Failing cam followers

[Nigel C]

I'll through my sixpence in here then!

I had the head off mine oooh 4years ago and whilst in that state I checked the cam followers I hadn’t replaced them, yea they were a bit pitted so balls out I bought a new set (well I did say I was going balls out on this little re-build!) from our friends that supply us and Europe (if you know who I mean)

Got to fitting them latish Saturday afternoon for a show on Sunday....well tried to fit them. They wouldn’t go down the cam follower bore. In fact I foolishly tried freezing one and it just about slipped in.and yes you guessed wouldnt come out! It did in the end by dropping ice cubes down! Why I thought it was worth pursuing I'll never know, desperate I guess.

Anyway I contacted (off the record and at home) the R&D from said supplier. He said "yea I've got some on the shelf from the states you can have them, they'll fit, don’t bother with the "other ones"!

I dually went down and purchased a set, which were black, had the oil drilling in them and a thin score/polished line down the side. This I was told was the mechanical way that they were tested to be the right size. And they were.

I fitted them (with no grief) and their still going up and down some 18000 miles later.

So why does (as seems to be the case regularly) the source of all things **** not even rate the products that they source/purchase/sell

Answers on a postcard?

[Mychael]

I dually went down and purchased a set, which were black, had the oil drilling in them and a thin score/polished line down the side. This I was told was the mechanical way that they were tested to be the right size.

So why does (as seems to be the case regularly) the source of all things **** not even rate the products that they source/purchase/sell

Answers on a postcard?

 

Some stuff works, some not, quality control or interest in it Zilch.

That polished line you referred to is called fluting, I had it done to my old followers by a cam grinding place at their suggestion.

This has nothing to do with checking size rather it was explained to me that it assists with oil feed/flow/return from above the followers.

 

Mychael

 

ps. Maybe the answer is to buy everything from the states.

Edited October 14, 2009 by Mychael

[Don Elliott]

I have over 183,000 miles on my 1958 TR3A from brand new. The cam followers in my engine are still the "original" ones which came with the car in 1958. On at least three ocasions during re-builds, I have found the flat bottom showed rectangular wear patterns on some cam followers while others showed the correct rotating marks on the flat bottoms. For those which showed the rectangular wear pattern, I lapped the flat bottoms with fine and finer wet and dry sandpaper using a 1/2 thick block of plate glass about 8" square as the lapping base. Never had an issue since then.

 

Someone mentioned above a slight dome or convex crown on the cam followers. Our engines have flat tappets and while other cars (maybe later TRs ?) and more modern cars may have crowned domed faces on the tappets to cause the followers to rotate, our 4-cylinder engines have always had and used flat tappets.. That's why it's so important that the oil have sufficient ZDDP additive. That's why I add some ZDDP Plus to my Castrol 10W30 oil since it is so essential for our flat-tappet engines.

 

The bores in the block where the cam followers (flat tappets) are located, are designed to be slightly off center so the cam followers will rotate without the need for a crowned or convex dome on the bottom end.

[Mychael]

Someone mentioned above a slight dome or convex crown on the cam followers. Our engines have flat tappets and while other cars (maybe later TRs ?) and more modern cars may have crowned domed faces on the tappets to cause the followers to rotate, our 4-cylinder engines have always had and used flat tappets.

The bores in the block where the cam followers (flat tappets) are located, are designed to be slightly off center so the cam followers will rotate without the need for a crowned or convex dome on the bottom end.

 

The cam grinders and the guy the does up TR motors all said you need a slightly convex crown but bear in mind it's so very very slight you'd not see it with a naked eye.

If you were getting some rectangular wear marks on a particular follower it would indicate to me it was no longer rotating as it should.

 

Been asking around, so far no retailers of ZDDP additive here in Oz.

 

Mychael

[Tony Millward]

The cam grinders and the guy the does up TR motors all said you need a slightly convex crown but bear in mind it's so very very slight you'd not see it with a naked eye.

If you were getting some rectangular wear marks on a particular follower it would indicate to me it was no longer rotating as it should.

 

Been asking around, so far no retailers of ZDDP additive here in Oz.

