Thread:

Checking out the bottom end.

622ci Chevy with dart pro1's. 14-1 comp, I forget the cam specs but its high lift. Motor has seen 150+ passes, most with 200+ shot of nos, and rpms up to 8600. Motor also has gotten fairly hot after a few runs(250+ degrees). Motor was in a T/E jet, now a P/E hydro.

We were finding some shaving in the filter and wanted to make sure nothing was coming apart. At first glance all the bearing looked decent. We were just going to put new crank & rod bearings and have the lifters rebuilt. Anything that we could be missing that should be attended to?

A couple of things that we saw
-A few scuffs on bearings.
-A few lash caps were beat up.
-Black residue in oil pan.


Pictures are on my camera phone so bare with me. I can get all the specs from my father tomorrow.

Is that evidence of main caps walking? center of the cap looks to have been moving around??

Cam gear looking alright? check cam bearings, and block face at the cam gear/belt.

Black oil could be excessive fuel....

Originally Posted by sleekcrafter

Is that evidence of main caps walking? center of the cap looks to have been moving around??

Cam gear looking alright? check cam bearings, and block face at the cam gear/belt.

Black oil could be excessive fuel....

All the mains were removed and looked over. None show anymore wear then the one pictured. I don't understand where you maybe seeing this.

The cam belt is going to be changed, I forgot to mention that.

Our engine builder said that the black oil was excessive fuel, over the phone.

We have not looked at cam bearing yet. My father seems to think that if the mains look decent then the cam bearing should as well. I'd error on the side of caution and look into it. Then again, I'm not the one paying for everything....

The springs all show uniform spring pressure and it has great/equal compression on all 8.

Look at the bottom of the pistons skirts. The shavings could be a simply as piston shavings. With stroke that long, its not all the unusal. It little looks like ton in you oil.
The cap is walking a little. See the roughness on the machined area around the inner bolt hole on the cap and on the block. Again, hard to control that in a BBC even with splayed steel caps with a stroke that long. You think that the LS, the Ford MOD, New Century and all Top fuel blocks have cross bolts because they are pretty? When you put the steam to an engine, things move. Period! I take it with that compression it gets spun up pretty good even even with that stroke.

The black does look like fuel in the pics. Which could add a little to the piston scuff.

Over all, I'd say it looks pretty normal.

The lash cap thing would have me more concerned more than anything elese.

How much power is this making? For that rpm and I'm assuming well over 1000 on the juice, I'd say it looks pdg. One thing I'd do would be to lose the stock Dart hardware and get some ARP studs in the center mains. That'll stop what little cap walk you have. You'll need to re-check the main bore and possibly have it honed a stroke or three.
The black in the oil can also be moly that has settled. Are you using Joe Gibbs oil by any chance?
What kind of "shavings" are you seeing? I think if the bottoms of the cylinders were sahrp enough to "shave" the pistons, there wouldn't be anything left of them before long, but I guess stranger things have happened. My thought was something on the heads and/or valve train might be chafing. Sounds like you may have some valve train issues.
Dry sump sure makes a difference.

I agree the black could be excessive moly during the built. Without know the number of hours on the thing or the number of times the oil has been changed, it is possible it is moly.
I agree I doubt that the bottoms of the cylinders are that sharp. But there does appear to be a little wear on the center of the piston skirts. Nothing bad, but that material went somewhere. No telling how littlew material the OP is talking about. With a strike like that, and the limited space to put a decent length rod in it, you end up with a pretty short, rocky piston. It the nature of the beast.
It would be intersting to know if any of the material came from under the springs for some reason.

X2 on the center studs. The cap walk isn't severe, and the studs would help.

I'll pass this along to my father who knows more about the internals then I do. I just wanted to get some more opinions then from his builder.

-We have in the past broken 1 lash cap.

-Everything in the motor has been cyrogenetic'd.

Originally Posted by steelcomp

How much power is this making? For that rpm and I'm assuming well over 1000 on the juice, I'd say it looks pdg. One thing I'd do would be to lose the stock Dart hardware and get some ARP studs in the center mains. That'll stop what little cap walk you have. You'll need to re-check the main bore and possibly have it honed a stroke or three.
The black in the oil can also be moly that has settled. Are you using Joe Gibbs oil by any chance?
What kind of "shavings" are you seeing? I think if the bottoms of the cylinders were sahrp enough to "shave" the pistons, there wouldn't be anything left of them before long, but I guess stranger things have happened. My thought was something on the heads and/or valve train might be chafing. Sounds like you may have some valve train issues.
Dry sump sure makes a difference.

990 hp@ 6600/6800, I forget because it was awhile ago. It was cam'd for a jet boat originally and now runs a higher rpm in a hydro. Dry sump would be nice, but at this point he doesn't want to put more $ into it.

I had an Ohio Crank in my 620 that broke last July. It will be going back together in a month or so with a new Sonny Bryant billet. Real similar power numbers and I spray more than 200 also. I just got the ARP main studs in that will assist in beefing up my bottom end. Suggest you follow Bob's advice and do same! I will be looking into coating the crown and skirts of my pistons as well.

Good luck!

John

Originally Posted by dja4260

990 hp@ 6600/6800, I forget because it was awhile ago. It was cam'd for a jet boat originally and now runs a higher rpm in a hydro. Dry sump would be nice, but at this point he doesn't want to put more $ into it.

Thought maybe it was dry sump. Are you running an external oil pump? I see what looks like a cap on the rear main where the oil pump goes.

What kind of cam? if it's a roller, it sure look funny for what you can see of it.

Originally Posted by steelcomp

Thought maybe it was dry sump. Are you running an external oil pump? I see what looks like a cap on the rear main where the oil pump goes.

That caught my eye right off as well.