How to tell if it's hydraulic or mechanical cam? - Team Camaro Tech
Engine General Engine Discussion.

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old Mar 29th, 08, 05:13 PM Thread Starter
Gold Lifetime Member
Jeff
 
Join Date: Mar 2006
Location: Fallbrook, CA
Posts: 403
How to tell if it's hydraulic or mechanical cam?

Back on the old project, 1969 block, 1.94 heads, 383 motor. Compression was all over the place 140 to 185 pounds. Intake roller rockers are 1.5's, exhaust are 1.65 (not sure why though). Anyway, assuming it was a roller hydraulic cam as the previous owner said, we reset all the valves today. Taking each cylinder to TDC one at a time, we took both sides to zero lash and gave it 1/4 turn more. It didn't fire and so I checked 1 and 3 real quick = no compression now. Maybe solid lift after all?

I suppose that means I just screwed up, but without taking everything apart, how can I tell what the lash should be set at? It's a Comp Cam setup, but we have no specs at all. Suggestions?

I hate being stupid, but it didn't run anyway so I really haven't lost that much ground...lol.

-shoe

Current Projects - See my albums
68 Coupe Restomod (7-2010 to ???)
67 RS/SS Convertible project (8-2007 to ???)

Old
67 SS 396 Coupe (sold 7-12), 68 SS 350 (sold 2-12), 68 383 stroker (sold 10-09), 68 SS 350 TPI (sold 2006), 69 SS 350 (sold 1987), 68 327 (1980 Bench seat column shift), 89 RS (son totaled), 88 IROC (son totaled), 76 LT1 (roommate wrecked)

Last edited by shoe; Mar 29th, 08 at 10:38 PM.
shoe is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old Mar 29th, 08, 09:06 PM
Senior Tech
 
Join Date: Nov 2006
Location: Bend, OR
Posts: 1,702
Re: How to tell if it's hydraulic or mechanical cam?

You would sure think that it wouldn't be a solid roller for the street! Those things usually have some sick lift.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
dubs68camaro is offline  
post #3 of 22 (permalink) Old Mar 29th, 08, 10:40 PM
 
Join Date: Apr 2000
Posts: 21,341
Smile Re: How to tell if it's hydraulic or mechanical cam?

Solids will hold the valves open when lashed too tight so it won't run at all right! Hy's- will bleed down OK then pump back up so will still run OK, at least until you can lash it warm like it need's to be done, imho.

And if you lash hy's- too far, they turn into solids and will do like them until loosened back up so that they can pump back up and turn back into hy's-.

It's best to lash both using the old "spin the p/r between the thumb and index finger" so you know it's at zero lash on the base circle and then go from there! Cold first at start-up, then lash hot idling like it need's!!

I always lash both hy's- and solids idling hot, BUT it was how I was taught as pup by the old Mechanics around town AND it is a "feelie" deal!!

Hy's, back them off until they tick, then a 1/4 to a 1/2 a turn down! Solids, use the needed feeler gauges and "feel" them as you lash! In and out w/ the gauges idling! And put a clean shop towel over the other 1/2 of the valvetrain that you aren't adjusting to help hold oil splash to a min.

pdq67



pdq67 is offline  
 
post #4 of 22 (permalink) Old Mar 29th, 08, 10:58 PM Thread Starter
Gold Lifetime Member
Jeff
 
Join Date: Mar 2006
Location: Fallbrook, CA
Posts: 403
More opinions on roller cam and lash?

Growing up I was taught to go 3/4 to 1 full turn on standard hydraulics, but never had a full roller motor. My neighbor is telling me to just snug it up to zero lash and stop there.

I played around with it a little more, did do the push rod spin trick, but once all the play is gone and I go 1/4 turn, its all over with the compression.

Extra note: When I first started into this, I noticed that at TDC, all the exhausts (1.65's) had a little gap to them, but the intakes (1.5's) were all tight. Not much, but tight. I just figured the 1.65's had backed off just a little. Starting to wonder now if they are solid and I missed the point.

-shoe

Current Projects - See my albums
68 Coupe Restomod (7-2010 to ???)
67 RS/SS Convertible project (8-2007 to ???)

