Some of you may remember my thread "351W stroked to 393 recipe". Well, the motor has run good for about 5 months, until today. First let me give you some info about it.

It's a warmed up 351W bored .040, World Windsor Sr. heads, Performer RPM Air Gap intake, Trick flow one piece pushrods, Crane roller rockers, Comp cam and lifters, MSD pro billet dist., MSD 6al ignition box, MSD blaster coil, Summit true roller timing chain set, stock spec. oil pump, and Holley 600 carb.

This is what is going on. I went out this morning and started it up. It haden't been run for a while so I had to feather the gas to keep it running. It ended up loading up with fuel so I stepped on the gas to blow the extra fuel out. Got going down the road and it seemed like it was loading up again. So as I was driving I stepped on the gas again to blow it out. I know I've got issues with the floats sticking but that's not my big problem at this point.

When I stopped at a redlight I noticed that it was tapping pretty loud. It definately sounds like a valve or two. Oil pressure looked normal at about 15-20psi at idle. Got back home and pulled the passenger side valve cover off. One of the rockers seemed a little loose so I reset the lash on all of them. Took it for a drive and seemed fine for a little bit then it started tapping again and now it was starting to pop out the carb. Oil pressure was acting kind of squirly too. It was not stable as it usually is. I also noticed a whining sound. It seems like its louder on the passenger side. I loosened the valves up a quarter turn on the pass. side because the way the motor was vibrating, it reminded me of a valve being too tight.

That didn't help. Started limping it back home and heard and felt a pop from the engine. Pulled both valve covers off to see what happened and nothing was broke or seemed wrong. Still got a whining sound, oil pressure unstable, and popping out carb and I think the exhaust as well. The popping is worse while accelerating and the oil pressure stabalizes but is about 5-8 psi lower than what it was before.


I allready have plans to change the cam and lifters this weekend so I'll be tearing into it a little bit anyway. I didn't like those lifters from the beginning anyway. There was two of them that would bleed off while we were setting the lash after breakin. I never could get them set right and they are a hydralic lifter which shoud be a piece of cake. I tried about 6 times to set them and two of those times were with it running.

I know I just wrote a book but I wanted to try to give as much info as possible.

What's you guys' take on my issues?

 

sounds to me like it eat the cam.........check and see if the valves are all opening with it running.........

 

Ditto to what HemiEater says. Specifically look at the exhaust valves for movement, if one or more aren't opening this would explain the "back fire"/popping through the carb. Excess fuel from misadjusted floats or closed choke plates wash cylinder walls and the raw gasoline ends up in the crankcase oil. Is oil level higher than it should be on the dip stick? Does it smell like gasoline? These conditions just add to the drama and the engine runs worse. Good luck.

 

Thanks for the responses! Yes all the valves are opening. I had my dad just crank it over with the coil wire and valve covers off and all of the valves were working. No the oil level isn't higher than it should be. There was one time when I started hearing the valves/lifters rattling and when I checked the oil it smelled like gasoline. I changed the oil that day.

Something that I forgot to mention in my original post, and it's probably a big deal, is that when all of this was happening I decided to check my timing and with it idling at about 1200 rpm's, spout connector still connected, my timing was at about 36 degrees. I retarded the timing to try to help with the popping but it didn't help.
Before I didn't have any vacuum at my spout connector at idle and now I do. I don't know why. I checked for vacuum leaks before but couldn't find any.

Let me ask you guys this, could my dist. gear pin be partially sheared off or my timing chain be shot? With the timing being so far advanced, the popping, and the unstable oil pressure I was just thinking that the dizzy is right in the middle of all of that and might possibly be the cause. Could my timing chain be stretched and have jumped a tooth?

Could a motor eat a cam that quickly like in a matter of an hour or so? I'm not being a wise guy, I just don't have that much experience with all this stuff so there's alot that I don't understand.

I just got my custom cam and lifters today so I'm changing it out Saturday. I still need some ideas of what to look for that caused this problem.

Again, thanks for the input!

 

check your firing order......could be 302 or 351W

 

you need to check timing with spout disconnected. this will give you a true base timing. if you look at the timeing and make adjustments with it still plugged in you will fight the computers effort to adjust it as well.

also make sure the motor is up to temp before setting the timing.
also your not using a fram oil filter are you?

 

I have been running the motor for about 4 or 5 months. The firing order is a 351 firing order, I'm sure of that. The motor ran fine up until the other day.

I did check the timing with spout disconnected. I now have the base set at about 11 degrees. It's not an efi engine so I don't have to worry about a computer. It's basically a "basic" motor without all the computer and smog stuff. It's in my 87 F-250. I have it inspected emissions exempt.

Yeah the motor was up to temp when I checked it.

No, absolutely not a FRAM oil filter. I learned about them a while ago. I think it's a NAPA gold filter.

Is my dizzy gear theory not even close?

Do you have any input on why I didn't have have vacuum at my port hose before and now I do? I tried two different carbs and didn't have vacuum on either one until the RPM's came up. The one carb was a bran new holley 750 vac sec. I now have my old holley 600 on it because I couldn't get the 750 tuned in right.

I'm going to start tearing the motor apart tonight for the cam change. I'll keep checking back in for more input and post what I find when, and if, I find it.

