Inliners International Forums General Discussion Hi Performance 1.84/1.60 Valves

Found a machine shop that is within my budget. I need to get valve guides cut so I can run a .500 lift cam, and I thought why not add 1.84 /1.60 vales, with out any more work will the larger vales make much of a difference? Would it be a waste of money? The cam is a Comp 268 on 108 instead of 110 LSA (comp says it will be the best cam to run idle to 5K)

What engine are you running?

I believe Tlowe engine dyno tested this combo, stock head then switched to a larger valve head, but w/lumps installed?

Ask Tlowe.

If you do the valves & camshaft change, you will see a difference for the better.

I you are not gong to install lumps ports I would profile the intake boss as to make the intake port window bigger & will not loose too much port velocity by leaving in the boss.

You want to have port velocity up to keep the torque of the engine.
Truck application, correct?

MBHD

I assume everyone who bumps up from the stock 1.5" exhaust valve to the 1.6" valve, adds a hardened valve seat insert to the exhaust side? Even with the later heads that have a heat treating to harden the exhaust seat on the casting, this surface process will be removed during the enlargement and so will not be hardened without the insert, correct? And the water jacket around the exhaust on all non-integrated head castings leaves enough room for the extra removal of material around the exhaust seat?

If you are going to install exhaust seats, use the shallower ones to avoid hitting into the water jackets.

MBHD

That's what I was wondering. Thanks.

The 1.8/1.6 is very worth while to do. The valve size change alone is worth almost as much power as a cam change.

Be sure to unshroud under the valves after the new seat size is cut. There will be a big edge left after that seat cutting.

It is a 250 in a 62 nova. I do not have the tools to port the head. I am looking to get more power through out the entire power band(idle to 5000). I have a offy/390 and a stove bolt header now. I do 1/8 mile drag racing, but is street driven mostly.

Are 1.6 exhaust valves ever installed without adding new hardened exhaust valve seats? Can a head be set up that way and live? What is the most common thing done? Jay 6155

If youre spending $$$ on the head, why not do the big valves and lump ports at the same time? Sounds like all you need is that and a cam and youre good for the 1/8 mile.

What times/MPH are you running now? Trans/Rear/Exhaust?

As far as hardened seats, I guess it wouldn't hurt, but of all our family fleet of Ford&Chev engines, I have never seen one pound the valves in unless it was in a hard working truck or a 100,000+ mile engine. For a typical hobby car that will see 10,000-20,000 miles, I wouldn't worry about it- especially if there is any risk of hitting water cutting to put the seat in!

Most performance machine shops no longer even recommend installing hardened seat any more. The bad gas issues of the 70's that first created this problem is long gone, and today with alcohol blended gasoline, engines just don't have this valve pounding problem much anymore. Plus, the damage from a valve seat falling out by someone that doesn't know what they are doing is worse.

Last time down the strip it was a 12.8 at 52 because of Massive tire spin. I have a Saginaw 4 speed with 3.50, 2.447,1.65 and 1.0. Right now I have a 2.41(7.5 10 bolt out of a 78 El Camino) gear, but was given a set of 3.23 of 3.42, I cannot remember right now. I plan on using only the first three gears for the 1/8. I cannot go much deeper than 3.42 or my first gear will be way to low. Buying a new tranny is out of the question. IS there much of a difference in power just between the 1.5/1/6 exhaust? Seen sketchey on the hitting water? Lumps and the port work would price the head way out of my price range. I am disabled and my wife works full time and goes to school too. I am scraping parts together and trading stuff to get what work I can get done. I wish I had the cash to drop on a new MrHotrod6 head but that is out of the question.

I install hardened exhaust seats into all the heads coming from my shop.
See many used heads with recessed valves. Some almost so deep, a seat can't be installed to fix.

It really is not that expensive to get the head work done.
Bolt in lumps 60.00
Head rebuild kit 205 (Contains all parts needed)

Then it is just machine work.
Some of it depends if the guides need replaced. I always put in guides. They are the basis for centering the new valve seat.
The lump kit, you may be able to put it in yourself. A Mill is not required to install them. A large drill press is.

When they cut in the seats for larger valves, while there, they can also cut out most of the valve throat area to gain flow. With same machine. Therefor almost no porting needed.

Straight Axle,
Well the good news is, you have a lot of work to do for free first (or maybe confirm that slow 52-53mph at another dragstrip?)

I built a Gonkulator file of your car, assuming 2980lb with you in it (have you weighed it?). I used "my" 250 engine, stock 250, offy/390, stock exhaust/muffler. Crappy traction and slow shifting Gonkulated to
Torq 219 at 3000
Powr 169 at 4300
3.14 60ft
12.41 at 60.0 1/8 mi
18.74 at 78.8 1/4 mi

To slow the car DOWN to that 52-53mph you got, I had to really cut the power back, down about 30% across the board, like pulling 2 plug wires (are you sure it isn't a 4-cyl in there?)
Torq 151 at 3000
Powr 117 at 4300
3.14
12.89 at 54.4 (about 3000 in 3rd)
20.03 at 69.1 (about 3800 in 3rd)

Never minding the times or traction, for a car to be down 6mph in the 1/8 mile is HUGE. Something is way off or very unhappy, wont matter what exhaust valve size is in there.

