Messages

361

General Discussion / Re: 400 block...

« on: October 10, 2008, 05:34:07 PM »

dutch,

Why not rebuild the 302 that you have on the engine stand

If that is the correct engine for your car and you have no plans to all out race the motor, just rebuilding that should be fine.
If you are keeping the engine for origiinality and just going to build the 400 to save the 302 for some future rebuild, then
I understand.

The 400 small block Chevy is a good engine, if built correctly.  In my opinion if you are buying new rods and pistons for the
400, I would switch it to 5.7 rods clearanced for the 400 stroke.  There should not be a lot of additional cost for that.

The is no substitute for cubic inches, but then there is no substitute for the quickness and high rpms of a 302 either.
 

I'll try again as I screwed up the last response...

  My 302 is original to the car and sits fully rebuilt and dyno'd in my workshop. It's very hard to get decent gas to run it around here and I built a 350 and used some of the 302 components on it so I can pull up to any unleaded high test pump and fill up if I so choose. Mainly the 302 sits for that reason along with the fact that aside from how nice it sounds it isn't really much fun to drive around unless one is winding it up all the time with so little torque down low.
  The 400 was a thought because of the torque output and therefore the ease of driving the car around town and I have heard and seen a couple of Chevelles locally that really honk with 406 engines and roller cams with a heavier body so I figured if I ever came across a decent 400 block it might be a good winter project to do. Have to put the car away in a couple of weeks anyway until next mid May, so the 400 deal sounded like a good way to keep occupied for some of that time.
  I will at some point drop the 302 back in if for no other reason than just to hear again how nice it sounds...

                                                                                                                                                                                Randy

362

General Discussion / Re: 400 block...

« on: October 10, 2008, 05:16:11 PM »

dutch,

Why not rebuild the 302 that you have on the engine stand

If that is the correct engine for your car and you have no plans to all out race the motor, just rebuilding that should be fine.
If you are keeping the engine for origiinality and just going to build the 400 to save the 302 for some future rebuild, then
I understand.

The 400 small block Chevy is a good engine, if built correctly.  In my opinion if you are buying new rods and pistons for the
400, I would switch it to 5.7 rods clearanced for the 400 stroke.  There should not be a lot of additional cost for that.

The is no substitute for cubic inches, but then there is no substitute for the quickness and high rpms of a 302 either.
 

363

Maintenance / Re: Starting problems

« on: October 10, 2008, 03:04:34 PM »

  Depending on the Pertronix version you may not be getting sufficient voltage at the module. Some versions require that you add a resistor or at least use the old resistor wire already in place for the original points set up to lower the voltage to 8 or so volts - the later Pertronox versions need or want to see full voltage without any resistor in the circuit.
  Not sure if this would make it impossible to work at all with too low a voltage of 8 or 9, bit it certainly could go a long way to make it run poorly for sure. Check the Pertronix unit you have to see what it calls for in the way of voltage to see if maybe this could part or all of your problem.
  I too added a Pertronix coil just to insure that everything went together since some coils have a resistor built into them to work with points setups and would lower the output to the Pertronix module so I reasoned that the Pertronix coil would obviously work with their own stuff better than other brands might. - Randy

364

General Discussion / Re: 400 block...

« on: October 10, 2008, 03:34:39 AM »

Rich
   Thanks for the good read. It sounds like the 400 has been given a somewhat undeserved reputation as a problem heater. The article makes it sound like it's a fairly decent addition the small block family and I hope to get a look at the one I can purchase in the next few days to see if it looks decent enough to warrant the price and trouble.
   The part that appeals to me about this smc variant is that it is a torque producer over all of the others apparently, and that always works well in a street driven car...  Thanks - Randy

365

General Discussion / Re: 400 block...

« on: October 09, 2008, 11:22:42 AM »

HR...

  Thanks for your info - great to know it doesn't take much because I'm basically pretty cheap and that sort of fits my budget well right now.
   Good warning about the #7 cylinder area though and I'll pay special attention to that spot when I take a look at the block. Does the cylinder crack in the bottom web area with overheating or anywhere else particular as far as you know? That's obviously the problem with any old engine as they could have had anything done to them and how would one know? I met a guy yesterday who will let me throw it in his hot tank for a few days and let it sit so I can really get a good look at the block cleaned up before I spend any money and time on it...
  I was hopeful that a set of vortec -type heads (possibly aluminum) and Air Gap manifold with a 750 Holley I have might work to continue with the cheapness theme and it sounds like it might and still make good power. I have always heard warnings about the cooling of these and it sounded like the steam holes always fixed the problem - but would you consider with the holes drilled it would be a match for any done up 350 or 383 when it comes to cooling issues or is it still a different animal on its own with the siamesed bores?
   Thanks for your input... - Randy

366

General Discussion / 400 block...

