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The seeds were sown, you guys just needed to water them a bit. Pulled the big ends, and glad I did. Tons of dirt in there, however the rod journals look like a brand new crank. Definitely an older CP set of slugs and definitely balanced. I am going to get new main studs and rod bolts, cheap insurance for $200.
Still need to open and measure the mains, but looking good so far.
This crank is cherry, the bearings look used and are ACL, but no where near max tolerances. Definitely some crud hidden around. I am not convinced that the main caps were anywhere near 40 ft/lbs. I think someone did the primary torque but forgot the second step. Also the oil squirters were installed with no crush washers but I think they might be taller ones or something, I'll have to check.
Feel free to try to convince me I don't need the squirters and should run Furrari bolts. This is an older build, I don't believe the pistons were off the shelf Miata pistons. They appear to have been cut near the intake valve reliefs and also on the skirt to clear the squirters. They look like images of JE pistons, but on the underside the CP logo is clearly visible.
Plan is to call Andrew's place Monday morning and see if he has replacement rod bolts. If not I can get them from Summit 4 for $50 or so. I will definitely need the main stud kit and I am thinking I should just get valves and light double springs. I mean, no way the machine shop is going to say that 250k **** boosted out of head is not going to need new valves and guides.
Thanks Tom, that's just the info I wanted to plug those squirters. I will leave this head stock for reasons. Maybe when I get another head, we can have at it.
My wife had a honey-do list a mile long today, so I have yet to look at the gaps. Still didn't pull the car in yet so maybe I can get the head off before Tuesday morning.
I have been lagging, car isn't even in the garage yet.
In case anyone is wondering, TSE does have the ARP replacement bolts. Cheaper than summit or jegs, even with tax and shipping.
I was painfully hacksawing my 10x1.25 bolts at an agonizing infinitesimally slow pace(kinda like a stock miata.) And there were the squirters staring me in the face, so....
Snipped with dikes, a few careful taps with a small sledge on an anvil, file the edges, pump with air to ensure seal. Done.
I will use these as the crush washers, from what I've seen, earlier motors have thinner squirters with crush washers and later motors have thicker squirters with no washers.
The number 1 rings were a bit tight, I opened them up to 015 & 020. The oil rings just state 015 minimum & do not file, they measured 022 which is in the middle of the stock spec. So that is how I will set the rest, assuming they are similar. This is for CP pistons, on the tighter side of the drag/road race suggested gaps.
Sorry, after checking again, these look more like the street/hi performance gaps now. Maybe I will open them up to 017 & 022, that would be half way between the forced induction/nitrous and drag/road race gaps.
Finished the gaps, .017 top, .022 2nd, and all the oil rings are between .020 & .022. This will suit my application well for the CP pistons. The previous builder had it set up for stock pistons, .009-.010 top, .015-.016 2nd. I didn't touch the oil rings, they say "do not file."
So far the only things that needed attention on this motor is the gaps and the torque for the main caps. Caps and gaps. Bolts and studs will likely be here tomorrow or Tuesday. Then I can reassemble, wrap and move the block aside to pull my car in.
Thanks for nurturing the seeds of doubt you guys, really glad I pulled this apart.
Timeline is ******* ASAP, yesterday, crap I am gonna miss another race this week.
No you didn't miss the teardown, I know you guys want to see, Lars want pics of the manifold, everyone wants to see low 12's, ect... Sorry guys, see the above time frame. Running and broken in, then teardown, unless it's obvious when I pull the head.
And my garage is so small, I need to assemble the block before I pull the car in. It is actually still in running condition, tack, tack, tack, tack.
Finally got a day to work on my car, about to go back after this break. All the mains measured around .0018-.0021 with the green sealed power plastigage. All the big ends measured around .0012-.0013, checked with the old bolts. I found some galling on the rod caps where the bolt heads make contact, so I cleaned it up with a file and sand paper for each cap.
Mains torqued to ~56ft/lbs in three steps. I don't have a bolt stretch gauge, so I just plan to use 30wt oil on clean threads/heads and torque to 60ft/lbs.
Here is a picture of the CP logo, they really are nice pistons. We'll see how they perform.
Back to where I started, except with proper gaps and main studs. All properly torqued this time, with the squirters shut. Now I just need to clean up and organize the garage. Maybe start teardown tomorrow, although my wife has a guest staying with us, hopefully that won't interfere with my plans too much.
07-22-2017, 08:54 PM
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And there were the squirters staring me in the face, so....
It was fun, I did 2 in half the time it took me to get through one of the studs.
