Motor rebuld/refresh/inspeciton advice (Long)

[Guest tony78_280z]

STOCK VALVE SPRINGS: VALVE SPRING PART NUMBER IS 3911068 INSTALLED HEIGHT 1.70" PRESSURE @ INSTALLED HEIGHT IS 80 LBS * PRESSURE WITH VALVE OPEN IS 267 LBS. THESE SPRINGS ARE GOOD FOR .550" LIFT BUT CLEARENCE BETWEEN GUIDE AND RETAINER MUST BE DOUBLE CHECKED BEFORE ATTEMPTING

 

These stock springs are going back into the stock heads they came out of. The heads I ported out to get some better flow. I'll be reassembling them soon. They are not the best heads, but I should be able to hit my goals with them and the cam I am looking at. These are not votecs. And I think vortecs only need seats machined so they can take extreme lifts.

 

 

Hope this clears things a bit.

[A. G. Olphart]

Hi Tony-

 

AFIK, lift is lift, the springs and valves don't much care if it is the result of a .500 inch lobe on your cam using 1:1 rockers, or a .250 lobe using unobtanium 2:1 rockers. Personally, I wouldn't even hunt for 1.7 rockers... that's big block stuff. I bought 1.6s, and have since found that pretty much whatever duration and lift a sane person would choose to use on the street is available for 1.5s.

 

The spring stats you quote are pretty wimpy. They may not bind until .550 lift, but that does not address the RPM they can handle at that lift. It is a really good idea to use the springs specified for the cam you buy. If you use other than the rocker ratio recommended by the cam manufacturer, you may require more spring. (As per above, the valve and spring don't know where the lift came from, they only need to travel the required distances in the time available at the RPM you wish to turn).

 

If you want to run stamped rockers and big lifts (not a great idea from valve guide wear standpoint) you should verify that the rockers have slots long enough to handle the cam/lift you choose.

 

Again, head gasket thickness is dependent on engine clearances. Most anything will fit, but it may not be optimal. The crank seals are not that forgiving- you either have an old style crank with the bigger seal area, or the newer smaller version, which also requires a different flex plate.

 

I was asking about measurements just to verify displacement... a lot of guys have bought 350's that measured out to be 305's. They all look the same.. Does your engine say 5.7 on the bellhousing flange?

 

HTH.

 

Edit: I forgot to mention that running other than stock rocker ratio can require modification of the push rod holes through the heads; all I had to do on mine was elongate the holes (closer to the rocker studs) as Vortecs use rail style rockers. I don't know what all is involved with a guide plate engine... if the plates are cut deep enough for 1.6s or not.

[Guest tony78_280z]

Thanks for the info much to consider

 

Yeah, 5.7 stamped on bellhousing. I'm not folling for that again.

 

I don't plan on pushing more than 6k rpm (probably more like 5.5k). I'm using a eddy performer intake with a stock stall converter the cam I'm looking at is rated for 1500-4200, I'm lookin to run 310hp within the 6k limit. So, you think those springs will be ok for the lift I'm looking at with 1.6s (0.448/0.472) ?

 

I bought 1.6s, and have since found that pretty much whatever duration and lift a sane person would choose to use on the street is available for 1.5s.

What do you mean "is available"

[A. G. Olphart]

Is available: You can buy a cam with the lift built in to it, designed to work with 1.5 rockers.

 

No, I don't think your stock springs will work for any of Crane's Z cams. "UDHarold" (Harold Brookshire, used to own Ultradyne, & designed Comp's HE268 per posts on Chevelles.com) recently designed Holley/Lunati's Voodoo line of cams. He mentioned in passing that cams with similar acceleration rates need similar springs. Logically the bigger cams in a series open farther by holding the rates over more duration; thus it doesn't seem like a good idea to try less spring, even on the smaller cams in a series.

