andy couchman Posted July 14, 2006 Share Posted July 14, 2006 After fitting the crossflow with some gorgeous roller rockers bought S/H, we've had problems with valve guides on No 4 cylinder exhaust. First time the guide wore out, I assumed it was either 'one of those things' or an engineering problem. But having worn out another guide within 1000 miles we decided to investigate. It seems that there is no wear in the roller rockers and oil is getting up to the rocker shaft OK but, while oil gets to no's 1 and 2 cylinders OK, very little if any gets as far as no 4 cylinder's rockers. Although some oil will doubteless splash there eventually, this could be the reason why the exhaust valve guide wore out... The oil used has been synthetic 15/50 or 10/50. Putting back the old rockers and shaft, oil gets to all valves fine. So we've gone back to that temporarily. The question is, what's the problem and cure? - poor quality roller rockers (I doubt that and eveything seems tight and beautifully made with movable bits moving freely)? - damaged in some way (doubt that too and the previous owner I trust 100%)? - oil too thin? Would a 20/50 mineral oil be better? - something else? Help! Andy Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2006 Share Posted July 14, 2006 Andy, very difficult without looking at it in the flesh. Does No's. 1 & 2 get a LOT of oil. If so the oilways may need plugging as the flow may be so great that there's nothing left for 3 or 4. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven to The French Blatting Company Limited Link to comment Share on other sites More sharing options...
Martyn Heesom Posted July 14, 2006 Share Posted July 14, 2006 Is the bore of the rocker shaft on the roller rockers obstructed - the oil is fed up through one of the rocker pillars and then along the shaft. typed a bit slowly! Edited by - Martyn Heesom on 14 Jul 2006 15:27:12 Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2006 Share Posted July 14, 2006 Martyn, I assumed that there was some oil at 3 & 4 but if none you may be right with the oilways out of line. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven to The French Blatting Company Limited Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 What ratio rockers are they? What cam spec have you.? Is there oil seals on the valve stems? oil lubrication might not be an issue here. R500 Mango Madness Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2006 Share Posted July 14, 2006 Pete, I've assumed it is: very little if any gets as far as no 4 cylinder's rockers Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven to The French Blatting Company Limited Link to comment Share on other sites More sharing options...
DohNut Posted July 14, 2006 Share Posted July 14, 2006 But Peter If he was using a high ratio rocker on a big lift cam (designed for normal rockers) Would he not have hit the valves on the piston before he got into rocker angle issues. 🤔 Although as I wrote that I thought that if you had normal position steel posts and high ratio rockers (or vice vera) you would not only have oil ways that may not line up but the rocker tip would not be centrally above the vavle stem Nick Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 No, they're standard ratio rockers and the cam is a Kent 244 - which is not too wild. We checked valve/piston clearances (dry build using plasticine) and that's fine. No marks on the piston either. Also tried oiling the rocker shaft from an oil can and oil can get to no 4 cylinder OK (so no blockage) but it tended to come out of no's 1 and 2 if left to its own devices. Roller bearings seem to be a 'looser' fit (if you're thin oil!) than plain bearings and we wondered whether that was the issue. The rockers themselves are a good fit on the shaft (i.e. not too sloppy and no signs of undue wear). It may be aggravated by the fact that the engine is dry sumped and maybe the nose of the engine is lower than the back end. We started the engine up without the rocker cover on and, with the normal rockers, oil quickly gets to no 4 cylinder. With the roller rockers it never seemed to get that far, even when revved a bit. With the rocker cover on splashes would end up around no 4 cylinder's rockers but there would be much less oil than around no 1 cylinder. Still puzzled Andy Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 The amount of splash feed in the rocker area of a x-flow is plenty to lubricate the rocker tips which contact the valve. The problem he is stating is that his exhaust guide is being damaged, this is what i am trying to resolve, it is the issue here. Nowhere stated is he saying that his rockers are being starved of oil. Knowing what posts/cam lift he does have and ratios could be part of the problem, as he might be experiencing accute angles of valve oppening. If he is not using the correct valve/ valve guide this also could be the problem What are you revving this too? Has the head been ported , if so how much metal is around the guide, if it also has been tipped the it might be overheating and cannot conduct excess heat through the head, another problem that use to be common. Lots of varying factors here. It could also be a duff cam lobe, also worth checking. R500 Mango Madness Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 Any valve stem oil seals???? R500 Mango Madness Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 We checked the angles and they seemed OK, although there was some evidence of the rockers just touching the rocker cover on no's 1 and 2 cylinders on the valve side of the engine. No 4 cylinder rockers showed no such problem though. Do we check for a worn cam lobe by measuring the valve lift? Andy Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2006 Share Posted July 14, 2006 Ok Peter, I'm with you now. However wouldn't they all suffer if it was high ratio's causing the problem. As I said without seeing it it's difficult to diagnose but still get a gut feeling the oil feed is losing pressure as it goes along the shaft so one gets most, 2 gets a little, 3 even less and 4 none at all. