budget 120cc head 500 running

gary kosier said:
Dave,

On post #4, picture #4, do I see a corner in the PS belt?  Are my eyes getting worse?

Gary Kosier
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Gary,

No, it looks like it in the pic to me too. I had to go downstairs just now and look. PS pulley lines up nicely with the crank pulley, and belt is nicely aligned. Weird.

Thanks for pointing it out though. Could have been bad.

Dave
 
Dave,
Does a regular truck power booster fit in there, or haven't you tried?  I wanna run power brakes on mine so just wondering. 

Looking good BTW
 
Andy,

Thanks. If it ever quits raining here, I'll drive it.

Pretty sure the brake booster would fit, it did on my old caddy powered 3/4 ton camper special. The 67-72s have such an ugly setup though. Big brackets stand the booster and cylinder out off of the firewall about 2/3 of the way to the front of the valve cover. I've thought about looking at a smaller booster. Either that or a larger piston master. The master has the wrong diameter piston. It takes a bunch of leg power.

Dave



Andy V said:
Dave,
Does a regular truck power booster fit in there, or haven't you tried?  I wanna run power brakes on mine so just wondering. 

Looking good BTW
Click to expand...
 
Drove it today. It ain't like boosted power, but it runs nicely. Didn't thrash it too roughly, although I did open it up in low once to 4000. Blows the worthless 33x21.5 hard mickeys off, but not like the turbo'd deal.  :weeping:

Q-J is pretty close on the primary cruise mix. Wide band says 14 to 14.5 at light throttle with 71s and 46 rods. Will drop the rods a tad with the APT screw to see if it'll lean up a tad at cruise. The somander grooves tend to make an engine like a 15-1 light throttle cruise mix, from what I've seen. Heavy throttle on the primary goes a little richer to the mid to high 13s. I suspect that'll be fine, but I might try replacing the 71s with 72s or 73s when I get time. Didn't notice the afr on the secondaries, but that's easy to tweak.

Needed more idle bypass air, as removing the carb showed that curb idle setting had most of the transfer slots showing. Imo, only apx 1/4 to 1/3 of the slots [apx .040" or so] should show below the plates at curb idle. I drilled the idle air bypass holes from .070" to .082 [they were .040" stock]. Will see how that works. Didn't want to go too far, as later tweaks on the advance curve may show me that it likes more advance at idle, and that may allow closing the plates a wee bit.

Dave
 
  Nice work,Dave,and great attention to detail both in building and tuning.  :thumbup: Your posts have been excellent and the project looks great.  :yes:

  Terry
 
I just noticed you had this in a 67-72... I am doing the same thing. Did you do turbo in the Truck? 4wd?

I am going Hyrdoboosted brakes.

Are you on www.67-72chevytrucks.com ?
 
Excellent work once again Dave. Is the Opel next, or a new turbo set-up for the truck?
 
Thanks guys.

grendel, yes, '71 with '67 front end. The turbo setup was a learning experience. Much of it was done through guesswork while there was no front sheetmetal on. Ended up with too little room, and could only get 2.5" downpipes from the turbos. this [I believe] choked it off early.

Edit: I've been at 67-72 trucks, but not for a while.

Sean,

I don't know what'll be next. Some fun for a bit, even if it's slow fun  lol. I might put a high compression engine together for a track rental event later this year. I have a solid can, rollers and most other stuff needed to do that. I'd like to re-turbo the truck, but it'll be next winter for sure. I would like to move the opel inside and work on it a bit too.

Terry,

It's been a while since I've played with a Q-J. Kinda fun. I will say that opening up the idle tubes and idle down orifices does seem to really make the carb snappy. It still needs a little more idle bypass air though. Going from .070" to .082" allowed backing the throttle plates down a bit more, but it's still 1/2 to 3/4" turn open from where it needs to be. I'll try a bit larger bypass holes, hopefully, I will not have to drill the throttle plates for add'l air.

Dave
 
Sweet job Dave. I love your truck.

I've done the same swap-- a 500 into a '68 short box. I'm always interested in how folks have managed their swap. Yours is an extremely clean setup.

I'm running a less built version of the 500 (than your motor) with a TH400 and 3.73 gears in the stock truck 12-bolt. My best time is a 13.23 on the quarter. I think you might break 12s. 

I used an aftermarket "low vacuum" power booster setup since my truck didn't come with power anything. It works really well. And I can't find pictures of it. I'm going to have to dig through some old CDs I guess.

