Does a 430 live with 0.0036" main clearance?

I built a 1967 430 (Riviera) a year and a half ago, and never got it to run properly. I rebuilt the whole engine. It was bored and honed to .010" with pistons and moly rings from TA, and the crank was ground .010" under. I performed all the usual oil system mods outlined on this forum, like 5/8" suction side, aligning holes in the main webs, enlarging and radiusing oil holes in the pressure side of block. Installed booster plate in the pump. Installed TA double-groove cam bearings. Plugged deck ports and converted to 455-style lifters and pushrods. Installed TA Stage 1 SE heads and roller rockers. Edelbrock performer intake. Mild TA 212 cam. Tried several distributors and carbs, even Fitech EFI. Drove only a few hundred miles because it never ran properly. Bad idle, shaky, popping in the exhaust. Finally I disassembled the whole engine, and found a flat cam, and metal shavings everywhere. The rod bearings were destroyed, like it had been running without oil. Main bearings looked bad, but not that bad. Oil pump housing was badly scuffed, as well as booster plate. I used mineral oil with Red Line zinc additive and Red Line Assembly Lube which also contains a lot of zinc. Seat pressure is 125 lbs. Not that much. Now, I purchased new bearings and piston rings, new timing cover, pump gears and booster plate. When I measure the main clearance (new bearings, caps torqued) with a micrometer and dial bore gauge, I get 0.00315 to 0.0036". According to literature, anything over 0.0025" is asking for trouble - not enough oil for rod bearings. They measure 0.0020". Do you think my mains clearance is too large, and might cause trouble? What confuses me that I get 0.0025" using Plastigage.

 

My mains were set at .0031, my application is race only seeing a lot of rpm, shifting at 6500 and trapping the same. So with that speed on the bearing oil flow across is important.

 

http://www.v8buick.com/index.php?threads/rod-bearing-clearance-too-tight.324157/#post-2718257

 

There's way too many unknowns in the post for the answer to your question and to point towards the failure.
First off, have you ruled out detonation wiping out your rod bearings, or assembly procedures?
Too much pre-lube plug the oil filter?
Are the bearings and rod ends burned or showed signs of grabbing?
Did the shells just fall out or are they worse in line with the vertical axis (towards the piston)?

The difference in gauged readings can be for a couple of reasons.
One is that the spring in a dial bore gauge can be strong enough to bite into the bearing, leaving a witness mark.
Another is that a dial gauge is a single point and won't catch any misalignment of the saddles or bearings as installed.
Also, is the plastigage old or procedure followed perfectly?

Next time...grind the crank after you get a measurement, rather than simply a std. undersized dimension
(Sorry for the broken record )

"Asking for trouble" related to that clearance is always relative.
You'll have to look closer at the physical evidence to determine more.
It's entirely possible to lightly lap the caps to take a thou out if you feel you really need to, or you'll know what to do for the next build.

Sorry I'm not answering your question, I see many other reasons for catastrophe than that one dimension.
This might be one of those times I trust the plastigage over the dial and mic.

 

Here's rod bearing.

 

I have to say the engine was soaked with gas in the first starts. The Quadrajet just flooded, although I didn't find anything wrong with it. An Edelbrock Performer 750 worked better, but not perfect. I need to add that in one of the starts, it blew off the oil filter gasket. In retrospect, the by-pass valve was probably jammed by all the debris, maxing out oil pressure. I changed oil to Red Line 10W40 at that point and replaced oil filter. In the initial rebuild, I checked clearances with plastigage in a couple of journals only: 0.0025" for mains and 0.0030" for rods. The machine shop had installed ARP bolts but had NOT resized the rods. They said they were OK which I now find was bullshit. They were out of round and I regret not checking. The caps were clearanced for ARP nuts, though. I just took the rods to another reputable machine shop who now resized the rods. The dial bore gauge and micrometer now give me 0.0015" for rods, while Plastigage gives 0.0020". It puzzles me that in the main bearings, Plastigage shows tighter clearance than micrometer/dial bore gauge, while in the rod bearings, it shows looser!

 

That bearing is worn through the babbitt lining and into the copper backing. It shows that a lot of abrasive material was present. I would be surprised if the crank was in usable condition without at least a good polish and blend operation, very possibly a regrind.
As far as measurement differences, micrometers that are calibrated are a must. Technique will affect results. The quality of machining, concentricity of the rods and crank journals, bearing crush, squareness of block, etc. will all affect overall bearing performance, and to some degree, measuring calculations vs plastigage results

In my opinion, plastigage has the upper hand here in that it will show clearance across the journal and not just in a particular spot.

