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Mechanics checking machine shops work

Murray_Calavera
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Murray_Calavera Mentor

Murray_Calavera

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Hi all,

I was wondering what peoples experience is with the mechanic checking the machine shop's work after sending the engine off for machining? 

After chatting with a few machine shops, seems it's pretty common practice that the engine is assembled by the mechanic without any of the clearances or other work performed being checked? 

I'm in the process of putting my rb25 together and I'm wondering if I just trust the machine shop, or do I drop something like $2,000 in bore gauges/mics/etc and check everything myself. Note I'm not a mechanic so these specialist tools will spend a lot of time gathering dust :(

KiwiRS4T Grand Master

KiwiRS4T

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43 minutes ago, Murray_Calavera said:

I did a bit of googling and couldn't find any place in Sydney that hire out specialist engine building tools. If someone knows of a company that does that I'd be keen. 

They are not specialist tools. Inside and outside micrometer, feeler gauges (which you will have) and as a final check on bearings plastigauge is cheap and accurate.

Murray_Calavera Mentor

Murray_Calavera

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I never said anything bad about Plastigauge. 

I'd like to for example, check the bores for size, roundness and taper. I can't see me doing that with anything other then a bore gauge. Decent bore gauges go for around $600ish? Then I'll need a set of mic's, so another $400ish? It's starting to add up real quick. Say I want to use a rod bolt stretch gauge, that's another $350ish?

I'd call these tools specialist tools, along with ring cutters, angle gauges,  magnetic deck bridge, magnetic base dial gauge etc etc. Some of these are quite affordable but it all adds up. Maybe they aren't 'specialist tools' but that's the sort of thing I'm referring to. 

Hopefully you can see where I'm coming from and tool hire would make a lot more sense for me in this position. 

I guess I'll keep sniffing around for a hire shop, if not I'll make do with what I have. 

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

If you are checking an engine you have just opened you will want to check for out of round, taper etc but when you get a block back from the machine shop you can assume that the bores will be round. When you are assembling the motor you are really just checking clearances so you want to measure the bore and the pistons. You will want to measure the ring gap. I haven't built as many engines as others on this forum but I do the basic checks. You can measure the crankshaft, main bearings and rods. I don't even know what a rod bolt stretch gauge is (I always upgrade the rod bolts). I check the fit of the mains and rods with plastigauge.

I own a torque wrench and some sets of feeler gauges and borrow the micrometers (but many hire shops rent them out).

There is a middle path between doing no checks and going to town checking every last detail.

GTSBoy Grand Master

GTSBoy

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Posted

'Twere me, coming from an engineering environment where ISO9001 rules and ruins our lives, if I were getting an engine back from the machine shop, I would want to see the record sheets for the measurements made at the end of the machining processes that shows conformance to the stated requirements.

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