At Crossroad With Engine

[mtocrs1]

Well I was installing a new cam and found a few things that bothered me so I tore a bit further down and....

Does this cam bearing wear look normal? I can feel the groove with my finger. Additionally all the rod bearings look like crap. Can anyone give me an idea of what would make the rod bearings look like this.

The edges of all the rod bearings also look like this at the break where the cap connects to the rod.

My original plan was to throw the cam in and have the heads redone. Now it looks like I need one cam bearing maybe, and new rod bearings. Another thing I couldn't capture in the pics is one of the rod journals has a scratch on the edge of the journal.
What would you guys do. Opinions?

 

[we4Mateo]

Post a pic of the rod journal. You may be ok with a quick polish and new bearings.

 

[mtocrs1]

I will post a pic of the rod journal tomorrow. The scratch feels pretty deep.... but it is small and on the edge.

 

[Paul Lohr]

It would help if you mention which cylinder a connecting rod belongs to.

That bearing wear which occurs at the parting line...I have no evidence to prove this, but I am guessing the caps move left to right on the OEM Buick connecting rods. This is nothing more than a guess. I don't see anything on the OEM Buick connecting rod that prevents this movement. Other connecting rods have dowels or knurled bolts (actually they are studs) to prevent this movement. On the Buick rod, tighter fitting sections of the rod bolt may be intended to prevent this movement but the fit can't be near as tight as a knurled bolt or dowel. I have not seen this parting line wear on connecting rods that use knurled bolts or dowels.

I could be wrong, but what else would cause this parting line wear? Perhaps the offset in the connecting rod that is necessary due to the off-center configuration? I am open to hearing what others have to say about this.

Paul Lohr

 

[fastblackracing]

Does the cam you removed have the grooved front journal? If so this normal for the front cam bearing but not good. I have used the harder durabond bearing with a little better success. What do the main cap surfaces look like.. Pitted how much ?I'm thinking those rods were detonated pretty good. Post up a pic of the main cap surfaces. The only real fix for that front cam bearing is to have a crank shop weld the groove shut and regrind it . My shop gets 75 - 100 to do it. How many miles on this setup? I would also double check the rods for straight and round-ness. I have seen some that were terrible. Hope this helps.

 

[lost2a6]

The odd rod bearing wear at the ends is normal. Bearings are thinner at the ends than the center, just the way that they are made.

 

[Nick Micale]

The cam bearing wear appears to be normal.

There are 2 comments I have about the rod bearings.

First, the wear is not unusual or bad, but they must be replaced.

My main concern would be the ARP rod bolts, or actually was the rod re-sized properly when the engine was done and the bolts changed?

Our personal experience is using ARP bolts in a stock rod is a bad idea, since the stock bolt has ample strength and have never seen one fail. But the real issue is indexing the rod and cap with the ARP bolt as it is very difficult to resize the stock rod as the close tolerances needed do not repeat well?

By the time and expense to try and upgrade a common stock rod, same one used in a stock front-driver Buick engine, a new forged rod could be used for little additional cost. A stock rod is not the weak link when using a cast crank.

In this situation, the crank should be checked for straightness and polished, and the rods must be re-sized.

 

[mtocrs1]

Does the cam you removed have the grooved front journal? If so this normal for the front cam bearing but not good. I have used the harder durabond bearing with a little better success. What do the main cap surfaces look like.. Pitted how much ?I'm thinking those rods were detonated pretty good. Post up a pic of the main cap surfaces. The only real fix for that front cam bearing is to have a crank shop weld the groove shut and regrind it . My shop gets 75 - 100 to do it. How many miles on this setup? I would also double check the rods for straight and round-ness. I have seen some that were terrible. Hope this helps.

Yes, the cam bearing is grooved.
The main bearing surfaces actually looked really good, the rear bearing had some pitting but nothing to bad. I will post pics later.

 

[mtocrs1]

The cam bearing wear appears to be normal.

There are 2 comments I have about the rod bearings.

First, the wear is not unusual or bad, but they must be replaced.

My main concern would be the ARP rod bolts, or actually was the rod re-sized properly when the engine was done and the bolts changed?

Our personal experience is using ARP bolts in a stock rod is a bad idea, since the stock bolt has ample strength and have never seen one fail. But the real issue is indexing the rod and cap with the ARP bolt as it is very difficult to resize the stock rod as the close tolerances needed do not repeat well?

By the time and expense to try and upgrade a common stock rod, same one used in a stock front-driver Buick engine, a new forged rod could be used for little additional cost. A stock rod is not the weak link when using a cast crank.

In this situation, the crank should be checked for straightness and polished, and the rods must be re-sized.

I guess its good that cam bearing wear is normal. So does it really need to be replaced if considered normal and will just happen again?
Well I hope the rods were resized properly. The short block was built by a reputable builder 12 years ago.
Im a little confused, you stated that the rod bearing wear is not unusual or bad but then recommend checking the the crank for straightness and resize the rods. Or were you referring to using a new forged rod?

