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Discussion Starter #41
My long block came back from Jasper just before Thanksgiving. Last week, the shop was able to start work reassembling and reinstalling the engine. First start was last night, and it didn't go well. One of the rocker arm studs pulled out of the cylinder head, and Jasper wants the long block back for diagnostics. Sigh...
 

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Ouch Scott, that's not good. Given it was a "long" block your shop had nothing to do with the heads & valve train geometry. Sucks it will be a return motor, Jasper does whatever, send back to your shop, repeat install, fingers crossed

good luck
 

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My one beef with Jasper is that they insist on only paying their specified labor rate for warranty repairs. When our van's Jasper transmission started acting up in a very expensive area of the country after only 21,000 miles, I was a bit disappointed at the amount of out-of-pocket expenses when it was either Jasper's fault or the shop that had originally installed it (boogered or missing bolts and such).

I would very much want to know what caused a rocker stud to pull out on a stock cam, stock valvesprings motor.... unless there's something you're not telling us about this Scott..😎
 

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Discussion Starter #44
I'm still waiting for more info myself. These were the original heads that had never been off the engine, and yes, a stock rebuild. They even supposedly tested the engine before shipping it back. Something just doesn't sound right.
 

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Where's Jasper's rebuild facility?

BTW, did you mark the heads and block before shipping it to Jasper? Whenever I send out 4L60E pumps and valvebodies for rebuilding, I always stamp them with some unique identifiers in inconspicious areas so I know if I got a different part back or not.
 

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Block with the serial derivation easy. Heads , about now , casting dates would be one thing to look at.
 

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We have no idea if those are your original heads unless marked as suggested above. I have had enough issues over the years that it's worth the extra money to get screw in studs added. I rarely stay stock and usually put a "cam" in my engines. DO NOT use the jobber studs, very easy to over tighten and crack the stud bosses. Again, IMO it's worth the money to machine the bosses flat and install an ARP-type stud. With that being said you did go bone stock, so there should be no issue with the stock press in studs. I wonder if valves were adjusted corrected, push rod length stock and correct lifters used.

As much as I would like to bash Jasper, I recently built a sbc and Had machine shop do machining and measuring and I did assembly. Brought it back and put it on their dyno, hot oil pressure was "lower than they normally see" but I was told to "install it and not worry about it" . Sure enough I installed it and went on a road trip only to find when I was 1000 km away from home that I was getting no oil to my top end. Got home, pulled the engine and took it back to machineshop. Turns out I had a 1 year only block where gm drilled a weird counter bore on the lifter bores. It appeared to be a block with roller lifter provisions, but when the lifters got to the top of the bore they bled off tons of oil into the lifter valley. This stuff happens and takes the wind out of your sails for sure.
 

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Jasper has really upped their game. Check out their "featured engines" page and look at all the tech. Note how many are using custom Jasper-designed pistons.
 

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Discussion Starter #49
No, the heads weren't marked, but they were supposed to rebuild and return my original block and heads. I also paid for documentation of the entire rebuild process. Anyway, after talking to Jasper my shop was able to get them to cover the installation of screw-in studs instead of pulling and returning the long block. Hopefully the car will be rolling again soon, and with screw-in studs it'll be stronger than it was originally.

The Jasper rep though that something about the heat used in their cleaning process might have contributed to the failure. Supposedly this was only the third time they've seen it happen. Those heads had never been apart and have been through thousands of heating and cooling cycles without issue, so I have my doubts about any weakness caused by cleaning.
 

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Discussion Starter #50
The car finally came home today. All seems good with the rebuild except for the issue with the rocker arm studs. Those were fixed with screw-in studs. Now we'll see if anything comes up as I start to drive it again. After the rebuild and reassembly we did find a few small issues:

The low oil level warning light was coming on due to an issue with the wiring connector that plugs into the sensor that fits into the oil pan. Chalk that up to brittle 25 year old plastic.

MAP and EGR faults: a new MAP sensor and EGR solenoid fixed those problems. The old MAP sensor was relatively new, so I have no idea why it failed. We did install a new EGR valve during reassembly, but I forgot about the solenoid. It was original, so I think I got my money's worth out of it.

The project took a while longer because I had the shop do several other things for me while they had the car, like swapping in a freshly rebuilt steering column (pro tip: make sure the clock spring is properly centered!), replacing the transmission fluid cooler lines, and adjusting the steering gear box. They also had to make some adjustments to the exhaust system because I switched from universal catalytic converters to direct-fit converters. My car is now basically brand-new mechanically with all of the other work I've done. It should be good to go for another 250,000 miles or so. I'll gladly recommend the shop that did the work to anyone looking for an honest, competent repair shop in northern Virginia.
 

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Good news! On your pro tip - EVERY time I disconnect the steering shaft, I very gently turn the steering wheel and count exactly how many revolutions it has, then center it. The one I'm working on now had 7.25 revolutions. Fortunately the Impala box only turns about a turn in either direction so there's plenty of margin, but yes, wise advice. Another thing - the steering shaft only fits on either end one way. This is a good thing.

I second your shop - a relative has had some very large repairs done there and they are always done well and done right.
 

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While the idea is solid , some clock springs, even the most gentle " find the end of travel" in the direction that unwinds it could fold back the tape on itself fracturing it.

If position is in question, depending on car, I would look for factory info first.
Some actualy have a center indicator in a window that shows at the correct number of turns.

I know cars first hand that correct straight ahead position is nowhere near halfway.
Wind up tight was , of coarse, more rotation the 1/2 lock to lock, wind loose was way more turns .
 

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I’m now turning 330,000 miles on engine and trans neither have been removed from the car since new. 🤞🏻🤞🏻🤞🏻
 
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