Roller Cam Installation

Here is a brief run through the fun and games...

Steve Payne had used CAT Engineering rockers in his car, and has done 80,000 miles fault free, so when I saw a set of CAT followers on E-Bay for a good price I bought them on the back of Steve's experience.

I had fitted these at Steve's place, and driven the 35 miles home no problems. I did about another 30 miles when I heard a noise from the engine. Luckily I was not going fast and was only a short distance from home, so limped home a slowly as possible.

I had a look down the holes in the head the pushrods pass through and noticed something out of place, so I took the inlet manifold off and found this.

Hole blown in valley pan gasket.

It had been caused by the rivet holding the link bar in place coming undone, and flying of and holing the gasket.

Link bar flapping about

Rivet and circlip from the top of the lifter.

Luckily the rivet and circlip had fell into the web of the valley of the block, so no harm done. I looked on the web for answers and found lots of sites with exactly the same pictures

It seems there was a batch of either poorly made or knock off lifters on the market. Mine came in a CAT box, but were nasty copies.

I was lucky it didn't wreck the cam, so I decided to follow the old saying that "you get what you pay for" and bought a set of top spec Comp Cams roller lifter.

Which failed after 7 miles. That's 58 less than the nasty knock offs...

The 1st sign of trouble was the hole blown in the valley pan gasket (again). Bear in mind that a valley pan gasket is £28, and rockers gaskets are not exactly cheap, it was now getting expensive keep ripping the inlet manifold off the engine.

What really shocked me was the damage caused. It had broken 2 pushrods in half, and I could only find 3 pieces. After lot's of fruitless searching I came to the conclusion that the missing bit had dropped into the sump.

This was now a major headache. I had to drop the sump to fish out the broken push rod. The windage tray also had a hole blown in it, and lot's of nasty dents where the rod had bounced around off the crank.

After lot's of cleaning I put it all back together while Comp Cams were sending new kit. They didn't argue when I explained how these pair of lifters had given no resistance when setting them up (unlike all the others where you could feel the resistance) and express delivered a pair of followers and 2 push rods free of charge.

They didn't offer to pay for a new valley pan and rocker gaskets, or the costs for sump gaskets and cleaning materials though.

As soon as the new lifter arrived I fitted it and immediately noticed a problem. The push rods were too short! After looking closely I noticed the replacement were a different design to the set that I had already installed. After a 2 day I.T. battle with COMPS anti spam and virus software I sent them the pictures below which shows the difference in the 2 lifters.

Same part number

Different design!

Another trans Atlantic call and it turned out there was a new design of lifter and they had sent me that. They said they would send the old design of lifter to me ASAP. As my original order was direct from Comp and was only a couple of weeks old I asked what happens if I need another lifter in the future. " May not be available due to the new design being stocked".

So basically my few weeks old lifters were obsolete and may not be available in the next few months!

After fitting and testing, and a trip to the 2011 Jensen Concourse show, all seemed well. I spoke too soon. The next time I started the car after the concourse show, 3 push rods broke and 1 bent...

I got back onto Comp and spoke to their warranty manager. We went through exactly what had happened, how I had set them up, how they had failed, etc. I sent pictures and details and no reasonable explanation could be arrived at.

During this last failure I had noticed the bent pushrod had fallen out of the rocker cup and was stuck under the rocker shaft. If the cam had lifted a fraction farther it out have broken this pushrod like the rest. This was a stroke of luck as we had been thinking the fault may have been too much preload, but now it seems it was too like.

Comps instructions call for "1 full turn of the adjuster". When I asked their tech guys they said ".50 to .100 thou of preload". I measured 1 full turn, and that was barely .50, so very little preload.

The other issue was the description for setting the valves. Comps description called for the inlet valve to be "Almost fully closed" to adjust the exhaust valve. How much is "almost fully closed?"

In the end I used my own method as Comps had not worked. I used the "Opposite Cylinder" method, which basically means you adjust the rockers in the firing order as below:

Take the spark plugs out to make turning the engine easier, then start with the inlet valves. Once you have done all 8 inlet valves use the same order to do the exhaust valves. This method is quick as when No 1 valve is at full lift, No 8 is just starting to move, and so on.

I then measured .75 thou with a digital calliper so that the preload was half way between the .50 minimum and the .100 thou maximum. This equals 1 to 1-1/4 turns of the rocker adjuster if you don't have a vernier calliper.

The engine has now had multiple starts and stops, with up to 7 days in between for the oil to bleed back to the sump, and it has been perfect so far.

To add insult to injury, in April 2021 I started the car, and a lifter failed. When I (again) took it all apart, the spring steel clip that holds the lifter together had sprung out, and the lifter had fallen apart. I had a spare that Comp had sent me previously, and that had a proper circlip to hold it together, rather than a cheap and nasty spring steel clip.

I cannot say I am impressed with Comp and its products...

I don't regret the project at all, but it has been frustrating having a lot of failures due to nasty copy kit, and worse, faulty top notch kit.

I have got to see parts of my car that haven't seen the light of day since Jensen built it!