Your Subaru's cylinders are where everything happens. When the bores wear, score, or go out of round, no piston ring on earth will seal them. We bore and hone Subaru blocks here in Kent, on our own machines, so the foundation of your engine is straight, round, and sized exactly to your pistons.
We are East Valley Auto Rebuild. Mark Bryant, known across the Pacific Northwest as the Independent Subaru Guru, has spent more than 30 years inside these engines. The machine shop is the core of what we do, and cylinder work is where a careful shop earns its keep.
Get a Subaru cylinder boring and honing quote in Kent, WA
When a Subaru block needs boring and honing
A lot of Subaru blocks come to our Kent shop tired but fixable. Here is what we usually find.
The cylinders have taper. After a few hundred thousand miles, the top of the bore wears more than the bottom, and the rings cannot follow that shape. You burn oil and lose compression. A bore that has gone oval cannot seal either, no matter how good your rebuild is everywhere else.
Sometimes the damage is sudden. A dropped valve, a broken ring land, or a piece of debris scores a cylinder wall. Now you are choosing between a bigger bore or a sleeve.
And sometimes the customer wants more. A Subaru performance engine build often calls for an overbore to fit larger pistons and pick up displacement. That is planned machine work, not a repair, and it has to be exact.
Ever wondered why a fresh rebuild still smokes? Nine times out of ten, the bottom of the problem is up in the cylinders. The bores were never trued.
The torque plate makes the difference
Here is a detail most drivers never hear about, and it separates real machine work from a quick hone.
A Subaru block does not stay perfectly round once you torque the heads down. The clamping load distorts the bore slightly. If you hone the cylinder while it is loose on the bench, it measures perfect, then it tightens into a faint triangle the moment the engine is assembled. Your rings fight that shape forever.
We hone with a torque plate bolted to the deck, loaded to spec, so the bore is round under the same stress it will see when the engine is together. When the plate comes off, the bore relaxes a hair. When the heads go back on, it pulls right back to round. That is how the rings seal for the long haul.
Does every shop do this? No. Should they, on an engine you are paying to rebuild once? We think so.
Our cylinder boring and honing process
We handle most of this in-house, in a clean machining area, with precision boring equipment, hones, and top-grade measuring tools. We rarely outsource, so your block does not get shipped around town.
1. Clean and inspect.
The block gets fully cleaned so we can actually read it. We check the bores for taper, out-of-round, and scoring, and we inspect the deck and case for cracks.
2. Measure your pistons first.
This is the order that matters. We measure your actual pistons, then bore and hone the cylinders to give the exact piston-to-wall clearance Subaru calls for. Pistons set the target, not the other way around.
3. Boring.
We bore each cylinder to the chosen size, whether that is a clean-up bore to the next standard or a planned overbore for a bigger build.
4. Torque-plate honing. We finish the bores under torque-plate load to the right size and the right crosshatch finish, so the rings seat fast and seal.
5. Deck check and surfacing. If the deck needs it, we surface it flat so the head gaskets get an even clamp. A true deck is part of a sealed engine.
6. Final measurement. Nothing leaves Kent until every bore measures where it should.
Scored or damaged cylinders, and sleeving
What if a cylinder is too far gone to clean up with a bore? We can sleeve it. We press a new cylinder sleeve into the block and machine it back to standard, which saves a block that would otherwise be scrap. On a Subaru with a rare or hard-to-find block, sleeving is often the smart call.
We will always walk you through the options. Bore to the next size, sleeve the bad hole, or, if the case is cracked beyond a safe repair, start with a better core. Honest appraisals are how we have kept customers for 20 years and more. We tell you what needs doing and what does not.
Pricing and what affects the cost
Cylinder machine work is priced by the job, at a real fraction of dealership pricing, and most dealers send this work out anyway.
A standard clean-up bore and torque-plate hone on a sound block is a predictable job. A planned overbore for a stroker, a deck resurface, or a sleeve adds bench time. The variables are condition, how many cylinders need work, and what your build is asking for. We measure, then we quote the whole thing before any chips fly.
