solid tappet / lifter conversion

[welshpug 1,657]

I have been asked to build a 2.2 similar to the engine I built for my ZX a few years ago, with one 'small' difference in the camshafts the customer already has, some solid profile PT84 cams, the engine will be using a gti6 cylinder head, hence will be new territory for myself in converting an engine, though I have experience of setting up the clearances in an 8v xu so the process from thereon is familiar, wondering if anyone here has any experience of what parts to use?

 

I've had a brief look and found Kent list a kit of tappets and shims, for around £500

 

Newman list some adjustable shim less for £300, no idea how these would work though

 

Would the head oil feed need restricting a little?   Oil spray bars may be modified or even removed, I'm unsure of the base circle of the cam yet.

Edited July 26, 2021 by welshpug

[Thijs_Rallye 87 4 Cars]

You will indeed need to restrict oil flow to the head with solid lifters and keep the spray bar. A mate and I are currently looking into a somewhat similar situation with an atmosferic Ford YB engine. The plan there is to use standard INA hydraulic lifters, remove the hydraulic part from that and using dedicated lash caps which need to ground down to the correct size. Those caps will be inserted where the hydraulic part used to be. (like: https://dbilas-shop.com/en/engine-valve-train/liftes-rockerarms/mechanical-spacer/5422/mechanical-spacer?c=11769 )

 

 

[welshpug 1,657]

thanks for the reply Thijs, an interesting idea, I know the springs that will be used are the same as the YB engine!

 

 

spray bar may not be able to stay, I had to modify their shape to clear my Newman PH4 hydraulic tappet cam, which is a bit shorter on lift than the pt84.

[petert 586]

At least you can do it faster in a GTi6 head than an Mi16 head, as you’re only undoing one side at a time. Still a very time consuming job though. You need to use stem type buckets and lash cap shims. I’d recommend buying eight 1.00mm shims to use as reference shims, to begin with. That is the minimum thickness. You won’t be able to finish it on the bench, as the head will move around when you torque it down. You’ll get close though, within 1-2 thou. Buy buckets from Arrow and shims from Shrick. Whilst I know you’re quite capable, I’m not sure you have the necessary skills to attempt shimless.

 

Anyone with a lathe can make you a brass restrictor to replace the one way valve. Use a 2mm hole.

 

Aim for 0.008-0.010” on the inlet and 0.012-0.013” on the exhaust. Any looser on the exhaust and it gets noisy. Any tighter you’ll ride a valve.

Edited July 26, 2021 by petert

[welshpug 1,657]

Thanks Peter!   good point on bolting the head down, always done the 8v as a built up engine, may not have considered that it could/would move.

[SweetBadger 94]

The shimless Newman lifters are adjustable via a grub screw that threads into the bottom of the lifter with a lock nut that you tighten when its set to the right height.

 

So that would be by far the easiest option, but I have no idea how reliable they would be. Would have thought there's a chance of things working their way loose which would probably not be great for the engine!

 

 

 

[petert 586]

I wouldn't use them. Too much risk. Plus they look heavy. The owner will own you if they go bang. By shimless, I thought you meant starting with longer valves and reducing the length to obtain the clearance. As you can imagine, it's not for the faint hearted.

Peugeot Mi16 Solid Lifter CF147.pdf

[Thijs_Rallye 87 4 Cars]

To be honest is I had to do this myself I would probably use converted hydraulic lifters with the dbilas/schrick lash caps which I posted above and convert the top spring bucket to accept a Yamaha motorbike shim for making it myself easier to maintain. Then you can have the lash caps made to identical lengths and use the shim for setting the actual clearance. But that will take quite a bit of measuring and calculating. The diameter of those shims are 9,48mm. Only thing I would have to verify first is maximum needed diameter for installing the collets, since you don't want to have the shim dance around in the seat.

 

Edit: that grub screw construction gives me the shivers.

Edited July 28, 2021 by Thijs_Rallye

[SweetBadger 94]

Another thought - Autosprint do or did a solid MI16 regrind with lifter convertors. Reasonably priced too (2008 prices listed on their website). 

 

Might be worth giving them a call to find out whether they still supply the solid lifter conversion kit.

 

http://www.autosprint.co.uk/?p=p_23

[petert 586]

This is what I meant. It's light, simple and standard practice.