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What compression ratio should I aim for?

I had already cc'd the chambers, I used washer fluid, and it worked nice. I called about 10 machine shops near me. The 3 that could mill a cylinder head were all the same guy, despite being different businesses, different addresses, different parts of town, and different phone numbers. This guy wants $450 to mill a head, and there's no chance I'm spending that.
 
OVERDRIVE said:
I had already cc'd the chambers, I used washer fluid, and it worked nice. I called about 10 machine shops near me. The 3 that could mill a cylinder head were all the same guy, despite being different businesses, different addresses, different parts of town, and different phone numbers. This guy wants $450 to mill a head, and there's no chance I'm spending that.
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That's hilarious. Ship it off to a shop outside the city, maybe?

For instance: https://maps.app.goo.gl/XoCVsN2QjUoesovv7
 
OVERDRIVE said:
I had already cc'd the chambers, I used washer fluid, and it worked nice. I called about 10 machine shops near me. The 3 that could mill a cylinder head were all the same guy, despite being different businesses, different addresses, different parts of town, and different phone numbers. This guy wants $450 to mill a head, and there's no chance I'm spending that.
Click to expand...
That is absurd. The machine shop in Eugene charges $60 to fly cut a cylinder head. His rate may have gone up in the last year or two. It certainly isn't $450.
 
2manyturbos said:
That is absurd. The machine shop in Eugene charges $60 to fly cut a cylinder head. His rate may have gone up in the last year or two. It certainly isn't $450.
Click to expand...
The cheapest over here is $130 for a skim and a clean, up from $70 a few years ago. The last head that needed 2mm removed was $185.
I need to buy a Bridgeport ;)
 
OVERDRIVE said:
I had already cc'd the chambers, I used washer fluid, and it worked nice. I called about 10 machine shops near me. The 3 that could mill a cylinder head were all the same guy, despite being different businesses, different addresses, different parts of town, and different phone numbers. This guy wants $450 to mill a head, and there's no chance I'm spending that.
Click to expand...
It's been all down hill for Brooklyn since the Dodgers left town.......

In all seriousness, I can't imagine a business running today (insured that is) that charges less than $125 an hour shop rate. I'm no machinist, but the setup for a head cut, machining, tear down and cleanup has to be 3~4 hours.
 
culberro said:
The cheapest over here is $130 for a skim and a clean, up from $70 a few years ago. The last head that needed 2mm removed was $185.
I need to buy a Bridgeport ;)
Click to expand...
I just got off the phone with Steve at Uhle's Machine shop in JC. He is still at $60 for an aluminum head. I asked him, how much if we want more like .040" off it. "Hmmm, that's a lot, I don't know." Ball park it. "I guess $100." Perfect.
 
DET17 said:
It's been all down hill for Brooklyn since the Dodgers left town.......

In all seriousness, I can't imagine a business running today (insured that is) that charges less than $125 an hour shop rate. I'm no machinist, but the setup for a head cut, machining, tear down and cleanup has to be 3~4 hours.
Click to expand...
It's less than an hour including the jet wash that's all automated.
But yes, shop rates are going up as everything else is. I think machine shop rates were pretty far behind the curve and they're just catching up. Couple that with a lack of engine machine shops and you get a point where they can raise prices and every one just has to pay them as there's no other option.
 
The last pair of aluminum heads I had "clean up cut" were at $175, but that might have included intake seals on valves. One 16V SAAB, one 8V Volvo. Prices have definitely jumped in the SE.... many small time shops are gone, and the environmental aspect of shops is not something most urban areas want. The depreciation on a 6 figure CNC machine is going to drive these costs, if that is how they are getting done now.

Back to the OP..... how much did you decide to cut your head for the 87 Octane fuel? Might be good for TB posterity to share your measurements and calculations on dynamic compression target. I may be doing something similar for a 94 squirter NA engine I just bought...... but don't want to push it into premium fuel.
 
DET17 said:
Back to the OP..... how much did you decide to cut your head for the 87 Octane fuel? Might be good for TB posterity to share your measurements and calculations on dynamic compression target. I may be doing something similar for a 94 squirter NA engine I just bought...... but don't want to push it into premium fuel.
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Hi, OP here. My head had been cut .008"-.010" already. After chamber work shown, I was near enough around 53.75cc per chamber. I am picking the head up after work today, I found someone to mill it .035" and put the valves back in for $180 cash. I will CC the chamber and post my findings when it's back together, fingers crossed tomorrow. I was aiming for 9.8 to 9.9:1, which would give me about the dynamic compression of an untouched B230F with a T cam.
 
culberro said:
The cheapest over here is $130 for a skim and a clean, up from $70 a few years ago. The last head that needed 2mm removed was $185.
I need to buy a Bridgeport ;)
Click to expand...
That $185 number is about the rate for removing anything over 0.010" where I live. If you buy a Bridgeport I may start shipping you more stuff to machine.
 
culberro said:
It's less than an hour including the jet wash that's all automated.
But yes, shop rates are going up as everything else is. I think machine shop rates were pretty far behind the curve and they're just catching up. Couple that with a lack of engine machine shops and you get a point where they can raise prices and every one just has to pay them as there's no other option.
Click to expand...
I feel spoiled living in a town with three. Although one is quite expensive, one apparently won't touch imports, and the last one is chill.
 
OVERDRIVE said:
Hi, OP here. My head had been cut .008"-.010" already. After chamber work shown, I was near enough around 53.75cc per chamber. I am picking the head up after work today, I found someone to mill it .035" and put the valves back in for $180 cash. I will CC the chamber and post my findings when it's back together, fingers crossed tomorrow. I was aiming for 9.8 to 9.9:1, which would give me about the dynamic compression of an untouched B230F with a T cam.
Click to expand...
Going standard HG or MLS? As stated, lots of thickness options with MLS (assuming still available, I've got one or two left). If you go that route, spray a light coat of HYLOMAR on both sides.... and I do mean "light". So you believe you can run 87 petrol with a 9.9 dynamic ratio?
 
DET17 said:
Going standard HG or MLS? As stated, lots of thickness options with MLS (assuming still available, I've got one or two left). If you go that route, spray a light coat of HYLOMAR on both sides.... and I do mean "light". So you believe you can run 87 petrol with a 9.9 dynamic ratio?
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you really don't need to put hylomar or any sealant on a new Cometic MLS gasket if the deck surfaces are properly prepared and surfaced. The gasket has a layer of viton on it and seals itself. If you're reusing the gasket and the coating is compromised I could see doing it.
 
OVERDRIVE said:
I had already cc'd the chambers, I used washer fluid, and it worked nice. I called about 10 machine shops near me. The 3 that could mill a cylinder head were all the same guy, despite being different businesses, different addresses, different parts of town, and different phone numbers. This guy wants $450 to mill a head, and there's no chance I'm spending that.
Click to expand...
That is bonkers. It's $80 in Canadian funny money all day long where I am.
 
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