Author Topic: How to lap a cold start valve?  (Read 2179 times)

cfm65@me.com

  • Associate Member
  • Gold
  • *****
  • Cape Town, South Africa
  • Posts: 739
How to lap a cold start valve?
« on: June 18, 2017, 15:46:00 »
Hi Guys,
I have a leaking cold start valve, it actually forces fuel through the cold start solenoid.
Yep, you read that correctly. Fuel is forced through the solenoid and seeping out the top. The cold start spray nozzles are NOT blocked.
I have tried 3 or 4 times to lap the valve and yet it keeps on leaking. I used tooth paste as recomended and it seems to be fine when trying to blow through. However, when all is assembled, it seems to be OK until the solenoid is activated. It then does not shut off securely and fuel seeps out the top of the solenoid.
Any suggestions on lapping the valve? It seems as if the valve has developed tiny grooves around the seat. Am I applying to much pressure during the lapping process or not enough?
Regards
Chris
28 Ford Model A Pickup
29 Chevy Phaeton
67 E Type FHC
67 250SL 5 speed
83 911SC
2015 VW T5 California Pop Top

kampala

  • Full Member
  • Platinum
  • ******
  • USA, CA, Beach Cities
  • Posts: 1246
Re: How to lap a cold start valve?
« Reply #1 on: June 18, 2017, 22:22:52 »
Chris,

I have had the CSV leak through the solenoid.  Its freaky.  However, it's a common problem and someone on this great forum has placed a solution and it worked for me.   

This will not resolve your other issue but it should stop the fuel from coming through the solenoid.    Read the section about "leaking valve, External"

https://www.sl113.org/wiki/Engine/ColdStartValve
250sl - later - manual
280sl - 1971 - Auto - LSD

cfm65@me.com

  • Associate Member
  • Gold
  • *****
  • Cape Town, South Africa
  • Posts: 739
Re: How to lap a cold start valve?
« Reply #2 on: June 19, 2017, 01:02:07 »
TKS Kampala,
Much appreciated, I did not realise there was supposed to be a small O ring to seal the shaft of the solenoid, thanks.
I think I was applying too much pressure while trying to lap the valve. Hopefully someone will add suggestions.
Regards
Chris
Cape Town
28 Ford Model A Pickup
29 Chevy Phaeton
67 E Type FHC
67 250SL 5 speed
83 911SC
2015 VW T5 California Pop Top