Thread: valve guides

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looking for information on r&r valve guides on a 350 chev. motor. Can one of you fine sirs point me in the right direction? Thanks

Changing out the guides is not a DIY job, needs to be done at a machine shop. Talk with them about what you want done.

OEM guides are cast into head--to change you need a machine and tooling to use piloted drill to drill out guide and then piloted reamer to ream hole to proper size hole for intererance fit guide to be installed(hammered in with a pilot) then ends cut to length, fitted for seals,hole then reamed/honed for valve stem clearance-----probably left something out???????????

Thanks Jerry. I have not yet torn down the heads. While cleaning the dust off(they have been on the shelf a couple years) I noticed the two inboard exhaust valves have what appears to be the guides slipped down to the valve head. Never saw that before. Have you? I am fairly well equipped here and could do the guides with a bit of instruction. Still, I have to dis-assemble first and try to figure what caused this to happen. Will keep you posted as to what I find out.

if the guides are moving then they may have locked up on valves .you will have to go over size if at 502 guide now .i would drill &ream up to a over size guilde and use a manganes bronze guilde that cut for a top for 530.PC seal with a shoulder and 545 O.d for a 11/32 valves they cost more not to hard to find PEP. Ferrea. PBM.CV .SBI. all sell them. there not cheap looking at 160. for 16. just did a set of pro comp heads on a boat by the time i did the guide work and honed them to fit the valves with the sunnen P-190 and check sizing with sunnenP-310 new ex valves. new heads may been another way to go if they needed any seat work i think would of been cheaper to throw them out or sell for scrap. you can use a cross over or make a new guide from guide stock they will sell you a false valve guide out of iron or manganese. AV&VS will sell you one but look in the cross over threw like SBI book and find a guide that will not need much work

Very informative, thank you. I still have not torn them down so dont know why the valves would lock up on the guides, overheating maybe? Lack of oil? Also noticed the pc seals on those two valves are coming apart. None of the valves appear sunk in so Im hoping I can get away with just grinding the seats. I expect to replace a few valves and guides but it seems like wishful thinking, may have to file 13 them and start looking for another pair.

Originally Posted by racemaster

Very informative, thank you. I still have not torn them down so dont know why the valves would lock up on the guides, overheating maybe? Lack of oil? Also noticed the pc seals on those two valves are coming apart. None of the valves appear sunk in so Im hoping I can get away with just grinding the seats. I expect to replace a few valves and guides but it seems like wishful thinking, may have to file 13 them and start looking for another pair.

one thing to keep in mind that it can be hard to center up on a worn out guide there ways to do this. to do job like that if some ones been there you can only hope he was on center when they cut it for guides as you can run out of iron on a head thats been worked over good you may have to put a seat in to clean up all the way around the seat.i seen nice heads turned to junk were you would have to use a bigger valve just to hang a 45 back on the seat if the guy did not want all new seats. some tooling can walk around some. a good valve job is only as good as the guides and pilot for tooling my pilots are made from solid carbide to hold down flex = runout .i do not grind much seats any more putting more then 4 angles would eat a days time up. i like to keep my valves under .005 up or down so i use the3D set up so when i get in new heads that have over 2.300/2.460 intakes its no big deal were stones getting clumsy .i can start with a raw head with a square seat no angles come down and form the radius to chamber 4 angle s and drop down in the start of the bowl. pick cutter out then drop in the bowl and cut that all out .i would hate to do the job with only stones so there only use some times for a touch up. some seats i do not even like to be around when the machine cutting on it. this stuff called berylilum i do not grind it its very bad news here is a all out race head and tooling i use for the job

Pat, words fail me. I have been turning wrenches 45 years. The head you show there, in my wildest dreams I never imagined something like that. Im lucky if I find a used pair of heads that are not cracked, grind them down and tap them for screw-in studs, do some pocket porting, and Im on down the road. Anything costing more than that and I would be walking. Might I ask where you learn to do all that?

