What Should I Expect From A Engine Machinist/Builder?

[Jahloha]

Team:

I have been thinking a lot about a rebuild or crate engine...simply put, both are great options in my opinion. But before I make my final decision, I am going to take the numbers matching engine components to a machinist/builder to talk through a possible rebuild.

This will be my first time doing a rebuild and I want to make sure I am at least clear on what things I should expect a machinist to do and any other things you feel any capable machinist/builder would offer in his services.

I know a lot of us on our forum have worked in the industry and can sniff out an incompetent machinist/builder in a heart beat; thats the knowledge I would like to gain from you all.

Mahalo!

[sean1969c10]

I am an ASE Master Automotive Machinist, 16yrs in the industry. Ask around, find out what shops other people like. I can tell you that the cheapest place probably won't be your best bet, but you don't need a full on race shop either. Look for a place that is reasonably clean with machinery that looks pretty well maintained. Ask about their boring equipment, the better equipment will use the main housing bore as a reference point to align the cylinders 90 degrees from the mains. A portable boring bar sits on the deck of the block, so if the deck isn't square to the mains then the cylinders won't be either. The shop should be using something like a Sunnen CK10 to hone with, hand hones are pretty old school and shouldn't be the main hone in a shop now. Ask if they knurl or replace valve guides, knurling is an old school band aid fix and should be a red flag. Ask about certification and experience, ASE's machinist cert has been discontinued but ask if their machinists had been or are still certified.

In the end the reputation of the shop is probably the biggest factor. Give me a shout if you have other questions.

[Jahloha]

Originally Posted by sean1969c10

I am an ASE Master Automotive Machinist, 16yrs in the industry. Ask around, find out what shops other people like. I can tell you that the cheapest place probably won't be your best bet, but you don't need a full on race shop either. Look for a place that is reasonably clean with machinery that looks pretty well maintained. Ask about their boring equipment, the better equipment will use the main housing bore as a reference point to align the cylinders 90 degrees from the mains. A portable boring bar sits on the deck of the block, so if the deck isn't square to the mains then the cylinders won't be either. The shop should be using something like a Sunnen CK10 to hone with, hand hones are pretty old school and shouldn't be the main hone in a shop now. Ask if they knurl or replace valve guides, knurling is an old school band aid fix and should be a red flag. Ask about certification and experience, ASE's machinist cert has been discontinued but ask if their machinists had been or are still certified.

In the end the reputation of the shop is probably the biggest factor. Give me a shout if you have other questions.

Sean:

Thanks for the thorough run down! Definitely some talking points for me to have when I call around to shops. I especially like the knurl or replace comment, thats the kind of thing I need to know.

Is there a location I can read/learn about what all is done during a rebuild, like a list of some sort? For example, I dont want to go to a reputable location and do work, but find out they missed a step that should have happen.

[68gmsee]

^ Good info from sean.

If you intend to keep your truck completely stock with numbers matching then make sure you let the builder know this. Some builders, for expediency, will use heads they have on the shelf rather than the ones the engine originally came with. May not be a game changer but still you need to be aware of it.

Another thing to keep in mind is the valve seats on the newer heads are specifically designed for unleaded fuel where the older ones that came with our trucks are not. A machinist once told me he reground his original heads on his own truck and had been driving it for several years with no problems. I did the same on my six cylinder and it's been running fine for about 7 years but it's not a daily driver.

[Jahloha]

Originally Posted by 68gmsee

^ Good info from sean.

If you intend to keep your truck completely stock with numbers matching then make sure you let the builder know this. Some builders, for expediency, will use heads they have on the shelf rather than the ones the engine originally came with. May not be a game changer but still you need to be aware of it.

Another thing to keep in mind is the valve seats on the newer heads are specifically designed for unleaded fuel where the older ones that came with our trucks are not. A machinist once told me he reground his original heads on his own truck and had been driving it for several years with no problems. I did the same on my six cylinder and it's been running fine for about 7 years but it's not a daily driver.

Good insight! So did you regrind your heads or go new? I am not opposed to buying new components (i.e., intake manifold, heads, etc.). I just want to have the engine be a solid daily driver and good to go for years to come.

[68gmsee]

Originally Posted by Jahloha

Good insight! So did you regrind your heads or go new? I am not opposed to buying new components (i.e., intake manifold, heads, etc.). I just want to have the engine be a solid daily driver and good to go for years to come.

