Cam timing Alignment Question - See Photos

DaveH...

...we (PHR team) got sent one of the tagged 360 engines as a "sweetner" when one of the race cars exploded...
it had bad cam timing (despite the hand made marks being ok) and a water pump leak.... When the cams were dialled in, the reference mark was much nearer perfect than it had been before, and the car was faster.

In one photo here, I see the timing wheel fitted with the crank pulley bolt missing..... that test is therfore useless. The crank pulley must be done tight, as the helical cut cam drive gear will slip along the helical angle up the crankshaft and timing will be wrong.

Dave H...

any comment on method of timing... what do YOU think about using point of max open on 308 etc, rather than actual open/close points....

 

Thanks Brian, that's kind of the point I was originally trying to make.

Why go to all the trouble of the paper under the cam bearing caps to hold all marks aligned, then reset the pins on the adjustable pulleys when Ferrari's marks are suspect.

If you are going to mess with the spocket/pulley to cam alignment, you have to measure cam timing via valve lift.

I think we agree.....

 

We appreciate anyone of you guys who could stay awake while kenny was rambling on...lol or for that matter if you survived the catered lunch..

Very interesting thread, seems you can really get some attention by just mentioning cam timing on this forum.

regards, Jim

 

Ken was OK in fact he and I got on very well. I always considered him a real asset at FNA. They stepped in it big when he left.

Catered lunch? When he came out to this coast he always took us to some horrible burger dump he loved.

 

I have yet to work for a better person, very knowlegable, likeable and a hell of a lot of fun to joke on....

Would not be where i am without him.

 

Lots of us.



If you see him tell him hi for me.

I still talk to or see Amette about every 2 or 3 months.

 

Hey Brian, I sure would like your take on the 355 motors cam timing if you have time to go through that. I am currently in the middle of my belt service. I think I have said before in other conversations with you my car is an ex challenge car and has had 3 belt changes. All of my cam marks are between the goals posts with the old belts and at what I think is TDC, checking with a dial indicator on No. 1 cyl. I would like to varify that by using a degree wheel. In the past I will admit I have put new belts on by putting everything back in the position the old belts were in. Using the assumption if the car ran fine before than I am OK.
BTW thanks you guys for taking the time to spread some your hard earned knowledge on us. Living in Montana all my life it is fairly hard to just find some who knows what "4 cam engine" even means, let alone what a Ferrari is. Regards, Vern

 

Very few cam grinders ecan get the cams to exactly what they say they are, and Ferrari is no exception to that rule. Due to this checking the opening and closing points of any of these cams is wasted time. The important points are the Intake opening and the exhaust closing points.
As the ramp on the lobe is a tough part of the cam to get consistant when being ground cam builders have you time the cams at a point higher up the ramp of the lobe. This is the reason that on these engines the checking clearance is a .5mm, the valves being checked need to be changed from their running clearance of .2-.25 and .35-.4 to .5 (change #1intake and exh and #8 in and exh) Set the degree wheel and pointer in place and zero to TRUE TDC. Either use the positive stop method as Brian described or check the degree wheel for a reading at 1mm before and after tdc and reset the pointer until you have the same reading. It should be about 12 1/2 degrees. This way you are taking into account the piston dwell when it is at TDC and finding the center of that dwell area. Set a dial indicator on the #1 intake valve and turn the engine in the direction of rotation until the valve shows .002" of lift, look at the degree wheel and you should show what the advertised IO point is (34 degrees BTDC in the case of US spec 308 carb car). Move the pin until that is achived (no easy feat here). Swap the indicator to the exhaust valve and continue to turn the engine until the valve movement stops, this is the exhaust closing point and the degree wheel should show the advertised EC point (somewhere arount 30 degrees ATDC, I dont recall the reading off hand). Once you have done this numerous times one can get a feel of this by spinning the bucket in place with a finger and forgo the indicator. Remember you can spin the bucket but the valve is still slightly open so adjust your finger pressure using the dial indicator first. Rarely if ever is a pin exactly where it should be. There is slop in the pin to cam and pin to pulley that is also good for about a degree to a degree and a half when adjusting everything. Once everything is good on 1/4 then the same is done on 5/8 while laying on your ear. Then you find out you cant get the exact same readings on 5/8 bank but you can get within "spec" so you go back to 1/4 bank and reset this to match within 1 degree to the results of 5/8 bank. Getting both banks doing the same thing at the same time is as important as getting the cams to spec.
Torquing the cam bolts back in place is where I got flamed last time I posted on a "cam timing" thread. Someone said to throw cardboard of some sort under a cam cap and torque it to spec. Talk about stretching aluminum if not cracking it! It will not hold 70 #s of torque being applied and will spin the cam and jump the belt. A dollar bill uner the cap will hold the cam from spinning on its own and jumping off a ramp but thats all. I have made nylon blocks that catch a couple of lobes and keep the cams from spinning when tighting the cam bolts but even that is iffy.
And so goes the shim type cam timing. Putzy, time consuming, frustrating, bloody knuckles effort! My two typing fingers need a rest before I can talk through the hydraulic valve cars
Dave

 

Ferrari LOST BIG TIME when John and Ken departed FNA. Lambo's gain was Ferrari's loss. Both of these guys made a major impact on my career as well. It is still a treat to have John stop by when he is in town. I still keep asking him if it is time for me to change the livestock badge on my shirt from a mule to a cow and he still shakes his head no

 

Mule to cow.... I love it

 

Vern, I or we will. Also I have not forgotten the other items we spoke about. This was the week from hell and I did not get to it. As I said don't be afraid to rattle my cage.

