254 replies to this topic

[CrashKnott]

pull the #3 plug wire at the plug, find a bolt approx the same diameter as spark plug to plug into wire (hanging out of the end of the boot), hold near ground then fire over the engine to check for spark...make sure you're getting spark to the plug before you get too concerned.

[OOBER]

Well, figured out why the truck wasn't happy

It definitely has spark to that cylinder, I felt it all the way down to my toes.









It doesn't look like there was any other damage besides the broken stud.

What would cause this? Over-torque?

Anybody recognize the brand? They don't have any markings.

[mtubenzie]

Does it have a rev-limiter? If not it could have stretched the rocker studs and eventually broke them. Without having any markings, they are probably cheaper grade. My old man seems to think its poor quality studs. He's been round a few motors in his day and is a machinist.

[CrashKnott]

likely over-torque. Rocker bolts and head bolts are the same...torque to yield, and only once ever. You torque 'em down in the wrong pattern, toss em all and buy a new set. This failure may have been a re-used bolt, or one that was just over-yielded.

I'd suspect them all and replace the set.

[OOBER]

This is the latest from Pirate.

Check the retainer to valve guide clearance.
Check the pushrod length, make sure the stud isn't hitting the rocker body.
Possibly the lock and/or screw is being overtightened.
How much thread engagement does the polylock have? The studs could be too short.
What RPM did you run and how much lift does the cam have?

The rocker body has some slight witness marks but they are on the wrong side if the pushrod were too long. I'm sure they had something to do with the rocker dismounting from the stud.

I couldn't get the adjuster nut out of the polylock, I was on the verge of breaking my allen wrench in half.

Found a spec that the effective stud length on the 7/16" studs is 1.900". The remaining stud on mine is 1.555" which would give me approx .345" of engagement. Seems like in a perfect world it could use more engagement but the issue wasn't thread holding, it was that the bolt broke which would happen no matter how long the bolt is right?

You gotta give me some slack though, I didn't even know what a polylock was until this morning :flipoff2:

I personally haven't had it over ~4K RPM before that, who knows...

Cam Specs:
Howards Mechanical Roller Cam
Max Torque
121153-10
Valve lift with 1.7 Rockers: 0.660 0.675
Duration in Degrees Advertised: 285 290
Duration in Degrees @.050": 248 255
Lobe Separation Angle: 110
Valve lash: 0.020 0.020
98631
Mechanical Roller Tappet 2500-6700 Good mid-range horsepower, rough idle. Needs 11.0:1 CR-up

That rocker possibly was a result of all the fuel you were dumping into the cylinder when it was not firing. Maybe it hydro locked and that was the weakest link:confused: Also was this motor fired on a dyno and broke in? Or has its only run time since built been with misfires etc?

I was told it was ran on an engine dyno and made 550+hp. For how long, I have no idea.

Not sure how long it had been running rough before I got it, but it has never ran right since I have had it. I haven't driven it more than probably 10 miles the entire time I have owned it.

There were quite a few issues leading to it being run with misfires etc. such as the 2 burnt plug wires, 3 broken plug ceramics, bad coil, fubar'ed distributor cap, and the MIA rocker.

[rennat_2006]

My 77 k10 had a dead hole when i bought it and i found similar to the same as you Oober, Mine had just backed off and fallen off though.

As far as carbs...I prefer edelbrock offroad, I have had multiple edelbrocks and multiple holleys. For performance a Holley cant be beat but for set it once and forget it Edelbrock takes the win by far. I had a Holley 750 non double pumper on my 77 k10 for a little while, It ran absolutely great on flat ground but was constantly flooding out wheeling because of the angles, Before somebody asks YES the floats were adjusted correctly and YES i know how to setup carbs. The truck avenger or whatever their offroad carb is may be better offroad than my conventional was but i have no expirence with them. I took the holley off and installed a 1406 Edelbrock(600cfm) and it could easily take twice the angle that the holley could, I think it has something to do with how the floats are setup, Center hung or whatever it is called on the edelbrocks and on outsides of the holleys.

Another thing to consider on choosing a carb, I have been told that mechanical secondary carbs need to be on a light weight vehicle or if it is on something heavy(like your truck in this case) it needs to be a manual transmission or have a high stall converter. I didnt see anything about what stall is behind that motor but im going to assume it is 3000 or so.

As far as a carb with no choke, I havent hooked the choke up on my 71 nova with a built 327 on either the 600 holley DP or the Edelbrock 600 that is on it now and it will start well below freezing temperatures. You just have to pump the throttle a few times then sit there for a few minutes holding it around 2000 rpms before it will idle on its own.

That is the same intake manifold i have on my Nova and i dont know how good it is going to be for offroading since it is a higher rpm manifold.

[OOBER]

IT MOVED!!

I finally manned up and just put the freakin rocker on. I read all kinds of manuals and specs on how to do it, but when I was looking at all of the other rocker arms, they were all pretty loose. So I simply took the rocker and set it to the same loose-ness as the others until I have it dyno tuned or looked at by a shop.

Runs like a scalded dog when you get it over 3k rpm and the tranny shifts like a dream :smokin:

Under that rpm it isn't too peppy but I feel like this engine isn't really set up for this big heavy mo'fo. I can't even imagine what it would feel like in a car





Got the tailgate put on with some help from LMC Truck. I haven't figured out if it is a good or a bad thing that their warehouse is only 10 minutes from my house :evil:


Long tubes get HOT, this is a pic of the dynomat melting on the pass side floorboard. I temp'ed the floorboard about 5 min after I shut it off and it was still at ~175*


NEXT:
Load it up with mulch and do some gardening
Fix leaks
Fix more leaks :shaking:
Put disks in the rear with my new RuffStuff brackets
Pick a color that I am going to start painting stuff so it is all at least the same color.
E-fans with a controller

[cknaffle]

She's got a little gangsta' lean going on.

