Camshaft

General discussion about our beloved Tercel 4WD cars
Rasmus
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Post by Rasmus »

i drove without vacuum assisted brakes in my tercel for a few months, hardly noticed a difference, the pistons are tiny and our cars are light
I love my tercel :)
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Typrus
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Post by Typrus »

I always notice a difference...
Actually, bigger caliper pistons and a smaller master cylinder piston will yield better hydraulic multiplication. Just too much travel of the smaller piston.

I'd imagine that if you are nuking the emissions stuff and just leaving vacuum brakes and vacuum advance, there won't be a problem. Worst-case scenario? Buy an external Vaccum Reservoir.
http://www.dougherbert.com/vacuumreserv ... 2e08b0491e

I'd imagine that the longer duration you have, the more vacuum lost. The guy with the 282 was probably near zero. The others with more than stock but less than that shouldn't be too drastic.

I seriously doubt that a 2, 10, or other small degree change will nuke your vacuum.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
shogun
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Post by shogun »

the problem is i now run mr2 sw20 two piston calipers, and later on ill be switching to 4 piston calipers, when i get to installing rear discs, that is why i ask, right now no vacum means you have to stand on the brake to get any braking
tercel 4wd custom suspension, under drive pulley, vented brakes, cold air intake, and plenty more to come
Typrus
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Post by Typrus »

Must be less overall area to the 2 piston setup, otherwise that wouldn't make much sense.
Well, if it all falls onto it, an external vacuum reservoir would be cheaper than a vacuum pump.
You could always convert to a dual-cylinder manual braking setup with proper lever arms and such? Drifters love the crap out of that setup as it gives fully adjustable biasing.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
keith
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Post by keith »

Typrus, I checked out your web site with the Schnieder Cams, I didn't see the 3/4AC engines listed. Did you correspond with them for these specs, do they have their own web site?

Have you corresponded with the guy on you tube to find the source of his cam and headers?

I've been googling for cams for this engine for two days now, no luck so far.
Typrus
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Post by Typrus »

He is in Iraq. That and a median punched a lovely hole in his oil pan. Go check out club4ag.com and browse for 4AC... I'll try and go find the thread and link to it.
http://www.schneidercams.com/cams/110a.htm


Olrighty then... Looks like club4ag.com is down for a while. Joy.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
keith
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Post by keith »

I googled schneider cams and found it. No part numbers so its not on the price list. Thats usually not a good sign (= expensive).

Bummer on Iraq and the oil pan. I'll check out the other leads, thanks.
keith
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Post by keith »

delete
Typrus
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Post by Typrus »

$200 for the cam. $60 for the set of double-valve springs.
I've done some homework.

He had one heck of a rig. I offered him $500 for the engine and radiator just before he left, but someone he knew had already hauled it off for $750. Oh well.
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
keith
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Post by keith »

That doesn't sound too bad, they make (or sell) new rockers too I believe. I'd replace those too if I go with the cam. Wouldn't want metal fatigue to ruin everything.
shogun
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Post by shogun »

thats my main concern also, metal fatigue, another thing nay body knows the specs on the 3asu cam y have one of those, and the engine it came from is 90 hp, also dual carb, so i wonder if its better induction or better cam ????
tercel 4wd custom suspension, under drive pulley, vented brakes, cold air intake, and plenty more to come
Typrus
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Post by Typrus »

Cam might play a part.

I want to know if anyone has roller-rockers available...
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
gatemaster
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Post by gatemaster »

$200 for the cam. $60 for the set of double-valve springs.

I believe I saw on their website $200 for cam or $100 if you send core for regrind.
anyone know what the increase of the 260 would be over stock?
An engines potential to produce power is based
mostly on it's cylinder head design.
keith
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Post by keith »

I used the blown engine today to do some measurements. I did two clay molds, one of the valve openings at TDC for the exhaust stroke/intake stroke transition. Both valves are open at this time. Because the piston is nearly as high at it will go in the cylinder when its +/- 10 degrees of TDC, I rotated the cam that amount so you can see the clearance in the picture below. There is plenty of room, about 5/16". I measured the valve lift at max open, it was about 5/16 to 3/8". This is a stock cam. Lobe height of the cam is a little less than a 1/4" from base. The rocker has a ratio of about 1.4:1 to 1.5:1, that is the valve opens about 1.5 times the lobe height.

Image

............. exhaust......normal cycle...........intake ...........................exhaust .......min clearance....... intake

The other clay mold was with the piston at TDC and the Cam rotated 360 to check for valve interference. As you can see, this is a non interference engine, but only by about 1/16". Much more valve lift and this will be an interference engine.

It looks like the cam specs from NAPA were based on lobe height and not valve lift. If the rocker ratio is 1.5, then the stock cam would have a valve lift of 3.19" Typrus did state it was cam lift and not valve lift, and this would be consistent with my measurements. If this is true, then all the Schneider Cams would make this an interference engine, but then most engines today are interference engines and we do keep up the timing belt change intervals don't we.
Typrus
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Post by Typrus »

The timing belt changes would likely need to be more frequent with a bigger cam. More stress from more opening I'd venture to say. Unless we could find some roller-rockers... That might balance it enough back out...

Thanks keith!

So you could do a max of a .0625 head shave before interference. At that point, you'd be interfering with the water jacket I'd guess. But thats not taking into account some other factors. That and we'd be talking a rather large increase in compression...

I need to find a syringe to cc the heads with... All the ones I have round here are 1.875 mL, 1.25mL, .625mL graduated. That'd be a lot of suck and squeeze to fill that thing up. Anyone have any idea where to get a maybe 10mL syringe? 100mL maybe?

Hmm... I'm pretty sure you mean .319 lift there keith. 3.19" lift is a bit extreme. Just a bit. Lol.


Another point of question... Is there enough clearance around our valves? Over to the wall-sides it seems a little close, don't you think? I'm not thinking of big-valving a 3AC, just getting the best possible flow. Any thoughts guys? I dunno how much room there is to expand anyway.


So we need 1.4:1 or 1.5:1 rockers. I want rollers.... I just dunno it that'd turn into a fully custom thing or not. .42 lift becomes .63 lift... Jeeze...
RIP 10-07- 1984 Toyota Tercel SR5 4wd Wagen 6 speed

RIP 04-05- 1986 Toyota Tercel SR5 4wd Wagen 6 speed

1st Terc- 1987 Tercel SR5 4wd Wagon 6-speed, Sadly cubed

1985 Tercel Standard 4wd Wagon w/ 3-speed auto, Living a happy life in Boulder last I knew
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