{"product_id":"kohler-valve-guide-inserts-and-seal-2-pack-ch25-ch740-vn-0sr7-cmi5","title":"Valve Guide Inserts and Seal Fits Kohler CH25 CH740","description":"\u003cp\u003eTwo bronze valve guide inserts and one valve stem seal that fit Kohler CH and CV cylinder heads. The seal replaces 25 032 14-S. Suits CH18, CH20, CH22, CH23, CH25, CH730 and CH740 and the vertical shaft CV equivalents. Why this part exists: on these engines the valve guides are machined into the head casting and the factory does not sell a separate guide, so there is no part number for one. The published repair for a worn guide is to ream it 0.25mm oversize with reamer 25 455 12-S and fit a valve with an oversize stem. These inserts are the alternative route, which is to bore out the worn integral guide and press a bronze insert into the casting. That is machine shop work. It means boring concentric with the valve seat, pressing the insert home, reaming it to finished size and recutting the seat to match, and it needs a head fixture, a piloted reamer and a seat cutter. If you are not set up for that, send the head and these inserts to a cylinder head shop. Specifications for the job: new guide inside diameter 7.038 to 7.058mm; replace at 7.134mm on the intake or 7.159mm on the exhaust; standard reamer 7.048mm and oversize reamer 7.298mm; stem to guide clearance 0.038 to 0.076mm intake and 0.050 to 0.088mm exhaust; seat and face angle 45 degrees. Measure the valve stems you plan to reuse as well as the guides. If the seats are sound and only the guides are worn, the oversize stem route may be simpler: intake 24 017 02-S and exhaust 32 016 02-S are the 0.25mm oversize stem valves, against standard 24 017 01-S and 32 016 01-S.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eTWO GUIDE INSERTS AND ONE VALVE SEAL - Two bronze valve guide inserts and one valve stem seal, the seal replacing 25 032 14-S. Fits Kohler CH18, CH20, CH22, CH23, CH25, CH730 and CH740 cylinder heads and the vertical shaft CV equivalents. Read the model and spec numbers off the blower housing decal rather than going by horsepower.\u003c\/li\u003e\n\u003cli\u003eTHE FACTORY DOES NOT SELL A VALVE GUIDE - THIS IS WHY THIS PART EXISTS - On these engines the guides are machined into the head casting. There is no guide to unbolt and no factory part number for one, which is why you will not find it in the parts list. The factory repair for a worn guide is to ream it 0.25mm oversize with reamer 25 455 12-S and fit a valve with an oversize stem. These inserts are the other route: bore the worn integral guide out and press a bronze insert in.\u003c\/li\u003e\n\u003cli\u003eTHIS IS BENCH WORK, NOT A ROADSIDE FIX - Fitting an insert means boring the original guide concentric with the valve seat, pressing the insert in, then reaming it to size and recutting the seat to match. That needs a head fixture, a piloted reamer and a seat cutter. If you have those, this is a straightforward job and a cheaper head than a new one. If you do not, hand the head and these inserts to a shop. Nobody fits a guide insert with hand tools and gets a valve to seal afterwards.\u003c\/li\u003e\n\u003cli\u003eTHE NUMBERS THE JOB RUNS TO - New guide inside diameter is 7.038 to 7.058mm. Replace when wear reaches 7.134mm on the intake or 7.159mm on the exhaust. The standard reamer cuts 7.048mm and the oversize 7.298mm. Stem to guide clearance is 0.038 to 0.076mm on the intake and 0.050 to 0.088mm on the exhaust. Seat and face angle is 45 degrees. Measure the stems you intend to reuse as well as the guides, because a worn stem in a new guide gives the same oil consumption you started with.\u003c\/li\u003e\n\u003cli\u003eDECIDE BETWEEN THE TWO REPAIRS FIRST - If the seats are good and only the guides are loose, the oversize stem route is quicker and needs no insert: intake 24 017 02-S and exhaust 32 016 02-S are the 0.25mm oversize stem valves, against standard 24 017 01-S and 32 016 01-S. If the head has already been reamed once, or the guide is worn past the oversize reamer, inserts are what is left. Check the seats and valve faces while the head is off, because a guide job and a valve job are usually one job.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Lil Red Barn","offers":[{"title":"Default Title","offer_id":68009619128474,"sku":"VN-0SR7-CMI5","price":44.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0397\/2346\/6909\/files\/612SKCbndML.jpg?v=1793382889","url":"https:\/\/performancesawsupply.com\/products\/kohler-valve-guide-inserts-and-seal-2-pack-ch25-ch740-vn-0sr7-cmi5","provider":"Performance Saw Supply","version":"1.0","type":"link"}