I reground mine only but as I mentioned I only drive it occasionally. I've put about 10 K miles since I reground them.

Since you're not concerned about keeping it completely stock with numbers matching, a crate motor or even a later year model swap rather than rebuilding would be a good alternative. Newer engines are made with much better alloys than the older ones and last longer.

[sean1969c10]

Glad to help. I can't think of a specific list of things to do and in reality every job that comes into a shop is different and every customer is a individual. It's not a one size fits all situation. The wear in the engine and to some degree your wallet will determine what has to be done vs what is good to do but not critical.

As an example, if I was building and engine, I align hone the mains and recondition the rods period, weather there was a problem or not. This way I could set the housing bore on the minimum spec to get the most bearing crush. Then I would install the bearings, measure the size, subtract the clearance I wanted and grind the crank accordingly. This was all done to control quality and insure the final product was "right", this is an example of blueprinting. On an engine that a customer brought in to have machine work done but they were going to assemble themselves, we would make sure everything was with in spec. If the customer asked to have the blueprinting done we did it but not if they didn't specify. A good shop should be friendly and willing to talk to you about what you want and what they can do for you.

[sean1969c10]

In reference to valve seats, in my experience, if you are going to use the truck for heavy work daily it needs hardened valve seats period, I saw this a lot with 361-391 Fords in big trucks, they would sink the exhaust valves 3/8" into the heads. For most people that use their trucks as toys with occasional truck like use it's not mandatory unless the machinist determines that the seats in the heads are worn out. Another caution about hardened seats, the head has to be bored out to accept the seat and there is always a chance of hitting the water jacket, many times if the seats are a little "low" it's better to install a bigger diameter valve.

68gmsee is right about shops "exchanging" heads, where I was we never did but some shops do.

[sean1969c10]

As far as replacing the heads goes, if you aren't concerned with keeping you numbers matching parts, rebuilding 40+ yr old heads can get pricy. Get and estimate from the shop and compare to replacing with aftermarket heads, even if the new heads are a little more, the performance gain is something to think about, stay away from remanufactured parts store crap.

[markallen]

Getting one built is going to be the least expensive route more than likely...however a small business machinist type guy isn't going to be able to match jegs or summits warranty

[Jahloha]

Originally Posted by markallen

Getting one built is going to be the least expensive route more than likely...however a small business machinist type guy isn't going to be able to match jegs or summits warranty

Yeah. I just found a shop that offers a 3 year unlimited miles ok engines they rebuild. Might be a solid option.

[markallen]

If you can get that kind of warranty that's what I would go with hands down

[volksworld]

do you intend to assemble it yourself? if not a crate motor may be less money...and no down time....many times a shop that caters to racers will keep putting your engine to the back of the line cause their regulars need their engines back by the weekend....not too bad this time of year , but when racing season starts,look out...rather than trying to get into every detail of it here,pick up a couple "how to rebuild your small block chevy" books and read up on the process,so you'll have an idea whats going on....keep in mind theres no substitute for new...in some cases like connecting rods, new parts usually cost less than properly reconditioning old ones(obviously avoid Chinese crap)....I've seen plenty of recon rods where the wrist pin hole and rod journal hole weren't parallel and/or were different lengths....so a new CNC part is superior....

[Jahloha]

Originally Posted by markallen

If you can get that kind of warranty that's what I would go with hands down

Yeah, I'm calling tomorrow to verify what their website says

Originally Posted by volksworld

do you intend to assemble it yourself? if not a crate motor may be less money...and no down time....many times a shop that caters to racers will keep putting your engine to the back of the line cause their regulars need their engines back by the weekend....not too bad this time of year , but when racing season starts,look out...rather than trying to get into every detail of it here,pick up a couple "how to rebuild your small block chevy" books and read up on the process,so you'll have an idea whats going on....keep in mind theres no substitute for new...in some cases like connecting rods, new parts usually cost less than properly reconditioning old ones(obviously avoid Chinese crap)....I've seen plenty of recon rods where the wrist pin hole and rod journal hole weren't parallel and/or were different lengths....so a new CNC part is superior....

I have a friend who said he's willing to help with the rebuild if I go that route. Having so,Rome beside me would help me lean to assembling it myself. Seeing as it's my first time.