 

I don't see the Z cam you have been looking at- .420/.433 lift. The smallest Z cam that I see listed on Cranes web site is the Z-256-2 (part number 113501) which is 206/218 @.050 with a lift of .432/.459 on 1.5 rockers. That cam, which shows a maximum RPM of 5200RPM/valve float 5800, calls for 114 pounds on the seat (spring pressure with valve closed ), 34 pounds more than your current springs spec out for new.

 

Based on the RPM you want to turn, the Z cam you might be led to consider is the Z-268-2, but it probably likes more compression than I think you have, and although the max useable RPM is more like you want (5800) it wants to cruise at 2600-3000.

 

If you are running about 8.5:1 compression, I'd also consider Lunati's Voodoo 256, part #60101LK (kit). You could possibly even get by with your current springs, but how tired are they?

 

From their web site: http://www.holley.com/types.asp?type=526

_________________________________________________________________

60101LK 256/262 213/219 .454"/.468" 112/108 1000-5500

60101 Description- Hydraulic: Best mild Performance cam. Works excellent in TPI fuel Injection applications. Makes approximately 19" vacuum at idle. Great for Performance oriented marine applications and heavy towing applications. Perfect "Street Rod" cam. Has slightly noticeable idle, works with stock converter, A/C, power brakes and stock valve springs in most cases.

_________________________________________________________________

 

Perhaps some other board members have favorites for (near) stock engines?

 

 

.

[Guest tony78_280z]

Oops, my bad. I was lookin at a different cam when I quoted those lift numbers. I haven't commited to a cam yet. The Z Cam with 1.6s figures out to 0.461 In and .489 ex. Still under the magic number of 0.500 and way under the 0.550 that the springs brag up.

 

If my stock springs are in a similar condition to the rest of the motor, I'd say they are just fine.

 

On that note, I took the time to look at my stock lifters. You know the ones I pulled out randomly and dropped into a baggy. The surface of the lifters was smooth. And the face still looked square to the naked eye. I could notice a bulsey like pattern on the lifter face, but it looked more like the metal was stained than worn. Interesting. But I'm still not comfortable with sanding and reusing.

[Here comes trouble]

Tony ...repair what is needed and get it together and back in the car. If it ain't cracked or broke... I cannot tell what is worn ...That is done with a compression testor and vaccum gauge and then micrometers where I ask for a second opinion. The only thing I can accurately test for wear is the crank bearings with the string off a Plastic Guage. Back in the car that engine will tell you everything!!!!! About hot cars.. I have been to a few cruises and what is really funny are the street cars that can hardly be street driven from being overbuilt and trailered in.

[Guest tony78_280z]

Tony ...repair what is needed and get it together and back in the car. If it ain't cracked or broke... I cannot tell what is worn ...That is done with a compression testor and vaccum gauge and then micrometers where I ask for a second opinion. The only thing I can accurately test for wear is the crank bearings with the string off a Plastic Guage. Back in the car that engine will tell you everything!!!!! About hot cars.. I have been to a few cruises and what is really funny are the street cars that can hardly be street driven from being overbuilt and trailered in.

I like your style!

 

You are probably correct in over inspecting. I wont realy know until I put it in and start it up. I've known people to tell me something would never work, and it continued to work for several years later. to me that is part of the fun. The lifter thing is not in the same catagory because if they don't wear right, and I destroy the cam, I gotta pull off the intake and everything on it, the radiator and front grill and put in a new cam and lifter set. Of course there is allways the while I'm at it syndrome, I could put in a bigger radiator and a lifter valley baffel etc.

[Guest tony78_280z]

 

Which one is Intake and which one is exhast? I'm thining the Intake is the one on the right, but I forgot. Also, what is the difference, and why?

 

Thanks

[A. G. Olphart]

The bigger, thicker one on the left looks like an exhaust valve rotator. Valve is rotated to minimize/ even out seat and valve wear.

 

 

.

