87_LG4

So I'm rebuilding my LG4, and at the moment I'm cleaning up the old parts to see which can be reused and which I'll need new. As the title of the thread says, do you think I'll need new main and rod bearings? (based on these pictures):


The blitz casts shadows on the rough parts, so I don't think it's as bad as seen on the pics. But I'll let you decide.

The surface feels slightly rough to the touch where you can see the wear, but is it enough to warrant new bearings? Also, if you notice, the wear is slightly uneven. Could this indicate an unbalanced engine? I haven't gotten a chance to look at the crank yet (as it is currently stowed in a box somewhere deep in the garage). But I will dig it out and measure it for wear if you think it's needed.

Just FYI, I've checked the cam bearings and they don't have any noticeable wear.

Thank you for your help.

Vader

Good macros. Similar photos of the journals would be good to see.

There has been some contamination as evidenced by the scoring. Only a micrometer will tell you what the clearances are, but just from the scoring and materials embedded in the soft metal you should at least replace them. Check the journal sizes and see if there is appreciable wear. You may be able to polish the journals only and install standrad shells, or may have to grind and polish for undersized shells.

FWIW, I'd never reassemble an engine with used bearings unless they are VERY low mileage and show no wear.

87_LG4

Ask and you shall receive. Thankfully the crank wasn't as deep in the garage as I had feared. As you can see they are full of lint from when I wiped of the rest of the residual oil on them, but other than that they feel smooth to the touch:



Thanks for the quick reply by the way.

88fastgta

iTrader: (9)

for the minimal cost of new bearings and just peace of mind i would get new one... and better ones at that...

87_LG4

Peace of mind does sound nice. And as I've looked around at other pics of different mileage bearings, it's pretty clear that I would benefit from new ones. Question is, which ones? I looked at these main and these rod bearings from federal mogul. If journal polishing is needed, these boast: They can actually polish your crankshaft! Other than that there's Clevite and Summit's own brand. Any suggestions?

Thank you.

InfernalVortex

iTrader: (4)

I know Summit's bearing used to be King bearings. They may still be, I have no reason to believe they're not, it's just that it's been a couple of years. King Bearings are pretty well regarded from everything I've seen. I've got them in mine.

87_LG4

Only other relevant search I could find also suggests that Summit's bearings are re branded King's. And at half the price of the federal moguls they do make an appeal to the wallet. Yes, I know bearings aren't the place to save money, but if they are the same as King's they can't be that bad for a near stock rebuild like mine. Also, I noticed that these are Silicon Aluminum alloy as well (the silicon part being the suggested polishing medium in the federal mogul bearings). So all in all, if there are no objections towards the summit bearings, I think I'll order them first thing in the morning.

InfernalVortex

iTrader: (4)

mw66nova used them in his old 305 and he spun that thing to 7k all day long. He's the one that suggested them to me. Spinning a budget sbc that high scares the crap out of me, so mine rarely gets much above 5500, but his bottom end on that 305 never had any issues.

Clearly, your mileage may vary, and I rarely spin mine much past 5500, but it's still got several thousand miles on it now and I've had no issues with them. It's been together about 9 months or so. His 305 had years of hard racing on it and he never had a bottom end problem either.

mw66nova

iTrader: (13)

they are in fact kings, and that little 305 saw 7200 rpms a few times. the engine is still alive and kicking in my dad's car to this day.

87_LG4

Well then, I guess that settles it. Summit bearings are on their way.

And now for something completely different:

As part of my tear-down-re-build I've started to port my 081 heads. Soon I'll have port matched the intake sides and will be moving on to the bowls. Here I see a lot of potential as the factory machining has left some pretty prominent edges and a lot of excess material. But at the same time I'm not sure how much material I can remove before I hit a water jacket. Or if there even is a water jacket between the bowls of the different ports. Can anyone help me deduce my clearances from these pictures I've taken:



Also, if you see any other places to exert caution when porting these bowls, please let me know.

