i have tried to find info on them i even called comp but no luck. has anyone ever ran them or know anyone that has? it is a 350 roller block i will have to line bore the cam holes for them but not sure the performance gains. or if it is worth the hassle. any info would help thanks.

 

when they do that mod its usually on a full out motor its a timkin style needle bearing you cant go back and the cam really moves around if its not set up corectly -- oiling it is tricky and if you check to see what the rockwell is you wreck the cam so its a guess how long it holds up -- if the core has a shift in it and the new installed bearings make the cam stiff and it wont turn than just re size it and leave it at that -- the gains are not worth the trouble -- and i am sure someone knows someone who and u know -- jz

 

I have both good and bad about roller cam bearings. Depending on the intended use of the engine, as far as extended high rpm use or just drag racing or street use. For extended high rpm it looks like they went back to a polymer coated cam bearing instead due to failure of the roller bearings. On the flip side the ease of friction on how the cam spins is alot less. As I was doing research on this same subject, I was talking to my local machinest who was impressed with how well roller cam bearings work. He told me of a story of when he was working on a drag racing motor that had 1000+ lbs. of spring pressure on it and was able to still spin the motor over with a 3/8" drive torque wrench set at 26 ftlbs. He said that they could spin the motor over and never break the torque wrench over. Of course the spark plugs were out of the motor. He swears by the roller cam bearings and thought that would be the best way to go for the street or even all out racing. He has worked for Chrysler in their R&D team for the Trans Am racing circut, Eddy Hill's pit crew on engine developement for his Top Fuel Dragster, Indy cars for Penske, and several other race teams of all different sorts. I feel that this man is very, very smart and knows more than most race teams out there. I hope this info helps you out.

Shane
Precision System's LLC

 

We use them for the big monster cams, we use in big monster motors.

1500+ HP and $30,000+. We usually order the block with them, I don't know anyone that does them here. You only get a few HP is what I've been told. But you do get a more stable valve train with the huge valves & seat pressures on those kind of motors.

It was between $1000 & $2000 last time I checked, to have an existing block done, not worth it. If you order it done when new, it's much cheaper, and we always do it on anything with big core, big lift cams. .900 or more.

 

mine is more street then strip and i dont have alot of lift 565 is were mine is. but i plan on spinning it to 8500 i work for a machine shop so i can get the block done.

 

We do a lot of roller cam bearing in blocks we machine them for our engine shop and we machine blocks to blue print for other shops accross the country as well. And to do 50 MM roller cam bearings in a stock 350 block you may have a problem as you can bore the cam tunnel to 2.283 but when you machine the the grooves in back of the cam bearing you may get into the water jackets.

We have dealt with roller cam bearings for years with zero problems if someonne is having problems it probably cause they were not fit right or something along those lines.

We build a lot of circle track engines and on the 010 blocks we machine the cam tunnel to the BBC size which makes the journal of the cam only .020 smaller then the 50 MM cam and using roller cam bearings they say that it takes more friction to turn all the little rollers in each cam bearing now times that by 5 bearings and using the Babbit bearing is just sliding on a film of oil and using the babbit bearings it takes harmonics out of the valve train as the cam is riding on a film of oil and its works more like a cushion.

The Cup engines Chevy are using babbit cam bearings now as the cam tunnel is bored to 2.283 and they are using the babbit cam bearing and running a 55 MM cam

Durabond makes a cam bearing for the 2.283 cam tunnel which was used for the 50 MM roller cam bearing for years now using the same cam tunnel you can install the GMP-55T cam bearing in the same bore and runn a 55 MM cam.

This year NASCAR just accepted the new block from GM that has a super raised cam tunnel and the chevy engines we be able to run a 60 MM cam core which is the NASCAR limit and there will be a lot SB-2 stuff for sale this years as nothing off the old blocks fits the new block.

At our shop we set up to blue print blocks using a HAAS 4-axis CNC machining center and we are also set up for blue print boring the cam tunnels as most shops bore of the original cam tunel which they are making them bigger not better as we have seen cam tunnels off up to .014 and from there we machine the lifter bores which makes for better peice when you are done.

Here is a pic of a Dart Aluminum raised cam tunnel block that we machined for the GMP-55T cam bearings.

 

I spin my 383 to 8500 and all I have is the Clevite "H" series bearings installed. The net lift of my cam with 1.6 rockers is .712". The springs are 620#. So if it were me, I would save the moeny and spend it elsewhere.

 

Clevite makes an H-series cam bearings HMMMMM is this something new as they make the SH-290's for stock replacement and SH-1349's for the performance engines so what is the P/N of your H- series cam bearings.

And going to a bigger cam core is always a better deal if you do this type of work as your correcting the cam tunnel where its suppose to be and with the bigger there is a lot les twist in the cam and you can get much better profiles using bigger cam cores.

And where 84camaroturbo works for a machine shop I am sure it will cost little or nothing to do the job and he will have a much better peice when he is done then using a standard journal camshaft. BIGGER IS BETTER.

 

thanks for all the info i was told i can go to a bearing store and get the bearings for stock cam sizes. I just want to make it better and hit 8500 or 9 like a bike would and i think the bearings would help it do that.

I have roller rocker. roller lifters complete knife edged forged crank. comp dry timing belt. it is the lightest 350 we have ever balanced at work so it spins fast now just want it better.

they also say you have to run a normal oil pump from the cam holes being plugged and you have less windage from less oil flying around.

 

What size cam are you going to use???

 

As said before a 55 mm cam core would be ideal for higher rpm. The valves will open quicker, the cam core will have less deflection as it moves the lifter's, you can get better lobe profiles, etc.. Look at the LS1 cam from GM, it has a 2.125" cam journal dia., they would not have went to it if it had not alot of advantages. The bean counters there probably didn't like the extra cost either, but they went ahead and used it anyway. Now, stock LS1 engines with just a cam change can pick up to 82 HP with a good cam profile. It may take some tedious work getting the project done but I think that you would be extreemly happy after you get it completed and running.

 

it is a lunati i cant remember what it measures but it is just the stock journal size. I would go with a bigger journal but had the cam ground earleir in the year. it is winter and my car hates the snow so it is tore down for the winter.