The PO dumped a 4 bolt main Chebby in this truck (uugghhh no accounting for taste or reliability) so I thought I could run it at least for a season....NOT! Tappet on #8 started to tick. I yanked the manifold figuring it had a collapsed lifter. Popped a new one in along with a new rocker, fulcrum and pushrod. The PO said that cyl. had bent a pushrod on him so he had a "friend" who was a self professed mechanic help him swap out with a new pushrod. I ran it for a few weeks this past summer with a less pronounced tick but, it just got louder and louder. Off with the valve cover, pull that rocker and low and behold I see that the rocker had "walked" to one side of the valve spring. Hard to do when the heads have a small slot for the pushrod passage. Acts as a poor mans pushrod guide. That's when I see it....the rocker had been off kilter so long that it had wore a groove in the rocker stud. No wonder right?
I pressed out the old stud, tap the hole and installed a threaded stud. Shaved the valve stem level again and replaced the rocker again for good measure. Put a less than fifty miles on it and, as luck would have it....it bent the new pushrod. TICK TICK TICK.....dang!! That cam lobe is so wore down that the geometry of the rocker can't keep the proper angle without undo stress on the pushrod. So...it's time to tear it down and install a new cam with lifters. Know a Chebby fan that would want to swap for a FORD engine?
Capt'n

 

I'd go ask Bronc. He'll be at the Hungry Clam for coffee.

 

Hey captn what kind of ferd engine do you want? I've got a 74ish 302 that's half deconstructed in my garage. We had plans but lost interest and if my mom no longer wants a donor, it's only taking up space then.

Came out of a 74 maverick as far as we know. Got it free from a guy who was moving, it sat upside down for years and all the internals still moved freely. It no longer has rods (we kinda lost them) but pretty much everything else is there.

 

I can't get outta the shop to go ask anybody. No hurry though. I'll stuff a cam and lifters in this Chebby so no matter who gets it, it'll be a good reliable performer.
BTW, who's Bronc?
Capt'n

 

Hey Dylan....a 5.0 would be a good base for someone to do a build from but, I'm afraid I need a few more cubes to haul this heavy ole panel around. I ultimately would luv to trade this fresh 5.7 4 bolt main Gen I with a fresh Turbo 400 with shift kit for an equally modded sized Ford (351, FE, 460/429 ?) with a C6 or AOD. The Chebby has an Edelbrock intake & carb. and is dressed in chrome with billet valve covers.


I believe this block was the last of the Gen I series (83) before GM lightened up the casting and started casting them in Mexico.
Capt'n

 

I figured the 5.0 would be a bit weak, just thought I'd offer. It ain't doing any good sitting there.

 

Bob Starr, used to own Starr Storage and the junkyard that used to be next to it. He's been driving one of McKays dump trucks to the mainland and back for something to do in his retirement so he is always at the Clam waiting for the Redeye.

 

Oh....Bob Star.....Yup...know who he is for sure. Thanks!
Capt'n

 

Got the top end of the engine tore down last night but, forgot to take home my gear puller for the crank dampener even though I had the presence of mind to set it out so I wouldn't foget.....DOH....I forgot anyway. Did a little shopping on the interweb and, so far, found that Summit racing has some reasonably price mild cams with lifter set for just over a C note. Ya'll have any suggestions? It still is a flat tappet motor.

 

What's the difference when the top speed on the Rock is a blistering 45?

 

You must be one of the chosen few that actually pay attention to the speed limit around here. I know...I know...it must be the Felix fear factor ( don't bother folks...only an islander would know). Fully understandable.
I have been known, on rare occasions, to actually leave the island and go to America. No seriously....I have witnesses!
Capt'n

 

Well, I did remember this time to take the puller home and yarded out the cam.
Hmmm...the lobes actually don't look that bad. Someone, in the motors history, went to all the trouble of rebuilding a set of 76cc truck heads (gen I) and added a double roller timing chain that still has hardly any deflection (stretch). The engines internals are as clean as the board of health.
The cam is a OEM truck (GMC) cam with the normal wear you'd see after about 40k-60k on it. I suspect whoever did the rebuild didn't bother changing the cam out since it was probably still in spec. but did replace the lifters, timing chain, remanned an earlier set of heads (68-79) and probably turned the crank 0.010 under and slapped new pistons and rings in it.
It still doesn't explain why the exhaust tappet on #7 cyl. likes to walk to one side. I put a straight bar across all the valve stems and the valve stem in question (exh.#7) is now about an 1/8" shorter than the others that are all nut on. I did have to file it down a bit due to the previous damage from the PO and his crack mechanic friend so that it was level again. And the new threaded rocker stud I installed just a few weeks ago? Yeah....it too now has a worn groove in it's side from the rocker walking even though it and, the rocker, pushrod, and fulcrum are all new and the truck head has the pushrod slot opening cast into it prohibiting the pushrod from ....wait for it.......yeah..that's right...walking to one side letting the rocker run off center.
Unbelievable right?
Next step I think will be to remove the head in question and replace that shortened valve (to correct the geometry) and damaged threaded stud along with the now bent pushrod. Stuff a new cam and lifter set in it and see what it does. If it starts ticking again I think I know where I can get my hands on some C4 and take care of this little problem.

 

It sounds to me like the hole that the stud screws into had been repaired at one time.

 

Well...one would think right? But, I pressed the old stock stud out myself and drill & tapped the hole for the new threaded stud that I replaced it with. Of course I used the "special" alignment/press tool to do it with so as to insure proper alignment. So, I'm still at a lose so far.
Capt'n

 

Dude, you live on an island, I bet there are a dozen people looking for a boat anchor. I hear GM provides the very best marine products . Although, C4 would be pretty cool.