positive valve stem seals

[DJK]

Has anyone installed positive valve stem seals on their flathead? Asking for a friend!!!! Been doing some research @ Don Terrill's Speed Talk.

[Adam H P15 D30]

With the valves facing up I don't see a need...  Some oil needs to get in there.  

I don't install any positive seals on my Hemi's exhaust valves for the same reason, they face up hill.

[James_Douglas]

I am looking into custom silicon bronze valve guides for my next flathead rebuild. I am thinking of valve seals on the intake side. 

 

James

[Dodgeb4ya]

Not the right thing to do.

Hundreds of thousands of hour of factory testing and today's people know more?

Doubt it.

[DJK]

What is considered "normal" oil consumption on a recent rebuilt engine?

[Sniper]

On 10/2/2021 at 12:43 AM, Dodgeb4ya said:

Not the right thing to do.

Hundreds of thousands of hour of factory testing and today's people know more?

Doubt it.

 

If things haven't improved since then we'd still be running flatheads in new cars.

 

Knowledge increases, materials get better, new ideas get proven and technology marches on.  I seriously doubt they spent hundreds of thousands of hours testing valve guide designs for the flat head.  I am pretty sure the valve guide design used in our engines was developed almost 100 years ago and not changed because it was good enough for the time.  Expectations were much lower back then and if your expectations remain that low then enjoy it, but please stop pooping on someone that wants to update stuff to a higher expectation.

 

As for the OP's question, can't help there.

[kencombs]

IMHO,  the low quantity of oil present in the valve chamber coupled with the vertical up orientation of the valve stem doesn't require a seal.   They were a new thing when valves pointed down and lots of oil was splashing around on overheads.  And, there is no side load on the valve stem to accelerate wear on the guides, just straight up and down.  Any side load would be at the cam/lifter interface.

 

Again, JMO ,but positive seals may be a bad thing if they prevented oil from entering the stem/guide gap as there is minimal lube there to begin with.

 

Anyone that has done a running valve adjustment on a flathead and a small block Chevy knows what I mean.

[Sniper]

Looking at all the carbon build up in my intake port on the spare 230 I am tearing down tells me too much oil is getting in there.

 

Silicon bronze requires minimal oil to keep it lubricated compared to the stock iron guides.  Which is what the OP is thinking about using. 

 

 

[James_Douglas]

I know that several of the preimenate Ford Flathead re-builders around the USA are taking stock valve guides and lining them with bronze and adding stem seals to them. They then can run tighter tolerances as the silicon bronze allows for that. Tens of thousands of miles later no issues with the guides and less oil being sucked.

 

The question is, that is significantly different, if anything, between the flathead V8 ford guide design and the MOPAR flatheads?

 

James

[Sniper]

Other than the Ford guide being a split design and not pressing in but being held in by a retainer I can't really think of anything substantively different.

 

Iron guides have the benefit of being cheap and durable enough.  You already know the benefits of the silicon bronze setup.   There was a company that was making guides with an internal o-ring in place of a guide seal  https://www.cheprecision.com

 

But they are a high performance oriented shop, might be way over kill for what you need.

[DJK]

I am almost a qt. low after 500 miles, some have mentioned to leave it a qt. low and top up to the ad mark as needed. During long down hill runs I noticed some blue smoke from the exhaust which has in my recollection meant oil past the valve guides. My argument is, if oil is required to be sucked in for lubrication, why do my modern engines consume no oil? The only oil leak I have is at the rear main seal which appears to be minimal due to the fact it is not blowing back onto the trans as it did before the rebuild. Again, I am just curious what others are experiencing as far as oil consumption. Thanks for all the responses.

[kencombs]

That blue smoke oil burning, but I really doubt it is guides.  Much more likely that the oil rings are no longer wiping the cylinders effectively and the residual oil is burning off.  On an OHV engine with lots of oil around the upside down valves, they would smoke under deceleration and prolonging idle, both conditions with high intake vacuum. Happens even with good guides when the old umbrella or oring ring seals harden and crack.