Every machine job we do carries our 12-month, 12,000-mile warranty. That is the same coverage whether you are a daily-driver Outback or a built WRX.
DIY builders, drop off your block
Plenty of our machine-shop customers do their own assembly, and we are glad to support that. Pull the block, bring it to our Kent shop with your pistons, and we will bore and hone it to your exact clearances while you handle the build. Bring the pistons. We cannot dial in piston-to-wall without them.
This is also why doing the bottom end under one roof pays off. When the same shop does your boring, your crankshaft grinding, and your cylinder head resurfacing, every clearance agrees with every other one. Mixed shops, mixed numbers.
Why East Valley Auto Rebuild in Kent
We are one of the only shops in Washington offering complete in-house Subaru machining and full engine installation in one place. No outsourcing the bore to one shop and the assembly to another. The block you drop off is the block we machine, and if you want, the engine we build and install.
Mark Bryant came up through Subaru-only work and has run this Kent shop since 2003, now out of a 7,000 square foot facility. He trained as a chef before he turned wrenches full time, and he brings that same fussiness about getting things exactly right to every block on the bench. Our team carries decades of combined Subaru knowledge, and we specialize in keeping high-mileage Subarus alive well past 300,000 miles.
Take a look at our full Subaru machine shop in Kent, or read about complete Subaru engine rebuilds if the block is one piece of a larger plan. When you are ready, contact our team and we will get your block scheduled.
See Why Subaru Owners
Keep Coming Back
The quality of work is top notch. Took my 2011 STI there to get the head gaskets done and could not be more pleased with the work they did and how they treated me through the process. Sent photos and videos of the entire process while taking apart the motor. Great people who really do want the best for the customer and their car. Would absolutely take my Subaru there again if needed.
I brought my 2017 wrx with a blown engine to Mark at east valley auto rebuild. I really liked how he took the extra time to discuss all my available options, from keeping it stock to going with more quality parts. Mark covered it all with his extensive knowledge while he tooks us out to lunch. He really made sure that what I wanted out of and from the car is what I got.
I have been coming to this repair shop for a couple of years now and just bought my second Subaru to allow them to keep maintaining my car for me. They have been so helpful to me over the years, always working around my budget, always squeezing me in last minute when they are busy. The owners are great people who genuinely care about their customers and the staff is very informative. Thank you, East Valley!
These folks handle all my auto repairs with extreme care and understanding
I've brought my 2011 Subaru Outback to East Valley Auto Rebuild a few times now, and every visit has been a great experience. Mark Bryant and his team do excellent work at a fair price, and they really know their stuff—especially when it comes to high-performance Subaru options. They're honest, knowledgeable, and easy to work with. If you're looking for quality service and trustworthy advice, I highly recommend them!
Some of Our Professional Subaru Services
Below are some of our most popular Subaru Services and Repairs and descriptions of each.
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Frequently Asked Questions
What is the difference between boring and honing a Subaru cylinder?
Boring removes metal to enlarge the cylinder to a new size and make it round. Honing is the finishing step that sets the final size and puts the right crosshatch finish on the wall so the rings seat and seal. A proper job does both, in that order.
Why does torque-plate honing matter on a Subaru?
When you bolt the heads onto a Subaru block, the clamping load distorts the bores slightly. Honing with a torque plate loaded to spec means we finish the cylinders under that same stress, so they are truly round once the engine is assembled. It is the difference between rings that seal and rings that never quite do.
Can you fix a scored or damaged Subaru cylinder?
Often, yes. If a clean-up bore will not save it, we can press in a sleeve and machine it back to standard. That rescues a block that would otherwise be scrap, which is a real benefit on harder-to-find Subaru blocks.
How much does cylinder boring and honing cost in Kent?
It depends on the block's condition and your build. We quote the full job up front after measuring. A standard bore and hone is far cheaper than replacing the block.
Do I need to bring my pistons in with the block?
Yes, please do. We measure your actual pistons and machine the bores to match them for correct piston-to-wall clearance. Without the pistons, we are guessing, and we do not guess on a rebuild.
Schedule Subaru cylinder boring and honing in Kent, WA, call
(253) 872-7468.
