Z Greek

Thanks Peter, I already knew the answer from our correspondence, I just thought others may find it interesting that you can get away with quite a bit of head and or block shaving and not have to resort to cam tower shims as the only way to take up chain slack.

Goodbye. I thought someone may find PETERS answer interesting. Life is too short for your sarcastic BS.

How far do you consider too far, Peter?

Excerpt from posting by TodyD "I might agree ARP might put a stamped part number on an instruction sheet, but common sense tells you these are METRIC and 7/16" is 11mm.... NOT 10! (3/8")" Tony, I have a U20 Datsun Roadster with ARP head studs. These are 10mm studs. The nuts use a 1/2" 12 point socket (not 13, 13mm is slightly larger than 1/2" and was too loose and slipped and rounded off the nuts, sound familiar?!). Never assume anything! I won't argue that Ben has made some mistakes along the way. Some of these mistakes rest squarely on Ben's shoulders, some are from shoddy machine shop work. Without experience to use as a point of reference, it is difficult for a beginner to recognize problems right away. It is also difficult for a novice building his first engine to dictate to the "expert" at the machine shop. Many of us on this site have been fiddling with engines for 30 + years. I started with two-stroke engines off of a "jumping jack" compactor which I put on go-carts when I was 12 or so. The local Wacker dealer would give me boxes full of "take off" engines for me to fool with. I would need a lot more space than this to catalog the mistakes I made with those engines. Then I graduated to a really simple push-rod V6 in a 72 Capri when I was 16. I remember my first look at a babbit bearing after my experience with the roller bearings in the two-strokes I had been fiddling with. What the f$#k is this?? After that I re-built several Chevy V8's. I did not tackle my first OHC engine until I bought my first 2000 Datsun roadster years later. I still remember the "deer in the headlights" look I got from the machinist at the head shop when I told him I wanted all valve stem heights to be set identical. Circa 1983 in Spokane, WA was push-rod engines, PERIOD! I think his reply was something along the lines of 'don't worry son, we know what we're doing. I guess my point is, without confidence, and a point of reference that comes with experience, it is easy to get railroaded by local "experts" at machine shops, and parts suppliers. If one of "seasoned" experts from this forum had been able to drop by Ben's place, and shown him a few things in person, he would not have had a fraction of the problems he has had. I truly think Ben is trying hard to do this right, and wish I lived close enough to drop by and listen to it start up for the first time, that's the best part in my opinion! Cheers Ben, Enjoy the Ride!

Perrrrfect. The only thing he lacks is the "figure 8" lapping pattern, and a mouth full of Betel Nut! Oh, and he's not chanting, "tocheaptapaya, tocheaptapaya."

I like Tony's solution. Wonder where a guy can get a hold of some Betel Nut........................................................

Wow Peter, that thing should really bark. Beautiful!

Your head gasket, depending on what it is made of, will compress to a different thickness than it was in the package. Not sure whether the 1.6 number you are using is before, or after torqued. All that being said, you should have more than enough piston to head clearance. I think you probably did before, also, but without knowing exactly how far out of the hole (negative deck clearance) you had before ( I know you measured with a straight edge, and feeler gauges, but in my opinion, honestly, trying NOT to be a smart ass, that is really not accurate enough), you may never know. When you measure piston deck clearance, you need to be really careful, when the piston is "parked" at tdc, it rocks, and deck clearance changes pretty dramatically, .004-.006 depending on piston to bore clearance. A proper fixture, and a dial indicator are the only accurate way to measure deck clearance that I know of. All that being said, I would be looking real hard at your valve-train. You said in the intro to this post that you had your head milled .080, and have cam tower shims. I am going to make the assumption that you shimmed the cam towers the same amount you milled the head? Next you say a "mild cam". Any reground cam will almost certainly have a smaller than stock base circle. Let's just say for arguments sake, your "mild" cam has a base circle diameter .050 smaller than stock. So now you have your cam .105 further away from your cam followers than it was stock. In order to correct this, your cam followers have to move pretty much straight up. In other words, approximately the same distance taken up on the adjuster end, and at the lash pad. Assuming my assumptions are accurate, you should have lash pads approximately .225 thick. If they are dramatically different than that, you might look really close at your cam followers on either end of the pad, but mostly on the "pivot" side. Look at 'em really closely regardless! Good luck, sorry to hear your having trouble!