 

Engines that consume no, or very little oil, have round straight cylinder walls, pistons and rings.  All the absolute correct dimensions and with the correct machined finish..   Modern CNC machines can duplicate those conditions over and over.   Engines of the 40s and 50s were never that precise and the materials, usually cast iron walls and rings wore quickly.

[Pete]

22 hours ago, DJK said:

What is considered "normal" oil consumption on a recent rebuilt engine?

 

My original P8 engine was rebuilt about a year and a half ago. I recently took it on two tours that totaled about 1,800 miles. The engine had about 2,000 miles on the rebuild when I started. The tours included a lot of mountain driving. I used about 5 ounces of oil total on the two tours.

 

Pete

 

Edited October 4, 2021 by Pete

[DJK]

32 minutes ago, Pete said:

 

My original P8 engine was rebuilt about a year and a half ago. I recently took it on two tours that totaled about 1,800 miles. The engine had about 2,000 miles on the rebuild when I started. The tours included a lot of mountain driving. I used about 5 ounces of oil total on the two tours.

 

Pete

 

I could live with that!!!! Anything done with the valve guides on the rebuild? My machine shop said mine were fine!!!!??????

[DJK]

10 hours ago, kencombs said:

That blue smoke oil burning, but I really doubt it is guides.  Much more likely that the oil rings are no longer wiping the cylinders effectively and the residual oil is burning off.  On an OHV engine with lots of oil around the upside down valves, they would smoke under deceleration and prolonging idle, both conditions with high intake vacuum. Happens even with good guides when the old umbrella or oring ring seals harden and crack.

 

Engines that consume no, or very little oil, have round straight cylinder walls, pistons and rings.  All the absolute correct dimensions and with the correct machined finish..   Modern CNC machines can duplicate those conditions over and over.   Engines of the 40s and 50s were never that precise and the materials, usually cast iron walls and rings wore quickly.

This engine was bored .020 over, ring end gaps set at .010, NOS ring set with 2 one piece oil rings, machine shop stated valve guides were OK, valves and seats were reground.

[DJK]

40 minutes ago, Pete said:

 

My original P8 engine was rebuilt about a year and a half ago. I recently took it on two tours that totaled about 1,800 miles. The engine had about 2,000 miles on the rebuild when I started. The tours included a lot of mountain driving. I used about 5 ounces of oil total on the two tours.

 

Pete

 

Is this the Pete from the P-15 Picnic? If so, sat next to you at the restaurant in Watkins Glen.

[kencombs]

1 hour ago, DJK said:

This engine was bored .020 over, ring end gaps set at .010, NOS ring set with 2 one piece oil rings, machine shop stated valve guides were OK, valves and seats were reground.

Maybe the rings and cylinders still need some miles to complete the breakin

[Pete]

1 hour ago, DJK said:

I could live with that!!!! Anything done with the valve guides on the rebuild? My machine shop said mine were fine!!!!??????

My shop reused all the valve guides and replaced only one burned exhaust valve.

 

Pete

 

[Pete]

2 hours ago, DJK said:

Is this the Pete from the P-15 Picnic? If so, sat next to you at the restaurant in Watkins Glen.

DJK,

 

Yep, that was me. A very fine tour.

 

Pete

 

[DJK]

19 hours ago, Pete said:

DJK,

 

Yep, that was me. A very fine tour.

 

Pete

 

Looking forward to next year in Vt.

[JBNeal]

On 10/3/2021 at 7:56 AM, DJK said:

What is considered "normal" oil consumption on a recent rebuilt engine?

I have rebuilt 2 flatheads with engines in the truck, including worn valve guides, as I read about how to do it in an old shop manual, no machining done other than lapping valves by hand.  I'd lose about a quart every 3500 miles, but I'd be changing the oil anyway at that point.  The best I can figure is tight valve guides seep very little oil into the combustion chamber as the lubricant surface tension resists vacuum induced flow.  Worn valve guides allow the lubricant to flow freely due to vacuum as the surface tension becomes irrelevant with the additional space for fluid movement.  Always check your tailpipe and body panels for extra carbon residue as some of the exhaust emission swirls and sticks to adjacent metal surfaces...a dirty backside is a clear indicator of poor engine health 

[47 dodge 1.5 ton]

Jumping back to the idea of changing material for the bushings, if someone went to another material, I’d recommend SAE 841 oil impregnated bronze. I work in the heavy industrial pump business and bearing material improvement is closely monitored. I have been involved with testing rotating equipment with almost any new trade material offered over the last 25 years or so and believe this would suit best for the application. 

