Technical SBC issues

Just when I think I'm finished with something, I'm not.

I finally got my car "finished" after 27 years, drove it about 40 miles, and got some disturbing noises.
So, the engine is a 383 Chevy that I was told only had a few hundred miles on it. I believe that is likely true because I swapped the distrib, intake and valve covers and what I could see still looked new. I am unsure how correct these specs are as the engine builder's original estimate and a few of the things I was told by the guy who purchased the engine don't quite match. So I don't know if the original purchaser was full of it or if he opted for some better components(I know for sure the rockers are aluminum roller instead of stamped steel like the estimate)..
But, here goes: ARP fasteners
Scat crank and rods
Speed Pro H860CP flat top hypereutic pistons(was told 11.4:1 but website says 10.4:1 comp)
Michigan 77 bearings
Speed Pro cam .510/.533 lift 308 duration(was told hydraulic roller, but the original estimate lists this cam)
Speed Pro true roller timing set
5 qt 'cheater' oil pan w/2 trap doors and crank scraper
Melling HV oil pump
Roller rockers(estimate lists steel Elgin rockers, but they were clearly aluminum rollers when I changed the valve covers. That's what leads me to believe the original purchaser really did opt for a few better internal pieces)
Patriot aluminum heads w/2.02/1.60 valves, guideplates, .575 springs
Weiand Team G intake with carb spacer
Mighty Demon carb(can't recall if 750 or 850 cfm)
Pertronix Flamethrower III dist and coil with Accel wires and NGK plugs
Edelbrock fuel pump(I think Performer RPM but can't recall for certain)
High volume iron water pump(can't recall now if EMP or FlowKooler), steel fan w/clutch, fan shroud

Now, my issues.
I got the car together and drove it a couple times but never wound it to more than 4000 rpm. It ran/sounded good. Was running 205 to 210 degrees. Oil Pressure was 45 to 50 pounds cold and 22 to 25 pounds at full operating temp.
The 3rd time I drove it, I got after it a bit. I was shifting at 5500 rpm or just under. It ran strong but died when I took my foot off the gas and clutched it. Weird. I let the clutch back out and it started back up and seemed to run normal again. However, I looked down at the temp gauge and the temp had jumped from 210 to very nearly 230 in about a 1/4 of a mile. Once I was keeping the rpm down, it cooled down to normal in 3 or 4 miles.
The worst thing, however, is this. I noticed when I was decelerating, I could hear the engine making an unhappy noise. It sounded kind of like a 1/4" nut in a small soup can. Oh crap! Now what?
I checked the oil and antifreeze when I got home. Both were at the appropriate levels. There were 2 little specks on the dipstick the first time I pulled it.
I have started it once since then just to have another listen. Same sound and I can only hear it when the rpms are coming down. Pulled the dipstick again and there was a small amount of black stuff on the tip(about 1/16" diameter, almost like grease).
So, that's where I'm at.

It doesn't sound like rod bearings to me. It also doesn't sound like the vehicles I have had in the past with lifter troubles.

Any help is greatly appreciated.

 

Drain the oil and pour it through a paint strainer. That will tell you if the bearings are bad. Dropping the pan after that will tell the you the rest of the story.

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what oil pressure at 4000? any oil smoke behind when you backed off?

 

I recently got was supposed to be a rebuilt small block Ford when I took the pan off to check.
The pan had about 2 inches of what looked like grease . Turned out to be an excessive amount of assembly lube in the bottom of the pan. The oil looked brand new when I drained it, but the assembly lube separated from the oil. That could be what you are finding. Don't trust anybody. Tear it down before you ruin it. Drain the oil pull the pan.
Turns out this was a fresh build , but had a piece of dirt in one rod bearing that was eating that bearing and would have caused problems.

 

Comp test and leak down.....check lash on valvetrain.....pull pan if all that is good....

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If the cam is hydraulic and the lifters are flat tappet el cheapos with the little wire clip retainers instead of the circlip type, one could have popped out and is allowing the lifter to come apart. Take the valve covers off and check the feel of all pushrods while someone spins the engine with the starter with plugs removed. Worth a check before pulling the pan.

 

Thanks for all the suggestions. Today kind of got away from me. Tomorrow doesn't look much better. But, whenever I get back to it, I'll keep you all posted.

