pparaska

John, Terry: Yes, the for/aft rock concerns me. I'll pull one of the rod/pistons (they are pressed pin, BTW) and take it to the machine shop to have it pressed apart and have them measure the pin/pin-bore clearance. Grumpy - thanks for the great post! If I got to 0.035" of quench clearance, should I use the AVERAGE of the two quench area (edge of piston nearest the lifter valley) deck heights I get by rocking the piston back and forth OR use the highest measured deck height? For instance, when measuring the deck height at the top of the piston's edge nearest the lifter valley, it is either -0.004" with the piston rocked down at the top (valley) or +0.022" with the piston rocked up at the top. Should I use the AVERAGE (-0.004" + 0.022)/2= 0.009" OR the HIGHEST (+0.022") when calculating the piston-to-head clearance? Using the AVERAGE deck height means I need a 0.044" thick gasket. I could use the 0.051" gasket here, I suppose. The 0.041" gasket would seem to thin, giving a clearance of 0.032"? I would probably just get a 0.043" Pro Copper Gasket from SCE for that deck, and have a 0.034" piston-to-head clearance. OR: Using the MAX deck height (piston rocked so it is as close as it can be at the quench area) of +0.022" (above deck), then I'd have to add 0.035" to that. I could get a 0.062" Pro Copper SCE gasket for here and have a 0.040" clearance. The probe pistons (the builder bought them) DON'T have the D-shaped dish, unfortunately. The raised flat rim around the piston edge is about 3/8" wide. But there's area inside of that in the quench area that is over 0.1" lower (part of the dished area). So quench is probably not possible anyway. What do you think?

Close, but I'm looking at piston-to-head clearance. That's a good post though!

To measure deck height, I use a magnetic base and dial indicator, and find TDC by tapping the piston down on the way up to TDC from both directions using a rubber mallet in the center of the piston (make sure to watch at the edge for the rod bearing bouncing off the crank - I tap it down just enough to take up the clearance.) Do this from both directions to about 0.020" below TDC, record degree wheel readings, split difference, move to that degree reading. Then I use the bridge and dial indicator to measure the front and rear (above the pin) near the piston edge. For/Aft deck height measurement (front and rear edges of piston): Rear (towards flywheel end of crank): I rock the piston about the for/aft direction (yes, the pin allows this to happen) by tapping the piston down at the rear, measuring for max reading at the front, then move the bridge to where I was just tapping (the rear) and measure the height relative to the deck next to it - that's the minimimum or lowest deck height for that position around the piston. Then I tap the opposite diametrical position on the edge of the piston (the front) to get the highest reading with the bridge, and record that. Front: Move the bridge/indicator to the diametrically opposed position at the (front) edge of the piston and record the deck height there which will be the minimum or furthest down. I know that just-tapped area is at it's lowest, so I record that as the minimum. Tap at the rear of the piston, and record the max registered on the dial indicator (highest). Deck Height near valley and near block outer edge: Repeat the above, but measure at the piston edge near the lifter valley, rocking piston both ways, and then measure near the block outer edge, rocking piston both ways. Need some advice on which values to use from above method!: O.k. So I did the above method on my 400 SB Chevy today. This engine has the Probe SRS forged pistons, and they were fitted to the minimum recommended NA piston-to-bore dimension of 0.002" (yes, that's tight for a forged piston, I know, but it's the bottom of the recommended spec that Probe has for them!) These are short pistons, for a 6" rod (1.125" compression height) and the skirts are fairly short too. What I found was A LOT of piston rock (in my opinion) for such a tight piston-to-wall clearance: Typical readings: (this is cylinder #2, highest recorded heights on even bank) Outside of block: Min: -0.002" Max: +0.023" (- is below deck, + is above) Valley side: Min: -0.004" Max: +0.022" Toward front: Min: +0.002" Max: +0.019" Toward rear: Min: +0.002" Max: +0.019" Yeah, the machinist went nuts decking the block, huh!? I was really surprised I could rock the piston for aft that much too! I don't know the pin-bore clearance (I didn't assemble the shortblock), but they are the pins the pistons came with. Anyway, I'm trying to figure out what gasket thickness to use. This is a 5140 I-beam steel rod (600grams each) engine, Scat Cast 9000 crank, and the pistons are fairly light (552 grams with pin). Redline will be 6500 rpm, peak power around 5800rpm (DesktopDyno2000 estimate) - the cam is pretty tame. I've read about people going with high 20s to low 30s for piston-to-head clearance, and think this would be possible in this instance, considering the light parts, steel rods and lower rpm. Am I correct? What concerns me is piston rock at TDC. With a deck height variation from -0.004" to 0.022" (range of 0.026", average of 0.009") at the quench side of the head near the cylinder wall, what number should be used to calculate the piston-to-head clearance? If I use the conservative maximum height of +0.022" (above the deck), and shoot for a piston-to-head clearance as low as 0.030", that'd mean I'd need a 0.052" gasket. I have a Fel-Pro PN 1044 which is 0.051" thick. Would that be o.k.? Obviously, if I go less conservative in my choice of what deck height to use, I could use the average at the valley : +0.009". For that a 0.039" gasket would work (PN 1014 - have that one too), to get a 0.030" piston-to-head clearance at the quench area. The other deck (odd number cylinders) has minimum deck heights at the valley side from +0.009" to +0.011", and maximums from +0.025 to +0.027". Averages go from +0.017" to +0.019" The machinist must have been further into his 6-pack at this point! So, for this deck, the conservative choice of using the max number (+0.027") would mean a 0.033" piston-to-head clearance would be obtained with a +0.060" gasket. Using the largest average deck height (+0.011"), a 0.030" piston-to-head clearance would result from using a 0.041" gasket (PN 1034). Or I could just use a 0.039" gasket and have a 0.028" clearance. Any advice (beyond throttling the machinist ) is appreciated!