Old
67 SS 396 Coupe (sold 7-12), 68 SS 350 (sold 2-12), 68 383 stroker (sold 10-09), 68 SS 350 TPI (sold 2006), 69 SS 350 (sold 1987), 68 327 (1980 Bench seat column shift), 89 RS (son totaled), 88 IROC (son totaled), 76 LT1 (roommate wrecked)
shoe is offline  
post #5 of 22 (permalink) Old Mar 29th, 08, 11:20 PM
 
Join Date: Apr 2000
Posts: 21,341
Re: How to tell if it's hydraulic or mechanical cam?

I bet it is a solid cam.

Lash it at .020" on the intakes and .022" on the exhausts cold and see what it does? Should turn into about .024" and .026" hot???

pdq67



pdq67 is offline  
post #6 of 22 (permalink) Old Mar 30th, 08, 10:15 AM
Senior Tech
Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,934
Re: How to tell if it's hydraulic or mechanical cam?

A Solid Lifter whether it is Flat Tappet or Roller does not Pump Up. You can not push down on the cup to bleed off the tappet like a hydraulic one.

With a small Mechanical Roller with lifts around .600" the COLD Tappet Clearance is approx .022" for Int and Ext. Pending whether the cam is asymmetric. That is same lobe design for both Int and Ext. If the cam is not asymmetric that is say a higher lift and longer duration on the Ext you usually add .002" to the Ext. Of course the bigger the Mechanical Cam the Bigger the Clearances. It would be a good idea to pull the Timing Cover and read core ID from the End of the Cam and get the Spec Sheet for it.

Setting Tappets at TDC is NOT a good Idea because you are not on the smallest radius on the Cam's Heel and you can easily get mixed up were the Engine indicates TDC for a particular Cylinder; such that, the Cam is on Over lap were both the Intake and Exhaust Valves are supposed to be open. A good example is comparing #1 and # 6 Cylinders were #1 is firing under compression with both Valves closed at TDC but #6 is on Overlap "savaging" with both valves partially open at the TDC indication for that cylinder.

This is how I Set Tappets whether the Cam is Hydraulic or Solid - Following the Firing Order for that CAM: Be aware that some cams have different firing orders.

1st slacken off all Tappet Adjusters to ensure you do not kiss a piston with a valve during the procedure.

Starting with #1 Cylinder adjust the Exhaust Tappet such that the lifter is riding on the lowest portion of the lobe heel with the recommended Spec's of say .022".

Intake Valve: When the exhaust valve begins to open, stop and adjust that cylinder's intake valve.

Exhaust Valve: After the intake valve has been adjusted, continue to rotate the engine, watching that same intake valve. The intake valve will go to full lift and then begin to close. When the intake is almost closed, stop and adjust the exhaust valve on that particular cylinder

You will rotate the engine several times by hand with the spark plugs out before you are satisfied the adjustments are right on. Move the feeler gauge side to side and do not roll it under the Rocker Rollers.

Z15CAM - There was a Viper in my Rear View
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

This was my 70 1/2 Z28

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Z15CAM; Mar 30th, 08 at 11:13 AM.
Z15CAM is offline  
post #7 of 22 (permalink) Old Mar 30th, 08, 10:23 AM Thread Starter
Gold Lifetime Member
Jeff
 
Join Date: Mar 2006
Location: Fallbrook, CA
Posts: 403
Re: How to tell if it's hydraulic or mechanical cam?

Thanks I will try that this afternoon if it stops raining. The previous owner did some nice work on this car, then totally whack things the next moment (like welding the leaf springs to the rear end). Seems like they put some money into the motor, but may have been a 1/2 way job in the end.

What the main reason for a solid lift roller cam as opposed to hydraulic, is it a racing thing or just preference?


-shoe

Current Projects - See my albums
68 Coupe Restomod (7-2010 to ???)
67 RS/SS Convertible project (8-2007 to ???)

Old
67 SS 396 Coupe (sold 7-12), 68 SS 350 (sold 2-12), 68 383 stroker (sold 10-09), 68 SS 350 TPI (sold 2006), 69 SS 350 (sold 1987), 68 327 (1980 Bench seat column shift), 89 RS (son totaled), 88 IROC (son totaled), 76 LT1 (roommate wrecked)
shoe is offline  
post #8 of 22 (permalink) Old Mar 30th, 08, 10:29 AM
Senior Tech
Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,934
Re: How to tell if it's hydraulic or mechanical cam?

