2000hp SBC help

[radialracer]

I have been running a steel capped Little M block for the last 3 years. In the beginning it made 1400 but is now making around 1800 with a turbo. Car has been 7.50's at 189mph at 3400#. Recently it has been walking a cam bearing out of it. The bearing is the one next to the rear of the block. The bore uses the standard bearing size and has been checked by 2 different machinist and verified to be within spec. This last time it was installed with loc-tite. So far it has walked out 3 times. This last time it has moved with only 10 passes. All bearings other than the thrust look like new but it's clear the caps are moving.

Also I have noticed the thrust bearing halves do not line-up perfectly and it causes excessive wear on the top thrust bearing.

Is it possible this block has shifted and is no longer good for this sort of power?

Is the iron eagle any stronger?

I'm not against swapping to the iron eagle if it's stronger but I'd like to stick to the standard cam location since I do have the belt drive system.

[radialracer]

I guess I should add it's walking to front of the block if that makes any difference.

Thanks

[want-a-be]

What does the bearing surface look like? Does it look like it's wiped a bit as if the cam and bearing made contact? Any marking on the cams bearing surface there? I can only assume that it's spinning it's way out. How much press does that hole have on the bearing? How much end play does the Cam have when installed? What kind of wear pattern on the distributor gears are you seeing? What kind of oil pump are you running? It's Pressure at RPM? What max RPM are you seeing?

Might check the oil passage to that cam journal and insure it's not blocked in any way. Might even have a crack or some kind or leak in that oil passage.

As for the thrust bearing on the crank. Are you assembling this engine? If so how are you seating the thrust bearing during assembly? If not how is your builder seating it? How much end play does the crank have? Are you seeing any problems with the cranks thrust surface?

What kind of dampner are you running? How well is the assembly balanced? Is it internal or externally balanced? What inch is this engine?

Sorry for all the questions. But I and others will be able to give a better answer with as much info as possible.

Don

[radialracer]

The cam bearing looks new. No contact or wear between the cam and the bearing is noticeable. I'm not sure how much press but I have taken it to the most anal engine builder we have and everything checked within spec. He mic'd the bearing and the journal and it was where it should be as far as press. He also set up the comp belt drive to within spec. Distributor wear looks great. Oil pump is a Moroso with big block pick-up with the oil restrictors just as DART recommends.

I shift at 7800 rpm and see 80psi oil pressure. I have checked and run cleaner through this feed hole the last time I had it apart. 10 passes later the bearing has moved again. It looks just like the block is moving and the bearing is loosing it's press. There are chatter marks on the main caps so I'm wondering if the harmonics can walk this bearing out.

I have assembled it twice and had 2 builders assemble it as well. Last time the thrust was seated by using the crank flange to square everything up. End play was .005. After 10 passes it was .008 which is why I went back in the pan. The thrust has been killed 2 times prior which killed my Crower crank. This time I installed a new Lunati pro series. 400ci 3.75 stroke internally balanced. Luckily I caught it this time before it messed the crank up again. The cam bearing ordeal has me puzzled.

[want-a-be]

What Dampner are you running? What manufacturer? Is it for an internal or ext. balanced engine? What Flex plate are you running? Is it for an internal or ext. balanced engine?

Aluminum or steel rods?
Thanks, Don

[radialracer]

ATI super dampner and BTE sfi flexplate. Both for internal balance.

Oliver billet super speedway rods. Venolia pistons.

[want-a-be]

How was the old crank messed up? What were the damages?

Don

[radialracer]

It was always thrust issues. 4 seperate occasions now. One time it was bad enough to need the mains turned .010. I have swapped converters from tight to loose with no progress. Checked and re-checked installation clearances. Swapped engine oils from straight to 20w-50 and back synthetic 30w. When the car made 1400hp and ran low 8's I could run nearly an entire season with no issues. Now at the 1700-1800 level, it's always something.

After speaking with John at Dart today. I will be moving to an Iron Eagle block.

[want-a-be]

Going to the Iron Eagle block sounds like a good direction.