The 406 should be in and hopefully sorted by the convention. I'm at the cam install and vavle install stage and hope to have the long block ready in a week - hopefully pull the 327 at that time and swap the oilpan,intake,flywheel,etc. over to the 406 and do a direct replacement then. Yeah, the old 1-5/8 block huggers, corvette oilpan will have to do for a while. Thanks for the offer of help - I'll let you know if I do! Looking forward to that ride in the quicksilver!

Comp Cams tech line (I know, I know) says that Ford ran one of the polymer gears on a distributor in a crate motor they were designing for a simulated 100,000 miles and it showed no appreciable wear. BTW, CVproducts.com sells the gear for about $90: http://www.cvproducts.com/cv/products/SpecItem.aspx?prodID=24003&keyword=12200&brandID=

Cool - you need to stop by and give me a ride!!! My Z is down for the count (327 making nasty valvetrain noises, 406 being assembled) and I need a fix!!!

When I first bought this manifold, the idea was to put the injectors in the runners under the lid (well as much as possible). I like the idea of sticking them in the valley under the manifold also - I don't know how long they'd live there - even if you shielded them from the hot oil bath... Yeah, the plan at that point was to get two 600 cfm Holley carbs and just use them as air doors. Then I decided to just use TBIs and maybe take a advantage of the heat of evaporation of the fuel in the plenum. I dunno if that will have any effect, but once the fuel comes out of the TBI injectors, it collects on the throttle plates and gets sheared off under them. Still droplets at that point, so you might get some mixture cooling if the fuel was to turn to vapor in the plenum. The Hilborn is what I ultimately want - the best throttle response, and great midrange and top end. Plus the "not just another 4bbl on a manifold" impact. The idea is to build 5 sides of a airbox on the injector manifold, using the hood as the top 6th side of the rectangular box. Then vent that to either the cowl with a filter setup in the cowl area, or run tubing forward infront of the radiator with filter(s) there. Pop the hood and you see the injectors and short stacks. I have a set of these that will fit once I cut them down just a bit: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4559227973&category=6755&sspagename=WDVW I'll cut them at an angle on the bottom so they don't interfere with each other. Hopefully that won't hose up the flow properties.