[Guest tony78_280z]

Lapped all the valves and then performed a leak test. On the first head all vavles leaked, and only three on the second head leaked. I suppose my technique improved as I went along porting, but it was far worse than I could tell by eye. Now I'm glad I went through the trouble of testing them all, and not just the ones I suspected.

 

So I'm gonna need to get most (if not all) the seats re-cut. At $4.00 a piece that is $64.00 for the lot of them, and $44.00 for just those that leaked.

 

My question is, am I right in assuming that once the seats are recut, the valves that are currently lapped wont seal properly anymore, and I'll need to replace them? If I replace these lapped valves with slightly used ones (I have a spare set from a different motor with same head castings) will these need lapping on the freshly cut seats? Or will I need to replace the valves with new?

[Guest tony78_280z]

Well, no replies on that last post. So.....

 

The Heads are back from the shop. I had all new seats cut and the valves re surfaced as well. $145.00 in machine work, and + $13.00 in grinding stones and my heads are done. This phase is over. Mildly ported stock heads with 64cc (at least 9:1 CR)

 

+150.00 Motor and Heads

+ 13.00 in grinding stones to mildly port the heads

+143.00 in Head Machine work

= 308.00 so far

 

I'm sure that when I move onto the Assembly Phase I'll need to fully understand this valve lash theory. What I know is that one rotates the crank until a particular valve is opened to its greatest peak. (how does one determine the greatest peak without passing it) And adjust the nut so that the lash has no play left. Then give the nut one more full turn. My confusion comes into play with the fact that if they are hydrolic lifters don't they have full extension only under full hydrolic pressure. So Don't I need to run the motor for a length of time (thus pumping up the lifters) before adjusting lash? Or do I adjust for lash, run the motor, then adjust lash again? I know I have a few more phases of my project to figure this out, but it is a question I have been wondering.

 

Onto the next phase..

 

The Cam

 

+85.00 (for those keeping score)

 

I'm expecting delivery on some parts, A Gasket/Seal kit and a Cam. With the mild ported heads, stock torque converter, Dual Plane Performer Intake, 750cfm Carb and 700r4 Tranny: I've settled on this cam...

Intake adv 262 (204), lift 0.42

Exhaust adv 272 (214), lift 0.443

LCA 112

Don't try to talk me out of it, it is already on its way. But I think it is a good choice. It advertises the optimum RPM range is 1500-4000. I feel it is perfect for my mild street build. It has a bit more umph compared to stock, yet only 43 degrees of overlap making it a decent street cam. I hope to hit 300+hp and decent mpg with this cam and my mild head job.

 

It seems like a rather strait forward install. I just put the new cam in where the old one was, right?

Steps

1. TDC #1 with two "markers" aligned.
   
2. Pull the Cam
   
3. install the cam with the markers still aligned
   
4. and I'm good to go.
   

Or am I missing something? My Haynes Manual is vary vague. (insert cam install advice here)

[Guest tony78_280z]

Cam arrived today

 

From SUMMIT, $105 for the cam kit, and engine gasket set.

$308 From above

+ 105

$413 So far

 

And all the big ticket items are purchased. Tomarrow I begin the cam installation, and reassembling the motor.

 

Decent instructions were included with the cam kit.

 

Valve adjustment is a little different than what I had imagined. All lash is taken out just as the lifter begins to rise, not at its highest point.

 

It says that after 100 miles the valves need to be adjusted, again. I assume that after break in the lobes/lifters wear enough to warrant this. Interesting.

 

The instructions also discusses this Hydrolic Lifter Preload.

 

 

in step b. it says "Allow a couple of minutes for the lifter to bleed down after placing initial preload on it." So that implies that in order to perform this step, the motor must be run so that lifters can be filled with oil. So preload checking needs to happen after the break in, while the valves are being readjusted.

 

But what is up with this step anyway? If everything but the cam and lifters is stock, and the heads/block have not been milled, how could there be a problem with the preload? To me, it seems like the preload could only be a problem if radical changes have been done to the valve geometry.

