[elohssa]

Hey guy's I've got a bit of a stumper and I'm wondering if anyone has any advice. I just got finished installing a comp 51-232-3 cam in a 74 formula 400. I installed the cam straight up and I aligned the crank and cam gear marks at 12:00 and 12:00 (no I did not degree it). I put in a new set of melling JB-951 lifters and the timing set is a new edelbrock unit. After setting the distributor at #1 tdc I gave the engine a try but couldnt get it to start (wouldnt even fire), Checked for fuel and spark and both were good. I noticed the engine was turning over faster and free'er than I thought it should and it sounded weird like it was turning over with the plugs out, so I decided to do a compression check and to my horror I had 0 psi on the gauge on all 3 of the cylinders I checked. So I pop off a valve cover and spin the engine over and all the valves are moving as you would expect. So then I popped the distributor cap off and turned the engine by hand watching for valve actuation in relation to the TDC mark on the balancer and the rotor position and everything appeared to be happening when it was supposed to both valves on #1 closed at the top of compression stroke and the exhaust valve open 360 degrees later just like it all should be So now I am getting very confused I figure the only thing that could cause all cylinders to have 0psi compression is if the valves are staying open, but what could cause that? Now keep in mind this is all stock rockers,studs, pushrods etc and I didnt adjust the valves for zero lash I just torqued the nuts to 22ftlbs as per stock spec but still If the cam is on the base circle the valves should be closed shouldn't they? So after contemplating this for awhile I set the engine up at #1 tdc compression stroke again (both valves closed) and I loosened off the #1 intake and exhaust rockers, What I noticed is that as I was loosening off the nuts the valve springs were decompressing and when I tightened them down again every turn of the nut was compressing the spring. Shouldn't hydralic lifters compress somewhat before the valve spring does? The way this is acting it looks as if there are solid lifters in there would this cause the problem? I am looking at the boxes the lifters cam in right now and they say melling JB-951 which is I believe supposed to be a hydraulic lifter. I admit I didnt look at them very carefully when I put them in though as they were obviously new and in the proper boxes. Sorry for the long winded post but I am really stumped.

[johnsma22]

to the board by the way.

Anything other than the stock spec cam and you can throw the 22ft/lb torque spec from the manual out the window. Your cam specs are most definately not stock. Torque the rocker nuts to that spec and you can rest assured that all your valves are off their seats. I made the same mistake some years ago. Your best bet is to get rid of the bottleneck rocker studs and go with big block chevy studs and polylocks and adjust to zero lash plus 1/4 turn to preload the lifters and lock them down. You can't just loosen the stock nuts you have now, they will continue to back off over time and you will have problems. You want to get this right before you continue as proper cam break in is critical. Once the motor is running you want to run it at about 2000 rpm for about 25 minutes then change the oil. Order a copy of Jim Hands book How to Build a Max-Performance Pontiac V-8's from our host here at PY. The proper valve adjustment procedure is on pages 80 and 81. The info in this book is invaluable. Get it before you go any further. Here is the link. Hope this helps.
http://216.178.81.107/iwwida.pvx?;it...0%201?comp=py1

John

[pippintook]

I agree, about the studs and adjustable rocker nuts. I figure it is is a small investment in time and money to upgrade to 7/16" studs and adjustable rocker nuts if you are changing cam/lifters/timing chain. I used ARP 7/16" studs and crane kool nuts. They are around $35-40? each for total cost of $70-$80. This will also get you better reliability and precision setting of the lifter preload.

[PONTIAC DUDE]

FWIW:
First off................ I would use 6 on the cam & 12 on the crank to align. You can easily get one tooth off over that distance of observation. When the dots are lined up on the timing gears then you are on #6, not #1 for firing.

You need to bring it up on #1: Watch the intake valve open and close, as it is closing, then bump it till the balancer line and mark on the cover line up on zero.

If you are using the factory nuts that bottom out at 22 ft/lbs then..............after you are on #1
loosen the nuts on both intake and exhaust for that cylinder. Then tighten down the nut untill you feel no play in the pushrod to rocker. Now tighten the nut to 22 ft/lbs and watch the # of turns it take to achieve this. If it is over 1 1/2 turns then you might have issues with the valve wanting to stay open. I preferr no more then one turn. Most have a screw-in studs, but Some heads don't have the ability to replace the studs without pulling the press-in one out. You then can go to a lock nut on the stud to achieve this. Small block Chevy 3/8" style. Also check to see where the rocker tip is riding on the valve tip to make sure the pushrod isn't too long with this aftermarket cam/lifter install. This will affect the preload.

If you have the right pre-load then I would check as you possibly used the wrong marks on the bottom gear to time your cam.
......Have seen & answered this a million times......
There are Two Dots for alignment on the bottom gear. One for the crankshaft keyway and one on the tooth to align with the cam gear.

[David Jones]

Verify your timing chain installation. I recently dummied-up a timing chain install on my engine and it absolutely refused to fire. Finally posted a picture of the chain installed and a couple of the guys here spotted a problem with my installation. I was using a multiple keyway (Rollmaster) timing set and had infact aligned the dots correctly but had a major brainfart with all of those keyways and the cam/crank relationship. Its a lot of reading but here is a link to a thread I put up about my problem and how I got it resolved . The solution was in about 6 or 7 pages, but its interesting reading all of the way through.
Davids thread.
in my case

[wj3v]

Sounds like you have the same problem I had.
The crankshaft sprocket on mine had 3 keyway slots. 1 for advanced, 1 for 0 and 1 for retarded. I lined mine up on the advanced by mistake and had the same symptoms you describe. Check and make sure you line it up on the 0 timing mark!