 

A gasket set and a few hours are cheap insurance. I've pulled too many "low mile rebuilt" engines apart over the years that had issues from far too much silicone sealer used that ended up clogging the oil pickup screen to parts just installed wrong.

 

Interested to hear what it turns out to be.....

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Your oil pressure seems pretty low for a high volume pump.
4yrs on and mines at 75-80 cold 45-50 hot.

 

I agree, i have almost exactly the same readings cold/hot on the Coupe w hot rodded small block

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Back in the day, we always stretched the oil pump spring to raise the oil pressure. I had a 283 in a 56 Chevy that would peg the oil pressure gauge on acceleration not to mention the mess it made when adjusting the solid lifters.
Thats the kind of stuff you do when your young and dumb.
Gary

 

Very seldom is a high volume oil pump needed. Smokey Yunick said 10# per 1k rpm was enough. Oil pressure doesn't lubricate engines better but increased oil flow thru the bearings does.
Very seldom is a high volume oil pump needed. I have one in the SBC in my roadster, but it also has the solid flat tappet lifters with the .012" hole to the inner chamber on the face of each lifter to better lubr the interface of cam lobe and lifter face. Comp cams rep said he thought it would be advisable.

 

I have used roller cams for many years on the street and having pressure and volume keeps my sh-t alive. Prob more oil to the top end than needed, but keeping big valve springs and roller lifters/rockers happy is a must....since this engine will hit 7000 rpm w/o much effort, i want that 70+ lbs

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I used to use Melling HV pumps too but the experienced engine guys will ask you what good is an empty oil pan.

 

Ah....old wives tale, been doin it on drag cars forever, and quite a few high horse street rods....it was disproved a long time ago...just sayin...

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Thought I'd update this thread.
It was bugging the heck out of me that this cam was listed on the estimate, but I was sure I had been told the build ended up using a different cam. So after going through every folder, drawer, etc that I have, I finally found the notes I made when I purchased the engine. Glad I did too because the cam used was not even similar to the one on the estimate. The cam is actually a Comp Cams 645/648 solid roller.
I got the lash specs from their site and checked everything out. Turns out 2 of the lifters were just a tiny bit loose and one was waaayyy out of spec(.040+). Now the valvetrain is not so noisy, although I don't know how a huge solid roller cam is supposed to sound exactly.
It still makes a noise(kind of like tapping on a tin can) part of the time. The part that seems really weird to me is that if I raise the rpm slightly from idle(1100ish) when the engine is cold it seems to go away entirely. It also seems to disappear almost entirely even at idle once the engine has warmed up.

Also, what oil should I be using now that I know this is a full roller? Since I was unsure in the beginning I used PennGrade 10w30. I don't imagine the zinc is much of a concern for a roller motor though.
Living where I do, The engine will likely be operating when the temp outside is anywhere from 40F to 95F.

 

Two thoughts on your elusive noise;
1. If you're running a mechanical fan, it may be hitting something slightly, especially after winding the engine up. They flex with increasing rpm. Also check the fan on the alternator - I just had a heater hose slip out of position onto the alternator fan, sounded like a huge air leak.
There is also the possibility that something in the oil pan may not have enough clearance and occasionally nicks the counterweights or something. I bought a used Nailhead Buick with a strange noise real cheap, turned out to be a pan baffle with a broken spot weld that just slightly hit the crank.
Hope it turns out to be something simple like that, good luck.

 

This has nothing to do with most of what you say, uh I think. You say that it may have a flat tappet cam or a roller tappet cam. break in is vastly different for the two of them. Do you know that the cam was properly broken in?

It would be nice to know what your oil pressure is doing while you are driving it. If it drops on acceleration or rises or fluctuates. I am not suggesting that you take it for a drive, but it would be nice to know.

 

Once I found the notes I made when I bought it, I've discovered that it is a mechanical roller. Unfortunately, I don't know anything about what was done/not done with regard to break-in. When I bought the engine it was supposed to only have 150-200 miles on it.

Oil pressure is as follows:
near 50 at start up
drops to high 30s low 40s when the engine is around 150 degrees
20-22 when idling at full operating temp
When I rev it up oil pressure will consistently jump.
I haven't had it on the road since I posted this originally. But, if memory serves, oil pressure would consistently rise on acceleration. I believe it was carrying high 20s cruising down the road trying to keep the rpms down(2k?).

