after installing my reconditioned 113 heads on my 85, i was very happy with the increased performance and fuel economy. no noticeable knock w/ 93 octane.the car ran great until last week, when i started to get some knocking from the engine. i thought it might be just bad gas, but the problem got worse, with alot of knock and some backfiring whenever i gave it gas. i pulled the plugs(new) and all were good except #1, which was black with carbon. today i pulled the valve covers and ran it. there was noticeable miss, but the worst part was that the #1 exhaust rocker was barely moving compared to the others. i checked and there was no play as i turned the pushrod. the cam is original(i think) the lifters are brand new comp cams. if it is a bad cam, what are your recomendatios for replacement?

 

sounds lke you found the problem, backfiring out the intake under accel only confirms it IMO.

 

Well, let's just hope its only a lifter. A flat cam would still give most of the lift if it is a solid lifter, but a hydraulic lifter will collapse if it is not pumping up.
Good luck.

 

It is likely a bad cam.

 

Does your 85 have a roller block?. If not, you shouldn't have changed lifters.

 

Always use new lifters with a new cam. Should use new lifters with a used cam as well.

It could have been the heat treat on that cam lobe or the nose of that lobe was not angled properly. Looking at a cam lobe from the side, it has a very slight angle. This makes the lifter spin. Watch your pushrods if you still have the engine running with a valve cover off. The pushrods should rotate. Could be that one lifter wasn't rotating and it pitted. Then rounded the cam lobe. Expect all that metal to be somewhere in the engine, hopefully stayed on the bottom of the pan. This is exactly why I do not like oil filter bypasses.

 

sounds like i need a new camshaft then
any recomendations?

thanks in advance

matt

 

Matt,
DON'T CRANK UP YOUR ENGINE!!
This should have been said first. The oil-filter probably weighs a couple of pounds.
When you wipe-out a lobe or lifter, you put a bunch of metal into the oil. When the oil filter gets restricted, it has a spring-loaded bypass that then sends unfiltered oil thru the motor. This sends metal oil filled with metal to your bearings, rings, cam and lifters, and heads etc. etc. etc.!
I would first remove your drain-plug and filter looking for metal. Next flush the motor with a liquid of your choice (everyone has their favorite and someone will post that what I use is wrong!). I use kerosene poured into each head with the valve covers removed. Filter what drains out the drain with a coffe filter. If you get much metal, you need an engine (a rebuild or replacement). If there if not that much, I would use a dial-indicator extension and place it on the edge of the lobe/lifter in question and turn the engine over by hand. Check the lift compared to the cam specs and see what you have got.
This will tell you where you stand without causing anymore damage.
By the Way, I never change a lifter on a flat-tappet cam. If a lifter is bad, replace the cam and lifters for new. You may 'get away with it' a few times but it is bad when you don't.
I hope this information is useful, Take Care, -John

 

Sorry I didn't read the post closer. I have hot cam and roller lifters on my mine since I just put one in my '94. :o

 

If you find the cam lobe is bad and feel that no metal particles have gone though the engine. Please consider spending $30.00 on a non-bypass oil filter adapter from Barnes. I am not a spokesman for them, just passing along some good information. I also like using the best screw-on oil filters I can get my hands on. If you can find Hastings filters, get a few of them. If not, Amzoil's good filters are Hastings rebranded. The filter media inside Hastings filters are very thick, so particles cannot work their way through, like folded media.

Here's the camshaft I would choose. With vacuum brakes, try to stay at or below 270 degrees of duration. Lift is good for torque. This is a kit so prepare for sticker shock. Convert to a hydraulic roller, you will like it

http://cgi.ebay.com/ebaymotors/LUNAT...spagenameZWDVW

 

Lunati also makes some decent flat tappet grinds also if retro fit rollers arent in th ebudget. 256 and grinds work well. Some headwork would really help wake it up.

 

On any cams we have ground we have them cut on a P-55 which is a performance cam core and on HYD. lifter we only use the ones right from GM as they have the hardest bottoms on them.

So far over the years we have had zero problems with cam and lifters and we use a 20/50 racing oil that has 2300 PPM of zinc for break ins.

 

Hello,
I am with BLOCKMAN, In that I agree with buying premium products and using the proper products during break-in.
I always recomend adding a bottle of STP oil treatment(in addition to all the Cam manufacturers stuff). I say this, the same as BLOCKMAN, because it is full of zinc. Zinc has been eliminated from most 'road-use' oils.
Take Care and Be Safe, -John

PS: BLOCKMAN, What brand of camshafts due you represent? I would prefer to buy a cam from a company that cares about performance, after the sale.

Thanks again, -John

 

We spec out our own cams for what we are building as we build a lot of circle track engines and and some street and strip when there is extra time in the shop we also supply machine shops and and engine builders with CNC machined blocks and rotators, We use Ultradyne, Bullet cams which both are owned by John Partrige and we have worked with Harold UD on some new HYD stuff on some of the last engines and those were good as well.

When ever ordering a cam you must ask for a P-55 core and they cost around 20 dollars more but well worth it in the end.

The oil we have been using has been the 20/50 oil from http://www.cen-pe-co.com/ and cam lube comes from Manley Performance P/N 40199 and this goes on the bottom of the lifters and cam lobes.

Hope this helps Carl

 

if you're going to have to smog this engine, call lunatti and get their recommendation.

 

BLOCKMAN,
I may consider one of your cams for My 57 Chevy. It is to be powered by a 427 Chevrolet big-block. I may run a flat-tappet cam in this engine. I run rollers in both of of my street cars and I still have not settled on a cam for my Big-Block 'Heavy-Chevy'.

I appreciate the info and Your Company's support.
You All Take Care and Be Safe, -John

 

Cam/lifter break in is critical. Never let the engine idle. Have the engine timed correctly so it starts fast without cranking too long. Bring the rpm's up to at least 1800rpm for 30min. Afterwards, let the engine cool and change the oil.

I have used reground cams in the past, never had any trouble with them. At least you know the heat-treat was good on the core because it had lobes left to regrind.

I used to be a solid lifter cam guy. Hydraulics do bleed off lift when the oil gets hot. Some will tell you there a is 30hp difference between a solid VS hydraulic given the same specs. Cam profiles have come a long way in recent years. Solids no longer make noise, even with .035 lash. Polly Locks don't back off like the old crimped nuts did. Roller lifters can have a much steeper opening ramp then conventional lifters. Their only drawback is cost, and the possibility of a link breaking and a lifter turning sideways.

 

thanks for all the input. i finnaly decided on this cam
http://store.summitracing.com/partde...K&autoview=sku

going out to take things apart right now. ill let you know what i find.

thanks

matt

 

lifter is totally shot!
completely concave about 1/8 inward

will post a pic once i figure out how

what happened?

matt

 

Replace cam and lifters.