Good news is, you can hunt this kind of thing down and fix it nearly for free I would guess. I would check the timing curve and compression first, make sure its hitting all 6 cylinders, is there a potato or rat or bird stuck in the exhaust pipe, etc. Something major to cut it down that slow.

Check out the carb, what's in there, is it way too lean or way too rich, is the secondary opening at all, etc. Pull the head, calc your compression - are you sure its a 250 and not a 194? It's something MAJOR wrong to be way down at 53mph. I would just lap the valves, make sure they seal, leave the head stock for now til you sort it out rather than throw money at it when something else major is going on there. Are the brakes stuck on? etc!


EDIT,
Here is another real world example.
Car Life Feb.1962 tested a 194cid 62 Nova, 3spd 3.08 gears, 2 aboard.
They got
19.00 at 70mph
0-60mph 13.0
(No 60ft or 1/8 mile back then, the Beach Boys 409/409 song didn't even exist yet!)

Gonkulator gets
2.72
12.06 at 58.0
18.91 at 71.0
0-60mph 12.8
So this is a bone stock 194-1bbl turning 58mph in the 1/8 mile. For yours to turn 53mph, again something major is wrong, or the clocks at that dragstrip are really messed up. Should be fun to resolve it!

My 60' was 3.1. I can contribute most of the slow time to my inexperience, I was spinning bad off the line, so I shifted into second, that dis not help, I hit my shift point and grabbed third and bogged. I am not 100% sure if the secondaries are opening, some how I do not think so. But I have since removed 1/4" of carb space, turned the carb to push pull instead of sideways. Right now the car peters out at about 4500RPM. The engine is a 250, it is from a 1970 Blazer, according to the casting numbers, compression is good. My timing may have been retarded, I have since do a lot of tuning and stuff, so I am not sure where it will be this year, if I can get it to the track, I am waiting on neck surgery and do not know when it will be. I know with zero more tuning and a driver that can drive better than me I know the time will be much better and the MPH will be there.

Tom I cannot install lumps at home I have no drill press and no place to put it. I live in a trailer par and have very little tools anymore, so I have to hire out damn near everything I do.

You have to make do with what you have at hand. The same shop opening up the valve sizes can easily machine for the lumps.

You are correct. I had a huge set back, just like a lot of people today and we are rebuilding our lives. Lost a house. 60 K a year job and a Military carrier. My wife and I are rebuilding now. I was lucky enough to keep my 62. All because of a stupid back injury. Man life can chane in just one day.

Yes life can change in one day. Good and bad. Hope your back gets better. Thanks everyone for the answers about hardened valve seats. Jay6155

A downward slide in finances is what caused me abandon my plans for a small block Chevy swap and staring learning about the chevy inline six and making improvements to the existing engine.

Looks good! The 250 car is a toy for me, it is rough and needs a crapload of work. My 65 on the other hand much better shape and had a brand new engine (290HP/250 and th350). The 62 is the last in line for any more parts for a while. I am going to get the valves, springs, cam ect as money allows over the next year. I hope to get it done. I love my inline engine too much. I get so many compliments from the fast v8 guys that love I race a sixer, heck I hardly have any time to play with the car with everybody that want to chat!

OK what valves to use, I found these three from a quick search on Summit
http://www.summitracing.com/parts/slp-v-2143/overview/make/chevrolet
http://www.summitracing.com/parts/man-11506-1/overview/make/chevrolet
http://www.summitracing.com/parts/man-11542-1/overview/make/chevrolet
There is a huge difference in price, will there be any real difference in power, or longevity? Are there better valves/values?

The valve you show.
First one is stock type or equivilent
2nd one nicer and has a higher price
3rd heavier duty and highest price.

You have yet to do the exh valves.

I offer this kit with all the parts needed to rebuild a head. Also if going with 1.94/1.6

http://12bolt.com/250292_products/cylinder_heads_and_rocker_arms

1.84 intake, 1.6 exhaust head rebuild kit

Want to work on your own head? Here is all the parts needed to rebuild yours.

Includes:

1.84/1.6 valves undercut stainless

Guides

Seals

Springs Performance

Exhaust seats

Lite weight retainers

Offset locks

Spring setup instructions



This kit contains springs that will work with a camshaft with up to .530 lift and handle 6000 RPM. Use less lift and higher RPM cam be achieved.

Are those Z28 springs in the kit?

The springs are not Z/28. The Z/28 springs could not take that much lift.

I used the Z/28 spring on my 292 but I'm under .500 lift. The stock spring is capable of up to .450 lift..then the Z/28 up to .500 and there's the 470 capable of up to .600 I believe...been awhile since I looked in my power manual. For my machine shop to install the lumps I think the labor was under $100...so $165 for lumps and to have them put in....the total cost to do the head was around $800 including all the parts and labor. Think you could wait a tad longer to save up more money to add them in? The lumps make a big difference themselves.