 

[mtocrs1]

So guys my main objective is to get the car up and going again to decide if I want to keep it. I seem to be losing interest in it. Had the car since I was 17 and I am now in my mid thirties. My priorities have changed with kids and such.
I don't mind spending some money but don't want to get out of control.
So if you were me would you install new rod and main bearings and call it a day? Does the cam bearing need to be replaced if this wear is considered normal. Can I install cam bearing myself or does the tool cost more than the labor from the machine shop?
The engine probably only has 15k on it but they are hard miles. I am not easy on it.
My kid is begging me to get outside. Opinions appreciated.

 

[Nick Micale]

................So if you were me would you install new rod and main bearings and call it a day? ......... Opinions appreciated.

My opinion is if you are going to keep the car and run it like you have been, have a qualified shop check the crank and rods, hone the cylinders, install new rings and bearing, then have them assemble the short block.

If you are going to sell the car, put in new rod bearing and be done.

 

[mtocrs1]

Nick, opinion of cam bearing? Need to be replaced with new cam?

 

[mtocrs1]

Worst pitting on mains was actually 3. What causes pitting?

 

[mtocrs1]

 

[mtocrs1]

Pic is rod journal

 

[jdpolzin]

I'd tear it down and go through a rebuild. You need to line hone it and recondition the rods. Might as well just have it done right. If you need a local shop, let me know. We have a place up in Des Moines.

 

[fastblackracing]

Pic is rod journal

Ok here's the deal,#1 The front cam bearing needs replaced it will continue to deterioate and cause more issues. Also why the cam change did the other one go flat or was it noisy? #2, is there a chip in that rod journal or is it just fuzz from a rag? #3 the crank can be polished with some 600 wet/dry paper cut into strips and lubed with wd 40. #4the bearings just look like they were beat on pretty hard to me like you said. #5 I would like to see a pic of the main cap mating surfaces this will tell how much detonation the motor took and possibly explain the bearing wear. #6 why did you take it apart was there an issue to start with? #7 looks like you saved it before any real damage happened but I still want to see how much knock it took.

 

[mtocrs1]

Ok here's the deal,#1 The front cam bearing needs replaced it will continue to deterioate and cause more issues. Also why the cam change did the other one go flat or was it noisy? #2, is there a chip in that rod journal or is it just fuzz from a rag? #3 the crank can be polished with some 600 wet/dry paper cut into strips and lubed with wd 40. #4the bearings just look like they were beat on pretty hard to me like you said. #5 I would like to see a pic of the main cap mating surfaces this will tell how much detonation the motor took and possibly explain the bearing wear. #6 why did you take it apart was there an issue to start with? #7 looks like you saved it before any real damage happened but I still want to see how much knock it took.

1. The other one did not go flat. It had some valve train noise. During investigation I ran the engine with the valve covers removed. Cylinder #4 had delayed oil flow up one of the rocker arms. It would take minutes after the engine was started before that rocker was getting oil. I suspected a collapsed lifter. Ordered roller cam. Once I removed the intake and heads I used my oil pump primer to get some oil flowing. All the lifters had oil instantly, my guess is that the one lifter would not pump up with spring pressure. Lifter bores, lifters and cam look good for the most part, one lobe had some slight scuffing.

2. Chip in rod journal

5. I will snap a pic later today.

6. Same as #1

Thanks for the help.

 

[fastblackracing]

1. The other one did not go flat. It had some valve train noise. During investigation I ran the engine with the valve covers removed. Cylinder #4 had delayed oil flow up one of the rocker arms. It would take minutes after the engine was started before that rocker was getting oil. I suspected a collapsed lifter. Ordered roller cam. Once I removed the intake and heads I used my oil pump primer to get some oil flowing. All the lifters had oil instantly, my guess is that the one lifter would not pump up with spring pressure. Lifter bores, lifters and cam look good for the most part, one lobe had some slight scuffing.

2. Chip in rod journal

5. I will snap a pic later today.

6. Same as #1

Thanks for the help.

cool, here is what I have seen a few times.... the cam is changed with one that has a grooved front bearing and all is well for a while then some valvetrain noise starts and the only thing that fixes it is to replace cam and lifters [flat tappet] and while changing cam you notice the front bearing is worn.... I think its safe to assume this worn bearing will cause some excess oil leakage and lower oil pressure in the valve train. I made up a tool to change the bearing they can be a little tricky to get in straight bit is do-able. That grooved front journal does nothing but cause us grief in our turbo blocks, I know it was needed for earlier blocks but it plays hell on the front bearing. Try to blend the edges of that chip some and see if you can get the harder dura-bond cam bearing. Have a good day.

 

[mtocrs1]

Well I guess I am going to rebuild this the right way so......
Getting cam bearings installed, crank polished, rods checked and whatever else the machine shop recommends and seems reasonable.
Is there any advantage to installing two center billet center main caps at my power level?
The billet caps themselves seem reasonably priced.