main jets: 57
Accelerator nozzle: 35
Power valve: 10.5
Secondary jet: 59
Secondary spring: One stronger than center

Punch list to fix:
1) slow water leak from intake. pull, clean out epoxy, weld on plates.
2) some sort of oil leak, think (hope, no pray) it's the power steering pump, but not certain. Oil isn't nice and clean since my oil change a few weeks back, so shouldn't be engine oil.
3) replace upper ball joint boot that i'd installed incorrectly.
4) slow oil leak on transmission line.
5) new hard gas line because there's too much rubber hose. They won't let me on the track next year with it.
6) fix reverse lights. with new 200-r4, lights are on in N-D, but not R. pull steering wheel and adjust and maybe grind.
7) get 'r dyno'ed. Lower priority right now.

Once that's all done, then I'll start on the interior. I keep thinking I'll put in AC, but many that's going to be tough.

Thanks again!

I made that one last change to 58 jets. Ever so slight improvement, there's just a bit of hesitation coming off the line (but the rear wheels are spinning). It feels like there should be more low end, but it's plenty good enough for now until I get the dyno. It might just be that I need to move to the 3.55 rear end (3.08 today). I did back the timing off just a touch to 6.5 BTDC since it's running richer.

To recap again:
Timing: 6.5 BTDC
Main jets: 58
Accelerator nozzle: 35
Power valve: 10.5
Secondary jet: 59
Secondary spring: One stronger than center

I disconnected the host to the power steering pump and it's still leaking. Man, must be that new oil filter I put in, but some things don't make sense. Maybe put another filter on it and see. I hear you can buy a nice kit with glasses to put phosphorous in your oil and see where it's coming out. Another filter is cheaper.

Oil leak might be the valve cover. The only way I can get them to seal is with enough silicone to make Dolly Parton blush.

Oh and no matter how new the oil itll still look black after running through these engines.

Maybe I missed it in the thread but:
* What cam did you end up getting? Need Lift I E, Duration at .050 I & E, Lobe Sep and Advance or Lobe Centers for both I & E.
* What was the compression and deck clearance as built?
* If you have full throttle yet, what RPM is the trans shifting at?

That will help the Gonkulator a lot thanks.
GREAT thread, this will be a great archive for folks building an engine up. Should be a Reality TV show, but not too many folks would watch probably.

I think you called it. I pulled off a bunch of stuff and discovered oil up by the thermostat housing. Certainly not coming from a power steering pump. I checked the hex bolts holding on the cover and found them to be finger tight at best. Must have settled in over time. It's Tom's nice aluminum head that in theory won't deform with tight finger tightening. So I tightened them all up and drove it a bit. Still a couple of drips, but not as bad as before. I still have a drip coming from transmission compression fitting that I'm kicking myself about (put the fitting where you can't get to it).

If I need to, I'll do the valve cover when I pull the manifold off to fix the leaking water plugs. (grumble grumble).

Thanks!

It's the "I know just enough to get me in trouble!" show. Haha.

I sure do gas it. Past break-in, using Valvoline VR1 (high zink) oil now. Probably 1000 miles or more by now. My gas mileage is pretty bad, but it seems that all I do is go out and floor it to see how she runs. Let's see if that gets better once I get on a long road trip....

Back to the topic. CAMs. I don't have a tachometer. One of those things one of these years is to swap out the console. I've got some gauges for putting below the dash cheap on sale, but haven't put them in either.

Comp CAM 280H

RPM 1500 to 5500
Valve Timing 0.006
Lobe Separation: 110
Intake Centerline: 106

Duration: Intake=280, Exhaust=280
Duration @ 0.050 Lift: I=230, E=230
Valve Lift: I=0.536, E=0.536
Lobe Lift: I=0.306, E=0.306

Valve Timing @ 0.006 Lift
....Exhaust closes 26 ATDC, Opens 74 BBDC
....Intake Opens 34 BTDC, Closes 66 ABDC

Engine is bored out to 0.040".

More notes...
1. New flat-top pistons from a 307. Compression ratio should be about 9.25:1.
2. New CompCams Camshaft 280H.
3. Head intake increased to 1.72', some porting work done
4. Crankshaft and rods balanced
5. Studs installed instead of head bolts for tighter fit
6. Manifolds installed with all bolts and thick flat washers
7. 200r4 transmission from cpptransmission.com along with 2200-2400 rpm stall converter (3.08 rear end)

I haven't done a compression check. I know it's a heap higher because the old starter would barely crank the engine over.

Still hope to get her dyno'ed soon. Once done, you can compare to the Gonkulator!

Should be practically a ProStocker!
Here is what spit back out of the Gonkulator - I gave it fairly slippery traction since you mentioned wheelspin even with the 3.08s:.