That's be a sharp truck when you get it all painted. What colors are you considering?

[CrashKnott]

She's got a little gangsta' lean going on.

That's be a sharp truck when you get it all painted. What colors are you considering?

I bet she don't lean after OOB's sittin in it


You gotta keep it Blue since you already named her and all.

Lookin good dood, and I love that body style!!

[OOBER]

She's got a little gangsta' lean going on.

That's be a sharp truck when you get it all painted. What colors are you considering?

Yea haven't figured that one out yet. I need to do some measurements and see if it is the body that is leaning or the suspension.


My color choices are blue, blue, or blue. I want to find something in a rattle can that comes close to what is blue already so I can paint the doors/tailgate to somewhat match.

[OOBER]

Random unrelated trailer tech.

My FIL has been working on rebuilding this old trailer. He built a nice fold down gate on it, but it ended up being too heavy for anybody other than him or myself to lift.

We looked at some coil springs like they put on gooseneck ramps, but I remembered seeing a setup like below on the little flatbed U-haul trailers.

So we drew some pictures and dug through my random offroad parts bin. Bill put it all together himself. When he first finished, the gate didn't even touch the ground. With the washers above the spring, it just lightly comes to a rest on the ground when you let go.

[OOBER]

Spent a good 12 hours on the truck today. Got A LOT done.

Hmm, think it backfired a couple times??


So, while I was removing the old carb I put my hand somewhat lightly on the distributor and knocked it waaay out of time...hold down bolt was loose.....imagine that...:shaking:

So I got the timing close enough to start with the new carb and but you could tell something was missing. Hit the headers with the temp gun and sure enough 1 and 7 aren't firing. Sad thing is, the engine runs/idles smoother on 6 cylinders with the new carb than it did on all 8 with the old carb....

Not sure why 1 and 7 are not firing, but I am about shit full of these Jegs wires. I am going to get a full set of 8mm generic auto parts store wires tomorrow. I already replaced one wire with a generic 8mm wire and the level of quality is waaaay better than the 8.5 "super" Jegs wires...

[OOBER]

mmmmm, disk brakes :smokin:


Lines up and out of the way. Don't want the zombies to get caught on them when I go Chuck Norris their asses :evil:


Note for people installing disks on their 14 bolt. The caliper on the left is a ~75' 4WD front 3/4 ton caliper and the caliper on the right is a ~75' 2WD front 3/4 ton caliper. Everything is the same except for the brake lines/banjo bolts. Keep this in mind when you order your calipers/lines from the store to make sure you get the matching stuff.


The level of dumb in this truck still amazes me


Took the buffer and some rubbing compound to the drivers side. Little better.



Vision of the future??? :evil:

[N2O_ZR2]

Nice choice on the carb, 850cfm?

The Jegs and Summit brand wires are crap, even if that is not your problem getting rid of them is a good idea.

And yes, you will find a lot of stupidity on the old stuff that has had to go through 40 years of idiots. I seen a Chevelle one time with a hole just like that in the center of the roof for someones cb.

Edited by N2O_ZR2, 30 April 2011 - 10:57 PM.

[big94GMC]

The Jegs and Summit brand wires are crap, even if that is not your problem getting rid of them is a good idea.

*cough* *cough* ACDelco wires....

[N2O_ZR2]

The Jegs and Summit brand wires are crap, even if that is not your problem getting rid of them is a good idea.

*cough* *cough* ACDelco wires....

I run the MSD super conductors on the Chevelle, but I'm also running a 6al.

That also may be an upgrade you might want to look into later on, I'm not sure if that HEI can keep up with those rpms as well. And not to mention the HEI is wasting some space.

[OOBER]

Getting this thread up to date since the forum was down for a while.



So I was sitting there polishing wheels with my new powerball and thought to myself "Wow, this is really starting to borderline BDMT....."

Don't worry kids, this thing is ganna be ratardedly awesome in a year or so. Just no tight trails

Before:


After about 45 minutes:


2 wheels done, 2 more to go.

[OOBER]

So, I was having such a good day.

Polished the remaining 2 wheels

Pulled the torched off studs out of the D60



This made the job extra easy:




Pulled all of the plugs and inspected them before I replaced the wires. Found one cracked ceramic and replaced it. They all looked pretty dark so she was running waaay FAT, 1 and 7 actually still had fuel on them.

After I was done with the wires she started on the second kick :grinpimp: but was still running rough, I could tell it wasn't running on all 8. So I pulled the cap and inspected for anything weird. All looked good.

Then I got the "oh shit" feeling and very defeatedly pulled the valve cover off.....







This time the exhaust studs on 1 and 7 popped

WTF

[ReDnekZ]

whoever put that motor together must be a total dumbass. how hard is it to read the proper torque specs, set the damn dial on the wrench, and do it right? Sorry to see you still having problems with that Oob. Hopefuly fixing it solves your 1 and 7 issues

[N2O_ZR2]

This time the exhaust studs on 1 and 7 popped

WTF

Maybe some cheap or bad studs, never seen anything like that with out some other clearance issues going on. Without knowing what it has for studs I'd change all of them.

whoever put that motor together must be a total dumbass. how hard is it to read the proper torque specs, set the damn dial on the wrench, and do it right? Sorry to see you still having problems with that Oob. Hopefuly fixing it solves your 1 and 7 issues

You don't use a torque wrench to lash the valves.