Road Trip Problem

[Rapid]

On the way to Clemson SC for a football game, had been driving 70-75 mph,
2300 rpm, going up a hill start to lose power and a jolt like I hit something. Turn down the music give her a little gas and pop, it is backfiring. Not all the time but when throttle is applied. Pull in to a station and hear a ticking from around the number one cylinder that gets louder and faster with throttle. Pull the valve cover,
no loose rockers.

Lifter? Cam? Both? 20K miles on Performer Plus cam and lifters.

If I need to replace, will moving to Performer RPM cam with Performer manifold and RPM heads do any good? She pulls hard to 6K rpm with the Performer Manifold and I am not sure I am interested in 6500 rpm.

 

[mrmustangman357]

put a vacuum gauge on it and see what it shows. also you should do a compression test on all cylinders to see where it is going. the tick isnt normal unless it is an exhaust leak

 

[woodsnake]

New timing gear set with the cam?
Is it still running?

 

[Rapid]

Yes on both. Seems to go as long as I don't aks too much. Just noisy and down on power. Not even too noisy. Am considering trying to nurse it home under it's own power.

I did not check to see if the distributor moved but I have no reason to believe that it would.

 

[bnickel]

if the noise isn't coming from the lifters then you likely either have an exhaust leak or loose spark plug. loose plugs are not at all uncommon so don't discount it until you have checked all the plugs, my great grandmother's old 73 galaxie 500 pit one out driving down the road at 40mph and she thought a bomb went off under the hood. all i had to do was simply pop it back in and tighten it down, never gave her another problem after that.

one other possibility is that the popping noise you're hearing is the ignition backfiring through the carb, which would indicate a serious mis-timed condition or rounded cam lobe or a burnt valve

 

[Rapid]

I inspected the plugs and checked the wires to make sure they were in the right order. I do believe the popping is ignition because it is not constant. Why would a cam go bad after so long? I have never had bad oil pressure.

Would a lifter cause a backfire like that? I can't figure how w/o timing also being a problem.

 

[mrmustangman357]

a vacuum gauge and/or compression gauge would provide answers to your questions

 

[Rapid]

I have both and will put them to work as soon as I get the beast home.

Thanks!

 

[Rapid]

Found my problem.. now why?

Found

.160 end play on cam... should be no more than .008

timing chain too loose

wiped cam lobe on # 3 intake with the expected wiped lifter.

Upgrading to RPM cam and intake to go with RPM heads

How to adjust for cam end play if it not within spec? I saw no wear on the cam or thrust plate.

 

[grainboy]

Was your cam a flat tappet or a roller? What kind of oil are you using? Did you break the cam in for 15-20 minutes at 2000 rpm?

 

[Rapid]

I am using Mobile 5000 10-W 30 with Mobile filter changed every 3K,

Cam was install over 20K ago, broken in as you described. I wish I could find a difinitive reason before rebuilding. BTW, I was wrong about the end play. I did not realize that the gear located the cam so the reading was off.

I anm ordering new stuff today from the local guy and will start the re-build tomorrow.

All ideas for what to check are appreciated!

 

[grainboy]

Flat tappet cams can't survive on todays oil for gas engines. I use diesel spec oil, even with my roller block. Rotella 15-40 to be exact. Some use Delo 400. Both have the sulfur needed to lubricate the high pressure areas, ie camshafts.

 

[Rapid]

Thanks,

I had also read about a lack of Zinc being a problem.

Do the synthetics take care of the problem?

 

[grainboy]

Based on the fact that there isn't a synthetic specd for heavy diesels, I would say no.

 

[Rapid]

Castrol make a 20w-50 syntec oils tha they say is specifically esigned for flat tappet cams. Higher zinc etc. I belive that the desiel route may be much more economical.

I am taking this opportunity to rebuild the engine and make some upgrades.

 

[CraigMBA]

Based on the fact that there isn't a synthetic specd for heavy diesels, I would say no.

Oh?

Mobil Delvac 1 5W-40