bent rods

I had reher-morrison build me a new 565 for blown alky combo. Wes put steel manley rods in it. Run time is only in my shop. I have at least 3 bent rods (the h beams look like a double s). What would cause this with a 14-71? Not enough rod or too much fuel? (DMPE set up the fuel curve and supplied all parts) The bearings look good. The only odd thing I've noticed is a peculiar smell in exhaust like too rich or detoniation. Runninf 10 plus w/ 8973 controller. Blower is BDS air loc w/ 28% od.

 

A load of raw fuel in the cylinder will hydralic a rod.
Might be a thought.

Blessings........Ron Clevenger.

 

what does the crank trigger do mike ?

 

Which rods are bent ?
Is the blower an open or delta bottom?
Is the blower set back?
What alerted you to the bent rod problem?
Jim

 

When we first started racing alky almost 20 years ago we bent a few rods just starting it up because the guy with the squirt bottle thought he was putting out the Yorba Linda fires or was in charge of starting the worlds largest BBQ.

Depending on your shut off proceedure you might be leaving a cylinder or two full of alky. If you don't back it down before spinning the starter again it would be crunch time.

RG

 

I am running a crank trigger with the 8973. I prime up the engine on race fuel with small electric pump. Kill the motor with the shut off valve (run it out of fuel) The blower is full open bottom no set back. I ran a 8-71 all last year using the same start up and kill procedure. The blower is new and all the fuel system is new from DMPE.

 

I know for sure that 4, 6, and 8 are bent. I just pulled the pan to inspect bearings because we were gonna make some test and tunes this weekend. The rods were obvious to the naked eye.

 

like randy said, did you back it down? if the car stalls, or you shut it off and then restart without backing it down, that can bend the rods. you said the bearings looked good, and if you have detonation, that usually hammers the bearing. mike is right too, so if you dont have it set up the way he explained, you might want to change that too, it can only help. also if the rod was bent, you might not have the normal amt of air in the cylinder (not enough?) causing it to smell rich.

 

It is a Leahy crank trigger. It does have a shiel that grounds to frame. The 8973 came with a shielded wire also that grounds to frame. There is one 6' length of MSD trigger wire that tie the two together that is not a shielded wire. It must be a common wire for msd (green and violet) used it on several msd"s igns. in the past. I think I know the answer= I had trouble getting it to fire when I first started it up. I remeber seeing alky/ race fuel come out of the zoomies. Would that be the culprit?

 

If it has enough fuel in the blower/manifold when it starts it can hydraulic. Sounds like there may have been enough fuel comming out the chimneys for this to be likely. Interesting that the bent rods are almost in the firing order. May pay to check number three closely.
Jim

 

It is odd that all three bent rods are on the right bank (4,6, & 8) was it parked on an incline (side to side) and the primer fuel puddled on one side when starting it ??

 

For what its worth BBC nitrous motors usually eat the even # cylinders first, they suffer more than 1357 as a general rule.

Richard Gavle

 

I have double checked all cylinder firing order, all is good. The car is not on any incline, it is actually 6" in the air on my car lift. I will replace the non shielded wire with one. Thanks for all the input. I am also replacing the steel rods with MGP aluminum rods and getting the motor rebalanced. I'm not an engine builder but it seemed to me that this is too much power for a steel rod motor. Thanks again.

 

14-71 blown alky steel rods, it didnt bend all of em?

 

No, two were severly snaked and one had a small ripple.

 

are your sure you are someone didnt squrit to much fuel when priming it and it tried to hydro lock the motor when you tried to start it