Edited October 8, 2021 by 47 dodge 1.5 ton

[Dodgeb4ya]

Some extra oil consumption info...

Correct type of oil and break in procedure to enable rings to wear into cylinder walls is needed to prevent oil consumption on sawa new engine.

Are the rings chrome or cast iron?

Chrome rings take more time to wear in.

Break in procedure generally requires a non detergent type oil for ring break in...no slippery synthetic oil... no long idling. Start the engine and run it at different speeds for the first hour.

When driving a new engine brief full throttle say up to 45 mph  then coasting down to 20mph several times to twist the rings. This helps promote ring seating.

New rings contaminated with engine assembly lube will not seal up as the lube is so slick.

This can happen with a newly assembled engine on a stand sitting for a day or more, cylinders pointed down and using assembly lube not paste on all the crank journals and bearings.

The slippery lube runs down into the cylinders and rings. The rings will never seal up 100%...

Valve guides on a MoPar inline flathead are generally not a cause of excessive oil consumption IMO.

Proper guide and orientation install is critical on both intake and exhaust.

OHV engines require tight guides and proper stem seals most certainly.

JMO?

 

 

 

 

[DJK]

20 hours ago, JBNeal said:

I have rebuilt 2 flatheads with engines in the truck, including worn valve guides, as I read about how to do it in an old shop manual, no machining done other than lapping valves by hand.  I'd lose about a quart every 3500 miles, but I'd be changing the oil anyway at that point.  The best I can figure is tight valve guides seep very little oil into the combustion chamber as the lubricant surface tension resists vacuum induced flow.  Worn valve guides allow the lubricant to flow freely due to vacuum as the surface tension becomes irrelevant with the additional space for fluid movement.  Always check your tailpipe and body panels for extra carbon residue as some of the exhaust emission swirls and sticks to adjacent metal surfaces...a dirty backside is a clear indicator of poor engine health 

Tailpipe looks good, no residue seen, only some blue smoke on long downhill decel conditions. 

[DJK]

10 hours ago, Dodgeb4ya said:

Some extra oil consumption info...

Correct type of oil and break in procedure to enable rings to wear into cylinder walls is needed to prevent oil consumption on sawa new engine.

Are the rings chrome or cast iron?

Chrome rings take more time to wear in.

Break in procedure generally requires a non detergent type oil for ring break in...no slippery synthetic oil... no long idling. Start the engine and run it at different speeds for the first hour.

When driving a new engine brief full throttle say up to 45 mph  then coasting down to 20mph several times to twist the rings. This helps promote ring seating.

New rings contaminated with engine assembly lube will not seal up as the lube is so slick.

This can happen with a newly assembled engine on a stand sitting for a day or more, cylinders pointed down and using assembly lube not paste on all the crank journals and bearings.

The slippery lube runs down into the cylinders and rings. The rings will never seal up 100%...

Valve guides on a MoPar inline flathead are generally not a cause of excessive oil consumption IMO.

Proper guide and orientation install is critical on both intake and exhaust.

OHV engines require tight guides and proper stem seals most certainly.

JMO?

 

 

 

 

Rings are NOS cast iron, 2 one piece oil rings, 15w-40 conventional diesel oil is what I am using, also to lube rings upon assembly. Break in procedure was done with easy throttle up to 45-50 mph then decel down to 25mph at least ten times. Back in 1995 someone at Nissan forgot to put a hole in the side of the connecting rods on the 3.0 V-6 engines to lube the cylinder walls, needless to say, I rebuilt many engines with no break in oil, proper fitting of pistons to bore etc. This is my first flathead and I am just disappointed with the oil consumption. Thanks for all the responses.