TR4a Cam Followers

[trchris]

Thanks Roger/Graeme

As I've read that the new standard camshafts from the usual suppliers are of poor quality the Newman one being the best for a standard engine timed using

the original sprocket marks so not too complicated . I too am not looking to race around so to speak just comfortable driving in a 4a I enjoy

Chris  

 

[BlueTR3A-5EKT]

27 minutes ago, trchris said:

Thanks Roger/Graeme

As I've read that the new standard camshafts from the usual suppliers are of poor quality the Newman one being the best for a standard engine timed using

the original sprocket marks so not too complicated . I too am not looking to race around so to speak just comfortable driving in a 4a I enjoy

Chris  

 

Do not bank on the original timing marks being correct.  They may well be but it is safer to check the installation timing than have the engine run badly. You are assuming the cam installed is the original and not some exotic regrind.

Simple to check using the equal lift on inlet and exhaust  lobes with crank at TDC.  This can be done head off with a couple of dial indicators and dummy push rods or with two sets of feeler gauges and  the head and rockers on.

See here for Macy's procedure, which I use as well as the equal open at TDC for a double check.

https://www.macysgarage.com/cam%20degree.htm

Cheers

Peter W

[Prefect]

Hi Guys I know this is an old thread, but does the PH1 Cam require a gas flowed head?

Thanks

[RogerH]

No.   I have a Moss standard steel head and a Phoenix extractor manifold on a TR4A and the PH1 works well.

 

Roger

[Andy Moltu]

A road/fast road cam doesn’t require a gas flowed head but fitting one may get a bit more out of it but at a cost! Ultimately you will be hit by the law of diminishing returns. Upgrade one area and it ceases to be the rate (power) limiting step, fix that and another area becomes the limiting factor. The further you go the more expensive it gets and the performance steps get smaller. Consider changes that might improve longevity like balancing and lightning the flywheel yet don’t directly improve power and a simple engine build can get expensive.

It’s about what you want from your engine and your budget. I am not sure if the US spec 4 pots had a lower compression heads fitted (compared to UK spec) in the way the US spec 6 cylinder engines had. If so a skim may be beneficial.

As others have said buy your cam and followers from the same supplier so in the event of failure they can’t play the “It was the followers that caused the cam to fail” game and vice versa. Use the specified cam lube for its assembly and time according to the manufacturers recommended figures.

Oil is a consideration too. Make sure it contains ZDDP - it isn’t present in many modern oils because it isn’t good for catalytic converters. This isn’t a problem for modern OHC engines but is for our engines camshaft life! Just because it “exceeds specification x y or z” doesn’t mean it is suitable so check.

[stuart]

27 minutes ago, Andy Moltu said:

 

 I am not sure if the US spec 4 pots had a lower compression heads fitted (compared to UK spec) in the way the US spec 6 cylinder engines had. If so a skim may be beneficial.

 

No they dont only cars exported to countries with very low octane fuels were fitted with a shim gasket to lower compression.

Stuart.

[Andy Moltu]

Thanks for that Stuart. Seen the shim gasket listed but never heard of it being used.

I will suggest that to our chairman who managed to fill his 4A with E85 on the recent European meeting in Sweden.  Spectacular pops, bangs and belching of smoke (the locals wondered if Sweden’s plans to join NATO had prompted a preemptive attack by the Russians.  

[monty]

On 10/10/2022 at 10:52 AM, Andy Moltu said:

A road/fast road cam doesn’t require a gas flowed head but fitting one may get a bit more out of it but at a cost! Ultimately you will be hit by the law of diminishing returns. Upgrade one area and it ceases to be the rate (power) limiting step, fix that and another area becomes the limiting factor. The further you go the more expensive it gets and the performance steps get smaller. Consider changes that might improve longevity like balancing and lightning the flywheel yet don’t directly improve power and a simple engine build can get expensive.

It’s about what you want from your engine and your budget. I am not sure if the US spec 4 pots had a lower compression heads fitted (compared to UK spec) in the way the US spec 6 cylinder engines had. If so a skim may be beneficial.

As others have said buy your cam and followers from the same supplier so in the event of failure they can’t play the “It was the followers that caused the cam to fail” game and vice versa. Use the specified cam lube for its assembly and time according to the manufacturers recommended figures.

Oil is a consideration too. Make sure it contains ZDDP - it isn’t present in many modern oils because it isn’t good for catalytic converters. This isn’t a problem for modern OHC engines but is for our engines camshaft life! Just because it “exceeds specification x y or z” doesn’t mean it is suitable so check.

Classic oils Heritage20/50 has a good ZDDP content.