1.60 chevy valve quetions
 

Can you use the stock valve seats if they are in good shape or do you need new seats for the oversive valves thanks

Re: 1.60 chevy valve quetions
 

If you have the 8BA block with the cast in seats yes, you can grind or cut in seats for the 1.600 valves. The 59AB with the pop our seats it's a little harder, I've done it but you should pop out the seats and have a shop cut the block for the 1.600 seats. Walt

Re: 1.60 chevy valve quetions
 

You won't see a difference in 1.5" or 1.6" on the street.

R

Re: 1.60 chevy valve quetions
 

I'm with Ronnie... The performance difference is going to be at rpm beyond what I would ask my engine for
Karl

Re: 1.60 chevy valve quetions
 

Me too!

Re: 1.60 chevy valve quetions
 

OK, let me beat this horse for clarification. First some background: the last flathead I rebuilt that I have not run yet, I bought a set of brand new stainless valves and a Neway seat cutter. So, I installed the new valves into the valve seats that I worked with the Neway. I did it this way because I did not want to sort through old valves and go to get a set ground because I do not have a set up for grinding the valves. If I do this again in the future, are you guys saying that I could get a set of Chevy 1.6 valves, treat the seats and then install them directly? This would give me the advantage of slightly longer valves that would work well with adjustable lifters? Also, I suppose that the Chevy valves are cheaper, true?

Re: 1.60 chevy valve quetions
 

no

R

Re: 1.60 chevy valve quetions
 

Well, that's clear! "no" what? L

Re: 1.60 chevy valve quetions
 

Hi guys, in order to effectively install 1.600" valves the original seats should (must) be removed and larger corresponding inserts put in place!

You don't want the 1.600" valves "seating" at the very outer edge of the existing seats, not a real good move!!

I would also add this, in order to take full advantage of the larger valves you need to do some internal porting, not just the bowls, but the runners as well.

Thanks, Gary in N.Y.

P.S. Just for comparison purpose here, over the years when we did this procedure, 1.500" to 1.600" on the SBC's, we've found very little gain in power until we ran the units over 5000 RPM. In short, until that rpm band is approached, the 1.500" valve platform will get the job done!

Re: 1.60 chevy valve quetions
 

36tbird, I'm not sure what the engine gurus who have already posted here are going to tell you since some have already said don't bother to use the 1.6" valves.
When I built my 59 engine I used the Chevy valves (1.6 int., 1.5 exh.) because I wanted to install new inserts anyway and the longer stems worked OK with the cam and adjustable lifters I used. The Chevy valves were readily available, are advertised to give better flow around the upper stem area, and were less expensive than the NOS Ford valves that I priced. If i had gone with the logic that 1.6" valve are no improvement over 1.5, them maybe I should have just left the bore stock, forgot the lighter Ross pistons, the L-100 cam, the stroker crank and all the other little things that were done with the hope of getting an overall better performing engine.

Re: 1.60 chevy valve quetions
 

thank for the info, JM 35 Sedan. could you please provide part numbers for the valves, brand name and a source? i am building an engine w/L-100 cam that is very similar to yours. any info you could provide would be greatly appreciated. thanks again...jack orchard

Re: 1.60 chevy valve quetions
 

Hi Jack, it's been awhile (~2005/6) since I bought everything to put that 59 together. I believe I bought them from Reds Headers when Reds still owned the business or maybe it was Patrick's, CRS :). I'll try to find my receipts for all the parts I bought for this engine build and get back to you with a PM.

Re: 1.60 chevy valve quetions
 

If you are seeking the part number for the 1.5 valves, it's the exhaust valve used in the small block Chev from 1955, until I don't know- all the way thru 350 V8... TRW number is s2090... I don't have listings, so I don't know the 1.6#, I think it's a box stock exhaust for a later Chev V8... I like the Manly brand, or a similiar knock off, for the cut down stem...
Karl

Re: 1.60 chevy valve quetions
 

OK, let me ask another dumb question. Aren't the exhaust valves the more critical as far as metallurgy? I mean, an intake valve gets cooled but an exhaust valve takes more abuse because of the exhaust gases, right? Therefore, why can't you use 1.5" Chevy exhaust valves for both intake and exhaust on a flathead and therefore have the same size valves as stock except for the longer stems. Please show me the error of my ways, oh learned ones.

Re: 1.60 chevy valve quetions
 

That's what is normally used, and Manley SS undercut 1.5" or 1.6" Chevy exhaust valves with chrome stems are hard to beat. :)

Re: 1.60 chevy valve quetions
 

Yes use exh in both holes.Just save money and spend on something else. 1.5" are the answer 1.6" needs machine work isn't worth the effort for the street.People do it and like to say they have 1.6" intakes whatever floats your boat.

R

Re: 1.60 chevy valve quetions
 

Heck, if I'm gonna lie, I'll just say it's massively re-worked and I put 2 inch Chevy valves in it.:D

Re: 1.60 chevy valve quetions
 

You'll probably also be able to tell them they're "water-cooled"???

Going to some 5/16" stems will further help!

Thanks, Gary in N.Y.

P.S. Keep in mind, the 1.500" valves will support 160+ HP (N.A.) below 4500 RPM. If you believe you are going to want higher HP or a higher RPM band, then at that point you will most likely need larger valves!

Re: 1.60 chevy valve quetions
 

Obviously the problem with making horsepower in a flathead is flow both in and out through some very convoluted passages. I'm with JM 35 sedan. I used the 1.6 Manley Chevy valves and lots of port work. There are three ways to get gasses into or out of an engine; volume, velocity, or pressure. I'm not running a blower so pressure is out. Velocity is an impossibility in a flathead because of all the turns creating high pressure zones. The only route left is volume. The additional room around the diameter of the valves plus the reduction of the stem to increase flow near the valve have got to help some. Argueably there could be some reduction in torque with reduced velocity at low speeds but flatheads are basically tractor motors; little torque monsters as were most engines of their day. Can you overflow an engine? Of course. Ford fans have to look no farther than the FoMoCo muscles engines of the late 60's/early 70's. Boss 302's and 429's were street dogs. Every roundtracker knew about epoxying up the intake passages on 351 Clevelands to increase intake velocity. But overflow a flathead? I don't think it's possible.

Just my two cents..........

Re: 1.60 chevy valve quetions
 

Installing larger valves in an engine has been a long tine racing practice and I agree using an expensive racing valve MAY add something to the performance of your engine. However there is aalso another reason for using a larger valve, a bad seat. From late 40 through 53 Ford did not usr a hardened seat under the intake and sometimes this area was in poor condition. Which could be solved by installing a hardened seat or using a larger valve. The 1.6 valve from PAW was an inexpensive soultion. For my sterrt engines I would undercut the valve at a 20 degree angle to improve breathing. AS been said here I don't think installing a 1.6 valve in an engine with a hardened seat because the seat may come loose causing major damage to the reat of the engine. I recommend the use of the 1.5 Chevy valve in both the intake and exhaust in any engine with a small base circle cam in a street engine, should last forever.