Thanks again!

 

if for some reason you had to raise the idle you might have the plates in the primairies up into the slot that control the port for the vacuum advance. In a case like this you would have to open the plates on the secondaries enough to allow you to bring the primary plates down to get them out of that port slot.

I think when you get that cam changed you will have to turn down the idle big time....and that will fix the vacuum problem...if the cam was bad, sounds like it though. Might even be a burnt intake valve making it pop....they tend to get worse real quick....

keep us posted OK

 

spray some carb clean in the air bleads on top of the carb.if they get some crud in them,and it doesn't take much,it will idle badly and run like crap too.

also 36 degrees at idle is ALOT.

 

Well Hemi and Millrat your guys were absolutely right. The #2 exhaust lobe on the cam and the lifter were trashed. That lifter was 3/16" shorter than all of the others. Man it is really chewed up. We got the new cam and lifters installed today and it runs better than it ever did. I can't hear the valves at all unlike when I had the other cam and lifters in it. I still say that I got a set of CRAP lifters from the get go. I will never buy anything else from Comp Cams. They burnt me once and it'll never happen again.

As for the carb and vacuum issue, I had vacuum at the spout connector when we started it up today but when we started to set the timing with the rpm's at 850 we had nothing again. I don't know, hopefully I can fix that issue when I rebuild the carb.

Bronco I'll try your suggestion. Hopefully it'll get me through until I rebuild the carb.
Oh, I totally agree that 36 at idle is alot. I couldn't believe it was that high. I know that I didn't set it that high. I think that the vacuum coming in all of a sudden is what caused that.

Well that's what is going on and much thanks to your responses! You guys hit it right on.

One more question, could it have been something that I did during install and setup that caused it to eat the cam or was it just a bad cam and lifter set as I suspect? I went through the recommended breakin procedure for the chewed up cam just at I did with this new cam. Man, I only had to do just the initial set for the valve lash on these lifters and they are right in there, like it is supposed to be. I struggled so much with those Comp Cam lifters and never could get the valves to quiet down anywhere close to these new ones. I can't hear the valves at all now. It's awesome!

 

your not out of the woods yet..........when a cam and lifter are new they can go bad in 3 minutes and never adjust right, or it can take a few thousand miles before you notice it .

it's not CompCams that is bad here it's the oil we now use. I have had more then my share of cams go bad on brake in. It just happens..... that's why we have roller now...lol

what cam did you replace? was it a XE274 by any chance?..I had one of those and I could not keep the rockers quit, made all kinds of noise...I sold the cam after pulling almost every hair out. replaced it with a 270s and all is well no more noise............

glad to hear you got it back together and runing....

 

Hemieater is right on target with the oil. The newer oil doesn't have enough zinc in it to aid break-in of a non-roller cam. You can use Rotella oil for the break-in.
Spray some ether, or carb cleaner right where the intake meets the heads while it's running. I've had a windsors that aren't easy to seal around the ports.

 

O.K. well that makes sense Hemi. I have about 2500 miles on the new build and it ate the cam. I don't like to hear that I'm not out of the woods yet . I thought, which my thinking is obviously incorrect, that once the initial breakin is successful that the cam was supposed to be good to go. Man I hate to think about it eating another cam.

The cam that is just ate was a FW XE262H-10 grind. I used Penzoil 15-40 diesel for breakin on that cam. Maybe that's where I went wrong. Should I have used Rotella instead?

I got this new cam from Cam Research. Scott told me to use Valvoline Racing 20W-50 so that is what is in it. Man I hope this cam doesn't get eaten. I really like building motors and working on them so far but I hate re-doing the same thing .

Yeah I have to agree, Comp Cams, from what I hear, is pretty good stuff. I was still pretty hot over the whole deal last night when I wrote that. Is there any way that I can find out for sure whether I had a bad cam and or lifters other than sending everything back to Comp?

Ken75 I'll try your suggestion. I really want to get to the bottom of the whole vacuum deal. Scott at Cam Research said the same thing about today's oils not having the right additives in them for proper break-in which is why he recommended Valvoline Racing 20W-50. He said that that is what they use.

So, how long does a cam take to break-in? (When will I be "out of the woods"?) When can I get it out on the road and smash it and hold it to the floor?

 

Now...........Go for it let'er rip..........

only reason I say it might take a few thousand miles is because of the preload in the lifter. if you got say .090 on the lifter you will have to wear that much off the lifter before you will notice it. All depends how much spring pressure you have too.

 

You got it Hemi! I'm anxious to see what this custom grind will do!

I'm not sure how much spring pressure I have. I'm running the Windsor Sr. heads and using the springs that came with the assembly. Scott ( Cam Res.) said that they were fine.

Hemi how do you set your lash? Do you measure the pre-load with a dial indicator? Many guys have told me just to go to no lash and then 1/4 to 1/2 turn more. I first learned about setting the preload when I talked to another machinist one day. I currently have the valve lash set at 1/4 turn past no lash. What do you recommend for pre-load for my motor?

Oh, I forgot to post the cam specs on the custom grind. I don't remember the grind number off the top of my head but this is the other stuff.

@ .050 200/205
Advertised dur 266/270
Lift 440/440
What do you think? This is the "perscription" that Cam Research gave me.