When to freshen a blower motor
 

I have a well built ProCharged and modified 454 Mag. Spared no expense on any parts (Valves, bolts, pistons, springs, all roller, etc.). I change oil upon any consumption 50 Valvoline racing oil, about every 7 to 10 hours. The motor has about 160 hours on it and some are suggesting a freshen up. Any thoughts? It's not a matter of the money but if I don't need to why.

Leakdown test will tell alot. Are you getting blow by out the valve covers? I ran my 502 w/procharger about 170 hours (3 seasons),it was leaking oil,had bad blowby and was burning oil when I tore it down. Rods and mains looked good but lifters were getting tired,head gaskets were on verge of failing,the cheap comp roller tip rockers I was running had the fulcrum balls turned blue and one was split but hadn't let rocker come un-done yet (was just lucky)rings had lost ductility and seemed soft when I pulled them off the pistons,timing chain was shot so it was way over due. I was running 8-10 psi of boost though. I ran my 540 120 something hours the first time,the valves were sawing thru the guides,lifter bodies were worn,timing chain was pitted on the rollers. At 100 hours the compression and leakdown were still good,at 120 hours it had changed signifigantly. I ran my 540 110 hours (2 seasons ) the second time,10-12 psi of boost,one head gasket was pushed apart but hadn't blown yet (was using the good arp studs,afr heads on merlin block with felpro 1047's),rods and mains still looked like new,compression was still perfect.leakdown was great on 6 of 8 cylinders but signifigantly higher on 2 cylinders. The stiff valve springs dampner had started cutting into the titanium retainers pretty far. I do a leakdown and compression test when motor is first broken in for reference then test it a few times a year plus cut every filter open and change filter every 4-6 hours,change oil every 8-12 hours. I have determined the way I run my motor that every 100-120 hours (2 seasons) is a good point to rebuild it,the 502 that I ran longer was acting tired and had lost a little speed,I won't do that again.Every time my rods and mains looked good because I changed the oil frequently and have a 14 qt oil pan plus a big oil cooler so I never hurt a bottom end but I have seen a pattern of valve train wear repeat itself. It really depends how hard you run your motor too,I spin my 540 6000 rpm's,Smitty

I agree with Smitty. Better to tear it down when it's not due to failurre. Much cheaper in the long run!!

Smitty, nice writeup! Interesting to hear where the weak links are. :ernaehrung004:

Michael

Smitty,
No I dont have any blow by or fuel in the oil. You did however point out some weak links I did not consider.
I will go through it in the off season.

I agree, compression test is good, leakdown tests are even better. As soon as the #'s start to slip rebuilding would be a good idea.. It is cheaper to do it like that then to need a block because you ate a valve or something stupid.. Pampering the engine & very good routine maintainace do also help in its longevity.. :) Jamie / Lakeside


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