« on: October 07, 2008, 06:12:28 AM »

Hi all:
  I've got a chance to pick up a 400 block (a #509 casting but I still have to confirm that) which I'm told is a 2 bolt version and out of a '72 pickup truck for my '68.
   Can anyone share their impressions as to how good a street engine this could be made into with a bore clean up and new pistons /heads and whether it could be a good purchase for that intended useage - assuming it checks out OK?.
  In a first quick look it appeared to have some cylinder ridge but decent bores which means it probably would end up as a 406 - but would this be a good candidate for splayed main caps / roller cam and decent heads to expect a reasonable 425hp - 450 ft lb  street engine to replace my 302 which resides on an engine stand now anyway. Does the 400+ small block version really require 5.7" rods to make it work better or will the stock rotating assembly, assuming it checks out OK, cut it?
   Can a 400 block be easily (and reasonably cheaply) built up to be as good or better than a 383 stroker using the many kits available for both of them or should I pass on it and jusy look for a good 350 4 bold block and do the same 383 thing as everyone else these days.
  The going price for me is in the $150 - $200 range and if anyone has input and experience as to which small block variant works better operation and cost-wise for a somewhat hot street engine I would appreciate hearing the feedback. - Randy

367

Originality / Re: 1968 z28 distributor

« on: September 17, 2008, 09:14:36 PM »

Anyone have an idea when the 68 Z28 distrib. changed from the  1111266 to the 1111467 piece?Thanks I am thinking mid January but not sure

My mid Dec cast, late Dec assembled block, manifold, and heads came in conjunction with a July stamped 266 unit which was apparently normal for what then was considered early production '68 Z's so any left over or unused 266's from late '67 production runs were still being used to that point - Randy 

368

Maintenance / Re: Surging...

« on: August 20, 2008, 09:20:40 PM »

Thanks Rich
  - No heat riser in the works and the order in my mind originally was to do the easy and less complicated stuff first to try and weed out the issues and your list and the advice from everyone pretty much correspond to my thinking. Actually I originally posted to see if there were any less obvious but yet easy things that I might be overlooking before I charged into it.

    By the way, one thing I meant to ask originally was do you or anyone else here know where I can get a Sun Super Tach II (a sort of day 2 or somehwhat period correct tach for the car) checked over and rebuilt if necessary? The needle on mine jumps around lots for some reason now and it is first on my list to disconnect before I chase fuel problems on the slim chance it may have some bearing on the surging problem as well. I figure that's a real slim chance but regardless I would like to get it reconditioned to settle it down. It doesn't have the box that I have heard some have attached to them as far as I can tell - appears to just be a straight wire hook-up to the coil and ground. Thanks again...
                                                                                Randy

369

Maintenance / Re: Surging...

« on: August 20, 2008, 01:22:39 PM »

I appreciate all of the input - I will try and get some time on the weekend to see what I can discover using the suggestions given... somewhat in the order of importance and ease. Thanks to you all again - Randy

370

Maintenance / Re: Surging...

« on: August 20, 2008, 03:59:12 AM »

Referring to Page D of the Diagnosis, Testing, Troubleshooting Section of the Glenn Mitchell, Inc. National Service Data TUNE-UP MANUAL for all U.S. manufactured cars between 1961-1969:  for a surging enigne that has reached operating temperatures; i.e. a "hot" engine,  the following (in the order show) are listed as the items to check:

A.  Carburetor is adjusted too lean
B.  Fuel pump issue - low flow or pressure
C.  Carburetor float level adjustment is incorrect
D.  Dirty or Obstructed fuel passages in the main metering circuit of the carb.

 Rich:

  When it is stated 'carb is adjusted too lean' does that just mean that the metering block adjustments are so - or is it referring to the main jets themselves? Obviously I haven't played with the jetting both main or idle circuit systems since I rebuilt the carb a few years back and it has always run pretty good and actually gets decent mileage if you keep the foot out of it and stay on the primaries.
  I did consider the fuel pump - but it's only got a couple thou on it since new and I was more inclinded to worry about the filters upstream initially and thinking that they might be starving the rest and therefore be the problem.

                                                                                                                                   Randy

371

Maintenance / Re: Surging...

« on: August 19, 2008, 09:08:10 PM »

I zapped myself offline before I finished the last part - The car hasn't backfired for years and doesn't run rich at all even with this new surging issue - so I doubt that the power valve is bad. I thought that surging is ususally a symptom of a lean condition if I recall correctly.
If my little vacuum port plug was in fact leaking due to the small crack in it, would or could that small amount cause it to suck enough air if it was jetted close to possibly get it into the lean spectrum of operation? Opinions? - Thanks - Randy

372

Maintenance / Re: Surging...

« on: August 19, 2008, 09:02:19 PM »

I removed the choke altogether years ago and plugged the holes in the body - it was a pian always ending up partially closed at some point and I just removed it rather than fighting with it or trying to wire it open. I have thought about the metering blocks as I had trouble with varnish or a small particle of something stuck in there a few years back and after fighting with it and finally dislodging whatever it was the difference was amazing in the smoothness and operation of the carb. The gas I stored it with this winter is the avaition fuel I mentioned which according to the guy who distributes it to our local airports and private operators, contains a certain staliizer compound so it won't varnish up in the carbs of planes on floats that sit unused over the winters here - so I'm assuming it shouldn't be varnish. The one thing I'm not sureabout is if it is hard on the rubber or viton needle and seat parts like racing fuels are.

