383 rebuild - kinda whimpy on the dyno?

[Killer6]

Again, double check the 90deg indexing of all the crankpins, don't just trust/expect that they are on.
If the 7/8 throw is retarded, the timing will be too advanced compared to the other 6 cyls., it will hamper output by either causing detonation in 7/8 &/or short-changing optimum advance on the other 6. If rod bearings getting pounded out w/o any evidence of oil supply issues is a repeat performance, check check check. It's gotta be poor crush or detonation............

 

[crackedback]

Sorry to see the rod bearings eaten up.

JMO, the engine was lean on the dyno. There could be 40HP right there, especially if the pump gas had ethanol in it.

Hope you get it back together and running well.

 

[moper]

Looks to me like those two cylinders pounded the bearings. Spots on the back of the bearing and the spalling on the wear surface. Oil clearance and flow was probably fine because it’s not welded together. Good catch. Buy some assembly tools and fix it.
And BTW get the right springs for that camshaft before that goes away too. Not enough is bad. Too much isn’t.

 

[fratzog lover]

And BTW get the right springs for that camshaft before that goes away too.

Yes. Cams and springs cant be "kinda close" or "I have these left from another build." They have to be matched to the cam. Open pressure, seated pressure, correct height, do the heads need to be machined before the springs go on, etc. Many factory heads had spring seat measurements that surely would not be referred to as blueprinted, lol.

 

[fishmens67]

Bummer, this was not the way I thought the build was going to turn out. But I guess the tear down will give you the chance to measure piston depth and chamber volume. a little work on the bowls and port on the heads and I think the dyno #'s will move up. I believe the combo is capable of 350 -375 #'s. The build is slightly over the 68 Roadrunner 383, about 1 step. imo

 

[moper]

I think the 375-425 area is where it should be given what he's running. If the heads are doing their job.

 

[Killer6]

The article referenced earlier in this thread would probably be Steve Dulcich's supposed-to-be-4-but only-did-three part series on porting BBM heads. It showed exactly how putting the larger 2.14/1.81 combo in with a standard 3-angle valve job really sucked a$$ w/o doing at least the DC/MP port-template job on them. Something a number of Us know, but seems to not get the attn. it really deserves................

 

[Garrett Ellison]

Years ago I seen some development work in an article by Dan Dvorak Port with some iron heads. Port work that would take full advantage of the flow of the larger valve sizes in a 906 head would turn a 383 or 400 into a whole different animal, indeed. Something that would take a minimum of 11:1 and a stout solid cam before reaching the limits of port flow. It would probably have a torque curve/rise rate more like a 340 than a big block

 

[JAndrea]

The article referenced earlier in this thread would probably be Steve Dulcich's supposed-to-be-4-but only-did-three part series on porting BBM heads. It showed exactly how putting the larger 2.14/1.81 combo in with a standard 3-angle valve job really sucked a$$ w/o doing at least the DC/MP port-template job on them. Something a number of Us know, but seems to not get the attn. it really deserves................

OP here...

Exactly. I’ve already torn down the bottom end. Crank is out... pistons will be soon. Oil residue in pan looked very clean. Also plan on fattening the Jets (I had a whole range ready to test on dyno day), depth checking pistons, micing and bore gauging every single thing before determining next step. Will definitely look into sensible rocker upgrade, recheck oil galleys/plugs, etc. Gonna match valve springs to cam... I definitely think those are wrong. I’m learning a lot about spring pressure at installed, open, and bind height. Also looking into porting the heads for hp street use. I’d like to do that myself... I know the exhaust/intake ports would be easy, but messing around in the bowls, angles, etc might take some serious instruction.

I know I have to maintain the match between lifters, cam lobes, pushrods, etc... but do I assume the lifters will find their home (as far as spin) on the lobes during re-assembly (that’s far off I know, but..)

Kinda &$@@ed I didn’t get more data on my dyno outputs... one would think oil psi would be standard on all outputs. I’m assuming 10 psi/1000 rpms... mine ran 55 psi pretty much through the 5300 power band... does that sound okay for my setup?

I’ll post pics of my main and other rod bearings as well...

