robm

Any updates on your problem?

Runner4Luke

Nothing yet, I haven't worked on the car since I last posted. Just not time..
My buddy has been driving it regularly though, and took the runner to a couple of autoshops during that period.
Blew some cash(no too much though), and big surprise, they just threw their hands up.
Sorry I got nothing.

robm

Figured I would update since I was having identical problems. So , I took the complete engine down to engnbldr around the end of March. I brought up to tod my concerns with the head. He originally built my motor back in December and the head gasket kept blowing. The issue was he didn't deck the block with the timing cover on and the timing cover was just higher than the block keeping it from sealing. I kept hoping that this issue was causing my misfire in the #1 cyl. So, he decked the block and assembled it as a long block for me, he also said he checked the head and there was nothing wrong. I picked it up first of May, put it in and low and behold #1 cyl misfire. I took my stock head to the machine shop and they freshened it up, including a valve job, all the exhaust valves were bad. My stock cam was completely garbage so I ordered a stock grind cam from 22reperformance. Basically, $500 to rebuild the top end with new gaskets. I wanted to completely take engnbldrs top end parts out of the equation, that's why I put a stock cam in. Finished putting it together today and low and behold, misfire is GONE!! Thing runs very smooth. Something is ˟˟˟˟ed up with either his head or cam. I will be calling him tomorrow to let him know, again.

Odin

Robm,
At least you got it down to one of the two.
I wouldn't be too happy about now having less power and having to spend extra money on bad performance parts that can't be used.

I'm just surprised engnbuilder didn't offer to rebuild the stock head for you just to get to the bottom of this. No good business wants think they've sold problemed parts but as it's already been stated it does happen.

Runner4Luke

Hey Robm,
You have oversized valves if I remember right? I believe Tod saids he cleans up the ports a bit as well when he does that.
It would be nice to know if we had variations in our heads (the head I'm working with is all stock), then only the cam would be the matching part..
I gonna start looking for cheap alternate cam to test it.
Lot easier than swapping the head.
God wouldn't that be glorious if that was it.

robm

It's bitter sweet! I'm happy to finally have it running right, been dealing with it for almost 6 months, but not happy about the cost.

I believe the head castings are the same between his stock head and the one I bought, just mild porting and the larger valves. I'm curious if he replaces the valve seats or uses the ones that come in the head.

robm

I found one other guy on Facebook with a similar issue, started with #1 cyl but he said he kept driving it and eventually all the exhaust valves burned up.

Runner4Luke

I'm glad to hear that you had a modified head from Tod, that tells me our heads are somewhat different, yours being mildly ported with over-sized valves, mine being all stock.
This increases the likelihood of a messed up cam, not to mention that fact that Tod machines those himself...more room for error.
I told my buddy to start looking for another cam, we'll throw that in sometime soon, and I'll let you all now how it goes.

Congrats on getting your truck running right, I hope I can join that party soon..

Shady Cadence

I don't believe it's a camshaft issue, the cam just rotates. This issue comes up above cranking RPM. Since the tappets aren't hydraulic, we can rule out a base circle error. I seriously doubt the cam lobe is expanding at higher r's, or that the cam is warping at speed. This leaves the reciprocating mass, the tappet and/or the valve.

My money says either the guide is damaged or the geometry is off

Runner4Luke

I agree about the base circle and your other suggestions.

I'm hoping the cam was simply machined incorrectly with the number 1 lobe being off time (Either off angle or possibly shorter lobe or something). Seeing as these may be hand machined (I think Tod cuts these himself?), a mistake of that nature would seem feasible though admittedly unlikely. If thats not it, then its gotta be the head. But swapping a cam is a lot simpler than pulling the head.. again.

I mean when you step waaay back and look at this whole issue again, the only thing thats changed since the engine ran perfect is a new 'stock' head, and a modified cam. Everything else is the same. I figure for $50 and couple hours its worth a try.

robm

So, I don't think it's the head. A couple days ago I took the head into a local machine shop to have him check it out. He pulled all the valves, checked guides and seats and said he couldn't find anything wrong with it. That just leaves the cam. I'm tempted to send the cam into delta cam in Tacoma, wa and have them spec it out.

Odin

If you have the extra money do it. It will perhaps be piece of mind.

And if it's found to be off you might think about throwing that other head back on.

That's a pretty good chunk of money just sitting there collecting dust.



.

Runner4Luke

I'm glad to hear that another machine shop check out the head and saw no issue, this further suggests the cam as the culprit.
I'm currently 700miles from the car for the summer, but my buddy is gonna go for cam swap solo (he's new to this stuff), so I'm waiting to hear how it goes.

I've got a fresh issue on my 87 I need to diagnose..

Runner4Luke

It was the bloody cam shaft, new standard cam is in and the engine is now firing on number one at idle. Jeeeezzze. Manufacturing defect for sure, the number one lobes must be off time, either wrong height or off angle.

Thanks everybody for all your help and suggestions, this was one mother to track down. No obviously clues, and an unexpected defect from engbldr. I'll be letting Tod know soon.
Cheers all!

Odin

Bittersweet for sure.


Was the replacement that solved it from Delta or a long established one like Crower?

Runner4Luke

I unfortunately Have no idea who made the cam. I didn't order it, my buddy did. At $50 I can't imagine it was of any renowned quality, but its not exactly a high stressed component, so it should be fine.

Runner4Luke

For those curious.

Tod qualified today that there was a defect in the camshaft. The centerline was slightly off causing a minor runout at the front end of the camshaft, which slightly messed up the machining of the #1 lobes, thus causing the cylinder one missfire @ idle.
Apparently loosening the valve lash a couple thou should have resolved the issue, but I had done that and it didn't resolve it.

Anyhow, specific problem found and solved.

JEEEEZE. hope that didn't mess up the cam journals..

Odin

If I'm reading you correctly it's something that should have been caught Before the cam was reground. Two people with the same problem in a short span on this site alone..
Sounds like they need to add another step in their quality control.

No telling how many more people are out there ripping their hair out and their motors apart because of it.

Runner4Luke

Yep and Yep. With any luck they'll stumble on this thread.

erndog

Well what long trail of troubleshooting.