I hate to beat a dead horse but I'm just wanting to get it right in my lil head as to how you are seating the thrust bearing. I know your using the thrust surface to seat it....But I'd like all the details of how your doing it.

Thanks, Don

[Awesome Bill]

I have seen this many times, your not going to stop it because you are looking in the wrong place. Either private message me or call me. My # is available. I can't believe all your anal guys missed this one! As far as the cam bearing turning in its saddle but not showing any signs of contact, that is a no brainer also. Hate to give up secrects, but if you send the block and hardware to me, it won't do it again! Call me or pm me.

[lun40119]

Wish I knew what caused it.............:rolleyes: Damn those secrets. :D

[want-a-be]

Wouldn't mind your sharing this with me also Bill. If you wouldn't mind. PM if you're intrested

Thanks,
Don

[CNC BLOCKS]

We have some shops we machine blocks for that build some pretty high end engines and we seem to machine quite a few of the Little-M blocks with the BBC cam tunnels.

Actually a guy from CA wants a SHP done the same way.

[Trmnatr]

The cam bearing looks new. No contact or wear between the cam and the bearing is noticeable. I'm not sure how much press but I have taken it to the most anal engine builder we have and everything checked within spec. He mic'd the bearing and the journal and it was where it should be as far as press. He also set up the comp belt drive to within spec. Distributor wear looks great. Oil pump is a Moroso with big block pick-up with the oil restrictors just as DART recommends.
I shift at 7800 rpm and see 80psi oil pressure. I have checked and run cleaner through this feed hole the last time I had it apart. 10 passes later the bearing has moved again. It looks just like the block is moving and the bearing is loosing it's press. There are chatter marks on the main caps so I'm wondering if the harmonics can walk this bearing out.

I have assembled it twice and had 2 builders assemble it as well. Last time the thrust was seated by using the crank flange to square everything up. End play was .005. After 10 passes it was .008 which is why I went back in the pan. The thrust has been killed 2 times prior which killed my Crower crank. This time I installed a new Lunati pro series. 400ci 3.75 stroke internally balanced. Luckily I caught it this time before it messed the crank up again. The cam bearing ordeal has me puzzled.

I assume it is a roller cam

If so, Anyone who suggests oil restrictors has fell down and bumped their head. That includes myself.

REMOVE THE OIL RESTRICTORS

You want the oil film to handle the load, You have alot of load on the cam bearings with roller cam spring pressure. Do not ever restrict the oil flow - NEVER

Would you want your blood flow restricted ? NO
Why restrict the engines blood flow (oil) ?

Bottom Line, throw the oil restrictors away

[lun40119]

I assume it is a roller cam

If so, Anyone who suggests oil restrictors has fell down and bumped their head. That includes myself.

REMOVE THE OIL RESTRICTORS

You want the oil film to handle the load, You have alot of load on the cam bearings with roller cam spring pressure. Do not ever restrict the oil flow - NEVER

Would you want your blood flow restricted ? NO
Why restrict the engines blood flow (oil) ?

Bottom Line, throw the oil restrictors away

I agree there, must have missed it.

[Awesome Bill]

Oil restrictors play no part in this and won't do anything to fix it. The heavy metals in his oil he is using right now show his oil and what is in it have enough extreme pressure agents, (boron etc) in it. Turbo people making over 1500 hp have to use a true race oil. I am a big proponet of not using oil restrictors, so don't get me wrong. His statement said the cam bearing was never touch surface to surface, it just spins. And locktite won't do nothing in this case. His rear thrust is his problem. I do agree with Carl here, (imagine that now that he is playing nice), the roller cam bearing would be applicable, even the standard bearing has more surface crush which will promote a more stable bearing.

As far as another block, if you are already dead set with this, the Compacted Graphite is what you want for strenght. We do not use the Standard Iron blocks with anything over 1500 hp. They do move around. But, Your thrust will actually be destroyed quicker if you tighten every thing up with a better more stable block.

