Right, after building up my engine from supposed good long block that was stripped, fettled and checked and I mean right down to the case being split, it appears that I have problem. It ran, but only just and the carbs are now correctly jetted (thanks Paul). I took it for a rolling road session as recommended with Peter Burgess who said it's the worst he's ever had :-(. I have to say he knows what he's talking about and has the patience of a saint. Will definitely be back when I have something that works. He thinks the cam timing is out and that the person who reassembled the long block has got it wrong. He compression checked it and it was reading about 160 suggesting the compression ratio is very high or the valves are not opening and closing properly (I think). Is it a big job to strip, check cam and put it back together again? There is also a leak from the oil pump. I haven't spoke to the builder yet so not going to start slinging mud but he is regularly advertising engines and has cost me a small fortune in labour to assemble and fit a duff engine. Think I'll chance the fresh tinware and carb set up on my old engine for now and hope I can be ready for dub island in August. Anyway rant over.
That sounds odd. You're going to be measuring compression when both valves are shut whatever the cam's doing, so I can't see how the cam can make a difference. High compression is more likely caused by the engine builder not checking deck height or slapping the wrong heads on. The cam's positioned just by lining up the index marks on crank and cam gears. Hard to get wrong, but possible. If it's out of whack, the engine will run oddly or not at all, probably with plenty of spitting and backfiring. Again, can't see how it can affect compression. To check the cam, you'll have to split the case. Is it a type 1?
What size engine is this? Is this the 1700 WO you bought off VZI? Did you ever conform it was a WO? If it is compression ratio is higher than a stock 1700. You can tell by the pistons as they are domed. Guessing you've done all of the obvious things first, check the valve clearances, checked the timing ? Timing on your other thread you send you had it at 5, that's wrong for this engine. Also, you do know type 4's have timing scales, you don't work off the split in the case? The symptoms you've described on your other thread of popping and banging is likely air leak inlet/exhaust and or bad timing. When you took it to the rolling road I guess the guy being an expert checked all your valve clearances and timing, jet sizes before making a start, or that he confirmed with you that everything was correct. As for the leak, it could just be a duff gasket, it happens
If it's a genuine WO btw it will also have slightly larger valves over stock as well as the domed pistons. It may also have swivel adjusters. It's a 914/411 engine. Just because it says WO on the case doesn't mean it's retained it's original parts though as they are often rebuilt. If it's genuine it's a good engine you've got if you can sort it
