Okay guys, an update. BTW, I was revving this motor to 6k, even kissed 6.5k a couple of times when I was running 2 Ducatis but then I spoke to my engine builder and he said don’t go over 6k as it wasn’t a scat crank. So yes, I’ve been over 5.5 a few times so maybe the damage is valve bounce? I will be a bit more gentle in the future, the motor has a heap of torque kicking back to 2nd and lighting the tyres at 80k.
I went to the engine builder, he had the shits that I talked to Yella Terra first but I explained I thought it was the roller rockers. I showed him the rollers and he said there was nothing wrong with them?? I picked up one of his rockers off the shelf and asked him if it was used. He said yes, it was 20 years old. I said why do my rollers have all these marks where the hard-facing is wearing off the bearings and yours is perfect? He grabbed a vernier, measured both rollers and said see, no wear??
So I showed him my valve top pictures and he said ‘that’s normal, that’s what they look like after I finish grinding them in the machine’? I picked up one of the many valves on his benchtop and said, show me any of these that have that pattern after you’ve finished them? I said I can feel the pattern with my fingernail it is so rough.
Then I said Yella Terra said it’s caused by valve bounce because the springs are too light. I asked him what the springs are and he said ‘Crow 7342 Dual Valve Hydraulic roller specific springs’. I looked at the specs for these and they are 390 lb/in.
He said the springs aren’t causing valve bounce, I’ll ring Yella Terra if you want and talk to them?
He said you need to drop it in so I can look at it, it may be a lifter and said I can fit you in in 6 to 8 weeks.
I then took a set of springs off for testing (after measuring heights) to a mate and they tested at 293 and 298 lbs. Yella Terra had told me springs tend to lose about 10lbs after being run but then they should test at 380 which is approx. 85lbs higher than mine test.
I sent all the rockers to Yella Terra to look at and check. Nic rang me and said they had some slight wear on the roller face but I could just refit them and use them. However, If I was pulling the heads and fixing valves etc, I should fit new ones or have new rollers fitted to these. He said there was nothing wrong with the rollers and I could sell them but I chose to have them rebuilt for $420 against $710 for new ones. He also mentioned that there was a funny mark on the underside of one near were the pushrod contacted like the pushrod had come out of alignment? Nic said they listened to the video again and it’s definitely not the rollers, he said it sounds like a roller lifter sound (which is what the engine builder said).
So this is where I’m up to:
1. New rollers on lifters
2. Pull heads and lifters
3. Remove all valves and get valve hardness checked by Phillip Head Services
4. If the valves are ok, I’ll clean up the tops or get the PHS to do them
5. If the valves are soft, replace them
6. Limit rpm to 5,500 and/or fit heavier valve springs. I’ll talk to Crow Cams valve spring specialists before I do this.
Thoughts?