[elohssa]

ok, I checked out a few things today and it does look like a valve iming issue. I put a dial indicator on the end of the #1 intake pushrod and rotated the engine over by hand, What I found is that the intake valve is open the whole way through the power stroke and doesnt close until about 45 degrees ATDC this would explain the 0compression but the question is how the hell did this happen? here is a picture I took before installing the timing cover you cannot see the marks very well but take a look at the cam and crank sprocket keyways, I compared the picture to a spare three keyway set I have on the bench and It looks o be correct for a 12 and 12 setup, I don't get it, There is nothing I hate more than doing a job twice grrrrrrr, Even if I had the crank sprocket off by one key way wouldn't that just advance or retard the cam? It certainly should still work. Thx for all the advice.

[frbird400]

Shouldn't the crank keyway be somewhere around 10-11 o'clock (just going off memory here)?

[pastry_chef]

elohssa,

Set up your dial indicator on the number one intake lifter and parallel to it (best to use the lifter body itself as plunger can move). Rotate the engine to put the lobe on its 'base circle' (zero lift) and zero your gauge. Then rotate the engine to true TDC on the exhaust stroke and measure how much lift you have at the intake lifter. If you have the comp high energy 218 @ .050 cam, you should have .060 lift at TDC when you are installed at the recommended 106 centerline.
The lobe will generate .048 lift at TDC when installed on 110 centerline.

Keep us updated.

[6t7gto]

elohssa,
i hope you didn't pick that call name just cause you are having a problem with your motor.
david

[wj3v]

The crank keyway on mine was around 1:00 position when it was in the proper position.

[elohssa]

Well guy's I dove in and tore it apart tonight and what I found is in the picture below, on the left is the edelbrock timing set that was in the car and on the right is a spare set that I had kicking around the shop, Anyone notice a difference? the edelbrock set has keyways on the crank sprocket that appear to be 45 degrees out compared to the set on the right this corresponds with what I noticed when I was playing around with my dial gauge before pulling it all apart, All the valve events seemed to be 45 degrees out. So the question is how is this possible? the crank sprocket fits on the crank perfectly(like it was made for a pontiac) So what is this thing actually meant for? Tommorow I'll install the spare set and hopefuly everything will work out.

[J Druin]

elohssa, I think you are looking at the wrong dot on the timming set on the right. The dot that is to the left on the tooth of the gear is stright up. So, if you turned the crank gear clockwise it would be the same as the other set.

[mikeb]

Actually, they are the same. I fought this myself; the markings aren't exactly clear.

If you look at the timing set on the right the alignment "dot" is to the left of the actual keyway. The dot you use is the one that is closest to the tooth.

On the set on the left (going by memory here) the keyway shape corresponds to "A" for advanced, squared for retarded, or rounded for straight up. The rounded keyway on that set is about at 2 oclock in your pic, and the dot is at about 12 oclock.

So, if you "rotated" the crank gear on the right to where the "dot" next to the tooth is at 12 oclock the corresponding keyway would also be at 2 oclock, the same as the crank gear on the left.

On the edelbrock set use the rounded keyway and the round dot, with the cam gear dot at 6 oclock and the crank gear at 12 (with the round circle marking) and I think you'll be good.

[elohssa]

Ok guy's I am going round and roundin circles grappling with this thing Here is a picture of the edelbrock set as it was installed in the engine i think the problem is in how I aligned the marks on the crank sprocket Are you supposed to align the keyway with the dot on the camm gear or do you use the dot on the tooth of the crank sprocket You would think these things would be straight forward but somehow they always find a way to complicate things by putting extra marks where they don't need to be! grrrr

[thumper78]

Have to agree with mikeb.

My Comp Cams timing set had multiple keyways. They marked each keyway with a different symbol.

The mark for lining up the sprockets is at the base of the tooth, counterclockwise from the keyway with the dot or circle.

And as Pontiac Dude says, line up dots at 6 & 12. Easier to be sure of correct position. Doesn't matter to distributor, as long as the piston is at TDC and both valves are closed when you set the distributor in. Remember, crank turns over 2 times for 1 turn of the cam.

BTW, are those treaded rocker studs in there. If they are, go get some polylocks and stop messin with that 'torque the rocker nuts to 22 lbs' garbage. Zero lash em and preload between 1/4 and 1/2 turn.

[mikeb]

The alignment looks OK in that pic if you used the "rounded" keyway in the crank gear. It's hard to tell from that pic if in fact that's where the key is. I'm guessing you used the square keyway and aligned with the dot for the round keyway.

[elohssa]

Mikeb, that's exactly what I did don't know why I couldn't see it yesterday but this mornig it is obvious from that pic that the dots are aligned but the crank is in the retarded keyway. thanks for all your replies, now on to another question that I have been wondering about Do you really need to change out the stock tapered studs when installing a mild cam? Is an adjustable valvetrain really necessary with this cam? At the very least couldn't I just get a set of locking nuts and zero lash adjust using the stock studs? a few months ago I installed a set of comp roller tip rockers on my 1976 T/A 455 and the instructions didn't say anything about installing new studs they just called for a zero lash adjust using the supplied lock nuts Which I did and the car has been running great all summer

[johnsma22]

The bottleneck on the stud allows the rocker to bottom out so that a torque spec can be achieved. Yes an adjustable valve train is nessesary with anything other than totally stock specs. Can you use polylocks with bottleneck studs? I don't know for sure but why bother. The straight studs are cheap and easy to install, assuming that the studs you have now are of the screw in type.

John

[74t/a]

I don't see the key either in the pic. It looks like it might be straight down. If that is the case, then the key should be pointed at TDC of #1 cyl. to #1 cyl. Set the chain up that way and try again.