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven to The French Blatting Company Limited Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 We did have valve stem oil seals but have now taken them off the exhaust valves at the suggestion of the machining people who did the guides. Andy Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 Yup, Norman, that seems to be what's happening. Certainly, with the old rockers and shaft back in, oil quickly works its way along the shaft, even with the rocker cover off. With the roller rockers no oil seems to get to no 4's valves at all, it all gushes out to 1 and 2 cylinders with a bit ending up at no 3 cylinder too. Andy Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 Norman, i agree also that lack of oil in the last pot is an issue, but i cannot see how it is causing a valve guide to sieze, in theory the do not even need oil, if bronze giudes are fitted the self lubricate. How big are the holes in the shaft? If they are Titan ones are the seals fitted either side of the posts? 🤔 R500 Mango Madness Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 Ahhhhhhhhhh.............. Seals, what seals? Took off a couple of rockers and a post and couldn't see any seals at all. Is this some sort of plastic seal? Certainly, the rockers butt right up against the posts (or can do - there is some free movement along the shaft). Can I get replacement seals then? Andy Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 I depends on who made them, i have seen some versions that do not have seals, there were early and late versions from Titan. Do they have needle bearings in? R500 Mango Madness Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 How about a picture? R500 Mango Madness Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 Yes, needle roller bearings and I'm pretty sure they are made by Titan. The ali bits are anodised orange if that's any help. Would you need a piccy of the whole thing or just say a rocker? Andy Link to comment Share on other sites More sharing options...
andy couchman Posted July 14, 2006 Author Share Posted July 14, 2006 Just had another look at the RRs. They are Titan. Also, had not noticed before, but they are handed. On no 4 cylinder they are the other way round to those on the first three cylinders. So perhaps they have been taken off and reassembled in the wrong order. Which could maybe result in lateral pressure on the valves and hence wearing out a valve guide very quickly? So maybe the oil feed situation is a red herring and it's just the case that the shaft needs proper reassembly? Andy Link to comment Share on other sites More sharing options...
Peter T Posted July 14, 2006 Share Posted July 14, 2006 Yes they would be handed.Try this first. Sounds like they are Titan. R500 Mango Madness Link to comment Share on other sites More sharing options...
Normans_Ghost Posted July 14, 2006 Share Posted July 14, 2006 Would assembly the wrong way be blocking the oilway between shaft and rocker? Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven to The French Blatting Company Limited Link to comment Share on other sites More sharing options...
Nigel Riches Posted July 15, 2006 Share Posted July 15, 2006 Perhaps the incorrect assembly of the rockers allows extra side loading which is outside the lube ability of the gravity oil supply to the stems and guides, it has already been mentioned that the oil supply decreases along the rocker shaft, so very little oil = very little lube, is it possible to fit the roller rockers on the original shaft? check the oil supply then, just a thought, definately worth putting the No 4 cylinder valve assembly to the correct "handed" orientation. 1982. 5 speed, clamshells. B.R.G / Ali. The True Colours. Link to comment Share on other sites More sharing options...
Roger King Posted July 16, 2006 Share Posted July 16, 2006 Guides need very little lubrication (many have seals to stop oil getting down them). But what material are your valves and guided made from? If the valves are E214N (a very common and excellent material for uprated valves) they are incompatible with std cast iron guides and things will wear out very quickly. In this instance you need bronze guides, or at least bronze guide liners. If you have this incompatibility it may be that the different angles that the rockers are running at is enough to cause extremely rapid wear. I never would recommend a 244, or any other cam in the same family to be run with rollers because the valve springs usually run into problems at some point in the rev range with surge. Link to comment Share on other sites More sharing options...
andy couchman Posted July 22, 2006 Author Share Posted July 22, 2006 Well, I've re-fitted the normal rockers. My engine slopes forward so, on tickover on a flat road no oil appears to work its way to the back of the rocker shaft with the rollers. I'm sure that while running, and especially when competing the G forces (even with me driving!) should ensure enough oil gets back to no 4 cylinder's valves. But in everyday use I just wonder whether there may be an element of oil starvation and that sitting in traffic with the engine getting hotter there could be insufficient oil getting to 3wethe top back end of the engine. I guess one option might be to fit the rollers back on when competing or on track days. Must admit Roger's suggestion not to fit rollers with the 244 cam (although I'm not entirely clear what the problem is) has also affected my thinking. Thanks all for your comments. Andy Link to comment Share on other sites More sharing options...
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