 

[moper]

Your oil pressure would have been ok during the test - there's a gage and sometimes a safety for that. 55psi IMO is a little low but should have been safe, and the bearing you show was not starved.

 

[JAndrea]

OP here:
More tear-down pics..

 

[JAndrea]

The valve springs that go with my cam are Comp 911-16 (according to their website anyway)

• Rate: 373 lbs

• 1.110'' ID, 1.524'' OD

• Seat Load: 122 lbs at 1.900''

• Open Load: 309 lbs at 1.400''

The springs I had on were:
110lbs seat and 230 open. That’s a pretty big difference I’d say.

Lesson learned.

 

[JAndrea]

Crank...
I’ll be totally respecing this. A bit nervous to pair this crank with the block again. But lots of inspection on both still to come before the remachining decision.

 

[JAndrea]

I’m sure another problem was the massive 4.50” bore opening (my cyl bores are 4.028”) on the fel-Pro 8519PT1 .039”. I’ll look much closer at other bore options (steel shims?) next time around.

 

[JAndrea]

Another problem... I have 3 lifters that aren’t spinning. The lifter bores came back from the machine shop with a fresh new surface, but I’m assuming the bores of these 3 will be another problem to sort out.

I haven’t gotten to the driver’s side yet, but I assume I’ll see the same type of thing on that side.

Thinking roller everything now.

 

[JAndrea]

Drivers side look better, but the lifters for piston 7 looked like for a time like they were spinning and for a time they were not. Not sure which came before or after, but interesting that these two were associated with 7, where the potential oil starvation occurred.

 

[Garrett Ellison]

Shew! I hate seeing the bearings and crank in that bad of shape. The bearings look more like wear from abrasion. It could be from the wiped lifters, but it looks more like there was grit left in one of the oil passages. No oiling problems though. The crank should be fine if properly reground/indexed/polished.

 

[JAndrea]

Shew! I hate seeing the bearings and crank in that bad of shape. The bearings look more like wear from abrasion. It could be from the wiped lifters, but it looks more like there was grit left in one of the oil passages. No oiling problems though. The crank should be fine if properly reground/indexed/polished.

Yeah.. the bearings look pretty bad, but maybe just because of the #7 and #8 bearing material that circulated thru? All of them are pretty scoured, but 7/8 rod’s are obliterated. I definitely checked the crank oil galleys before assembly, but didn’t manually check all of the block oil galleys, so I’m thinking that could be the source of the problem. I’ll get to that shortly.

I’m also assuming that my stock oil pan has enough volume for around 400hp?

 

[fratzog lover]

The springs I had on were:
110lbs seat and 230 open. That’s a pretty big difference I’d say.

Lesson learned.

230 open. That builder didn't do his homework. Or, the dog ate it.

 

[JAndrea]

Cylinders, Pistons, and rings look good, except for #6 rod pin, which has some serious binding going on... this was not like that when I assembled.

#6 cyl has some rust/combustion res.?... it was assembled for about a year.. not ideal, I know.

 

[fratzog lover]

It doesn't take much metal in the oiling system to damage an engine.

 

[JAndrea]

230 open. That builder didn't do his homework. Or, the dog ate it.

This was on me also. The builder suggested the cam for me, but must not have relayed that to whomever they sent the heads out for rebuild. I should have done my own cam/spring matching homework, then found out where they were going and made a call. I assumed the head guy knew what cam I was using.

Lesson learned.

Sooo many details...

I do absolutely enjoy even this part, the tearing back down to see the results of how parts did or didn’t work together.

 

[fratzog lover]

This was on me also. The builder suggested the cam for me, but must not have relayed that to whomever they sent the heads out for rebuild. I should have done my own cam/spring matching homework, then found out where they were going and made a call. I assumed the head guy knew what cam I was using.

Lesson learned.

Sooo many details...

I do absolutely enjoy even this part, the tearing back down to see the results of how parts did or didn’t work together.

It's all gonna turn out ok. Just a little more than you planned to spend!

 

[Garrett Ellison]

A quick rundown on oil system mods for a B motor

If the budget would allow it, this would be a good time to port the heads and go with a 3.75 inch crank and associated hardware...

 

[crackedback]

What were the clearances on your bearings. If tight and the oil was not up to temp, that will scuff and kill them quick.