Engine question

[70herald]

Hi I will put it here since there are a few engine builders who watch this forum.

My rebuilt engine (1296 Triumph) has new 1500 head going on it soon.

Now after having burned the valves on the old head, I started looking into this and see that the valve springs (new) are not nearly tight enough to get the closing force needed for the head/ cam etc.

I need ~0.2" of spacer to get it the the correct closed valve spring height.

(Triumph specs called for either 1.3" installed height or 1.07" my head gives me 1.3, but I really want to compress the spring to ~1.07" to get the necessary spring tension)

Any recommendations as to how to do this are welcome.

 

[Hap Waldrop]

I'll take a stab at this, it's all about tow things valve spring seat pressure and coil bind. For the Spitfire motor I'd shoot for about 85lbs, seat pressure, and then with the head and and rockers on the bootim end you need to rotate the engne by hand to check for coil bind. If the spring you have don't create enough seat pressure you can use shims to increase the seat pressure, this is kinda a PITA with the Triump heads, and the valve spings sit flat on the head and not in a spring pocket like for example a MG, so alot of times you have to make some sort or spring bottom locator that will accomonadte the needed shims, and keep them in place, I don't know of anyhting on the market for this, I had to make pieces in the past. Not Triumph bashing, but this is a poor design factor in these heads that makes the job harder than it needs to be.

 

[70herald]

Thanks Hap
The bottom of the spring is supposed to be centered by the lower spring collar but of course this doesn't provide any normal method of holding the shim in place.

I am ordering a bunch of hardened bronze thrust washers to use as shims. Since they are rated for about 1000lb force they should hold up. The real problem is of course keeping them centered. To get a thrust washer with an OD larger than the collar, the ID will be larger than the valve guide. I think I will make up a bronze bushing to fit around the bottom of the valve guide to keep the thrust washer properly centered.

I will post some pictures when I work something out.
Yisrael

 

[Hap Waldrop]

Thanks Hap
I am ordering a bunch of hardened bronze thrust washers to use as shims. Since they are rated for about 1000lb force they should hold up. The real problem is of course keeping them centered. To get a thrust washer with an OD larger than the collar, the ID will be larger than the valve guide. I think I will make up a bronze bushing to fit around the bottom of the valve guide to keep the thrust washer properly centered.

I will post some pictures when I work something out.
Yisrael

This more or less what I done in the past, I use aluminum, but pretty much the same idea, VSI or Silver seal is one of the very few folks to make val;ve shims in the world, the same size shim used on a MG A-series engines (Spridgets) is the sae shi used on the Spitfire/TR6 engines, and this shim has a large ID, so what I was make a bushing if you will that fit over the guide, and centered the shim/s Then I machined a groove in the guide to house a circlip to hold the bushing in place, of course I still had to leave enough room above to use a posi loc valve seal.
I often though that maching a valve spring pocket in the Triumph heads and using a longer valve spring might be the way to go though.

 

[70herald]

I was in my local well stocked hardware store and just happened to find some real nice steel washers 1/2" id, 1.2" od. They fit around the valve guide quite nicely. The spring is held in place by the bottom retainer in any case.
Now I just need to figure out a good way to measure the spring force.

 

[Hap Waldrop]

They make a fairy affordable spring gauge that can be used in a vice, try Goddson tolls, CV products, Summit, or jegs, you should be able to find one there, I have a Rimac spring tester, but those things are like 700 bucks these days, and the smaller unit that works in the vice does the same thing.

 

[JerryB]

well I don't know what you'r using this engine for......

Your fairly creative but going the rong direction.....

Hardware store washers are not very concentric nor are they flat and vary in thickness. Dont use them against a valve spring...

Why not use valve spring shims...
Datsun uses an 820 VSI insert .523" id x 1.200" od .060" thick and are case hardened.

But then if you need more spring pressure, rather than stack a bunch of shims, use a longer spring with a larger wire size. Assuming the o.d. is 1.200" you have about 15 choices within .020" variance in diameter that came on various cars and are readily availiable.

Certainly you have engine rebuilders and automotive machine shops in Israel....
look in a Pioneer of Elgin or Sealed Power spring catalog.....for shims and cups a VSI catalog.