Yes. The Hilborn is at a friend's place now to be converted. He has a machine shop, so it'll be easier for him to do than me. Problem is that he moves a bit slow. Recently I've had a noise from the 327 that I haven't been able to trace. Sounds like valvetrain. I found 3 pushrods with broken off ends (pressed end 3-piece type junk). Replaced all the pushrods, but the noise is still there. The outer springs look o.k., as do the retainers, locks, the valves don't stick. It might be bad inners (I doubt it), a slightly wiped cam, the gear drive (likely), or who knows what. I may take the time to swap a timing chain set onto the engine to see if that's it, but I'm now working on making my 406 shortblock into a longblock to be able to swap it in soon, so I've about given up on the oil burning 327 for now. The upshot is that now I'm moving on getting the 406 in and sorted so that I can have it at Watkins Glen in mid-August for the ZCCA convention. I think I can make it... For induction on the 406, I'll put the Holley Dual plane (PN300-36) with the 700cfm tbi that are on the 327 on the 406 first. I can swap the 65 lb/hr injectors out for 85s that I have that should feed it fine, but the flow probably won't be there to serve the 406 anyway. I have an intermediate intake setup that should feed the fuel and air adequately. I just need to make some adapters for the throttle bodies and linkage, and a few wiring changes. It's an Offenhauser copy of the 69 Z/28 Cross Ram manifold: http://www.camaros.org/crossram.shtml And I have 2 Holley 670 cfm 2bbl throttle bodies to put in place of the 2 4bbl carbs. They have 85 lb/hr injectors in them. They flow about 570cfm at 1.5Hg, which is how carbs are rated, instead of the 3"Hg that the 670cfm is rated by. That should be plenty of flow and fuel for the 406, not to mention looking a bit different than the typical single 4 bbl carb under the hood! The large plenum and large, long runners in the Offenhauser manifold ought to provide great midrange on the 406. Mixture distribution may be a problem, as it was for the original Z/28 designs with 2 carbs, but the Offenhauser manifold is a copy of the final design of the GM cross ram where they had worked out most of the mixture issues. Putting TBI's on maychange that a bit, but it may help also. The two 2" throttle plates line up almost perfectly with the smaller 4150 opening(s) in the dual 4bbl top plate for the Offenhauser manifold, if you turn them 45 degrees. Holley makes an adapter to put the large 2bbl TBI on a 4150 manifold, but it tapers the opening down going from the 2bbl to the 4bbl, since they keep the throttle shaft angles the same. I've eyeballed it and it looks like some thin (3/8") AL plates with the 4bbl bolt pattern, held down with flathead bolts into the manifold top, and nut-serts for the 3 (on each TBI) bolts to hold the TBI down will do it. I mocked this up on the 327 while the intake was off a few weeks ago and there's about 6" from the forward edge of the forward carb mounting pad to the hood. The TBI body is very short, about 2". I should have room for two drop base 10" or 11" air filters on top of the TBIs and still clear the hood. I hope to plumb cool air to these. I'll just use the TPS, MAT, and IAC off of one TBIs to send to the the MegaSquirt, and have one of the injectors on one TBI connected in parallel with one on the other TBI, and likewise for the other pair of injectors, and then run alternating squirts like I am now. The Hilborn, that probably won't happen for quite a while - all depends on when I get it back!

Just dropping a note - another Z on MS. The Pro-Jection 4D computer is in the tirewell as a backup . Nothing special - Just running fuel with V3.000 code at the moment - plan to run EDIS with MSnS-E in the future. MS Success Story: http://msefi.com/viewtopic.php?t=9411

Mike, any further thoughts or progress on this?