Thank you

tom3

If you're going to beat on this engine at all I'd take the crank to a good machine shop and have it polished. Not a lot of money. Then check it for size and buy OS bearings to suit if needed. Bearings are avail at .001 and .002 for a crank that's just a bit undersize, and many are. Bearings are "crushed" into the rods and block, reusing old bearings might get you a spun bearing pretty quick, disaster there. Most important part of a rebuild is that bottom end.

87_LG4

When you say not a lot of money, how much would you say is a reasonable price? Cause I checked with the local machine shop (yes, we only have one where I live) and they quoted me around $1000 for crank polishing and a valve job. And on top of this I also have to pin or get screw in rocker studs and grind the valve guide bosses for lift clearance. Starting to sound somewhat expensive if you ask me.

Guest

That does not sound like a small amount of money to me. I guess given where you live... thats the going rate. I'd have to guess thats a $6-700 valve job and the rest for the crank. Ouch.

The crank does not look bad, but then again looking at a picture with micrometer eyes its hard to tell what condition its really in. I would say if it mic's out ok and is not out of round, run it like it is unless you're building a engine for racing. It at least looks like the surface is level across the journals, so from the last machining it saw its probably just scratched up and not worn.

Whats the other plans for this engine?

87_LG4

Probably won't see any racing, at least not more then at the local 1/8 mile track (they only arrange races like twice a year), but reliability is preferable as me and my brother are planning on taking a road trip to Germany this summer. Would suck to have it break down on the autobahn. As far as mods go, I'll be throwing in an xr258hr cam from comp, I've started to port my 081 heads, getting 2055 headers from hooker, a bit of carb tuning, and hopefully I'll get an L69 chip for my ECM (I've heard they are better the the LG4, but is it directly interchangeable?), and I have a dual air intake that I got from my dad's old van (I do however doubt that it'll fit under the hood). Other than that the engine and drivetrain is stock (for now).

Guest

I dont see it breaking down. Even an engine I took apart (L98) that had a rod knock and the crank was .020 under without any machine work on the front rod journal still ran well enough to drive it was just noisy. I have a car in my garage right now, put new bearings on a slightly worn (but round journals and within spec) crank and it still runs fine and I've absolutely abused the engine. As long as it checks out ok and the damage is as minor as it appears, shouldnt be any issues. If you have the money to spend, no reason not to but if you're on a budget and it really is going to cost that much... I can see why you would pass up spending that kind of cash.

mw66nova

iTrader: (13)

i got my crank polished for $25. if i needed a grind, it was going to be $100. valve jobs around here are typically $250.

i got the block bored, crank ground, both magnafluxed, cam bearings installed, balanced rotating assembly, all for about $800. no headwork though.

87_LG4

Interesting side note to the valve guide clearance aspect: The installation note on my cam says heads will need machine work, so I sent an email to Comp asking about this. Their answer was that my 081 heads would not need machine work, the note was, and I quote: "...for a vortec style cylinder head. If you were using a vortec head you would need to machine the valve guides." However, I have seen several different threads here on TGO where people say that 081 heads only support lift up to ish .470". (my cam has .487) Like this thread: So which is correct?

Obviously the safe thing to do would be grind to the heads regardless, in case I want 1.6rr some day. But as you can see from my earlier post, machining isn't exactly cheap here in Norway. So if I could be spared of the expense then so much the better.

On the other hand, in that same thread it's been suggested buying your own guide grinders and just use a drill. But unless I misunderstood the specs of the grinder, that would also widen the spring seat bore, which I can only assume is undesirable if my new springs already fit the old seats.

Can anyone shed some light on the matter?

Thank you

87_LG4

Bump...

InfernalVortex

iTrader: (4)

Can anyone provide a part number for these valve guide grinders that you put on a drill? I've not once been able to figure out how to find one of these. I know they must exist, but I've never been able to find a part number.

87_LG4

Guide Cutters and Arbor/Pilot