hi.. My friend just installed the 07-468-8 on his Lt1 -92, the bottom end is stock and so is the camdrive ( stock but new ). But he have installed the cam with comps hyd, roller lifters and beehive springs and uses 6,95" pushrods and 1,5:1 RR and all the parts thats required from comp. The heads are ported stock with BBK 58mm and ported intake 30lb injectors and so on! The problem is that this engine did never get the piston/Valve clearance check mostly due to the hope that Comp wont sell a cam from the shelf that wont work with the engine it´s made for. The engine turned nicely when installed, i came to his garage earlier this evening when he was about to start up. First try the engine stumbled a little then shut down, second try the engine started, but showed no oil pressure ( most likely cause it did´nt reach the sensor yet ). He tried again and the oil pressure came up on the gauge (550kPa).. Soon after the engine started to rattle ( ticking sound ). And we shut down. Pulled all the plugs and ran the starter. The engine was quiet and smooth, the compression seemed fine on all 8, ( Did´nt have a real tester at the time so i´ve just used the finger in the hole method for the moment ). the RR have not touched the valvecovers.. the oilpress showed 400kPa just with the starter.

So my question is, does any of you know if this cam can be used on a stock Lt1 block? With stock pistons/heads etc.? Anyone used this cam before? the link for the cam is

http://store.summitracing.com/partde...8&autoview=sku

Only trying to help him out here so please if you have any clue please help..

Thanks.
/Johan. Sweden!

 

How did he determine pushrod length? Is the geometry correct? I mean are the rocker tips centered on each valve stem and not off to one side or the other, or front to back? Does he have correct push rod guides? Just seems to be a lot of questions not answered.

 

Hi.. He used Comps adjustable rods for checking. The rocker rolls from from left past center and over to the right and then back. The guides are standard but have enough lash for the pushrods.


/Svante.

 

"any of you know if this cam can be used on a stock Lt1 block?"

I don't see why not.
Cam is listed at 58X / 57X lift with 1.6 rockers so 1.5's give about .540ish which is not a uncommon lift used in LT1's.
Pushrods seem very short for engine.Stock is 7.200.
I cut my block 25 thou to get zero deck and only dropped to 7.150 pushrods.

Are the rockers adjusted correctly?

 

this cam needs the computer reprogrammed,did he get this done?

 

Holy cr4p, why so big of a cam with the stock heads? ?

A tune is minimum he needs to do...I hope things work out for him but he just turned his car into a dog.


In the future cam selection blame cant be thrown at the guy at the other end of the phone, your friend needs to do his homework.
If the Summit "tech" really did recommend this he needs to have that cam shoved up is azz for stupidity. .

This is why I harp on not letting a 10$/hr chart reader pick your cam.

 

[QUOTE=cuisinartvette;1562592387]Holy cr4p, why so big of a cam with the stock heads? ?

A tune is minimum he needs to do...I hope things work out for him but he just turned his car into a dog.



In the future cam selection blame cant be thrown at the guy at the other end of the phone, your friend needs to do his homework.
If the Summit "tech" really did recommend this he needs to have that cam shoved up is azz for stupidity. .


This is exactly why I call cam manufacturer and talk to their tech dept>

 

I am running the Comp XFI 467 in my LT4 with 1.6 roller rockers. They advertise the lift on these cams with 1.6 rockers. If you are running the 468 with 1.5 rockers then you are not getting the advertised lift. So, I doubt that you have any valves hitting the pistons. My block was decked to zero, I had the heads shaved, and I am running a thiner head gasket. I still had .100 piston to valve clearance.

The push rods do sound to short as well, with all the work I had done, mentioned above, I am running a 7.100 long push rod (7.200 is stock).

I would go threw all the valve and make sure they are adjusted right.

Did he use an adjustable timing chain with 3 keyways on the crank? I know a guy that installed one of those wrong and all his intake valves hit the pistons.

 

Hi again, the problem is found. It was the new starter that touched the flexplate when the engine was running. About the pushrod lenght i can not say why we ended up with 6.95" He uses the EPWI RR and Comps roller lifters.


/Svante.

 

Did I miss something? I thought comp cams said the lift #'s are with "factory rockers". Don't LT1's have 1.5:1 rockers?

 

all xfi cams are based off 1.6 rockers.