Sold my NB to a local miata guy. He got a MSM cam so he installed it, put everything back together, and started turning the exhaust cam for timing. Turns out it was nearly impossible to spin the exhaust cam. He found the problem, see the attached picture.
The head had about 40-50 miles on it since it was rebuilt by a local machine shop. New valve guides, stem seals, head shaved, etc etc. The engine last ran spring of 2011 and seemed completely fine, no noises or anything unusual and it's just been sitting since then. The metal shaving in the picture looks fresh and the guy said that's the only shaving he's seen.
I don't know all too much about engine assembly and I'm hoping the machine shop I had the work done at can resolve the issue. I'm hoping the good ole boys that worked on it weren't too confused on the solid lifter design vs the rocker arms they're use to.
Any help is appreciated. I was about a month out from putting this engine in my car too
That shaving looks like aluminum scraped out of the lash adjuster bore from the shim kicking out the side.
I have a dollar that says the machine shop didn't check the clearance after doing the valve job, and that valve is so tight that the cam physically smashed the shim out. That's assuming dude is smart enough to have put the cam in correctly.
When the shim popped out, the lobe is in the well of the lifter and has jammed the lobe, that is why it wont turn. care must be taken unbolting the cam, to take it out, and not crash the lobe. Do not try to force the cam to turn! If you/he has access to the oem tool to change the shim, I would give that a try to get the shim back in place first.
You say he changed this cam that has the problem? Sounds like installer error to me.
I have no useful help on how to fix your solid lifter head. But I do really hope, for your sake, that head wasn't machined by the same guy in Maryville that torched my forged block.
Haha, yeah it was done at Hitch's Repair. I'm not sure if it was the same fellow though. Hitch's was referred to me by the owner of East TN Race Prep, he's had lots of race engines worked on with them for the past 20 years. I think it's a hit or miss with them and I think around 2 years ago they had a terrible machinist working on miata parts
He pulled the cam and got the lifter out, says there's a scuff on the lifter's cylinder wall. He should have more pictures for me soon.
I'm putting money on tight clearances, that were obviously acceptable because it ran fine before, mixed with it sitting for a year and a half, and turning the cam over with it being completely dry.
So he was able to turn the engine over, noticed it was kind of hard, figured it was on the compression stroke. Took out the spark plugs and turned it a full 3-4 rotations before he noticed the exhaust cam wasn't moving. However both the intake cam and the crank pulley were spinning. He also said the bolt that holds the exhaust cam sprocket was finger loose, which is confusing. I haven't touched the cam sprocket bolts since I got it from the machine shop.
So I don't think he ever turned it backwards, but it got wedged on that one shim then smashed that one shim and sheered off the tab on the front-end of the exhaust cam. The damage that's pictured and has been described to me seems forced, but I'm obviously not 100%
He's taking it to the machine shop, which thankfully isn't the same shop you used Jonathan. I figure they'll give him a good explanation on how it broke.
He said the first rotation was really hard, he just thought it was the compression stroke. But if the engine was broken from the start it would of never had a compression stroke cause the exhaust valves wouldn't of moved.
I think it broke on his first attempt of turning it and he just kept going even after resistance. The cause I'm thinking a mixture of too tight clearances set from the shop and dry cam lobes and lifters.
I can give a thought. Head was set on a table flat. Valves on that cyl were open and it bent the valve. when it tried to turn, shim popped out. The lobe got stuck in the lifter. The pin on the cam broke trying to force things.