Valve guides

[Unkle Krusty]

Heads are off. Bore looks good. Removed two valves. Intake is quite snug in guide. Exhaust has a small amount of wiggle. Book does not talk about valve guides, but it appears there are guides.
So, do the guides punch out fairly easily?
I will blow out all the passages while the pan / sump is off. Is there a preferred fluid for flushing / cleaning all the passages? Thank you again.UK

 

[pnora]

Heads are off. Bore looks good. Removed two valves. Intake is quite snug in guide. Exhaust has a small amount of wiggle. Book does not talk about valve guides, but it appears there are guides.
So, do the guides punch out fairly easily?
I will blow out all the passages while the pan / sump is off. Is there a preferred fluid for flushing / cleaning all the passages? Thank you again.UK

The FSM does discuss guides.

 

[493 Mike]

What are you doing for machining? Guide work is quite fussy and valve seats will need to be ground to ensure concentricity.
Mike

 

[RemCharger]

^^^^ the factory guide is just drilled into the cast iron. It's a slight ordeal. How many miles or K are on it

 

[rickseeman]

There are no guides to "punch out". They are part of the head casting.

 

[gkent]

Generally worn guides are drilled and tapped and a new bronze guide threaded in - much like a Heli-coil - "set" into the threads then reamed for the proper fit. Then the seat is done based on the guide. Not a job you'd do in your shed !!!

I had a set of heads that someone had drilled and installed solid bronze guides and cracked every port around the guide. The wrong way to do guides !!

 

[pnora]

Generally worn guides are drilled and tapped and a new bronze guide threaded in - much like a Heli-coil - "set" into the threads then reamed for the proper fit. Then the seat is done based on the guide. Not a job you'd do in your shed !!!

I had a set of heads that someone had drilled and installed solid bronze guides and cracked every port around the guide. The wrong way to do guides !!

I thought the holes were sized and the liner pressed in. Never heard of threading the hole for a screw in liner.

 

[DeltaV]

Teenage me took my 318 heads to the machine shop and they gnurled the guides. Never any notable issues over the six subsequent years and many miles of use and abuse.

 

[gkent]

Teenage me took my 318 heads to the machine shop and they gnurled the guides.

This doesn't work very well on cast iron. When you knurl a guide you don't remove metal, the knurl process moves metal to make the hole smaller and its then reamed for the valve stem. But cast iron doesn't like to be moved around.

Its worth asking the shop doing the job though.

 

[Unkle Krusty]

Thank you all for the replies. Got it. No guides to bang out. Check side play, if too much off to the machine shop and get bigger shaft valves. At the moment I am in take it apart mode. About 50,000 miles. 318 was running good. But need a bit more power. Camper van weighs 6600 loaded.
Any thoughts on flushing debri from engine. Mostly gasket bits, very small amount of sludge.
Today i will remove all the valves. Inlet seat looks good, exhaust has carbon on valve. That is from the two I removed yesterday. Now to find the dial gauge and make a bracket to hold it.

 

[gkent]

get bigger shaft valves.

That's not the way to do it.

 

[Fran Blacker]

https://www.klineind.com/k-line-service-tools/valve-guide-liner-system.html

Installing Valve Guide Liners Guide sleeves top link bottom The tools to do it, cost?

 

[493 Mike]

I have had a UTP guide knurling set for over 50 years now. I was taught in college how to use the tools and have done many heads over the years. My tool has a arbor that accepts a diamond edged roller (tiny) that is mounted on a angle. It is actually rolling thru the guide displacing iron that can be reamed to size. It allows a tighter than stock clearance because the groove holds oil. I would never use one of the "tap" style knurlers. I used it last on my 2008 3.8 V-6 mini van engine.
Mike

 

[dvw]

You can clean up the valves and give them the wiggle test. If they are to loose the guides will have to be replaced or lined with bronze liners at the machine shop. This will also require a valve job since the guides are never 100% in the same spot. Daily driver? If the guides aren't to sloppy? Even if they are somewhat loose? You can lap the valves with lapping compound. Apply compound to the seat. Lube up the guide and insert the valve. With the valve in the head chuck the stem in a drill. Spin the drill and pull the valve against the seat. Then move it away and back. 20-30 seconds remove the valve and look at the seat and the valve. If it has a even grey pattern all the way around on the valve and the seat. Your done. If not repeat the procedure, Usually 1-2 cycles is all it takes. Is this the best? No. Will it work and keep it running 10,000-20,000 miles or more ? Yup.
THis is the normal way to test, 2 methods shown.

Interesting test here. Never used it. But if it doesn't pass this test? My bet is the guides are pretty bad.

Doug