[Guest tony78_280z]

Update:

(I get crazy days off Wed, Thurs & Sat.)

 

305 Came out last Wednesday, 350 was assembled that same day, and was dropped in by Thursday. Saturday I got rained out, so the project is on hold until this coming Wednesday & Thursday. I have minor reinstalls (carb, alternator, thermostat etc) and fluid refills. Biggest obstacles are electric fuel pump install and proper pressure regulation, and the initial cam break in (It's got me nervous, hope I did it all right.) I'm optimistic though! I even updated my webpage to reflect my new motor.

 

I've spent another $100.00 on silly stuff. Fluids, filters, wires, hoses, etc.

 

Cross your fingers for me on Wed & Thrus

[A. G. Olphart]

I hope you've got it right too!

 

Summit did include cam break in lube to butter the lobes and lifter bottoms, didn't they?

 

Have you prelubed the engine? Old school used to put the lifters in a can of oil and work the plungers up and down to fill them with oil... that way the engine would fire right off without a prelube. (Assembly lube kept things slick until the pressure came up, and filling the filter with oil ensured that it was up fairly quickly). During assembly we adjusted the rockers on each cylinder (on its' compression stroke) to take up the lash plus about 1/2 a turn. A few slow revolutions by hand would allow the lifters (which had been fully pumped up, as described above) to "bleed down after placing initial preload on it."

 

Main points (were there any?)--

1)lash is taken out while lifters are on the heel of the cam, not on the lobes.

2)engine should be prelubed. I ground the gears off an old distributor and spin it with an electric drill until the pressure comes up. (A screwdriver like shaft won't work... the dist. housing is needed to seal the system and allow pressure to build).

3)I don't know why pumping up the lifters has fallen into disfavor- it always worked for me.

[Guest tony78_280z]

Thanks for the input.

 

I did lube butter the lobes and lifter bottoms and bearing journals.

1. My research has led me to believe that soaking the lifters in oil is next to worthless. Had I gotten this opinion from you sooner I may have done it anyway.
   
2. Initial valve lash has been set to the best of my knowledge/ability. I'll need to readjust the lash after the break in anyway, and I think I got it set good enough for the break in.
   
3. I have not prelubed the motor via the dizzy yet. I have a spare, but you say I have to grind off the gears? That sounds... dificult. Any other way? I may check the local parts stores and see if they have a tool for rent/loan that will get the job done. How many drill RPMs are needed to replube the motor? I got a cordless that doesn't push alot of power. Or is the purpose here just to simply circulate the oil?

Anything else?

 

Start up and break in is scheduled for Thursday.

Point of interest... The cam that came out of the motor seemed more aggresive than the one I put in. And this simply can not be for a stock cam. I used a piece of string to wrap around the lobes (to get the overall circumference) and compared it to the one I just bought. From my unscientific experiment I could determine that the circumference of the lobes were larger on the other cam. And the cam I took out had a lobe for the fuel pump. 87-92 motor did not have a mechanical fuel pump. This leads me to belive that the cam had been replaced at some point. And this explains the leaking front seal. The dampner wasn't rubbing, the cam/seal/dampner was not installed properly. Not knowing it's exact measurements, I'm sure I'll be happier with the cam I know is right, but I'm kickin myself for not just getting the lifters researfaced (see above) and going with this cam for a bit. I bet this used cam would go into my 305 and liven it up a bit too. Perhaps I'll offer the 305 and this slightly used cam for sale/donation together.

[JMortensen]

Point of interest... The cam that came out of the motor seemed more aggresive than the one I put in. And this simply can not be for a stock cam. I used a piece of string to wrap around the lobes (to get the overall circumference) and compared it to the one I just bought. From my unscientific experiment I could determine that the circumference of the lobes were larger on the other cam. And the cam I took out had a lobe for the fuel pump. 87-92 motor did not have a mechanical fuel pump. This leads me to belive that the cam had been replaced at some point. And this explains the leaking front seal. The dampner wasn't rubbing' date=' the cam/seal/dampner was not installed properly. Not knowing it's exact measurements, I'm sure I'll be happier with the cam I know is right, but I'm kickin myself for not just getting the lifters researfaced (see above) and going with this cam for a bit. I bet this used cam would go into my 305 and liven it up a bit too. Perhaps I'll offer the 305 and this slightly used cam for sale/donation together[/size'].