Torq 205 at 2000 (less than a bone stock 250!)
Torq 268 at 3800 (now it wakes up)
Powr 246 at 5300
Below 3000 it WILL feel soggy, less punch than a stock 250 up to maybe 2500rpm or so. Above that it wakes up.

Shifting at 5400rpm

2.39 60ft
10.15 at 69.7 1/8 mile
15.82 at 85.2 1/4 mile
7.86 0-60mph

Even shifting at 4000, your 0-60mph times should be in the 9's if its running right, at full throttle. REALLY need a tach in there though for any full throttle runs so you can see whats going on.

I always short-shift a new combo on purpose, ie let it shift at 4000 or so - then I see how it clocks out vs the Gonkulator. If its running right, then I let the revs go up. If not, why scream the revs until you figure out the problem?

Your hot combo does like a bigger carb, A 550cfm Holley added 1 ftlb and 7hp for 253hp. However, it made very little diff on the clock:

Same as above, but with 550 Holley
2.38
10.13 at 69.9
15.79 at 85.4
7.82 0-60mph
Point being, if that carb keeps giving you trouble, why not try another one? I usually try at least 3 different carbs on a combo, just to see which one it "likes" best. Even a different 390 Holley, or a 450 Holley, 550 Holley, 500 AFB, 500 Autolite 4100 (I like those on the Chevy 6's) etc. That carb may just be an ornery one!

ON THE DYNO STUFF:
The GOnkulator says 143 RWHP, but I don't find it too useful to compare chassis dyno RWHP numbers, they tend to be all over the place. Good for tuning the car, but the numbers don't mean much.

Best is, get it running right, then hit the strip, get some timeslips. Best "dyno" I know of. And a lot more fun.

Hey DeuceCoupe, thanks for the analysis!

What does the Gonkulator say about stock 230?

What do you think about FITECH EFI?
Holley 570 CFM? THANKS!

Stock 250 (no other changes from above 15.82 at 85.2):
Torq 229 at 2600
Powr 154 at 3800
2.39 (same as above across the intersection)
10.99 at 61.1 1/8 mi
17.53 at 74.4 1/4 mi
10.4 0-60mph
That's about 16 carlengths behind your new build, LOL.

No idea on that EFI, never run it myself. I'm sure it would run at least as good as the carb and use a lot less gas, just depends on the price.

Those 570 / 670 / 770 Street Avenger Holleys are kinda strange. I have never had one but have heard the idle transition circuits are not as good as the old Holleys. Maybe they fixed that who knows. And I don't know how they are "flowed" but per the venture & throttle sizes:

570sa = 450cfm Holley old school
670sa = 600cfm
770sa = 780cfm
So the 570sa would be a good fit for your engine except I cant comment on that idle transition funny business.

Damnit, Mark! We're practically building identical cars!

(that's on my list for next year)

As soon as I put in my 2004r I'm likely going to do 3.55's and a posi so maybe I'll outrun you yet!

I think this summer we both need to get onto 1/4 strips and trade timeslips. It'd be really interesting to compare the two. The only difference will likely be the rear end, exhaust setups, and time zones.

Never occurred to me but I think youre right, near identical 67 & 68 Camaros. Looks like Mark runs a bigger cam. I have both in the Gonkulator, they are about a carlength apart and the 1/4 mile traps. So close it would come down to weather, tailwind, track prep.

Game on! Never been on a track. Just lots of slow speed go-carts. Should be fun!

I was a little surprised the 2 cars Gonkulate so close since Mark has a much bigger cam, so I looked back at the Gonk. Right now Mark's Gonkulator file has that 3.08 gear and 1960's era street traction ie none.

By just adding a 3.55 gear and decent traction (making the 2 cars equal in those areas), and then shifting the big cam at 5600, the difference is now over 0.3 sec or about 3 carlengths. Equal race down low but then the big cam pulls away.

The 3.73 rear in Mark's car cut off almost another .10 sec so either gear would fix it.

Would still make a great timeslip race though, since things don't always turn out as Gonkulated!

I'm ordering a different cam today, then. Engine is going to be out next week anyway.


Which cam would give me the biggest advantage here? Can't let Mark beat me!

{grumbles incoherently...}

regardless I'll still have the faster time slip at the end of the day no matter what because if I'm going to the track I'm bringing two cars.

My little 6er and my 2014 Mustang GT Coyote with 430hp, 390 ft-lbs. That one should do 12.7 after I put on 285's out back.

gbauer,
It might be hard to go much bigger, I have your trans down in the Gonk with a 1900stall which is kinda tight. So too big of a cam will hurt it. I tried a Comp264S solid cam,
220-220-108 .513 .513 gross lift
Torq 256 at 3700
Powr 232 at 5100
Shifting at 5400:
2.23
9.93 at 69.6
15.67 at 84.9
Is .17 worth a cam swap? Depends how bad you want it, that still puts you at a disadvantage to Mark but you have a more streetable cam too.