Personally, Carls point with the 55 or even 60mm cam bearing is what I would go with. There is 25% more area contact with the larger bearing. But you will continue to eat up thrust. It is a quite simple area to address to make the thrust live. Anyone ever done any sled pulling with a clutch lately? this should give you all you need? If not, I guess we have never done any real power pulling! Secrets, more likely in this point called SCARS. Got a few of them and never want another one once you find out what causes it? Now I get paid for my scars that I have, if not I just live with them. Chicks dig emmmmmmmm!

[want-a-be]

point taken.

Don

[CNC BLOCKS]

We have 2 sled pullling engines that one is a Dart raised cam tunnel 9.325 deck and one is a Brodix raised cam tunnel 9.500 deck with 8-71 blowers and make about 1600 horse then pull in Canada and the U.S. and these 2 engines have won championships 6 or 7 years in row 1st and 2and, The both have BBC cam tunnels and we use the GMP-1 Durabond cam bearings over the nose pressure is around 1250 and so far no issues with either engine.

The Dart block is number 073 and its been around many years and resleeved it 2 years ago.

[Awesome Bill]

The other problem he in particular is having is loosing the thrust, this means the rear main is getting hot and contact is being made? Some pullers have this and some don't. I mentioned this particular class of racing because it has similar thrust problems sometimes. We modify to correct this. He has problems with this and does not have a clutch but still yet has taken the thrust out several times and every time he takes it apart, the thrust is being abused. No doubt the larger cam journal will help control his cam bearing problem.

[radialracer]

The other problem he in particular is having is loosing the thrust, this means the rear main is getting hot and contact is being made? Some pullers have this and some don't. I mentioned this particular class of racing because it has similar thrust problems sometimes. We modify to correct this. He has problems with this and does not have a clutch but still yet has taken the thrust out several times and every time he takes it apart, the thrust is being abused. No doubt the larger cam journal will help control his cam bearing problem.

Thanks for everyones input. I have made the jump to big block for more reasons than the issues here. I'd still be interested in hearing your opinion on thrust issues though Bill if you have the time to speak. The thrust issues seemed to come and go but as the power level increased, the problem got worse. Of course as power increased, I had to tighten the converter.

I'm sure I could have fixed the cam bearing issue with a larger bearing but the chatter marks on the caps showed the blocks fasteners needed to be larger. The move to the iron eagle was for the larger fasteners and for the big block cam journal.

I was running the restrictors per DART's request. I had them at almost double the size they recommended.

[Awesome Bill]

Going big block and making more power will only take the thrust out again. Your missing a big problem. Good luck with the switch to big block, as you have admitted, as power level increased, the problem got worst with the small block. This alone will surely happen again with even more power? You have not fixed a problem until you know what causes it, just putting another engine in and not knowing what caused it and now making way more torque will only let it happen faster.

Granted, the big block thrust is somewhat larger and will displace the heat and pressure a little better, but, you will now make way more torque and power and make more heat and pressure and will possibly have a worst problem?

[radialracer]

The big block deal is for reliability. You can't say a 2000hp big block won't live longer than a 2000 Little M block. It got to the point where maintaining the small block at this level was costly and time consuming. It was trouble free at 1400hp. 1800 it was to the point of needing gaskets every 15-20 passes even if the thrust wasn't an issue. The move to a symmetrical port like the SBX is not the way to go IMO when you look at all the custom one off parts required. The big block was the logical choice.

[Awesome Bill]

The big block will handle the power better but will do the exact same thing to the rear main if you use the same stuff over! Think about it.

[radialracer]

Thanks for your time on the phone the other day. It was good to confirm that your opinion was along the lines of my concerns. I'll be addressing it.

[Awesome Bill]

I have seen that numerous times and its always what I told you. That information is worth a fortune in purchasing the proper built right stuff in the beginning. A ton say they do it right but I have seen even the large named stuff do that! Have fun with that big block.

[ash]

did the cause of the cam bearing and main thrust actually get spoken about ??

we run a twin turbo sbc , little m block , and have had no problems
granted it may be only showing 1400-1500 hp

i found by run all clearances loose....including converter - flex plate - converter pump ......and put more oil into the system ( bbc oil pump) , most parts come out pretty good.

[montecarlo84]

I's a builders secret that bill knows

BO knows ? Well ,BILL knows Horse power.