Good service and fair pricing

Told me a week to get the job done and only took 3 days

Rude and unprofessional. I took in some heads in for resurfacing, got quoted half the price they ended up charging me, and still received terrible service when I payed the increased amount. Will not be using them ever again. Robert was the guys name that was helping me, what a complete waste of time.

Best machine shop in town! The machinists there are very helpful and have helped me many times.

Best machine shop in San Antonio. Ask for Russell.

Worst customer service ever the guy on the phone hung up in my face with an attitude

Bob took good care of me and my small project - drilling out two bolts and placing correct inserts in a motorcycle part. Very professional.

Awesome customer service and they do what they say there going to do

There ok

Great machine shop. Did a bunch of work on my Subaru engine. It all measured perfectly when it came back, engine went together great, and made great power. Will be always be taking my stuff there.

Nobody in town as good, nobody in town as professional, nobody else is going to get my business. They’ve done two cylinders for me, impeccable workmanship!! Even the cross-hatching was absolutely perfect.

I dropped off the cylinder head for machining on Friday, it was ready on Tuesday, so they are fast! Good pricing on labor and supplies. I will be going back next time I need machining done on my cars. Friendly staff! Thanks for the repairs duffin!

Duffin Machine shop has resurfaced several flywheels for me including aftermarket/performance/lightweight. They are always prompt and friendly with an incredible price point. They even take on Horizontally Opposed engines, during a rebuild on a Subaru I had, they resurfaced the heads, installed new Valves, Guides, and seals. Also cleaned and honed the short-block, re-ground the crankshaft and ordered new bearing for my application. Amazing, knowledgeable, and affordable work by an awesome team of people!

Professional, accurate estimate. Very quick repair. Pleasant experience all around. Thanks guys! Appreciate the great work

The most professional knowledgeable place Ive ever been thank you all

Super great guys. Send my 5.9 head for a check and resurface. Came back perfect!

Prices are very fair and workmanship is exceptional. The guys are very experienced. Ive had several parts cleaned, crank checked and ground, rods worked, and now Im taking all the rotating parts in to get em balanced.

They did not honor their quote on assembling the engine. They said they had problems and $150 became $500. They put the rods in backward. I got them to fix that. I took the engine back apart later. They had ground the crank and never cleaned it. The oil passages were completely blocked with sludge. The engine would have siezed if I had tried to run it.

We have been using Duffin for years, no, DECADES. They are professional and they are the best Machinists in San Antonio. When our shop needs engine work, Russell always takes care of us. I highly recommend Duffin Engine Services for any engine rebuilding you need!

The people are super unprofessional & rude. I brought in a motor part on a Friday the gentleman told they would have it by Tuesday and after calling all week they never gave a date when it was going to be done. Every time it’s a different excuse. They kept telling me they would call to update, but all the calls have been made by me. I really wouldn’t recommend unless there’s no option, and even then good luck getting professional help. I would just stay away from here. Super disappointed.

What a great machine shop. After Experiencing a different machine shop that basically destroyed my block Duffins was a much needed change. It took the less then a day to resurface my head. Millers Machine Shop on Grissom doesnt hold a candle to duffins. The place was well organized and oily engine parts where not sitting everywhere there wasnt trash. The dam sure wasnt a customers block rusting in the corner. Thank you Duffins. As long as they are open I wont be taking any engine I work on somewhere else.

Used several times, good turn around, fair pricing

Best machine shop ever

Quality machine work no matter what your ride is.

Worst possible experience ever!! These guys are crooks!! Dont ever do business with them. I took some 327 heads in there for a rebuild and they lost one of my heads after telling me that they were junk!!! they just wanted to sell me some newer more expensive heads for my engine. The old man was extremely rude and a total schmuck. They have the worst reputation in san antonio and are horrible machinests. Dont ever do business with them unless you want to walk away with ur behind hurting.....

Great fast service, thanks!!

Great knowledgeable staff

Never used these guys, but, anyone charging 2700 for an old school Chevy 350 rebuild is definitely not good. You can buy a brand new engine for less than 2000.

Great machinist, great references from friends!!

Smartest folks in business.

Very good service