I think it would take more converter and/or more gear to make a bigger cam work.

I happened to have my manuals open, found the specs on the engines. I started with a stock 230. Nevermind that it was probably running about 40% down on power with engine trouble. My best 0-60 on the road was about 20 seconds.

The gonkulator really tells the story, high RPMs really shine!


Comparison to my stock 230

stock 230 => Torque 220 at 1600 HP 140@4400
stock 250 => Torque 235 (+7%) at 1600 HP 155@4200 (+11%)
big cam 250 => Torque 205 (-7%) at 2000 HP 246@5300 (+76%)

My big cam on the gonkulator
Torq 205 at 2000 (less than a bone stock 250!)
Torq 268 at 3800 (now it wakes up)
Powr 246 at 5300

Gonkulator Stock 250 (no other changes from above 15.82 at 85.2):
Torq 229 at 2600
Powr 154 at 3800

2200 stall...

How can I beat Mark? That's what's important here.

Screw it! Nitrous kit

Turbo????

gbauer,
Ok the 2200 converter helps. With the Comp 264S cam 220-220-108 that gives
2.17
9.81 at 69.6
15.54 at 84.9

I then tried a bigger cam, Erson TQ20, 232-232-108, .515 .515 gross lift. I set it up 4 advanced to equalize that:
Torq 254 at 3900
Powr 238 at 5300
Even shifting up higher at 5600 Gonk to:
2.18
9.85 at 69.9
15.56 at 85.2
the bigger cam never makes back what it gives up at the line, so I'd stop with the Comp 264S or similar unless there are plans for even more converter or gear.
Either way it is getting very close between the two cars.

Isnt NOSS illegal unless you run a "NO FEAR" windshield banner, a big coffee can tailpipe, and wear a baseball cap backwards and say "dude" all the time? Oh wait, there's Street Outlaws and their "Street" Cars.

What if you ran a 4L60 trans 3.06 1st gear? Yes its a bigger RPM drop into 2nd - but it'll launch a lot harder and pull harder through the 60'. Plus you get OD for criusing.

You can use a 700R4 and get the same thing without the need for an ECM.

Here are a couple interesting Gonks I did on gbauer's car, with the 232-232-108 Erson TQ20 cam:
2.75-1.57-1.00 200-4r gears
2.18
9.85 at 69.9
15.56 at 85.2

3.06-1.63-1.00 700r4 4L60 gears (I JUST changed the gears no other changes)
2.13
9.82 at 69.7
15.55 at 84.9
The wider ratio has the advantage of .03 thru the 1/8 mile, but only .01 at the quarter. The RPM drop offsets most of the small gain.
Instead I just tried swapping to a 3.90 gear instead of the 3.55, it seemed the easiest change. With the old 200-4r 2.75 ratios this Gonked to
2.14
9.78 at 69.7
15.47 at 86.0
That's a .08 gain in the 1/4 mile, and with the overdrive, still plenty good to keep the cruising revs down.

Going to a 3000 stall and staying with the 3.55 rear gave
15.39 at 85.3

And the 3000 stall with 3.90 gears was best of all of course:
15.30 at 86.1

Of course we can keep going forever, another cam swap, etc, I was just surprised that the 3.06 1st gear didn't really seem to help, in the Gonkulator anyway.

The 700R4, 4L60E etc, trans has a huge drop into 2nd gear and unless you have a turbo or huge torquey engine it is going to have a hard time pushing through 2nd gear. Two cents
MBHD

Would the 3.06 first gear of the 700-r4/4l60e help more if the car had a mild cam like the Comp Cams 252? In theory, the car would have more torque after the 1-2 shift with the smaller cam. Of course top end horsepower would be down. Jay

A torque converter with a little more flash, (not to be confused with stall) will aid in powering through the steeper gear change. The six cylinder's greater rotating mass, (heavy crankshaft) will help too.

