qkingston Posted January 17, 2020 Report Share Posted January 17, 2020 Putting my 4a engine back together and I have a couple of questions; picture of cam followers below, all look nice and clean (engine rebuilt fairly recently by PO) and flat on the contact surface, except for the one second from right which has some pitting on the surface. Any idea what might have caused this on an isolated piece? Also what is the opinion on composite head gaskets? I have some advice which says go that route, others say copper/grease (as original) Many thanks David Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 17, 2020 Report Share Posted January 17, 2020 What condition is the corresponding cam lobe in? Is there any measurable lobe wear compared to the other 7 or surface damage like the follower? If so it's probably toast and suitable for a regrind. Peter W Quote Link to post Share on other sites
qkingston Posted January 17, 2020 Author Report Share Posted January 17, 2020 no none whatsoever Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 17, 2020 Report Share Posted January 17, 2020 A failing cam follower, caught in time before it did any other damage. Renewal is probably the route of that one or maybe all 8 to be on the safe side. No doubt someone else will be able to advise on this. Cheers Peter W Quote Link to post Share on other sites
peejay4A Posted January 17, 2020 Report Share Posted January 17, 2020 I'd measure the lift on the offending cam lobe. I had the same thing happen to my 4A. The follower was pitted but the lobe was smooth, however the lift on that lobe was only about half of what it should have been. If I were you I'd swap cam and followers (Newman cam and their chilled iron followers in my case) and remove all doubt. Quote Link to post Share on other sites
iain Posted January 17, 2020 Report Share Posted January 17, 2020 I would be very dubious of that cam. Followers 4 and 5 are also unusually marked. Iain Quote Link to post Share on other sites
Motorsport Mickey Posted January 17, 2020 Report Share Posted January 17, 2020 (edited) Do you want a lifetime out of it after rebuilding ? Fit your choice of NEW camshaft and followers (both from the same supplier) and also using the suppliers recommended cam lube. Break in by running the engine at NO LESS than than 2000 revs for at least 20 mins, if you can do it use a rolling road and tell the operator what you want so he can load the engine and watch the revs. (probably about £50). Or as alternative if using the public roads, take an emergency tool kit with you, phone and with spare oil and water and trying to use motorway (if easily accessible) or low traffic B roads with little traffic lights in place and keep those revs between 2000 and 3000 until you notch up about 200 miles. At traffic lights keep the 2000 lower limit, (ignore public curious glances). The cam then should be broken in and can be driven normally (don't forget the cylinder head retorque before 500 miles comes up (I do it straight away after the 200 mile break in). There is a possibility after checking the camshaft to make sure lifts and condition is ok (number 4 and 5 cam followers are looking doubtful also) of fitting just a set of new cam followers with cam lube and follow the above procedure and all may be ok. There are varying opinions that say the 200 mile distance at 2000 revs or 20 minute time break ins are not required, and if you feel that is correct ...well it's for you to decide. Mick Richards Edited January 17, 2020 by Motorsport Mickey Quote Link to post Share on other sites
Dic Doretti Posted January 17, 2020 Report Share Posted January 17, 2020 One cam follower has broken through the case hardening and two more are on the way out and this on a newly rebuilt engine? Possibly the incorrect oil has been used or running in procedures or both, check the zinc content of the oil. To be safe change all the followers and possibly the cam and run in as Mick suggests, the Haul Road between Coulport and Loch Lomond would be perfect with plenty of hills to vary the load conditions and little traffic providing you don't meet a nuclear convoy. Cheers Richard Quote Link to post Share on other sites
qkingston Posted January 17, 2020 Author Report Share Posted January 17, 2020 Thanks Richard, Problem is I know the engine has been rebuilt and evidence suggests fairly recently (6000miles, but I can't prove it despite several attemts to contact the PO in the States) so I'd be loathe to change the cam unless there is clear evidence of a fault with it. I will certain plan to replace the followers Quote Link to post Share on other sites
iain Posted January 17, 2020 Report Share Posted January 17, 2020 I’m with Mick. The followers are toast. The faces are badly marked, the sidewalls show evidence of scoring.......but not vertical marking, rotational. My guess.........I made the same mistake, rebuilt by someone who thought the followers were fit and forget......wrong, they need to be fitted to the engine. Ensuring rotation in their bores on fitment. These have been catching as heat builds and have caused damage to the followers and most probably to the cam lobes. This post may help....it helped me. :-) Quote Link to post Share on other sites
Ian Vincent Posted January 18, 2020 Report Share Posted January 18, 2020 11 hours ago, qkingston said: Thanks Richard, Problem is I know the engine has been rebuilt and evidence suggests fairly recently (6000miles, but I can't prove it despite several attemts to contact the PO in the States) so I'd be loathe to change the cam unless there is clear evidence of a fault with it. I will certain plan to replace the followers It’s easy enough to measure the lift on each lobe of the cam with a dial gauge and then decide what to do. In the cost of running a car a cam isn’t expensive anyway. Rgds Ian Quote Link to post Share on other sites
qkingston Posted January 18, 2020 Author Report Share Posted January 18, 2020 Thanks all, lots of good advice there. I'll check out the cam as suggested and replace the followers in any case Rgds David Quote Link to post Share on other sites
