Cam Failure !! .. Solex Upgrade ? STORY

GotaT · 10-13-2007, 07:21 AM

Upon reinstallation of my cams and going to set the Chain spacing I was able to tourque the drv side cam just fine w/ no problems to the 110ft lbs. I was using a crows foot 46 and .... i know what you all might say... a 17mm wrench w/ a Cheetah pipe Firmly attached to it..

As said. The first one went on fine without Any problems. it was a Very smooth tourque.

I began installing the 2nd cam nut and tourqed it to 85 using the same procedure and then went to the next step of 110 ft/lbs

Everything was going just fine and smooth having one person hold the cam from turning while I was tourquing w/ my snap on to 110 and another watching the procedure to ensure all was looking good. ALL of a Sudden!, SNAP! The END of the CAM just Broke OFF! . . AND Silence filled the shop as we all were Extremely perplexed and set back by what had just happened.

Retrospectively I know the problem areas that caused this to happen and its My own fault to some degree...

1. On my previous rebuild I used an Air gun on the Cam.. which could have put a hairline crack.. not recommended thus going to do a better job this time

2. Not oiling the Cam and nut

3. Not stepping up the ft/lb in 3 increments

4. Not using the correct tool, which I now think distributes the proper Load on the end of the cam

Pics to COME. .. ..

So.. What seems bad may actually be a benefit. I am hoping.

What I mean is , now that I am in need of "a" cam Im considering replacing them w/ the Solex cams..

Id like to know All the things that need to be done to my engine in order to use this setup.
I have a 2.4T with Webers. The heads have just been sent back from JB and 10 thousandths were taken off All factory spec heads. The intake and exhaust valves are OE and Im running a .25 base gasket, leaving 15 thousandths. I also have a set of 2.2 t Cams that are usuable for regrind or trade up. Will it be necessary to have my rocker arms resurfaced if I install a New or Used Solex ? I also understand I will need to do some different jetting to my carbs, which Im not too concerned with. Is there anything else that I am missing?

What kind of HP gains will the Solex bring to the table?

GotaT · 10-13-2007, 07:22 AM

Anyone have a Set of Good Solex or can do an exchange for my 2.2's that have been Reground to Solex spec?

andrew15 · 10-13-2007, 07:32 AM

I have a set of L cams that would work. they would need the front 'snout' machined off, but the cams themselves are in great shape and ready to be installed:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMESE%3AIT&viewitem=&item=180123224420&rd=1

If link doesn't work, it ebay item# 180123224420

I may also have a set of centerlube solex cams.

Regards,
Andrew M

911quest · 10-13-2007, 09:25 AM

Not 100% here but I dont think the valve pockets on the "T" pistons are deep enough to run Solex cams The Solex cams are a pretty high lift cam.

304065 · 10-13-2007, 04:28 PM

Solex lift is .455". Way more than a 911T.

Check out a Solex Piston vs. a T piston, plenty of photos in the archives. You can see a big difference in the valve reliefs.

GotaT · 10-13-2007, 04:46 PM

Thats what Im beginning to find out... Im still doing my research..
Will E cams work ?

911quest · 10-13-2007, 05:13 PM

If you are running "T" pistons you are more then likly going to have to run "T" cams

GotaT · 10-13-2007, 05:38 PM

Quote:

Originally Posted by 911quest

If you are running "T" pistons you are more then likly going to have to run "T" cams

Why so?
Any other knowledgable guys can chime in?

Anyone been here before?

911quest · 10-13-2007, 05:53 PM

Mitch here is a picture of a 2.0 "E" piston a 2.0 normal had a similar piston
as you can see the relifs in the piston are there to keep the valve from hitting the top of the piston. If you look at your "T" piston it has very small relifs they are almost none there so if you try to use a "E" or Solex cam you will run into a clearance issue

GotaT · 10-13-2007, 07:27 PM

Guys thanks for all the posts, but aftering doing some homework and hearing what you've all said Ive decided Not to go w/ the Solex cams...

I will have to get a set of cams and I would prefer to get some that will allow me to continue using my Stock T piston while providing More Power, of course... Im looking into seeing if E cams will work.. I see there is a difference in the Valve overlap between the >71 cars and the 72> cars MFI. Its looking like to me If I get an E cam from an MFI car ( 72 + ) it just might work....

My T cam has valve overlap of 2.6 and the E cam (72+) is 2.9 .. Now still I will have to find out about the Intake and Exhaust Lift

Any input is appreciated. Thanks

andrew15 · 10-14-2007, 05:35 AM

I didn't realize that you were still using the T pistons - I think you will be running into clearance issues regardless of Solex or E cams. I have a normal piston, 69 E piston and T piston. Like it was posted above, the early normal and the E have very similar cutout - the T has almost none.
I suggest looking for a used T cam to replace your broken one.