In my humble opinion, you are chasing your tail with piston to head interference. Your method of measurement, straight edge, feeler gauges, etc., is not accurate, however, unless you decked the hell out of the block, you should be no-where near interference, especially at idle. I have taken apart a number of stock, running flat top engines, and have seen as much as .014 "out of the hole." Unless my feeble old age eyes are letting me down, I do not see what you are looking at in your picture in the earlier post, when you are referring to interference. The intake valve has a funny grainy appearance to it, but the quench pad looks fine. I would really keep looking. You say you shimmed your cam towers. Did you use thicker lash pads, and carefully reset your rocker geometry? Look carefully at your cam followers, is the cam running off the back of the pad?

Thanks, I was really happy with the way it turned out. I don't know about standard to beat, but it's a pretty good engine. Peter at PMC has told me about some stock engines he has built that made a lot more power than this. 170 whp was my goal, and I would have been happy with 160, so 178 was over the top. My buddies ran their Datsun Roadster with a N/A SR20 in it the same day on the same dyno, and made around 146 whp (and they have podium'd 5 times with that car, including 4 checkers). This same car (the roadster) made over 160 on another local chassis dyno. As we all know, any chassis dyno is only good for relative measurements. I feel back to back runs comparing my engine to the roadster engine was relevant. I run nothing better than pump premium, and 35 degrees total advance. You can see the A/F numbers on the dyno run data. I am going to try some different needles next year to try to get some of that mid-range richness out of it. Last year this engine ran with a welded 3.9 diff., this year I will be running a welded 4.11, so I may try a cam to move the power band up 2-300 rpm. I am building a new car this winter for next season (74 260 I bought for parts last year). The race for next season on my home track was just announced, it will be a 36 hour enduro. Starts at 9pm Friday July 5th, checker drops 9am Sunday the 7th. Should be a blast! I posted a short video of the engine on the run-in stand last summer. Also posted a picture of the car as it sits right now. It's coming along, but July will be here before you know it!

peter, If I lived in Australia, I'd voulanteer to work for you for free. You build the coolest stuff!

I put together a 2.8 last summer that put 178hp to the ground on a brand new Dynojet 24. Very close to stock. Cam is .475 lift, 224 @.050 duration, 109 LCA (Isky "stage 1" street cam, 9.65:1 compression (flat top pistons, P79 with 49.5cc combustion chambers), cast pistons (1mm over), good three angle valve job with seats blended pretty nicely, SU's, stock airbox, pistons all set at exactly .010 "out of the hole", balanced, and a really crummy old header that I pulled off of a car at the local pull and save (I used the header mostly to save weight compared to cast manifold, I doubt it gained me anything). I received some great tips from Peter at PMC race engines that I employed, but mostly just lots of attention to detail. I have WAY less than $1,000 into this engine (I'd have to add it up, but probably around $800), and it currently has 45 race hours on it, and going strong. It does not have to be complicated, or expensive. I attached my dyno runs if anyone is interested. All_Runs_Data L28 version 2.0.pdf

Why do you not have any? I have 5) 5-speeds. I keep an eye on the pull and save yard(s) up here. Everytime a Z comes in, I check to see if it has a 5 speed. If it does, I come back with a few basic tools as soon as I can, and 20 minutes, and $50 later, I have another one!

30 sounds way too high, Ben. 15 or so should be fine for an 8mm bolt.

Ben, No problem re-using lash pads. It sounds like you are going with a stock cam? Look carefully at where the rocker tip interfaces with the lash pad, this is the only wear surface on a lash pad. You should be able to see where it has run, but definitely not be able to feel anything. If there is a wear pattern you can feel, toss that lash pad. I have a bin full of stock lash pads, I would be glad to pick out a dozen good ones and send to you. As long as your machine shop did not sink your valves into the head, or otherwise leave the installed height all over the place, you will be fine. Get some layout blue (or a black felt tip works in a pinch) and see how wipe looks. They should be pretty close to centered on the cam follower (or rocker, whatever your terminology is). In all likelihood, the pattern will be fine since you did not change the base circle of the cam. If you see something you don't like the looks of send me a picture, and/or give me a call. Good luck! AK