Has anyone had any experience in running a solid roller camshaft in an LT4 (possibly stock heads and stock bottom end)?

Thanks.

 

We have and can do solid roller conversion on LT1/LT4 (as well as LS1, etc.) type vehicles - I have a LT4 headed 396 solid roller buildup underway!

A couple things you need to consider -
1) Valvesprings - stock heads will work, but they will really need to be pulled to do valvesprings. The pressures you run with a solid will make it near impossible to do the swap (valvespring) under the hood, and as for true "stock" well, you will probably need some slight machining for a good reliable solid roller quality spring to fit.

2) Rockers - you will probably want to upgrade your rockers - if you have to you could get away with the 3/8th's, but I don't think it will be reliable, and I wouldn't do it/recommend it. You really want a 7/16th stud and rocker in there, and if you get really serious on the cam/springs a stud girdle also.

3) Restrictors - this will depend quite a bit on your intended usage. For a constant road race vehicle you will definitely want some restrictors in the block to keep you from filling up the valvecovers with oil at constant high-rpm usage. On the other hand you don't want to let a restrictored motor idle for long periods of time (20+ minutes) like you might on a traffic jam on the highway - since oil is what cools the springs. A high idle can ameliorate this (1000+rpm), and thermal coatings on the valve springs also can reduce this problem, but it's something you need to consider.

4) Cam - you need to be carefully to not overcam the car - solids, will tend to hold out their peak for longer than hydraulics - even one with a near stock idle might be stressing the limits of the stock shortblock. I would keep shift points no higher than 7200.

5) Lifters - you can go with anything from the crane cheapies (which are still good) for 200 or so to something much better like a comp cams endureX which basically takes care of all your oiling problems mentioned above - but it's 2-3x the price.

6) Rev kit - I would still run one with a solid roller to take out the slack (from lash) on the lifter-lobe.

7) Timing chain - if you are turning rpm's like that with a solid roller I would highly recommend a elec. waterpump and double roller conversion. Do not use the keyway/offset bushing to advance or retard the cam as it effects the spark and injector phasing by the same amount


It's really rather straight-forward, there are just a few things like the ones mentioned above that you need to ensure are up to spec, since we are talking greatly increased spring pressures.

I think the benefits would be awesome - first off the cam would idle 100 times smoother than a hydraulic that made even within 10-15hp as much - the solid would make more power - as well as torque, across the board, and would have a much broader powerband. You could also safely take the rpms up past 6800 or so, where hydraulic rollers really start to become and issue.

 

I just sent an e-mail to Chris K about a solid roller yesterday. I think this might be my next engine project.

 

Chris B replied with a very excellent post. I did the conversion on my L98 383. He seemed to hit all the info on the head.
I looked into those endrue X lifters. Yes those are pricey. I stuck with the 891-16 small base circle cam lifters.

As for springs you may get away with the com cam 1.46 springs in your stock pockets. They will get you the 155 seat pressure for most street cams.
I went with a 236-242 comp cams extreme solid roller.
This equates to a smaller cam when comparing specs to a hyd roller.

I feel with todays technolgy adjusting the vavles in not all like it use to be. You can probrably go thru the summer or more without adjustment.

Dennis

 

Thumper,
I think I said this in the mail, but you were actually the 3rd email that day about solid roller camed LTx motors!!! When it rains it pours. I am just glad to see that people are now opening up to the fact that solid roller cams can give you so much more without the sacrifices of a large hydraulic cam.

 

ChrisB: This is a simple question: The OEM rocker studs are 10 mm. I understand that switching to another camshaft it is best (even required) to use adjustable rocker arms. Would installing a 7/16 stud just be a replacement of the 10 mm or will machine work be required-in other words is the portion that threads into the head same diameter on either 3/8 or 7/16-this might be obvious but I haven't seen the topic discussed before.

How about knock sensors-will these need to be deactivated (PCM reprogram) or not?

Is noise significant-the type one could hear inside the vehicle?

Would GM Severe Duty Timing chain be adequate?

BOWTYE8: Could you provide the rest of the specs on the camshaft you are using? Comp Cams website is not too user friendly anymore

Thanks for all the information.

 

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The stud will screw into the head and from the head up be 7/16th's (as opposed to 3/8th's stock). No machine work required, just the appropriate roller rockers.


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:[/color]<HR><font face="Verdana, Arial" size="2">
How about knock sensors-will these need to be deactivated (PCM reprogram) or not?
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I really haven't seen/had any issues with them - more than what one may have on a hydraulic car. As long as they aren't over-torqued in the block they are generally fine. Worst case you can wrap some teflon tape around them and this almost always desensitizes them enough.

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Is noise significant-the type one could hear inside the vehicle?
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It depends on what kind of lifters you use, if you use a rev-kit, etc. But the noise is really not bad at all (vette valvecovers are also much quieter than f-bodies).


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:[/color]<HR><font face="Verdana, Arial" size="2">
Would GM Severe Duty Timing chain be adequate?
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I would think so, it's just expensive. For the same price almost you could get an elec. waterpump and a double roller [img]http]//www.corvetteforum.cc/ubb/smile.gif[/img]. But at the least I would do the severe duty.