Drewmotty Posted January 18, 2020 Report Share Posted January 18, 2020 Looks like a good excuse to fit a (slightly) hotter cam if you haven’t already got one. The composite head gaskets are a good improvement on standard if you have a reworked head and in my experience very reliable. The Racetorations one is worth the extra few quid. They are expensive so if you are in the habit of removing the head regularly a solid copper one fitted with Welseal will work well and is reusable. Quote Link to post Share on other sites
peejay4A Posted January 18, 2020 Report Share Posted January 18, 2020 Don’t just replace the followers. You’ll likely regret it. Quote Link to post Share on other sites
Ian Vincent Posted January 18, 2020 Report Share Posted January 18, 2020 1 hour ago, Drewmotty said: Looks like a good excuse to fit a (slightly) hotter cam if you haven’t already got one. The composite head gaskets are a good improvement on standard if you have a reworked head and in my experience very reliable. The Racetorations one is worth the extra few quid. They are expensive so if you are in the habit of removing the head regularly a solid copper one fitted with Welseal will work well and is reusable. Agree, the Racetorations one does work well but at £150 by the time you have paid the VAT and had it delivered they are quite a lot of extra quids. Rgds Ian Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 18, 2020 Report Share Posted January 18, 2020 Page 6 https://www.trshop.co.uk/special.html uprated head gasket £ 99.50 Peter W Quote Link to post Share on other sites
qkingston Posted January 18, 2020 Author Report Share Posted January 18, 2020 Looking down the bores of the followers, the cam lobes look, but will get a second opinion on this. Bearing in mind that this was a US import I can see some numbers stamped on the shaft of the camshaft - C2417 0703. Does this mean anything to anyone? It would be nice to know what it is. Rgds David Quote Link to post Share on other sites
iain Posted January 18, 2020 Report Share Posted January 18, 2020 This is a pretty good comparison .....can’t see those numbers. http://tildentechnologies.com/Cams/TriumphCams.html Iain Quote Link to post Share on other sites
Ian Vincent Posted January 18, 2020 Report Share Posted January 18, 2020 5 hours ago, BlueTR3A-5EKT said: Page 6 https://www.trshop.co.uk/special.html uprated head gasket £ 99.50 Peter W Peter, If the head has been modified to remove the shroud around the inlet valves, (perhaps because bigger inlet valves have been fitted) and the liners shaped to suit then the TR shop gasket won't fit and you need the Racetorations one. Rgds Ian Quote Link to post Share on other sites
iain Posted January 18, 2020 Report Share Posted January 18, 2020 (edited) .... or a solid copper gasket. I have had them made if your interested. Edited January 18, 2020 by iain Quote Link to post Share on other sites
Chilliman Posted January 18, 2020 Report Share Posted January 18, 2020 Quote or a solid copper gasket. I have had them made if your interested. Which is the way I have now gone, the Racetorations gaskets are by far the best I've used over the last few years but if you're pushing the engine & likely to be pulling it apart each season it's a tad on the expensive side, I now have a solid copper gasket that gets annealed & re-used... Quote Link to post Share on other sites
RogerH Posted January 18, 2020 Report Share Posted January 18, 2020 3 hours ago, qkingston said: Looking down the bores of the followers, the cam lobes look, but will get a second opinion on this. Bearing in mind that this was a US import I can see some numbers stamped on the shaft of the camshaft - C2417 0703. Does this mean anything to anyone? It would be nice to know what it is. Rgds David Hi David, you have the evidence in front of you. Repair it properly. I would not recommend a standard cam unless you get it specially made as they are quite poor. The Newman PH1 is very good quality, will put a silly smile on your face and will not stress the engine. Either use the Newman chilled iron followers (£££) or the Moss lightened on (£££££££). Ensure you use a decent engine oil with plenty of ZDDP. Roger Quote Link to post Share on other sites
trchris Posted January 18, 2020 Report Share Posted January 18, 2020 Hi Roger I am also plagued by the tappet gremlin on my 4a so a camshaft and follower change is also on the cards so am thinking of the Newman PH1 and matching followers does the valve springs also need changing with this cam? Chris Quote Link to post Share on other sites
graeme Posted January 19, 2020 Report Share Posted January 19, 2020 4 hours ago, trchris said: Hi Roger I am also plagued by the tappet gremlin on my 4a so a camshaft and follower change is also on the cards so am thinking of the Newman PH1 and matching followers does the valve springs also need changing with this cam? Chris No, Ken Newman recommends using the standard springs if in good condition. I also use the Newman PH1, it is a great cam. Cheers Graeme Quote Link to post Share on other sites
RogerH Posted January 19, 2020 Report Share Posted January 19, 2020 12 hours ago, trchris said: Hi Roger I am also plagued by the tappet gremlin on my 4a so a camshaft and follower change is also on the cards so am thinking of the Newman PH1 and matching followers does the valve springs also need changing with this cam? Chris Hi Chris, as per Graemes reply. I fitted a new Moss cylinder head (it is very good). However they fit uprated springs and these killed the aged standard cam that was in there. I went back to standard springs and it has run very well for the last three+ years. For my style of driving I don;t need performance parts as such. The PH1 cam was fitted because of its basic quality not necessarily its performance. Roger Quote Link to post Share on other sites
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