Jay,
That seems to work - I think the 3.06 1st favors tight stalls and mild cams, ie a nearly flat power curve so the drop doesn't hurt so much. I grabbed my old 250 Nova as an example, stock 250cid, 4bbl, glide-3.08rear.
2.64
11.45 at 61.8
17.88 at 76.0
That much is pretty much what the real car ran on the GTECH.
Then I swapped in the Gonkulator to a 200-4r trans, 2.75 1st:
2.39
10.82 at 63.8
17.05 at 78.2

Finally, I just keyed in the new 700r4 GEARS, 3.06 and 1.63:
2.35
10.75 at 63.6
17.00 at 78.1
So that's a .08 gain in the 1/8 mile, and holding a .05 gain thru the 1/4 mile.
Still a small gain, and the thing to me is, the whole purpose of those fancy upscale transmissions is to have a lockup converter, so you could run higher stall, which would again negate the gain of the 3.06 1st gear. Well that was my intuition anyway. Then I repeated the Gonkulator, same setups, 3000 stall:

200-4r=2.75 3000 stall
2.24
10.51 at 64.1
16.72 at 78.4

700-r4=3.06, 3000 stall
2.16
10.43 at 64.0
16.65 at 78.3
So the 3.06 1st gear keeps, even adds to its small edge even with higher stall. Why? Because with that 3000 stall, we are back "on the converter" after the shift so it softens the 1-2 RPM drop. Very interesting.

So I'd just say, mild ie factory vanilla cam likes the 3.06, bigger cams like the 2.75 1st. In between probably it a tie.

Thanks Deuce Coupe. That is some interesting info. In the late 70s I think there was a school of thought at GM that said use a deep first gear, would work the same for performance with a higher rear gear .the 700r4 is an example. Another example would be Lifeguards Camaro with a 3.50 first gear three speed.i am still tossing around a trans swap. The 200 is the easy fit, next would be a 200r4. A 700r 4 would be more work but might be worth it. For about $500 a 3.06 first can be had for the th350 but the jump to second would still be 1.52. I have a 2.73 rear axle so the OD won't help much even with a low rpm cam that I plan to run. If I had a power glide car a th350 or th200 or a 200r4. Would one of the first things I would do. The first two are almost a bolt in for some cars, not sure about an early nova. Looking at your nova, the 60' gain is huge. Driving on the street would be mor fun too. Some time ago, you ran my car through the famous Gonkulator and said the gain for going to a 2.74 first from 2.52 wouldn't be worth it. Jay

Yeah, I think you were on to something when you recommended the 4spd for my application instead of the 3spd, when I mentioned how hard it is to find a good speed from a stoplight to go from 1st to 2nd. With my 3.50:1 first gear (2.73 "perf" ratio in open carrier), the jump from that to 1.89 in 2nd is pretty steep. Breaking that shifting up into 2.47 and 1.65 would ease the transition. Or just going to a 3.11:1 1st gear 3spd (or 4spd might be better than a 3spd). When you get to the standard 2.85:1 3spd of pre-'75, there seems little point in shift twice rather than once before direct drive. The deeper first allowed a higher rear end ratio, which is a stop-gap fix on their way to overdrive transmissions. The Gonkulator gave me a 0.2 second 1/4 mile improvement from changing 3.5-3spd to a 3.5-4spd. But there was no improvement for the 3.11-4spd (maybe I should have had him run the 3.11-3spd too?). And changing to a 3.08 rear would be marginal improvement. Here, this is probably simpler:

3.5-3spd/2.73 = 3.5-4spd/2.56 = 3.11-4spd/2.73 < 3.5-4spd/2.73 = 3.5-4spd/3.08 = 3.11-4spd/3.08

The deeper the first gear, the more gears you need in-between to smooth transition. That's why a deep 3.06 1st in a TH350 was probably never attempted. But once you have OD, you don't need a real deep first. With the 4 gears on a 700 or 200, the 200's first gear makes more sense with a deeper rear end gear being the advantage of the OD 4th.

I looked at how GM changed 1st gear and rear end ratios over the years and the pattern I saw was:

2.85/3spd - 3.08/std - 3.42/perf - (3.73/hi-perf?)
3.11/3spd - 2.73/sted - 3.08/perf - (3.42/hi-perf?)
3.50/3spd - 2.56/std - 2.73/perf - (3.08/hi-perf?)

The TH350 kept getting the lower gear as the 3spd without changing the 1st gear. So it had a 3:08 pre '76, then a 2.73 pre '79, and finally ending up with the 2.56. So sounds like from the Gonkulator a TH350 with 2.73 is ok, but if going to a 200, then a 3:08 rear should be used?

IIRC that read about the 3.06 first gear th350 in a off road fourm. Think rock crawling. In a auto trans the converter softens the drop somewhat compared to a manual. Like was posted on this thread before, a looser converter would help cover the drop better than a stock unit. Looks like to me those GM engineers were on to something. How well do these o.d. auto transmissions work without lock up? Does it overheat the trans like i have heard or is that just a myth? Jay

Not sure on overheating. I've only had two 700 vehicles and never disabled the lockup. But the lockup is what made them so fuel efficient compared to the TH350, so I'm not sure why i would do that?

That softening may be why autos are always a gear less the manuals in the same cars?

Yeah, that gear swap for the TH350 has been around since at least the late '80s. I remember seeing it in catalogs then.