I'd think those numbers are like the jersey numbers of the great ball players - not to be reused. I have a difficult time taking mine off the road for anything. It needs work on the fuel system, the engine replaced with the 406, etc. But it's alot more fun to drive than work on after 11 years off and on of working on it! Hopefully you'll keep it mostly OFF the jackstands

The issue is that with ZERO driveshaft u-joint angles, the rollers in the u-joint cups don't roll, and you get a brinnelling of the u-joint cross. Not good. You want a little bit of angle, which is not so hard to do since it starts out so large with a JTR install and the R200 in the stock location (no mods to the mounting or it). http://alteredz.com/drivelinemods.html

Vinh - I have a correction to your history. The last of the six Daytona Cobra kitted cars that Paul (Dung Duong) sold to a gentelman in MD/VA is different than the one that guy I've emailed you about has. Glenn McCoy (gmccoy383 here on HybridZ) has yet another Daytona Cobra kitted Z, that he installed the body kit on himself, after all the others were built by Tom Nalle. Tom gave him the last kit as payment for some of his labor on the kitted Daytona Cobras. So that 6th Daytona Cobra that Paul had still is out there somewhere. Glenn actually owned a company back in the 80s that another Glenn here worked at (he sold my the 280ZX side marker lights on my 240Z). Anyway, the name of the company was Accessories, LTD. and it was in the Annapolis Maryland area. Glenn installed several of the Nalle body kits onto Z's for Tom Nalle. Tom then either did or had done the final body work and paint before he sold them to customers (some of them are most likely the people that Paul bought them from). Glenn and I are very interested in meeting with you on your trip south. Glenn's Daytona Cobra is having fueling problems (crap in the tank) and he doesn't feel like driving it out to my place in Laurel. He lives on Kent Island, about 30 minutes from I-95 if you're headed through the area that way. But let Glenn set up when and where to meet. He's a computer newbie and is wondering about how to post his first message here - but has read this thread and we were talking about it today. I guess this will be the first thread he (Glenn) posts to! (Glenn, just get your son Alex to help you learn how to post (it's easy) - he's the young computer whiz Valedictorian anyway - might as well use that talent! ). Cheers, Pete

Sweet! You'll have to leave the JackStandRacing guys though .

Way to Go!

I'd look to see if you have enough retainer to valve guide clearance. If you have Vortec heads and they didn't have the guides shortened, the non-Vortec retainer or the lift of your cam could easily make the retainer hit the guide and cause a bind. But I'd think that would show up on more than just one rocker and maybe bend a pushrod or 8 as well.

Understood. Sorry to mess up a happy thread with my whining.

Other than what's been listed as causes, what about valve float? It can play havoc with OE type rockers. Check the spring pressure maybe?

Awesome! :hail: That looks like a a jet coming off a carrier catapult! Personally, I'd get bored running 1/8th mile. But if it's close and good for tuning, what the hey! Luckily I have 2 1/4 mile strips within a 1/2 hour of where I live.

