Washersspacers under valve springs

"Hi fellas, I just changed o

"Hi fellas, I just changed out all the valve springs on my VP 170 motor. I put in all brand new ones from Sierra. During the swap I found 2 additional broken springs in addition to the 2 I already knew were bad. So the broken springs are as follows. #2 in., #4 in.,#4 ex. #6 in. . I cannot figure out why 4 springs would break after less than 10 hours running. These springs were used, and supposedly good on a head I bought w/ valves and springs already in it. The springs were all intact when I put the head on. I also found that each valve spring had a spacer or washer under it, sitting in the well in the head where the spring sits. These spacers were stamped "6025" and appeared to be brass or copper. They were the same outside diameter as the spring bases, same inside diameter too, and appeared to be approx 1/16 inch thickness, as if stamped or machined from 1/16 inch sheet stock. I have no idea what these spacers are for or if they should be there or not. Any help on these guys? In anycase I left them in under the new springs. I have not put the whole thing back together yet because I thought I might have to go back in and pull out the spacers depending on what I learn from you all. Could the spacers be a cause for spring breakage? IE could the spacers cause the springs to be compressed too much all the time and contribute to fatigue of the springs? Perhaps someone put the spacers in in order to sort of "shorten up" the springs to make up for poor spring rates on old worn out springs?

should I leave the spacers in under my brand new springs?


By the way, I used the "rope fed through the spark plug hole" trick to hold the valves up as I messed with the retainers and springs. (no compressed air in my shop so standard proceedure was no go.) The rope trick worked like a charm!!


Thanks for any and all help.


Matt"

Matt I believe those washers a

Matt I believe those washers are shims used in the assembly of the valve train in the cylinder head to adjust valve seat pressure. This pressure is determined with a special tool while the heads are being assembled. I dont know of a method to check the seat pressure with the head on but you could rotate the engine by hand and watch the shimmed springs to see if your getting close to coil bind.

keep in mind if you have hydraulic lifters they will pump up with the engine running the clearance will decrease.

Good idea with the rope inthe cylinders!

"Will, Thanks for the reply.

"Will, Thanks for the reply.

The credit for the "rope trick" goes to Lois Vella a member of the forum here who suggested it to me earlier. I agree with you that the shims are there to increase valve seat pressure. But I wonder if with my new springs the shims will be helping or hurting. I will put the rocker assembly on and adjust a couple of valves to spec.s and then roll the engine over by hand and see if I am getting close to a bind in the springs. I wonder if the shims were put in when the head was rebuilt and were not needed and resulted in binding and the broken springs I have experienced.



I am hoping someone like E.P. will weigh in on this "shims in" or "shims out" issue definitively, and soon. That would save me some time messing with the rocker assembly.


Thanks again!

Matt"

"Shims are used to adjust valv

"Shims are used to adjust valve spring height. If the valve seat is resurfaced as is often the case when rebuilding heads, the valve sits slighter higher in the head and the shims make up the difference. Broken valve springs usually result from plain old wear or over-revving or combination of both. Most folks replace all the springs when they experience broken springs."

"Li, thanks for the reply. I

"Li, thanks for the reply. I went back in and pulled the shims out. My reasoning is as follows. Because I don't know the cause of the spring failure (old springs or bind due to shims being in there and not needed) If they are needed and should be in there the motor will probaly run poorly without them and I will then know that they are needed but I won't wreck my brand new springs to find that out. If I left the shims in there and ran the motor and the shims are not needed I would probably wreck my brand new springs because of spring bind due to the shims being in there. Also, the guy I bought the head from said that it had just had new unleaded gas compatible valve seats put in and I believe that if the valve seats are new there should be no need for shims. Aren't shims usually used after the seats/valves have been subject to several grinding jobs and the cumulateive deepening of the valve into the seat requires the use of the shims in order to maintain correct valve pressure against the seat? Presumably new seats would eliminate the need for the sims right? I probably won't have time to put her back together and run her in the lake until next spring then I guess I will find out what's what.


I did the rope trick again and it works great as long as you remember to put the rope in to secure the valves BEFORE compressing the spring and removing the retainer. If you don't, the valve falling down into the cylinder makes a very distinctive and sickening sound! I was able to get the stem back into the guide by fishing around in the cylinder with a piece of stiff wire and many tries. It went right back into the guide once I got it lined up perfectly. It took me about an hour to get it back in there. I WON"T be doing that again!

Thanks again for the help.

Matt"

The simple solution is to rese

The simple solution is to research the correct valve spring height and measure yours. But if the seats and valves were replaced you would be correct in your assumption that shims wouldn't normally be needed. It would be unlikely that you could rev a marine engine high enough under load to experience spring bind. Good luck.

"geez, i gotta think the Volvo

"geez, i gotta think the Volvo service manual would be very descriptive and clear on the process to shim. The VP manuals are very good. This is a lot of trial and error labour. Reading for a few minutes might save a lot of work and damage."