Sounds like a base circle difference to me. The lift is from the heel of the cam to the top of the cam lobe. A not realistic example: You could start with a cam that was 1" in diameter, and add a lobe that was .5" tall and compare that to a cam that was 10" in diameter and had a lobe that was .1" tall and if you did your string test the 10" diameter cam would look gigantic compared to the .5" lift cam, even though the .5" lift cam actually has 5 times the lift of the .1" lift cam. Easy way to test a cam's lift is to put it in a V block and rotate it while measuring the size of the lobe with a dial indicator. The dial indicator tells you how much tall the lobe is vs the base circle.

 

That's the way it works for L series engines, I would assume its the same on a V8...

[A. G. Olphart]

It isn't just soaking the lifters in oil. A person has to work the lifter plunger up and down until the lifter no longer emits bubbles... The lifter now has oil, not air, inside. Now when the bottom of the lifter is raised by the camshaft, the push rod is also lifted (rather than compressing a pocket of air).

 

Grinding the teeth off the distributor gear isn't difficult, just takes a grinder with a relatively coarse wheel. Have to take the teeth off because they mesh with the cam, and we don't want that during prelube.

 

Since your lifters are dry, the object is to bring some sort of pressure into the system and fill them a bit. You will also fill all the oil galleys, and thus should have almost instantaneous oil pressure for the bearings. I don't know the relationship between lifter plunger travel and cam lobe lift, but if the lifers are dry, you will have way less than nominal valve timing and lift until they normalize.

 

Jon's exaggerated example is a pretty good explanation of how a hot reground cam is made... They cant really stretch the lobes, so they grind a bunch off the back, and make the lobes look taller.

 

A final thought: if you decide to reuse the old cam in your 305, consider resurfacing the lifters as previously discussed. No two blocks are machined in exactly the same manner, so the established wear patterns are no good. It is starting over.

 

 

.

[Guest tony78_280z]

Delays delays...

 

Stress is always in the details... Plumbing changes with the performer intake. That damn oil pump and trying to line it up with the dizzy at TDC. Electric Fuel pump and wiring and filters. Jeesh!!

 

Fired it up for a few seconds today. Timing was off.. other than that I don't know because I had to shut it down!

 

I didn't even get to break in the cam because...

 

The bottom of the balancer/dampner was rubbing on the steering "thingy" that crosses from one side to the other. Pretty orange sparks were flying off where the two touched.

 

I'm sure I'm not the first SBC HybridZer that used the MSA mounts with a larger dampner in a 280z, but I never heard of this one.

 

My 305 has the smaller style dampner on it. So...

[Guest mofaster]

Flat tappet lifters and cam must be replaced together, period. They break in together. Putting the wrong lifters back on the wrong cam lobes can result in excessive metal shavings in your oil pan. These shavings can make their way up into the MAIN BEARINGS which will lead to loss of power, spun bearings and possibly catastrophic engine failure.

[Guest tony78_280z]

There, I figured out how to post pictures so here it is.

SO exciting, and delays are so frustrating. I'm amazed at how many "little things" there are in swapping a 305 and a 350. Almost as much work as from the L28 to the 305. (Not realy, I can't back that up.) Can you spot the orange parts that I reused from the original 305? Can you figure out what I did with my heater hoses and why? Georgia Flash, does that Front float bowl look familiar? How many zip ties can you count? See the bent hood pin? I kind of 'fell in' while putting in the dizzy. Notice the cowl, aka the tools and parts rack?