So why is it always cylinder 1 having the cylinder pressure issues? Every one always breaks the rockers on cylinder 1 as well when you turn up the HP. I am inclined to believe that number 1 is suffereing from some harmonic mojo on the crankshaft causing the piston to reach TDC out of time or the block is flexing causing the piston to have more protrusion than normal. OR...... is it the CPS causing a timing error on cylinder number 1?
Why does cylinder number 1 have all the problems
- Thread starter Gearhead
- Start date
Thats the one that let go on mine a few years ago. Broke rockers, rocker towers, bent push rods, blew head gasket and bent rod. Was running on the dyno when it went.
Was running 238/80's and a 38r with stock springs. I blamed it on the stock springs and too much back pressure from the 38R.:shrug:
Was running 238/80's and a 38r with stock springs. I blamed it on the stock springs and too much back pressure from the 38R.:shrug:
Dieselboy.
New member
Any chance it was an 80hp economy tune....
I've done pushrods on number 4. And blew my pmr motor on 7 and 8.
Stroker#66
New member
My rocker broke on #2 intake
I think it has to do with the fact we are looking at the end of the crank and you add in block flex with the possible addition of as you indicated a certain vibration frequency the end result is a short rod on number 1. Consider also that main walk has been seen in a number of engines with TQ levels IIRC as low as 1200 ftlb or slightly under and up. The only fix I have seen is a full bedplate. Girdles still had evidence of walk from what I have seen posted.
I personally think these damn blocks seem to flex so easy that it at the root of most all the issues even the PMRs breaking.
I personally think these damn blocks seem to flex so easy that it at the root of most all the issues even the PMRs breaking.
PowerstrokeJunkie
Active member
They were designed for 235 horsepower :shrug:
Buffalo444
New member
My 02 blew the number 1 pmr out the block.... Completely stock -_-
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Sent from my LG-C900 using Board Express
V-Ref
Active member
Is the #1 cylinder failure rate the same for filled or bedplated blocks vice unfilled or stock bottom end blocks?
jwlandry
Active member
Probably because cyl one sees the fuel first, the highest injection pressure with the least air flow.
V-Ref
Active member
You lost me here.
I considered this but with everything.happening.so.fast is this really why? Or does it.have more to do.with cyl1 being out at the end of the crank? Excessive endplay due to flex in the center of the crank. Seems a bedplate and something to eat harmonic frequencies would do it but some harmonic balancers have been speculated to "help" motors blow.
Im about to order parts to build my motor so this is giving me a gut ache thinking about doing this and then blowin up! Im not discouraged tho.
jwlandry
Active member
Mine is getting a bed plate so I'm not too worried.
Cyl #1 is first in firing order. But I dont think every time cylinder 1 is up to bat the inj press is.magically at optimum. This is assuming slow operation before applying throttle. Im going with the crank position/rotation of/and endplay due to flexing of.the.block. Seen it in other motors that were turned up, especially forced induction motors.
jwlandry
Active member
Coming from a different vendor.
My buddy said he can make.me one for 1500. The boughten ones are about a grand more so its expensive just to make. He was gonna just do it.for me. No.labor.charge cu thats how we roll.
Yes but so was the cummins by that spec. LOL But its more about TQ IMO on this as we are dealing with twisting force and CP. I sure wish they had gone with a straight 6 in these even with HEUI.