You're on the right track, and jt1 has some very good points too. I'd do the following, before getting into the V8 swap: Make sure it's structurally sound for your application. If it has visible and hidden rust in the structural areas of the frame rails, inner and outer rocker panels, etc., don't do the V8. The Z body is a bit of a flexi-flyer, and when these areas rust (or other areas in the load path from the suspension to the other end of the car), you don't want to make it a higher performance vehicle. Ditch it and get a rust free body from the Southwest USA or something. Consider weld-in subframe connectors. They can make a rusty-floored Z a bit stiffer, and if there's any rocker panel rust, can help replace some of that missing stiffness to the chassis. Consider a well designed roll bar/cage. This depends on what you want to do with the car. Do a lot of searching in the chassis forum before you do anything. Get it reliable: Make SURE the fuel system is ready for daily driving. That means probably removing the tank, having it cleaned, if it's been sitting a lot. Some people have done away with the stock hoses and expansion tank in the right sail panel area, and just use the top rear fitting on the tank as the vent line to the filler tube. Plug off the other vent fittings to the tank (top front, and one near the muffler area). Getting all those hoses out of the interior will pay dividends and not hurt how the car runs. Replace the rubber hoses in the lines from the tank to the engine, if they are old. Maybe the electric fuel pump too, if there's one at the tank (probably not on a stock 71) Replace all rubber fuel hoses in the engine compartment if they are original or in bad shape. (An old car can cause you a ton of trouble in the fuel system if it's been sitting. Take care of this first.) Get any Electrical System Issues worked out. Get the Brake System in good working order, and consider upgrades now if you're going to be doing track days, etc. This can mean rebuilding the stock brake system if it needs maintenance, new rotors, rebuilt calipers, high performance brake pads, shoes; rebuilt or new wheel cylinders. Rebuilt or new Master cylinder. Hopefully the brake booster still works. Inspect the operation of the distribution block below the master cylinder. Or get a 280ZX master cylinder and talk to RossC or others that have brake kits. This is not cheap, but if you plan on having a bunch of power in the V8 and drive it hard, do it now if the brakes are in rough shape. Suspension: Replace all the bushings with Urethane, replace the steering coupler with urethane or nylon part, REPLACE THE STEERING RACK BUSHINGS WITH AFTERMARKET ONES THAT HOLD THE RACK TIGHT. If you intend to do track days, or need inboard clearance for wide wheels you plan on using, look into a coilover setup. You can do this fairly cheaply these days. Do a lot of searching here on the suspension forum for how to do the coilover swap and consider how to lower the car and keep bump travel - either section the struts or use a shorter strut top mount. Match any aftermarket strut cartridge replacements to your uses and whether you section the struts, and to the spring rates you choose. After all of that, you'll have a reliable car with a chassis, suspension, and brakes ready for daily driving and hopefully ready for the level of power you intend to add with a V8 (this can vary from 200hp to the-sky-is-the-limit) and the use you intend for the car. The V8 swap should be done only after you've done all of the above, IMO.

Yes. I have a V2.2 Megasquirt computer (not running it yet) that I hope to hook to the Pro-Jection 4D harness in the car now, during this week. I plan on going to MSnS-Extra to add EDIS later. I have a 36-1 tooth sprocket to mount on the crank, and all the EDIS-8 stuff from a 4.6L engine (bought from boostengineering.com for about $160 used). After MS2 is released and the codebase moves toward the MSnS-Extra code, I may move to that. Yeah, the HEI is going by the wayside. I'm REALLY tired of burned through rotors, irrepeatable mechanical advance, etc. The MSnS-E with EDIS will give me distributorless ignition cheap and fairly easy. Ford parts to run a Chevy Engine! What a mongrel!!! Yeah, whatever works - the parts don't know what engine they came from . Plus, that HEI won't fit with the Hilborn

You are so right. Guess I'm just lazy hoping that someone will do it for me. I can see this as a project for next winter....

MikeJTR, have you given this any more thought? We still don't have a solution for long tube headers from what I can tell.

FWIW, I ran a Moroso 14x3" drop-base air cleaner with a Holley 4bbl on a Holley hi-rise intake PN 300-36, (copy of the 70 Z-28 hi-rise) on my 327, WITHOUT the 1/2" spacers between the crossmember and frame rails, and had 1/2" clearance between the hood and air cleaner. I didn't use the spacers, as I need to keep the front of the engine/trans up as high as possible for equal front and rear driveshaft u-joint angles in the vertical plane (see my drivelinemods page on my site for mor info).

What we have here is a failure to communicate . The issue with the S&S 28-34 Ford header is NOT only the collector height, it's the height from the bottom of the bolting holes on the head flange to the bottom of the primaries right after they bend back towards the collector. For me to consider their headers for this application, that is just one of the things that would need to be changed (the length of the vertical part of the primaries). But that's not all. Of the ones I've seen or heard off (Mikelly's, jcb3's, Jim M.'s), they are not all made the same shape. They interfere at different places on different cars that use the same mounting setup (JTR), in the lateral direction. My guess is that their jig is not good enough to really hold the tubing shapes as tightly as we need. Well, I'm not too sure about that. Some members here have seen the S&S header we're discussing and they are REALLY thin, nothing like 16 gage, more like 18 or 20. And this is in a non-bent area, so it's not that they got thin at the bend or anything.