I got this Evo with Kelfords already in it and didn't think about what size they were until I had the engine built, oh what a smart idea . The vacuum at idle has been 11-12 even before rebuilding the engine. I also have about 45 miles on this new build everything is going as it should, even did a early compression test, 150 across the board. I had the engine built and I still have the same vac at idle as I did before the engine was built. The engine always had the Kelfords in it though. Everything is hooked up as it should be.

Engine:


Cylinder Head:

Ported polished intake and exhaust
Ported polished combustion chamber
Kelfold (SIZE?)
Brian Crower Valve Springs and Titanium Retainers
Supertech valve stem seals
New Valve guides
Head pressure tested


Short Block:
Wiseco Pistons K666M855AP
Manley H-Beam Connecting Rods
ARP Cylinder Main Stud kit
ARP Head studs
ACL Rod Bearings
ACL Main Bearings
ACL Thrust Washer
New Balance shaft bearings

------

So, Is there an easy way to identify what camshaft I have? Car runs very well and has plenty of top end power, but I would love to understand the low vacuum. Since the engine is already running and assembled, I cannot look at the cam gear side of the camshaft to see if they etched in the size duration of the cam, (if that is where it is located)

Do 264's give you that low vac?

 

:d

 

Couple of questions---what makes you think you have low vacuum? what do you consider normal and what was it before the build? Can timing will effect vacuum at idle as well. Advance the intake and retarding the exhaust will increase vacuum resulting in better lowend and midrange --but may decrease high rpm perf. Look for some part numbers on the cams and go the website for kelford and figure out what you have...good luck.

 

Engine was at same vacuum before the build, but the car had those cams in the head. Iv tested the vac with three different gauges, including a pressure/vac hand pump to verify. I figure, 17-20 in/mg-squared is a normal engine without cams.afriend of mine is running 272's and has 15 in/mg-squared, mine being lower I am just wondering if I have 280's? I'm not disappointed in what I have, but like we all know, knowledge is power, and I enjoy understanding and knowing what I have.🤔

 

It's not a "built" engine unless you've degreed the cams.

There's 2 stages in identifying the cams.
The easy stage and the hard stage.

The easy stage involves measuring the base circle. That's because Kelfords are reground stock cams.
I can't remember the stock spec for the base circle but lets just say it's 30 mm.
If it's now 28.5 mm then the cam can't have more than an extra 0.75 mm lobe lift and (times by rocker ratio 1.6?) 1.2 mm extra valve lift. Knowing that you can eliminate some of the options.
You can also measure the lobe lift which is the difference between the smallest and biggest measurement in the lobe diameter.

The second stage involves measuring the opening and closing points of both intake and exhaust valves at zero lash.
That's easily done by shimming a stock HLA with washers.

You can do that to any unknown cam, it's easy but takes a lot of time and best done with the engine out of the car.

Once you've done that a few times you'll understand that you never actually get what you pay for.

 

I will have to check once I pull that cover that cover back off. Hoping someone will chime in with numbers on the camshaft I can check, they may be generic for all kelfords though, so I guess we will see.

 

Just measure the lift on the intake and exhaust. Subtract the smallest cross section from the largest, and that's your cam lift. Go to Kelford's site, and find the cam that matches.


Kelfords are not stock regrinds.

 

I believe I may be able to see where they would put the number I was looking online and there was a zoomed in picture, I will check this weekend when I am back a t home.

 

I got home this weekend and per Kelford, they said to check the thrust face of the camshaft. Sure enough the marking were located there. I have 272's.


Just thought I would update everyone so this may be useful in the future.

Cheers.

 

11 vacuum on idle with 272 cams would be common with standard timing.
Most add more timing in idle areas to get more vacuum.
You lose that stomping lope though sometimes.

 

That does make sense. I found out I have 272's which I am glad to at least know now.

 

Thats what I would have guessed. Very rare to have different sizes. Most popular Kelford is 272's. And to Freds comment, I do not believe they are regrounds... I can verify with a phone call.