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Clear as mud
https://www.slantsix.org/forum/viewtopic.php?t=24368		 Page 1 of 1
Author:  dakight [ Tue Aug 07, 2007 11:03 am ]
Post subject:  Clear as mud
OK, I've been following Bren's travails and not wishing to repeat his mistakes I want to clear the air. Let me first lay out my overall drivetrain plan. The, a 62 Valiant Signet, is intended to be a weekend cruiser. Most of it mileage will be in town and/or on urban freeways. There will be occasional jaunts cross-country of up to 1500 miles one-way. In addition, I just might hurl it down the track once in a while but the optimization should be for low to moderate speeds in an urban environment. Now the details.
cast iron 225 bored .060 over.
Stock crank turned to .010-.010
Head ported and polished by me ( a work still in progress )
1.44 / 1.70 oversize valves
the cam I have chosen is an Erson 270 but that can be changed if not suitable.
"Super Six" manifold and 2-BBL carb.
Stock type, flat top pistons.
A904 bushbutton tranny
-- now for the questions.

1. Where should I set the Compression ratio? I don't mind running pump premium ( 91 Octane ) but I don't want to have to buy racing fuel or octane modifiers.

2. Should I shave the head, the block, or both to achieve the desired CR?

3. What rear-end ratio makes sense? I was thinking a 3.55 but haven't bought the gears yet. They will go into a late ('74) 7.25 rear with a sure-grip.

4. What about the converter? Do I need one with higher stall or will the stock converter be satisfactory.

5. Is there a satisfactory shift kit for the early torqueflite?

The head will be going to the machine shop within the next 3 or 4 weeks so I would like to have a plan in place by then so I can tell the machinist how to proceed.
Author:  sick6 [ Tue Aug 07, 2007 11:39 am ]
Post subject: 
1: I think 9 to 9.5 to 1 would be pretty good. if your going to limit it to 91 octane I'd leave it around 9.

2: most people now-a-days prefer to shave the block rather than the head. I have heard this gives it a bit better squish distribution, I could be wrong. Dan might chime in on that. I shaved both the block and the head on my duster.....but I am running at 10.4 to one.

