IDJ 455

idrivejunk · April 08, 2018, 01:31:08 PM

My hydraulic flat tappet cam and lifters are not in perfect condition, I would like to replace them.

They are aftermarket and the Pontiac 455 is an older rebuild that runs fine with (guessing) 25,000 miles. I've driven it nine years.

Is healthy oil pressure a sufficient indicator of rod and main bearing condition that I may do so without visual inspection of those?

If so, what is "healthy"?

Thanks in advance

chimp koose · April 08, 2018, 04:53:41 PM

when drag racing , 10 lbs pressure for every 1000rpm . If your oil pressure is fine , cut apart your oil filter and see what its catching . 25000 miles is a relatively fresh motor . I would toss in a new cam and lifters , use the proper break in lube . Then enjoy .

idrivejunk · April 08, 2018, 08:57:06 PM

This look OK :?: Came off it maybe a hundred miles ago and was on about a year. :?

Those are pretty much the same spot but moved the flashlight. Not as clear as I would like but the inside is in the background and I don't see anything sparkling.

Crosley.In.AZ · April 08, 2018, 10:12:56 PM

I do not see any metal flakes in that oil filter media. Looks good from here

chimp koose · April 09, 2018, 12:40:41 AM

get busy! don't get crazy with the cam . I like to run them advanced a few degrees , better bottom end , what you lose on top end you rarely get the chance to use .

enjenjo · April 09, 2018, 07:52:13 AM

The one thing to remember, in a * contest, every one gets wet.

58 Yeoman · April 09, 2018, 08:45:17 AM

Quote from: "enjenjo"The one thing to remember, in a * contest, every one gets wet.

So true. In HS, I had a 59 Ford, 292 w/3spd trans. We were always racing at a 1/4 mile that we had striped on a country blacktop near home. One night I raced a 57 Buick Special w/3spd trans. I missed 2nd gear so bad that it broke the trans case. He pulled me home with his Buick, and the next day his clutch bit the dust. We both lost big that time.

idrivejunk · April 09, 2018, 08:58:48 AM

Frank this truly is not related to one of those. I have worried over this for many years and Uncle Sam charged me way too much last year. Theres a sporting chance for me to replace my worn cam and lifters now. When I put up pics of lobes and lifter faces, folks thought I ought to replace because the lifters are too flat. Its maintainence, not *. I like the cam profile thats in it just fine but will have to pick from scratch. If any of you think I have damaged bearings, I will abort this hopeful plan and continue driving it until its knocking.

I saw sparkles this morning. Theres glitter. I had just cut it open before the first pics. Now, look. They can be picked up with a magnet.

Please look again, sirs.

It looks to me like the filter is catching cam and lifter chunks alright, so maybe I am in time. I don't know, so I ask. I will have to screw an oil pressure gauge in to check that. Should I bother or am I already driving junk? These are not trick questions, I am not a mechanic.

idrivejunk · April 09, 2018, 01:44:48 PM

I just showed the paper to the guy who does engine work at the shop. In daylight, with right side up bifocals. He gave the go ahead too. I don't think its bad enough yet to worry about. I am cool with not checking oil pressure but if the new pics make you guys think I really ought to, I can. Not looking to borrow trouble and it hasn't given me any.

If theres no further input on what I asked so far, I'll move on to the next question soon. I have better heads and distributor and will need cam opinions. I do want my junk running good for a grudge match, but am hoping for no yellow puddles. Thank you gents

chimp koose · April 09, 2018, 05:05:59 PM

Before selecting a cam ask and be honest with yourself , do I want a race car with occasional street use or do I want a street car with occasional track time .

enjenjo · April 09, 2018, 06:28:05 PM

Just remember that without a ton of work on the oiling a Pontiac 455 is not an RPM motor. They start eating main bearings. Choose a cam that will give you the torque down low, and run out at about 5000 RPM. The right convertor would make a heap of difference too. Call a convertor company and tell them your weight, RPM limits, final drive ratio, and tire diameter. You can find some great help there, and still be streetable, at a reasonable price. If nothing else you can switch from a 13" convertor to an 11" convertor to loosen it up off idle.Back in the day the trick was a 10" Vega convertor, but I doubt if you could find one now.

Does it have a posi?

idrivejunk · April 09, 2018, 08:52:45 PM

Don't be trying to skip ahead to the fun parts yet!