Due to the problems you are having, it appears that the basics have been missed during the machine shop portion of this job. As much as it stinks, the only correct way to resolve this is to start over and examine each and every one of the parts you intend to put together. the block should be checked as if it has never been done. Let the facts be what they are. Only after a thorough examination will you be able to decide where to use discretion as far as clearances. The clearances you choose will be somewhat affected by the intended use of the engine. Generally speaking, IMO, roughly .002" for the rods and .0025" to .003" for the mains will work well for a street driven engine at stock to mild performance trim. High HP, RPM's nitrous, etc. require a little more.

Also, the lifters are going to have to be disassembled and cleaned, and perhaps polished due to the abrasive contamination.

 

Out of round after a failure? Say it isn't so!
One good hard run with an over rev or too much heat can do that too.
Reputable or not it's tough to say after the fact what happened, but I suppose there wasn't fresh hone marks when you assembled it.
All you can do is look everything over closely this time.
There's a certain amount of eccentricity in the finished dimension with the bearing installed, so being there isn't a turned bearing, no contact at the parting lines, and .003" vertical clearance fully torqued, I'm leaning away from that being a contributor.
I could guess all day thinking about the differences in plastigage, even hard gauging 'could' show up .0005" difference without day in-out usage or expertise. I wouldn't sweat that much.

It's tough to tell what I'm really looking at here but it does seem like in addition to the assumed particulates embedded from the oil pump and starvation...there seems to be some detonation indicators.

 

If the cam is worn on multiple lobes I suspect he'll have to get a new cam and lifters to fix it so no old lifter work required.

 

This time around, I would measure EVERYTHING! I'm not a pro by any means, I usually spend way more time measuring than I do assembling. I usually cant afford to do it twice, so I think part of the key in a good build is double checking everything you can, even triple checking. My rods were resized and were too tight (linked thread above) and the machine shop got them to were I had .0017-.0018. Still a hair tight for my liking but if I would have just assembled this motor without checking I'm sure it would be toast. My mains were a bit tighter than yours, but I don't think that was your problem. It took me awhile to get a feel for the mic's. Once you can repeat measurements time after time I feel comfortable. Never had luck with plastigauge, not that its worthless but if you have the measuring tools just use plastigauge as a reference for the width of the bearing as ziggy mentioned. Hard to say what caused the failure, I think it may have been a small combination of things. With gassed up oil, loose clearance at the rods, wiped cam, and the potential oiling issue blowing the filter gasket it could be any of those with possible detonation adding to the mix.

 

I was able to lap the caps slightly. Now the #2, #3 and #4 measure 0.002" while #1 and #5 measure 0,0025" using plastigage. Dial and mic show just a tad wider clearance. The bores are round.

 

Here's a pic of my garage.

 

New data! I took the TA Stage 1 SE heads to a pro shop to have them checked before I install them back. They called me and asked what the spring pressure should be? I told them the cam card calls for 110 lbs closed / 280 lbs open. The TA head build sheet states 125 lbs @ 1.825" installed height, 280 lbs open @ 1.350" (0.475" lift). Why do you ask? Because the spring pressure is 150 lbs closed which is a bit high for a flat tappet cam in street use. I went over to see myself. They build Pro Stock engines too, so they know their stuff. Sure enough, 150 lbs closed / 300 lbs open. And the spring installed height is 1.800", not 1.825" as stated. This difference in installed height does not explain the 25 lbs difference in seat pressure. So I checked the specs for the TA 1125AL springs installed. The TA catalog states 125 lbs @ 1.900", but my installed height is 1.800", and the 0.1" difference explains the difference in spring pressure. This could have promoted to the flattened lobes.

 

is your installed height 1.80" with shims? if so, remove some shims. If theres only 1 thin shim then you may want to change valve springs to the 1107's thats what I typically use on street/strip motors. I've also milled the valve pocket .030 to gain some installed height.
gary

 

No shims to remove, just locators (.045" thick). But I found some usable Comp springs at the local speed shop that will give me some 120 / 270 lbs combination. The bad thing is that I had to purchase new retainers and locators as well.

 

ok, the TA 1107 would have been a simple replacement though, are the retainers compatible with the Buick keepers and valves.

 

what are the chances to find Buick 11 degree retainers at a local speed shop?

 

One in a million! GL

 

I'm using Comp 986 Springs, 740 Retainers and 4771 Locators. These springs give me 110 lbs closed @ 1.85" installed height and 275 lbs open. Just what the cam card recommends. The TA 1434 valve locks don't match the 10-degree Comp retainers, but they don't match the TA 1450 retainers either. In both cases, they are loose on the bottom (small end), and allow the retainer to rock slightly

 

Are you saying you ran it with the incorrect locks?