 

Thanks for the update. I've long been an advocate of using a roller cam setup. I wonder why solid lifters were used. Was this going to be a high revving engine? I like to use high volume oil pumps with a 50 psi relief setting. Melling used to have pumps that were factory set but now it looks like they have adjustable pumps and a selection of springs. Too much pressure causes more wear on the cam and distributor gears. It can also put too much oil to the top end. Volume keeps enough oil where it's needed. Bypassing oil can cause heating but not much at 50 psi. At the temperatures you're operating at, a 30 weight should be fine but you could also use a multi viscosity. You don't need zinc but it won't hurt either.

 

There is little break in on a roller. Its not like a flat tappet that needs to be burnished.

The reason I asked about oil pressure is that a spun main a lot of times will show a pressure drop on acceleration.

@Engine man brings up a good point too much pressure is bad. Above 110 for example it will wash the babbit (sp?) off the bearings, although this has little bearing on this thread. LOL That said if you are flooding your top end that could cause some real odd noises.

It doesn't;t sound like you have too much spring pressure but aluminum rockers have been known to crack at higher spring rates and there is no reason to believe that they won't crack any time. You may look at them, perhaps one has cracked in the fulcrum and when it is loaded up it doesn't;'t wiggle around as much as it does under back lash. You may also check your valve lash and make sure that everything is copacetic.

 

Based on the cam, intake, carb not to mention 4k stall that was in the auto trans that was behind it when I bought it, I'd say this engine was definitely built with rpm in mind.
The highest I've seen the oil pressure get is when it is not under a load and I rev it up it will touch 70-75 lbs. Although, I can't really say what it was doing when all this started as for those few moments all I was watching was the tach and the road ahead of me.
Speaking of distributor gears, will it make a bunch of racket with the wrong drive gear? I ask because Comp recommends a composite drive gear, but the guy who actually built the engine appears to have used a regular gear. Now, bear in mind, the guy who built this engine has been doing this for a living for about 30 years. So I don't know what to think about this.

 

I'm listenin'

 

Did you use a small base camshaft with the stroker ??

 

"1/4 inch nut in a small soup can"... Something rattling under the timing chain cover? If rockers are intact and not making contact with the inside of the valve cover , the timing chain cover would mimic the sound you are describing as well as disconnecting the fan belt/belts to make sure noise is not coming from alt., water pump, etc.

 

This is the cam the builder used
https://www.summitracing.com/parts/cca-12-863-9/overview/make/chevrolet

 

No contact with the valve covers. As I said earlier(#17), now that I have checked the lash and reset the couple that were out of spec, the valvetrain seems to have quieted down considerably. It still makes some noise, but I don't know what a solid roller cam is supposed to sound like. Initially, the noise seemed to be coming from the front of the engine. But, after I fixed the lash issues(worst was #1 intake), the noise I am hearing now seems to be coming from the rear of the engine.

 

You have to run the correct gear with a roller cam. Most take a different gear than a hydraulic cam does. Put a timing light on it and see how steady the timing is. Use the gear the cam mfg recommends.

Ran solid rollers for years in dirt late model engines, never noticed any strange noise but we always had open headers, too. There are a few more "metallic" sounds coming from a solid roller engine but I was just use to them I guess.

Personally wouldn't run a solid roller on the street, too much maintenance (expensive springs, adjustments, hard on valvetrain, etc) but maybe it's a pretty small roller compared to what we ran.

SPark

 

Cold lash vrs hot lash after warm up.....roller rockers? It will be a little noisy when running if its a full roller engine. I would definately check retainer clearance at full lift. After running it a few times, run through the valves again. What are you set at for lash, .018-.022 or so? Roller cams on the street is not a big deal, but slightly less spring pressure isnt a bad idea unless your are buzzing the engine constantly. I go down some in open pressure and use a rev-kit to help stablize the valve train. It will require more maint due to the nature of the beast, ie. checking lash routinely, observing for unusual wear, valve spring checks, etc....10w30 is fine, but u need good clean oil....i like syn such as Mobil1 in my hotrod engines. Dist. gear must be bronze or composite if the cam is billet, although they have started putting iron gears on the billet sticks that allow normal dist. gear to be used