You can Rev a Mechanical Cam much higher then a Hydraulic Cam simply because it is Mechanical using higher Spring Pressures and does not depend on Hydraulics to pump up.

I highly suggest you pull off the timing Cover a see exactly what you have there and get the Spec sheet for the cam. Hopefully the info will be engraved on the front and not the back of the cam in which case you will have to pull the cam itself.

Z15CAM - There was a Viper in my Rear View
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

This was my 70 1/2 Z28

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Z15CAM; Mar 30th, 08 at 12:10 PM.
Z15CAM is offline  
post #9 of 22 (permalink) Old Mar 30th, 08, 12:39 PM
Senior Tech
Tim
 
77wolf10.85's Avatar
 
Join Date: Mar 2007
Location: Oklahoma
Posts: 3,222
Re: How to tell if it's hydraulic or mechanical cam?

I would just look down into the top of a lifter to see if there is a keeper or not.

No little clippy keeper = solid

Tim Smith
77wolf10.85 is offline  
post #10 of 22 (permalink) Old Mar 30th, 08, 01:09 PM
 
Join Date: Apr 2000
Posts: 21,341
Re: How to tell if it's hydraulic or mechanical cam?

Good point Tim!

pdq67



pdq67 is offline  
post #11 of 22 (permalink) Old Mar 30th, 08, 03:18 PM
Gold Lifetime Member
Don
 
Join Date: Jan 2005
Location: 2 Dog Town in West Texas
Posts: 11,154
Re: How to tell if it's hydraulic or mechanical cam?

Quote:
Originally Posted by 77wolf10.85 View Post
I would just look down into the top of a lifter to see if there is a keeper or not.

No little clippy keeper = solid

What I was about to say, Sometimes you can see a wide flat bi-metal looking snap ring too. Sorta concave looking.

Don
TC # 349
Zdld17:69 Z/RS,306, NOR141111, 9N554XXX, 12A, X3G, 59/59,723, AFR 195,CCC282/290HR, TKO 600, BU1122B1E Owner since Dec 1968

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
zdld17 is offline  
post #12 of 22 (permalink) Old Mar 30th, 08, 03:27 PM
Senior Tech
george
 
Join Date: Sep 2006
Location: detroit
Posts: 2,291
Re: How to tell if it's hydraulic or mechanical cam?

fwiw..my piddle valve style solid lifters have a snap ring inserted above the cup.

George
68 Camaro
8-71 blown 461 Rat on E-85
fatblock is offline  
post #13 of 22 (permalink) Old Mar 30th, 08, 05:17 PM
Senior Tech
Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,934
Re: How to tell if it's hydraulic or mechanical cam?

A keeper or snap ring does not necessarily identify whether the lifter is Hydraulic or Solid; as fatblock mentions. Often the same core is used to make either a Solid or Hydraulic lifter. Piddle Valves do not compress but direct pressurized oil from the lifter galleries up the push rod to lubricate the push rod ends and Rockers. Harley Riders often convert a Hydraulic Roller to a Solid Roller lifter.

I take it the car is new to you. Why don't you talk to the previous owner or mechanic to get information on the engine?

Z15CAM - There was a Viper in my Rear View
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

This was my 70 1/2 Z28

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Z15CAM; Mar 31st, 08 at 12:06 AM.
Z15CAM is offline  
post #14 of 22 (permalink) Old Mar 31st, 08, 10:57 AM
Senior Tech
 
Join Date: Dec 2003
Location: Wyoming
Posts: 1,635
Re: How to tell if it's hydraulic or mechanical cam?

If you back off a rocker, let it set for a bit, then tighten the rocker to 0 lash, then slowly tighten the rocker, does it push the pushrod down more or is it solid? You might need a dial indicator for this. I don't remember how much 'spring' a hydraulic lifter has but solids have 0. I think I wrote this clear, maybe not, but I tried.
deerhunter is offline  
post #15 of 22 (permalink) Old Mar 31st, 08, 04:03 PM
Senior Tech
Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,934
Re: How to tell if it's hydraulic or mechanical cam?

I understood what your saying a believe a dial indicator would determine if the lifter is one or the other. I would suspect the Hydraulic to have somewhere between a .060" to .100" travel. I agree the Hydraulic travel is hard to detect by hand.

Z15CAM - There was a Viper in my Rear View
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

This was my 70 1/2 Z28

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Z15CAM is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome