BMW E31 850i "Glacier" - V12 Piston Machining & Cerakoting - Episode 15
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- เผยแพร่เมื่อ 21 ต.ค. 2024
- In this video, I am forced to take steps to rectify bad workmanship by another machine shop, who skimmed one of my M70 V12 decks "out of flat".
My only option was to machine four of the piston crowns, reduce the weight of all the pistons to compensate for the weight reduction and then send all twelve pistons for Cerakote finishing.
This car will be finished in 46 years. Unfortunately I won't be here, but I appreciate what you're doing.
Your channel, and "another BMW channel" are without doubt my favourite viewing of all time. I'm not a BMW car builder, I would on BMW bikes, specfically the K series. Keep going with your quest for perfection, we all know you're going to get there. We'll be along with you on your journey. Please don't give up Steve.
That's a shame about the issues you're having with these machining shops. I have no doubt that the engine will run like a dream once you're done with it. Looking forward to seeing it running!
Nice car ,you've got there geezer. That's a nice thorough restoration. You're really giving it the tlc it's needed for sometime now. You can really see the transformation and what a contrast😊 Nice one👍
A good solution to a mess not of your creation. Good thing you spotted it. I hope all goes well. Thanks for the cool videos. I'd love to see the car some time. My inlaws are in Navan so I'm in your general area at times. Keep going and I loom forward to the next update.
Interesting solution to a horrible problem. Hope it works out!
name of machine shop that did shenanigans work please?
You are a brave man ;)
Hi Steve, good to see you again. Real bummer about the block, it's hard to find people you can trust to do a proper job nowadays. even Streten at M539 has fallen foul of bad machining. I know it's probably not your style, but I think I might have mentioned to the machine shop in question that letting 8K+ people know not to take their engine parts there may have at least warranted a reply. I am thinking that the discrepancy amounts we are talking about are not enough to cause a mis-alignment problem with the inlet manifold, seeing as the heads will be slightly out of kilter. The pistons look better than original now with the new coatings, should turn out good in the end. I have completely re-built my rear subframe, you are right, there's a lot of work involved. I may be too late here, but when I did mine, 2 out of three of the "rose joint" bushings were available from Lemforder (they made the originals) at about 1/2 the price of BMW, and the third which is part of the top arm is now available exchange from Gerry Speechley at Phoenix Motorsport, again, cheaper than BMW but still very dear at £300 a side. He also does some nice re-enforcement plates for the rear shock mountings which have a common fault of metal fatigue cracks.
Thanks for the info! I just missed out on the Lemforder ones, hopefully they are available again soon. I am slowly building the rear end parts collection.
supports for rear shock left BMW 411 481 52997 and Right side 52998, these are factory upgrade E31 body much thicker than pre July 1992 models where this plate is 1.5mm. one drills out the spot welds then position , get in the boot and spot weld from inside. they're only £20 each
@@stevesbmwbarn Hi Steve, good to hear from you! Apologies for length of this but it may help you. At the time I did mine, I was working for Euro Car Parts who have a direct account with Lemforder and can special order just about anything. Using Lemforder's on-line catalogue information, I cross-referenced the BMW part numbers from RealOEM, then got work to order up the parts for me. Having gone to all that trouble, we have a local parts supplier here in Huddersfield, A to Z Motor Factors, and whilst checking for other parts I found that they had the Lemforder bushings in stock and slightly cheaper than I got them on my staff discount! Always worth a shop-around.
@@bobfrankish8883 Thanks Bob, i have a good bulk of parts coming from Ed at V12 Throttle, will check them out for sure.
Jezus.. Just ran across your video. Rather than creating a small weight imbalance with the pistons shaved to different conditions, and different quench patterns, it would seem to be better to find yet another machine shop - somehow insure the work/block, and have them simply mill both banks flat again enough to use a thick custom copper head gasket in your defined thickness. (Granted + ss o-ringing the cylinder). Custom copper (reusable) head gaskets should be reasonably easy to source as long as a maker can have a DFX file of the OE gasket. Yes, you don't use the OE MLS gasket anymore but at this point..... it would seem like an option. Then IDK if it's worth using the courts to make the other machine shops pay for what they fudged up.
Sorry to hear about all the issues you're having with the machining shops. I am really enjoying watching the progress you this project and can't wait to watch the work on the car body too. Forgive me for this, maybe, dumb question but won't the material removed from the pistons cause engine unbalance? Or is that so minor that the weight difference is negligible?
The answer is in the video. 🫡
@@voodoomelons I guess I wasn’t attention when that was mentioned 😁
EDIT: I rewatched that part paying attention. The solution was to remove some material from the piston pins on all pistons so that the overall weight of each piston is the similar 👍
Small Claims Court send them a letter 1st telling them that you will take them to court within 14 days... Little lesson before taking a head to get it skimmed make measurements with pictures beforehand.. measuring the casting to a known point at 4 points from the deck...
Make sure your valves don't hit the pistons on number 5 and 6, because you removed 0.6mm from the top of the piston, not from the valve relief that was machined in the piston. The valve relief is 0.6 mm closer to the valve!
All the valve reliefs were also deepened the correct respective amount.
@@voodoomelons @ 41:26 doesn't seem like it, 6 reliefs seem shallower than 5, hope you are right ...
Small claims court be an option?
That's why you never machine engine parts if they are not fucked.
For example if the block has an excessive amount of warp or twist beyond the accepted OE spec, you machine it because it's already fucked.
If the heads are warped beyond accepted values you machine them because they are already fucked
There is absolutely no gain in machining parts that are "good enough"
I have a 3.2 VR6 Turbo engine that spits about 630HP which was rebuilt twice (I cracked some pistons because of high boost), and I have 30K km with it since the last rebuild. engine and head were never machined.
I feel your pain :(
100% correct. Down the rabbit hole...
Takk!
Doesn’t take any rod bearings?!!
This is not the correct way to fix the issue
Reservice the deck is IMHO the way to go. The whole cilinderhead isnt level now.
Yep. All covers sprockets etc won’t align
All of this just cause someone fed up the messurment and basicly ruined the block