408 push rod length (pic inside)
408 push rod length (pic inside) Well I had my 408 built and on the dyno twice. First time we had problems with timing and we pulled the motor apart and verified timing was correct. Had it on the dyno today and the car wouldn't make power past 3000 rpm and timing is still off from what it should be. The cars idle seems to be inconsistent in how the valves seem to open (idle doesn't seem to drop or rise, it just sounds different all the time.) My tuner mentioned to me that in the past he has seen incorrect push rods be the culprit for not making power so I pulled the valve cover off and used sharpie to color the top of the valve and turned it over and in the pic is what I came up with. Looks like my push rods are too long. The car only made 332hp and 340ftlb before it fell on its face. Before any one beats me up over not checking the lengths I didnt build this motor so I figured it was right when I payed someone to build it. Is this the total cause of all my lost power or do I need to look else ware? Thanks in advance for any help.
Im running out of places to check, I did a compression test last night and without holding the throttle open every cylinder was between 220-225 PSI, so its pretty consistent. This is getting frustrating.
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A) Unless you have roller tip rockers, the wipe pattern is going to look like that with the "scuff pad" design of the stock rockers, so it's probably OK.
B) Pushrod length will not fix the wipe pattern. This isn't a SBC. The LS rockers are pedestal mount, so changing the wipe pattern involves raising or lowering the rockers is relation to the valve.
C) I've seen similar symptoms on two different cars. The first had an issue with the 24x reluctor separating (it's a two piece reluctor) and was fixed by replacing it. The last one was fixed by replacing the reluctor and clearancing the oil pump from the timing chain. Someone forgot the oil pump spacers with a double roller chain, so the chain was digging into the pump housing HARD. Not sure if that fixed it or it was replacing the reluctor, but the car ran flawlessly after that.
B) Pushrod length will not fix the wipe pattern. This isn't a SBC. The LS rockers are pedestal mount, so changing the wipe pattern involves raising or lowering the rockers is relation to the valve.
C) I've seen similar symptoms on two different cars. The first had an issue with the 24x reluctor separating (it's a two piece reluctor) and was fixed by replacing it. The last one was fixed by replacing the reluctor and clearancing the oil pump from the timing chain. Someone forgot the oil pump spacers with a double roller chain, so the chain was digging into the pump housing HARD. Not sure if that fixed it or it was replacing the reluctor, but the car ran flawlessly after that.