the rest of the questions I am not qualified to answer, I use a stick, but the going favorite seems to be a set of 3.55's (milageage versus take off versus noise on the highway) from what I have read, but what size tires are you going to run? that will make the difference with gears and converter.
Author:  dakight [ Tue Aug 07, 2007 11:53 am ]
Post subject: 
I plan to keep the tires to stock height, or as close as possible. I'm thinking right now that I'll go with 205-60R15 but that is subject to change as needed. 9.5:1 was my initial thinking but since I haven't cut anything yet I can set it where ever it needs to be.
Author:  SlantSixDan [ Tue Aug 07, 2007 11:56 am ]
Post subject:  Re: Clear as mud
Quote:
OK, I've been following Bren's travails and not wishing to repeat his mistakes
That will not be difficult. His main problem all along has been the nut behind the wheel.
Quote:
62 Valiant Signet, is intended to be a weekend cruiser. Most of it mileage will be in town and/or on urban freeways. There will be occasional jaunts cross-country of up to 1500 miles one-way. In addition, I just might hurl it down the track once in a while but the optimization should be for low to moderate speeds in an urban environment.
This is good: you're already miles ahead of those who've had projects go badly, because you've defined a clear, realistic goal in terms of how you intend to use the car. You're thinking in terms of what you want the car to do, rather than in terms of having the biggest number of cubic inches or more power than a 440 V8 or a particular number of horsepower.
Quote:
cast iron 225 bored .060 over.
Stock crank turned to .010-.010
Head ported and polished by me ( a work still in progress )
1.44 / 1.70 oversize valves
the cam I have chosen is an Erson 270 but that can be changed if not suitable.
"Super Six" manifold and 2-BBL carb.
Stock type, flat top pistons.
A904 bushbutton tranny
All sounds good so far, given how you've stated you intend to use the car. You don't mention what you'll be doing for the exhaust, though. With this setup as listed so far, as you might guess, I would recommend a thoughtfully-configured system built around Dutra Duals.
Quote:
Where should I set the Compression ratio? I don't mind running pump premium ( 91 Octane ) but I don't want to have to buy racing fuel or octane modifiers.
I haven't used the Erson 270 cam, so my advice ("no higher than 9.2 actual") is generic. Those who've used this particular cam can probably comment more specifically.
Quote:
Should I shave the head, the block, or both to achieve the desired CR?
It's beneficial to have the pistons come as close as possible to the block deck, so you may want to measure your piston deck height before deciding on this matter.
Quote:
3. What rear-end ratio makes sense?
That is dependent to some degree on what tire size you'll run, but if it were my car put together with the engine as listed, to be used as stated, I would probably pick 2.93 / 2.94 . It'd cost me some time down the drag strip, but that tradeoff would be well rewarded every day in the city and on the highway, in the form of a queter, more fuel-efficient ride. Acceleration with the engine you describe in that lightweight '62 will be snappy even with 2.9 gears. If I were running big tires, I'd pick 3.23s. I would definitely not pick 3.55s, which will let you smoke the tires at every green light but will drive you mental hearing the engine scream on the highway (for 1500 miles at a time...yum yum!) and waste a lot of gas. Let the engine you're building work for you!
Quote:
What about the converter? Do I need one with higher stall or will the stock converter be satisfactory.
Stock or near-stock will do nicely. I can't see anything in your build or usage plan that would call for any kind of a radical converter.
Quote:
Is there a satisfactory shift kit for the early torqueflite?
Yep, Transco/TransGo makes one. Talk to Pat Blais, tflitepatty@verizon.net .
Author:  slantvaliant [ Tue Aug 07, 2007 12:50 pm ]
Post subject:  Re: Clear as mud
Quote:
2. Should I shave the head, the block, or both to achieve the desired CR?
A clean up pass on both, at the least, to help square everything.
Quote:
3. What rear-end ratio makes sense? I was thinking a 3.55 but haven't bought the gears yet.
With the 205/60R15's, I agree with Dan on 2.94/2.93 or 3.23's. I run that size tire with a 2.94 on my '64 Valiant, and find it good for long runs and just fine around town. The speedometer is pretty close at the speeds I drive. A 3.23 would be a little more fun at some cost in fuel and wear.
Author:  dakight [ Tue Aug 07, 2007 1:17 pm ]
Post subject: 
For the exhaust I had intended to initially use a single pipe, 2" all the way back through a "turbo" muffler since that is already on the car. Dutra Duals are certainly something to consider depending on budget. I have a set of 2.76 gears in the rear end now but I figured they were a tad too tall for that cam.
Author:  Dart270 [ Tue Aug 07, 2007 1:27 pm ]
Post subject: 
I have a fair bit of experience with that range of cam and those desired driving situations.

You are asking for city driving, AND 1500 mile highway trips, so gear ratio will be somewhat limited. Personally, I would use 3.23 gears and get a pair of tall tires (like 215/75-14s) for long trips. 3.55 will be great around town, but will not be fun on that 1500 mi trip. Wear is not a big issue as long as oiling is good. I have cruised for days with 3.23s at 3600-3800 rpm (80+ MPH), which was loud but no ill effects.

That is not a big cam, and could be made to work well with a stock converter. However, even the small MP 244 cam benefits quite a bit (acceleration-wise) from a higher stall converter. I would recommend 2500 RPM stall, and you give up essentially nothing in terms of economy and drivability.

The head porting will be a big key to power here. Compression should be in the 9-9.5 range for that cam and best perf/econ on pump gas. Personally, I would do 9.5 to allow for bigger cams later and 87 octane if I get my ign advance map right, but 9.0 would allow 87 octane no problem.

Head or block shaving? I don't think anyone really knows which is better. I have shaved heads on mine and that has worked well. 0.100" is about right, but you'll have to measure everything first and do the calcs.

Make sure to mark/measure the head/block before shaving so that you KNOW the shop did it. I got screwed once (only shaved 0.010 when I asked for 0.090") and found out later when I got smart.

Lou
Author:  dakight [ Tue Aug 07, 2007 2:32 pm ]
Post subject: 
I measured the deck once and if I remember correctly it was between .178 and .183 in the hole to the top of the pistons. Of course, I'll measure that again both before and after machining. If it doesn't make a lot of difference it seems to me that it would make sense to do the cuts half and half to preserve as much "meat" on the block and head surfaces as possible. If I can run 91 or lower fuel at 9.5:1 then that's where I'll set it up. When it comes time to set up the distributor I'll have a whole new set of questions, but first things first.
Author:  Aggressive Ted [ Tue Aug 07, 2007 3:19 pm ]
Post subject: 
16,000 on a new rebuild.