 

Jim,

I'm still confused. I had read on Fchat that you should be able to see these marks on the cams with the covers installed. Here are pics of the intake cam pulley on the 1-4 side of a 78' 308 GTS. These pics were taken at TDC (#1 piston at top). There are four pictures. The first two are during cycle #1 and the second two are for cycle #2. There are two for each cycle so that you can see the cam/engine side and the cam/pulley side. I just wanted to verify the timing before I change the belts but I can't seem to find any marks that make sense. Looking at the pics. can you tell me where the marks should be? I don't know why there is sloppy paint on the cam shaft or any of the other little marks. I hope this is still relative to the thread because someone had asked for pictures of these marks too.

So... Am I looking for scribed lines, dots, holes, paint? Where exactly are these marks and finally, if I find a mark, what is it relative to i.e. what does it line up to? Any help would be appreciated. Also, I don't see any marks on the flywheel but I am still looking.

P.S. If this is in a thread, forgive me for I have been looking all morning.

My head is under the wheel well with a hand on a 36mm socket wrench turning over this V8 thinking this is so freakin' cool! Sunny and 50 in Colorado today.

-Rjay
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I was under the impression that the yellow paint was a factory mark to show that the cam pulley nut had been properly torqued. You should also see it on the nut in the center of the pulley.

I also thought that exterior cam marks came later on the QV's

 

Thanks Meister,

The bolts do have the splash of yellow too. As far as the marks, can anyone else verify that they were not on the early 308's (78)? This will help me to stop looking.

I suspect I will have to hold the current position and just finish with the belts. I would love to pop the cam covers but that is a little too deep surgery for me right now. It was running when I started. Reading all about Dave Helm's experience has got me thinking that I may take it down to Scuderia for this to be done properly some day!

-Rjay

 

the notches i spoke of will be on the other side of the cam (not the pulley end), on the back side of the head under the rear cam covers. usually across the aluminum plug in the back of the cam to a notch in the back cam cap.

regards, Jim

 

Jim,


"the notches i spoke of will be on the other side of the cam (not the pulley end),"

I get this part.

"on the back side of the head under the rear cam covers"

On the other side (non-pulley) of my intake cam is a distributor (one one each bank of four cylinders). Is this what you are referring to i.e. pull the distributor caps and look inside? Also, the exhaust side has a small smog pump pulley on it. Is there a mark there?

"usually across the aluminum plug in the back of the cam to a notch in the back cam cap"

Can you try and describe this relative to the distributor parts?

Sorry for not picking up on this, It's still not clear.

Thanks,

Rjay

 

Hey Brian, No apologies needed. So you have weeks from hell too huh? As always thanks for takin' the time to educate us. These are the type threads I look forward to. Oh, BTW Phil, Verrel, Jim and Dave this is great stuff thanks for your time too. Hey Dave you should quit this slackin' crap and get back to what your gettin' paid to do. Do your "bosses" know your wasting this time on us? Wow, sorry I blew up there! HaHaHa Regards, Vern

 

sorry, I was under the impression you had a newer car. on the one you have, only one cam will be marked - 5/8 bank exhaust cam. the mark is on the end of the cam. not too good for much else that verifying that one cams timing.

best regards, Jim

 

Rjay, not to get into a question that I was not part of but just a quick comment. I think Jim is talking about newer ferrari cams. My 348 and 355 have marks that are stamped into the rear of the cams opposite end of the pulley side. The engine assembler apparently puts these there vs. the stamped marks on the frt. that put there before the engine is assembled. Go back in this post Rifledriver talks about this. Hope this helps. Regards, Vern

Edit: sorry didn't see the above responce I was doing other stuff while I was putting together my post.

 

Jim & all,

Thanks for the help. At least I know what I am facing here. I can see the intake cam lobe through the oil filler cap hole (someone said this somewhere - this is the type of little thing that is so great to find out). Once I stopped sweating about the alignment and continued with marks on all pulleys at TDC, the left belt came out quite easily. I would have liked Verrell's new cam lock but I only have this weekend so I rigged up something quick. The old bearing taps out fine. Can't use it of course, because the bearings took the bulk of the tapping. The new one pressed in easily with a socket loading the inner race and a vice. All tensioner parts cleaned and waiting for reassembly tomorrow. If anyone is interested, I can photo the old bearing and the old belt. Both of these looked fine. The belt was worn but not cracked at all. I don't know when it was replaced, hence the reason I am doing this.

These threads are great. It's like having a pro looking over your shoulder /

Thanks again,

-Rjay

 

I am happy to hear that but if 35 degrees is the desired timing spec you have just done it wrong and the cams are incorrectly timed.

And if 35 degrees is not the desired outcome I have no idea what you have done.

 

What you have done wrong is to use wrong or incomplete information to prove a conclusion you have already come to.

I spoke up in an effort to provide accurate information to help you to get your car to run the way it can and should. I do not come here to argue and my ego does not require me to win arguments.

You win.


Vern you need info on how to time your 355, if you don't have my email I'll pm it to you. Gene you are in the neighbor hood, I'll let you know when I'm doing a TR and show you.