373

Maintenance / Re: Surging...

« on: August 19, 2008, 05:31:06 PM »

  
  Changed the points, Set dwell and timing. Reset float levels( holley 670 Street Avenger), Adjusted mixture w/ vacuum guage. Surge/Jerkiness now gone.

   How old are your ignition system components and what is the condition of the disributor?
   I look forward to other's comments on this subject as well. Others are more qualified for diagnostics than I.
   Footnote: I switched to full manifold vacuum( for vacuum advance) as per John Z's advice.

I am using the 266 distributor from my 302 and it is in perfect condition and has the limiting sleeve for the shortened advance  - threw in a Pertronix Ignitor II a couple of years or so back replacing the points so dwell and adjustments are not applicable here. Aside from points I wondered if the weights might be sticking since the car sits 10 moths of the year - but assumed it wouldnt idle down well if they were doing that.
What's with the full manifold vacuum? - I had heard a bit about it in the past but I must admit I am not quite sure where to obtain it from - right now I am pulling from a port on the front passengers side of the carb approximately 1/2 - 2/3's of the way up the metering block and I suspect that is what is considered ported vacuum. How do I get full - right off the manifiold somehow? And what does it do better than the ported type?
I just went out and looked at the carb and I see that the port that is on the front of the base plate that I had capped (which might be a full vacuum port?) has a very small tear in the end of it it so I will try another one to replace it - could it be that is maybe all it could take - hard to imagine but I will try it anyway...
I haven't yet as I said, tried anything to cure this surging problem and was just hopefull the majority of any and all suggestions posted back would help me cut down on the things I would need to try before I could get it solved.
The full vacuum is interesting but I seem to recall putting the dist canister line on the lower post that I mentioned and I couldn't get the timing to settle down at idle sufficiently to warrant using it. - Thanks for you input - Randy

374

Maintenance / Surging...

« on: August 19, 2008, 12:15:28 PM »

Hope you guys can lead me some here so I don't spend a lot of time wasted...
My '68 suddenly developed a surging or jerkiness when driving and I would like to have some input to where anyone (everyone) thinks I should look for a cure. The car suddenly lately seems to require a lot more cranking over to get it to catch than previously after it sits for a few days and seems a bit rougher until it warms up some. It does still drive normally until I either let it cruise under 2000 rpms at a steady throttle or take my foot off the pedal slightly to decellerate some - then it starts to buck in any gear. It gets progressively worse to the point where I either have to stick in the clutch when approaching a light (much sooner than I would normally) or drop it down a gear or two to get the revs up but it is only a cure until it slows and starts it again.
I'm not lugging it as this occurs between 1200 and 2000 rpm and it never did this previously - just started the other day and seems to be getting a bit worse and somewhat harder to start after it sits for a while (hour or more) where it started great previously in that timeframe. It still idles great and has good pull through the gears.
My thoughts were in some order of importance and effort (a) float level issues which I haven't checked yet (b) carb issues with needle and seats being the prime area to look at after a general clean out (c) I've got a new set of plugs ready to go in (delco R45's) but these characteristics don't really make me believe that they would fix a surging problem (d) changing the inline fuel filters to try and get any type of fuel flow improvements that might bring - but the ones I have in now don't appear to have any crap in them and my tank was lined a few years back and never has shown any junk in the fuel (e) I am runing 100LL aviation fuel and it seems to work great - this is the only thing new to the set up and operation of the car in the past year or two prior to the surging issues lately which appear to be getting slowly worse as I mentioned.
Any ideas as to where I should best aim my efforts so I don't head off on a tangent here. Specs - 350  / 9:75 cr / Holley double pumper 650 / '68 Z28 intake & heads / mild cam 232 - 238 degree @.050" / headers / timing 14 degees initial - 34 total @ 2600 rpm...
Thanks for any comments or suggestions so I don't spend a lot of time endlessly wandering through this...  Randy
   

375

Mild Modifications / Re: '69 "Comfort Grip" steering wheel

« on: July 09, 2008, 02:00:45 PM »

Randy--that's the wheel I'm going to use. There was no Comfort Grip '68 wheel. In fact, I'm picking the stuff up tomorrow! There is no more than an inch difference in depth to the driver if you use the '68 walnut wheel hub, which is not as shallow as the '69 hub. How it will seem once installed in the car remains to be seen....chuckle. I simply like the black wheel better than the walnut '68 wheel. I'm covered up with a hundred other things, but I'll let ya know as soon as I put it on. I'm crossing my fingers that it'll work. 

Thanks for getting back - I'd be curious to know what you think of it when it is installed. I too love the look of the black rim on those wheels verses the wood style - it's too bad someone deosn't choose to reproduce them exactly to the '68 dimensions because I think they could be quite popular and a good alternative to the rosewood or walnut repros if the price was decent. I'm assuming they could be produced for the same or less than the repro wood style ones as the graining and detaiing etc wouldn't be necessary in the black comfort grip type and should make it less problematic to produce.
I'd be interested in hearing of your impressions once it is in place.       Randy