Regards,
Andrew M

MBruns · 10-14-2007, 03:14 PM

I can change the cam you broke to a bolt drive style and you will be back in bussiness, but you may find a "T" cam used for a song as they are plentiful.

Mike Bruns JBRacing

MikeSpraggi · 10-14-2007, 11:44 PM

Can anyone tell me what the timing specs are for the Solex cams? My engine builder needs the specs to install my Solex cams. Thanks

shbop · 10-15-2007, 08:01 AM

Are you sure the cam-nut doesn't have the eccentric, on one side, for driving an old fuel pump? btdt Very painful learning curve.

johntyboy · 10-15-2007, 09:32 AM

Hi

I would be surprised if your cam snapped because you used a windy gun. what normal happens to the right hand side cam is the large washer that sits behind the nut is not properly located, as you can see from the photo the cam sprocket has a recess and the cam nut can be tightened up with the washer not located in the recess. This puts a shearing force onto the end of the cam and the result is a snapped cam. Its always important to ensure the washer is correctly located. HTH.

Regards John

GotaT · 10-15-2007, 09:39 AM

Thanks for the reponses.. Im looking into a fix and possible upgrade at this point.

After looking in Waynes book on the Cam grinds I noticed that an E MFI cam is not That much diff than my T MFI cam but would give a little more power. Can anyone confirm if this cam will work w/ my T pistons.

tom1394racing · 10-15-2007, 04:21 PM

I've got a shelf full of single T cams.

I can sell you one if you like.

GotaT · 10-20-2007, 07:13 AM

Ok guys.. Ive decided to Try a Set of E cams in my motor. They will be coming in next week. I'll test fit them for clearance using the "cheat" way for clearance by turning in the Valve adj. screws. From what I understand it'll be worth the Effort. im still a little skeptical about if it will work but a few rebuilders tell me its worth it to Try and that it Should probably work out just fine. I should also see about an additional 15HP to the wheels, and that to me sounds like a Significant gain and worth the Trial and Error test. I'll keep you all posted....

Ive been told that even 1 turn on the Intake and 1.5 turns on the Exhaust will Still leave enough room for Clearance.. Sounds tight to me.. but if it works.. im good!
Any suggestions for Rev limiting.. will it be needed? 6500
Should I Jet my carbs to an E spec engine? Or make some changes due to my T pistons?

GotaT · 10-29-2007, 11:55 AM

Ok guys.. As I said, I would be checking the E cams in my motor.

Quick facts: 2.4 Tpistons, .010 taken off the OE spec heads, using .25 base Gasket, E cams. The bottom end has not been touched or opened by me.

So, I was told the valve overlap on these is 3-3.3 mm or .118- .130 in
and to set them to the 3.3 for maximum performance.

I was able to dial the driver side one to Exactly .130 and the pas to .126 after turning the motor over Several times. I was very pleased!Now for checking the Clearance. Its my understanding as mentioned that 1mm on the Intake and 1.5 on the Exhaust would be "plenty of clearance"

I could, with NO problems whatsover, set the Intake to .75 and Exhaust to 1.25 and it Worked SMOOTH as Silk.

I next turned the Intake to the recommended 1mm and exhaust to 1.5 bumped the crank and everything worked . SO, I proceeded to Turn the motor over and Did NOT seem to have any problems or binding. I turned the motor over several times in a smooth manner. The only thing I heard at a specific point while turning was a Slight "tick" sound.. after examining it closely It appeared to be when a Valve would be Touching Back at its Seat on the Head. To me it appeard to be ok.

SO, I proceeded on, looking for an Interference issue which seemed to be when I turned the Intake Between 1.125 and 1.25 and Exhaust to 1.625 and 1.75.. Basically just shy of 1.25 and 1.75.

I did this procedure by first only turning the Intakes, then backing them off.. Then turning in the Exhaust and checking . and lastly Turning them All in Equal distances in a step procedure paying Close attention to any Sounds/ Binding and these were my results.

What are your Expert opinions on this? Will It be enough Clearance Once the Engine warms up and the Cylinders expand and with all other factors considered. ...

If needed I could Re-calibrate the Cams to the Lower side of the spectrum at the 3mm or .118 which would allow for a little more clearance.

RoninLB · 10-30-2007, 09:01 PM

Competition Engineering on deck height

http://www.competitioneng.com/DeckHeight.htm