I'm interested in knowing what tranny crossmember you used. I'm using a double hump style because I've got clearance issues and wanted to tuck the exhaust as high up as possible. I'd kind of like to rework that because I ended up using some 1-inch stainless tube to space it so I could everything lined out nicely. Any pics?

Thanks in advance.
 
Earl,

Heck, I'd be really happy with I could match your et! Just how mild is your engine? Mine is pretty darned mild.

I built a crossmember out of 1.5" tubing. My truck is sort of a "medium bed"  lol. Was a long bed, but I cut 9.75" out of it. I boxed my frame in the middle, so the stock xmember would not easily work. Here is a link to a thread that might show pics of it:

http://www.cadillacpower.com/forum/inde ... 467.0.html


Thanks for the kind words.
Dave


Earl junior said:
Sweet job Dave. I love your truck.

I've done the same swap-- a 500 into a '68 short box. I'm always interested in how folks have managed their swap. Yours is an extremely clean setup.

I'm running a less built version of the 500 (than your motor) with a TH400 and 3.73 gears in the stock truck 12-bolt. My best time is a 13.23 on the quarter. I think you might break 12s. 

I used an aftermarket "low vacuum" power booster setup since my truck didn't come with power anything. It works really well. And I can't find pictures of it. I'm going to have to dig through some old CDs I guess.

I'm interested in knowing what tranny crossmember you used. I'm using a double hump style because I've got clearance issues and wanted to tuck the exhaust as high up as possible. I'd kind of like to rework that because I ended up using some 1-inch stainless tube to space it so I could everything lined out nicely. Any pics?

Thanks in advance.
Click to expand...
 
Not a problem, your truck sounds similar to my deal. Not looking for glory here. Ain't much in an 8.7-1 CR deal.  lol


Earl junior said:
I'll get my own thread up and running when I find my pics. No need to steal your glory.
Click to expand...
 
Fwiw,

Engine runs well for what it is, imo. 30 miles or so on it. Haven't beat it real hard, but does well to 5000. Doesn't seem to know 2nd from high [pulls nicely even in high].

Was a little paranoid about two things: #1 rocker tees that I sanded .040" on belt sander to get preload with chevy lifters. #2 spring shims that fit a little loose on the spring pads. Had another set of tees milled, and swap shims out for something that fit. Done one side, got sidetracked, but will swap other side out tonight. Leaked one side. Worst cylinder was #4, at 5% at 100 psi pressure cold. Others on that side were 3.5-4%. If the other side is that tight I'll be happy for a used std bore.

Grooves *seem* to make the engine like the others I have grooved. It runs really well at as lean as 15.5 cruise afr, but I am running it at 14.5-1 due to concern for the exh valves and seats.

Dave
 
edit: dragstrip trip - Re: budget 120cc head 500 running

All,

Recap:

Drove my truck to a track rental at pittsburg raceway park today. Had 110 miles on it when we left this morning. Pulled in, left some air out of the tires [mickey thompson pro 29x18.5 -went down to 18 psi]. First pass was 13.70 at 95.x with 32* and 72 jets and .057" secondary rods. Tried timing first, 34*, 36*, 38*. 36 gave best mph. Swapped metering rods next. Went from .057" long tip to .053" long, to .053" medium to .040" long to .030" long. The .040"s gave best mph and ET. Ended up at 13.39 at 98. Sixty foot time was 1.84 on most runs, with a range from 1.86 to a best of 1.82.

All runs made on 87 Sheetz gas. No sign of ping on the plugs. I was a tad dissapointed with the mph, but all in all, I'm happy with it, for what it is. A std bore, std crank, re-ringed '75 500 with a slight compression increase [.013" block cut and .024" head cut], a 3 hour port job, an edel intake and a cam and valve springs. Truck weighs apx 4000 lbs.

Needs more gear for the 1/4. Went through at apx 4200 with 3.55s. Shifted at apx 5100 in drive. Might tweak the gov' for a lower shift point next time. Did not like more than 5100.


Dave
p.s. - I won a 50/50 drawing at the track for $120 :)
 
LOL. Yea, apx 13.5 gallons to get there and back, and apx 6 gallons burned during the testing [15 or so runs]. The fee was $75, so I still went in the hole.

Track is 1250 feet elevation. The other "local" track is 550'. That difference, some 4.11s, a lower shift point = *maybe* a 12.99 out of the grocery getter 87 engine. But then, I promised myself that I wasn't going to thrash it any more until I have another engine built and ready.
Dave
 
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