I wanna say something funny here but words seem to fail me right now- widen out that pic so we can see more Pat and don't forget to show a pic of the dozens of pilots it takes to cover all the sizes/clearances!!!!!!!!!!!!!And welcome back from the BANNNNNNNNNNNNNNNNNNNNNN

i first started doing valve and port work on heads over 20years ago had some basic tools then was doing the 3 angle basic valve jobs with a newen seat cutter and motor driver used sioux grinding stuff but i wanted to put my own seats and guides in.i did not have the money. what push me in getting more tooling and machines.it was poor work that i paid for seat and guide work at this time i had to farm out. my friend was doing valve work on harley heads and in time we started with his IDL machine for seats and guide work at my shop.but i could not do valve jobs or much trick stuff and customers asking for this work . i had guys wanting me to weld up heads from other shops .so before i new it there was nothing for head work i would not do with the machines and learned by doing . what i wanted to see was a prefect job that match or beat the jobs when i was paying for is work at that time i just bolted engines together but even then there were many that knew when i had parts at the machine shop i was very well known for heavily re worked parts so in time sioux 645 valve grinder. sioux seat grinder. a newway seat cutter setup with a motor driver . my buddy was doing most harley stuff i was doing all the car stuff at the same speed were he was only cutting 4 seats. i was doing 16. and doing big valve jobs with the neway so he took his idl machine as time past we just did not see eye to eye . at this point in time i had the same machines the small auto machine shop had in town. i pickup better machines that needed work i rebuilt them made parts if needed or i knew i could build a machine i did so.building and working on the machines that helped me understand what was going on when the job or machine was not doing a good job in time knew what it took to do a better job. now i have one of the bigger shops in town for auto /race setup .were i learn it from ? i did body and paint.frame work i was getting paid by the job i did 90hours of work in less then 38 hours so i free time and hang out at the machine shop watching machine engine parts. my free time i was building race engines street /strip and painting any thing that paid . heath went to hell slowly stop painting and body work .pickup more machines and tooling .i make my own hours . cost of them big chief heads bare 1600.each and up the head in photo as a 2.450 valve in it and is titanium . one of them heads i welded up started me down this road when i needed a seat in one kind of a full circle deal

Originally Posted by jerry clayton

I wanna say something funny here but words seem to fail me right now- widen out that pic so we can see more Pat and don't forget to show a pic of the dozens of pilots it takes to cover all the sizes/clearances!!!!!!!!!!!!!And welcome back from the BANNNNNNNNNNNNNNNNNNNNNN

well yep pilots are 150.each with shipping. there no photo of me in there just my big ego .you will not see many photos of me. as i never seen many photos i liked of me.. hard for me to under stand why so many cameras are screwed up ? oh i seen you want the photo wider to see how much money i have in tooling well i was thinking you wanted me in the photo ? well i have a forest of them line up in the tool holder like jack pines not all are carbide just some sizes if i am starting from a bare head i will use one .that snap shot was a photo of a clean counter top with some tooling not close to all of it even i was inpressed i could see the work table so i snap it

Pat, I want to thank you for all the valuable information. I dont know anywhere else on earth I could get such information. Well done. Thanks again!

Thanks for posting Pat, it's always good reading.

OK, so I pulled one of the valves and the valve and guide slipped right out. The guide then slid right off the valve easy. So they were not seized up. The valve is not bent and the face and valve seat look ok. The guide is paper thin. The side of the guide near the valve face looks burnt for about a third of the length and the end is opened up a bit.The valve has numbers near the tip, 01769R and 1-1-W1-1. Now as I recall, the motor only had about 5000 miles on it, and the reason I pulled it out was because it would go two or three blocks and all the water would dissapear and it would get hot. Now it appears some of the head bolts did not have any sealant where they go into the block. So my question now is would overheating cause the guides to come out like that? When the motor was put together(about 7-8 years ago) I had the heads done at a local shop and some guides were installed, I dont remember how many. When it started overheating I would shut it down and have somebody pull me back home. I know its asking a lot with no photos, what do you think?

so you are talking about a bronze guide liner type deal-----------guide in head probably was repaired with a liner but was too oversized for the liner and/or liner was not broached into the head guide. If this was the case you can repair the head with a .502 guide-


In overheating cases(no matter what the cause) engines with two exhaust valves together (sbc, olds,etc) suffer pretty bad in those cylinders---------exhaust/intake valve placement has always been a big item in engine design---people who do the heads and people who do the intake/exhaust manifolds don't seem to get along---------check out BBC!!!!!!!!!!