When I do the valvetrain, I do the entire valvetrain.....cam, lifters, pushrods, valves, springs, retainers, locks, and seals. I also do a valve job and just scratch the surface of the heads to remove any indentations made by the head gasket and to be sure it is flat.
In your case, I would just want to check the condition of the springs to see if they lost any pressure. If not, them let them go. If they lost 10 psi of more, then they will need to be changed. We could just do the springs in the boat in that case. Eddie |
You do a lot on a (top end) refresh now I see why you say you go ahead and do the bottom at the same time. I do motorcycle engines and it's valve springs breaking that we see but some of our stuff revs to 17000 rpms but with not as much load as a boat has all the time. Do you see them breaking or is it the head popping off the valve ? I have been lucky with the only problem ever was a rod broke on me the first time out in my Nortech but Terry Sobo was great and paid for the parts then no problems aside from a fuel pump stated leaking oil.
When do youn change rods or do you Xray and treat them once or just go new rods and pistons every rebuild? |
I never replace the rods unless something has broken. I will magnaflux them, replace the bushings, change the bolts and resize them. That is why I use top notch parts. There is no reason to replace them since they don't wear out. I do replace the pistons. The only parts I reuse are the bare connecting rods, bare block and bare heads...plus the accessories. You essentially start all over with a new engine at a small fraction of the price. For example, it is under 20K to freshen up a 75K engine.
I have never had a valve break.....or anything other part for that matter. I error on the side of caution to prevent any failures. I use the best parts I can buy, put it together very carefully, take the time to tune it right, make sure the boat is set up correctly, and rebuild it before anything can get worn out. Hope this helps. Eddie |
What rods do you use ? The one in my motor was a Manley H beam that snapped in the middle, the builder said it was just a fluke and rarely every see's that.
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Those Manleys are only rated for about 700 hp. I think they may be imports. I not positive, but I think they are. There is nothing wrong with that. It's just that they have their limits.
I use either Oliver billet rods or Carillo's. I use the Oliver's 95% of the time. I have used them in blown alcohol engines turning 8000 rpm with 30 psi boost making over 2500 hp and they survived. I figured that if they could survive that, then they will do just fine in anything else. Eddie |
Originally Posted by LapseofReason
(Post 3003215)
So if you set your 1200 up to run @ 1000hp on 87 what are the rebuild times for top end then bottom end ? What if any of your motors go about 200-300 hours for the heads then 400-500 hours for the total rebuild. That is the time frame I am looking for I would only be doing 3-5 Poker runs a year and would think only 10% of the time would be above 90% throttle.
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Originally Posted by Beak Boater
(Post 3004299)
Lapse, what are you looking to do this time? Are you going cat, or another big V? What ever you do, good to have you back out on the water.:drink:
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