 

Mychael

 

Hi Mychael,

 

Have a chat with Penzoil people. I recollect seeing somewhere that some of their oils contain ZDDP. I'm using it in my car.

 

Cheers

 

Tony

[Mychael]

Hi Mychael,

 

Have a chat with Penzoil people. I recollect seeing somewhere that some of their oils contain ZDDP. I'm using it in my car.

 

Cheers

 

Tony

 

 

 

Thanks Tony,

I found a yellow Penzoil bottle called GT Racing or GT classic, forget now, anyway I noted it specifically said it contained added Zinc. However gave no levels as to how much added and as we don't know the starting levels it's still a grey area. I suppose I could email them.

 

 

Mychael

[RogerH]

Hi Nigel,

I had exactly the same experience from the same supplier (see my previous post). However having measured all their followers and put them into o.ooo5" sizing groups they were all returned to the same box and mixed up

I ended up with the black ones but from a Shop for TR's further into London.

 

Roger

[57 Iain.F]

Hi everyone

The difficulty I have had could be cam, followers - or both. I am the other Iain who discussed this point at the Duxford Triumph meet earlier in the month with Ian Cornish. The engine my 3a was built to a road spec with the usual additions of HS6 carbs, extractor exhaust manifold and a second hand (though unfitted / unused ) Moss alloy head. It has lightened followers and a road sport cam (TT1104N) new, not reprofiled. Assembly was relatively straightforward using lots of cam lube on the rubbing surfaces and set up with a timing wheel. The engine was run up as recomended at varing revs for around 15 minutes (neighbors are now talking some four years on).

 

The valve train became increasingly noisey after about 1500 miles and though the valve clearances did begin to increase slightly it was difficult assess because I was adjusting them regularly to try to adjust out the noise.

Finally after much thought ( and another 3000 miles ) I decided to take the easy option and drop the sump off and inspect from underneath. This is a good way of inspecting the cam surface and it was clear that most of the lobes were worn/ pitted. I anticipate that the followers will be likewise. The engine has not been regularly thrashed at high revs and is used with care (allowed to warm up etc). Unsurprisingly I have kept a close eye on clearances.

 

So even though I actually like having a low lift cam (very easy driving - lots of torque) the winter rectification will involve another new cam (TT1004N) and a set of standard followers. I will certainly check that they spin freely in the bores though. I will be interested to see the condition of old cam and followers. I wonder if I could get a refund if the parts are sub-standard?

 

Iain.F

[Guest ntc]

Iain

Who ever told you to bed the cam at variable revs wants shooting it should not be done like that

[57 Iain.F]

Hi everyone again,

as brief follow up to the other problem mentioned by IanC. 0n 9/10/09

The ALLOY head had exhaust valves that had incorrectly hardened stems.

The result was that the tops were nicely peened over by the rocker and invoved a full head strip and new valves after only 500 miles of gentle running in. But thats another story.....

Cheers Iain.F

[Mychael]

Just as a follow on to this thread. I'd mentioned earlier I was getting my original lifters (and some spares I acquired) tested and re-ground.

All the ones from my engine came up ok, Rockwell 'C' of 50 or better, most around 53.

Of the half dozen spares I'd aquired 5 came up to a reading of 53 but one was failed by the re-grinders when it only achieved a hardness test of 46.

 

Now this was one from used old stock and had been in an engine so most likely original item and it was not badly pitted but failed the hardness test, so how bad must the new ones be then in terms of hardness. Makes you wonder.

 

Mychael

Edited October 16, 2009 by Mychael

[johnny250]

Another thing to watch for, is the fit of the pushrods into the followers....I noticed a distinct difference of wear marks on the 'mushrooms' on mine, when pulling the head recently to deal with burnt ex.valve. They were all replaced together with the new followers when the engine was rebuilt a few years ago.

 

In regard to parts quality, I received an email link from Rimmers this morning.....A complete engine rebuilding set of parts for a 6, for £450ish

 

http://www.rimmerbros.co.uk/Item--i-GRID006506

 

When I bought ONE Hepolite piston recently it cost £80...(x6 =£480).....It makes you wonder what quality we are getting with all those rebuild parts ......

 

john