I have run 2.76, 2.93 and 3.23 gears with a 254 .435 regrind. My tires are 235/60 14" using a 29 tooth speedometer gear.
I had it checked with the 2.76 Posi and it is 1 mph higher at all speeds. I had it dynoed for $40 and is certified.

After using all (3) 8 3/4 rears, I prefer the 2.76. I still have awesome punch and good mileage too. Weight is the big issue on performance. With an empty trunk, no back seat and half a tank of gas I am 3200 pounds. It will break loose pretty easy and scoot like a 318. At 3500 pounds it is not as spunky and little wheel spin (Auburn Posi).

I am running a ported manifold with 2.25" exhaust and a Flow Master 40. That made a huge difference over the stock pipe and muffler.

I would think the extra cubes and compression ratio would get you there.

Hope this helps.
Author:  VDART [ Tue Aug 07, 2007 5:15 pm ]
Post subject:  62 toad 1500 miles
Hey David-- is that with the a/c on or off?

Nice to hear it is starting to take shape, Lawrence
Author:  Rug_Trucker [ Tue Aug 07, 2007 6:28 pm ]
Post subject: 
3:23's are neat on the street. Trust me mine has made multiple trips to SW Florida and back @ 80-82 mph. Never got hot and got 18-22mpg with the air off.
Author:  Dart270 [ Wed Aug 08, 2007 5:48 am ]
Post subject: 
I would recommend at least hogging out your stock manifold a little and using 2.25" exhaust. Dutra duals would get you more substantial gains.

Rug_trucker, are you bringing that car to the Bristol race in Sept??

Lou
Author:  sandy in BC [ Wed Aug 08, 2007 7:25 am ]
Post subject: 
Sounds like you are on the right track ...........


Ill add to the advice already given.

I run 9.25 CR and a Comp 264 3.23 gears (3.55 as soon as my drive shaft gets back)



You should have no trouble running 87 at 9.25 with the Erson 270....but you will need to curve a dist. A stock EI curve doesnt work well with my combo....but a '65 Prestolite points curve was very close.


I chose to deck the block because I radiussed around the valves and wanted to avoid block notching. Its easier to keep the expensive head with a larger chamber available for any CR by taking meat off cheap blocks. I definitely recommend working/ balancing the chambers.

I would use 3.23 gears if you dont have an OD. That will give you 100mph at the top end. Deeper gears may be no fun at 75mph all the way to Vegas. Go 3.55 with tall tires (+ 28" tires)

I would go to 2.25 pipe all the way back . The bigger pipe made a significant difference on my car.....and in my case killed the dreaded HUM.
Use a good turbo muffler. My shop bent my 2.25 pipe using the factory route and bends (they had a little card with the stock pipe specs) Im not sure they could have done 2.5 pipe the same way......

Your build is very similar to my build......I think you will be pleased with the performance and particularly the driveability with this combo.....its kinda the ultimate Super 6 build. (I wish I had the Erson 270)

MAKE SURE THE SHOP DOES A BOWL HOG. I got mine done before I did my head work ....then sent the head back for final finishing.

Make sure you know your final chamber size before block decking. I finished the head before we started the block.....and was adamant about hitting my target CR.
Author:  sandy in BC [ Wed Aug 08, 2007 7:28 am ]
Post subject: 
Now....its time for you to ignore our advice and do what the guy in the bar told you his brother did in 1967......
Author:  dakight [ Wed Aug 08, 2007 7:49 am ]
Post subject: 
:lol: I know you're kidding, but I don't go to bars and I didn't ask advice so I could ignore it. I am taking all this very much to heart and, FWIW, it is corresponding pretty well with what I had been thinking. My original choice for gears was 3.23 but I was concerned that with the 270 cam I might be losing a bit on the low end so had about decided to do the 3.55, which are about $100.00 cheaper anyway. But, you guys have convinced me to go with the taller gear and maybe add a higher stall converter. That's an additional expense I hadn't planned on but I'm in this to do it right. I'll start with the single pipe probably but the DD setup is probably in the works for "Stage II" along with a carb and mainifold upgrade. The nice thing about Dutras is that you don't have to waste the original pipe.

Lwarence, I haven't completely decided what I'm going to do about AC except that I will have it. There are several options that I'm looking at. Thanks for the encouragement.
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