home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > maintenance & nonperformance

Reply
 
Thread Tools Display Modes
Old 05-27-2019, 05:16 PM   #1
vwbusman66
Eisen-Stein
 
vwbusman66's Avatar
 
Join Date: Oct 2016
Location: Kingsville, MD/Morgantown, WV/Your mom's house
Default B20 Cam retainer/thrust plate wear tolerance

Pulled the cam out of the 71 and found the plate looking like this:



How worn should it be before replacement? Is that groove on the ID supposed to be there to clear the cam gear?
vwbusman66 is offline   Reply With Quote
Old 05-27-2019, 05:50 PM   #2
hiperfauto
Board Member
 
hiperfauto's Avatar
 
Join Date: Nov 2011
Location: So Cal
Default

It's hosed. It should be flat on both sides.
hiperfauto is online now   Reply With Quote
Old 05-27-2019, 07:01 PM   #3
vwbusman66
Eisen-Stein
 
vwbusman66's Avatar
 
Join Date: Oct 2016
Location: Kingsville, MD/Morgantown, WV/Your mom's house
Default

Quote:
Originally Posted by hiperfauto View Post
It's hosed. It should be flat on both sides.
Outstanding. Is the steel one on VP a good upgrade/option?
vwbusman66 is offline   Reply With Quote
Old 05-27-2019, 07:06 PM   #4
Harry Tuttle
Board Member
 
Join Date: Jun 2006
Location: in your ducts
Default

Quote:
Originally Posted by hiperfauto View Post
It's hosed. It should be flat on both sides.
Back in the day, we used to flip those over if one side was still flat, as there seems to be a force driving the cam in one direction. Your opinion and/or experience?
__________________
I came into this game for the action, the excitement. Go anywhere, travel light, get in, get out, wherever there's trouble, a man alone


Quote:
Originally Posted by dl242gt
It's always better to get into a turbo volvo and drive.
Harry Tuttle is offline   Reply With Quote
Old 05-27-2019, 07:10 PM   #5
hiperfauto
Board Member
 
hiperfauto's Avatar
 
Join Date: Nov 2011
Location: So Cal
Default

Steel thrust plates actually came stock on B18 engines and are definitely an upgrade over the brass ones.

I'm not sure if VP is selling an OE plate or one they're having made.
hiperfauto is online now   Reply With Quote
Old 05-27-2019, 07:19 PM   #6
hiperfauto
Board Member
 
hiperfauto's Avatar
 
Join Date: Nov 2011
Location: So Cal
Default

Quote:
Originally Posted by Harry Tuttle View Post
Back in the day, we used to flip those over if one side was still flat, as there seems to be a force driving the cam in one direction. Your opinion and/or experience?
I've heard of this being done but the fact is that the plate is worn and the cam can walk back and forth so I recommend replacing it. Besides, the timing gear kits come with the thrust plate. It's the tight wads that want to replace just the fiber timing gear that flip the plate over to save a few more $$.
hiperfauto is online now   Reply With Quote
Old 05-27-2019, 09:47 PM   #7
JohnMc
PV Abuser
 
JohnMc's Avatar
 
Join Date: May 2004
Location: St. Louis
Default

At low RPMs, the torque on the cam gear can go back and forth (as the cam lobes pass center and the valve springs push it forward) - and a little slack can turn into a bit of a rattle.
__________________
'63 PV Rat Rod
'93 245 16VT Classic #1141
JohnMc is offline   Reply With Quote
Old 05-27-2019, 09:59 PM   #8
Harry Tuttle
Board Member
 
Join Date: Jun 2006
Location: in your ducts
Default

Quote:
Originally Posted by hiperfauto View Post
It's the tight wads that want to replace just the fiber timing gear that flip the plate over to save a few more $$.
Yeah, I may resemble that remark. They were just old cars that people wanted to drive, not restoration projects. TBH, I don't remember if I actually did it, but I would have...

I agree with all arguments against it.
Harry Tuttle is offline   Reply With Quote
Old 05-28-2019, 08:12 PM   #9
cwdodson88
Board Member
 
Join Date: Oct 2011
Location: The Dalles, Oregon
Default

Quote:
Originally Posted by JohnMc View Post
At low RPMs, the torque on the cam gear can go back and forth (as the cam lobes pass center and the valve springs push it forward) - and a little slack can turn into a bit of a rattle.
Doubt itís the cam lobes doing anything to cause walking. Pretty sure itís just the helical cut of the gears that directs the thrust almost constantly towards the front. Engineered to keep the gear from ever possibly contacting the engine block.
__________________
Quote:
Originally Posted by mikep View Post
Build it, break it, build what broke stronger, lather, rinse, repeat.

The Build Thread
SVEA - PUSHROD TURBO!
cwdodson88 is offline   Reply With Quote
Old 05-28-2019, 09:22 PM   #10
JohnMc
PV Abuser
 
JohnMc's Avatar
 
Join Date: May 2004
Location: St. Louis
Default

At higher RPMs it gets into a constant load on the teeth and it will quiet down.

If you hve the crank gear off and turn the cam around you can feel it push forward as a lobe passes TDC. And I have heard clattering engines (that quieted down when revved) from worn thrust plates before.
JohnMc is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 05:10 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.