You are both preaching to the choir now. Anything beyond 4,800 in an unported non ram air iron head Pontiac is just making perilous noise. I'll go five grand if feeling particularly ferocious but the fat part of the torque curve is right where I land shifting around 4,800.

Fact is, if I can ID the cam in it I would consider another just like it. Works nice. All I know is the brand until I have a peek. Engine was built for a Stude but only got brief use in a Firebird before me. That must have been fun!

It does have posi, a 3.31 by my best guess. 12 bolt Camino rearend. B&M Torkmaster 2000 which also works great, IMO. It is a lucky, happy combo that moves the 2 1/4 ton car like a Firebird. Already yanks and goes harder than people expect it to, being so big.

I am just wanting to keep the stream of questions digestible and logically ordered. Theres zero time pressure but I'm counting on the advice. If it works out in theory, I hope to give reality a stab.

Here is the next thing- The machine shop saw me coming, holding Pontiac heads. In pre-forum days. For the 400 that the 455 replaced.

I have what should still be a pair of very low use (since machined, and they were checked out after the 400 failure) 4X-4 cylinder heads, unported and unshaved, not cracked. Bronze valve guides, back cut, five angle valve job, hardened exhaust seats, one piece stainless 2.11 / 1.77 valves, BBC screw in studs, and HS roller rockers.

I sold the XE268 cam /lifters and magnum pushrods I bought for it. Now heres the funky part. I would prefer to use the Comp 995 valve springs that matched that cam. I probably do not want that fast ramp XtremeEnergy lobe profile for the 455. But

according to the machinist, steel retainers would not work in my case so I have titanium because they were the only ones with correct dimensions. All Comp stuff. As you see, I spent so much on iron heads that when the bottom end went away shortly thereafter, I had to abort a build of that. Bought a crap block before aborting.

Now I am betting theres a suitable cam choice for the 455 that calls for springs like the Comp 995s. They are suggested for the XE274 grind also, for example. If not, OK. But now you know why I might want to use those if I can. I suppose it may be time to unwrap the heads and take inspectable pics. But that may excite me. The chambers are wall to wall valve just about. Probably notvas pretty as when I put them away. There is a bit of taking a deep breath first factor, as much as I love the engines Pontiacs do fight me pretty hard. That last one did anyway. I just really don't want to get my hopes up about the 455. It can't help but be badass if I just don't ruin it.

Theres another few exciting facts to throw on the pile anyhow. It has small valve #66 heads now, and I think it was a 71-2 fullsize car engine.

It is kind of refreshing to have engine thoughts. I will dread the work but be oh so happy if I can do this

rumrumm · April 10, 2018, 08:43:31 AM

Stay away from the Comp XE line. They are all fast ramp cams and I don't think that would be what you would want. You are better off with the Magnum line. Call up Comp, give them your specs, and tell them what you want. They will probably recommend something in the neighborhood of 220-224 degree duration at .050. I run a Magnum 280 single pattern cam in my 383 (.480 lift, 280 degrees @ .050) which idles at 775 rpm. It is lopey and requires a 2400 stall converter. It works well on the street. For me it is perfect because I like a hot rod sound and performance but it may be a little much for your application.

idrivejunk · April 10, 2018, 02:11:15 PM

Quote from: "rumrumm"Stay away from the Comp XE line. They are all fast ramp cams and I don't think that would be what you would want. You are better off with the Magnum line. Call up Comp, give them your specs, and tell them what you want. They will probably recommend something in the neighborhood of 220-224 degree duration at .050. I run a Magnum 280 single pattern cam in my 383 (.480 lift, 280 degrees @ .050) which idles at 775 rpm. It is lopey and requires a 2400 stall converter. It works well on the street. For me it is perfect because I like a hot rod sound and performance but it may be a little much for your application.

Thanks, rum.

I thought I had just said that I don't think I want an XE cam and that I shift at 4,800 RPM. I have Comp #995 valvesprings and it would save trouble and expense to keep them in place but ....

Oh what the heck... for the sake of this thread right now I am putting a stock Melling cam in it. That work?

Anybody think changing from 66 to 4X heads is a problem? Will cc-ing both sets of heads be required or are they close enough?

rumrumm · April 10, 2018, 02:22:42 PM

I would use matching springs for any cam you select. I don't know anything about Pontiac parts, but if in doubt I would cc the heads to make sure the change doesn't adversely alter your compression ratio. Maybe the chamber size in Pontiac heads don't vary much like Chevy heads do.