cam to rod interference

[juan89]

Hello,

I have a question. On my stage 2 stroker engine, it seems that the cam lobes will contact the rods,if
the timing chain breaks. Is this normal for a stroker Buick v6 ?

Regards,
Juan

 

[Squid4life]

What stroke and rod length?

And yes, if the chain breaks expect unholy things to happen... Broken camshaft, rods, pistons, lifters, valves bent, possible crank breakage or at least cosmetic damage, plus a little extra ventilation of the pan rail sides of the block.

 

[juan89]

The specs are
6.35 Rod Length
3.625 Crank Stroke.

With the timing chain installed straight up, I have at least .060 clearance between the cam lobes and rods.

 

[Squid4life]

What kind of rods? Got any pics of the rods and rod/clearance? Many SII rods are made to be installed only one way, as they have more clearance and less "shoulder" on one side.

 

[Chris Hogeland]

That will be fine. If the chain breaks or if you don't have the chain on there and spin the crank over it will hit on the cam. Everything has to be in time to be happy.


Sent from my iPhone using Tapatalk

 

[juan89]

 

[Chris Hogeland]

Here is some rods I clearance.

Sent from my iPhone using Tapatalk

 

[juan89]

Thanks Chris.

I just don't like the fact that if the timing chain breaks it can destroy the engine.

 

[Chuck Leeper]

If you are going to use really high psi springs, I'd suggest you talk to some of the TSO guys...
AIRC, some yrs ago, they had issues w/ broken chains. Think I saw at least 2 @ the Reynolds race.

 

[Chris Hogeland]

On very high spring psi I put belt drives on most.


Sent from my iPhone using Tapatalk

 

[juan89]

I have 150# on the seat and 350# open pressure. Is that ok with the chain?
I was just wondering if it is normal for stage engines to have interference on the rods without the timing chain . I am using a ProGear PG3132ST timing set.

 

[bison]

I have 150# on the seat and 350# open pressure. Is that ok with the chain?
I was just wondering if it is normal for stage engines to have interference on the rods without the timing chain . I am using a ProGear PG3132ST timing set.

That's not enough spring for those lobes if you plan on getting the most out of your engine. You are ok with 1.55 rockers up to about 6000rpm. 1.65 rpm will be limited. I regularly run 500lbs open on the roll master sets. If you plan on having higher loads than that I'd look into other options. Any engine that is altered to have increased stroke is at greater chance of having interference. There's nothing you can really do to prevent it. You're stuck with the physical dimensions of the block and the cam location can't easily be altered. It's not common to have a timing chain fail. I've never had one fail in one of my engines or anyone else's I've setup.

 

[kidglok]

Mine interferes on a stock stroke 109

 

[Chris Hogeland]

What lifters are you using?


Sent from my iPhone using Tapatalk

 

[juan89]

I am using the Comp Cams 15853-12 SBC short travel hydraulic roller lifters.

 

[Squid4life]

I don't think any of your setup is going to work. Go ahead and sent it to me. I will PM you my address.


Just kidding. I know it is close, that's why everything has to be timed and clearanced like stated above. There have been a few threads in here about chains vs gear drives, and some guys have had bad luck with each, and great luck with each. I honestly feel safer with a gear drive on a race car or street car with a lot of cam/spring. If not crazy aggressive, I guess just pull the front cover periodically to check the streatch of the chain.

 

[J-B Racing]

With those Rods and Crank you are using I had to Notch my Rods with the Cam I am using. My Lobe Lift is .420" so Check yours. I am using the exact same Stroke and Rod Lenght. I am still running a Chain.