Motor was installed 5 years ago and now has about 12500 miles on it I had a flat lob on my lunati 247/251@ 50 with a 555/565 lift on a 110lob center so i installed my new cam. Isky 254/258@50 with 555/565 lift on a 106lob center after the install I had more blow by then befor so I ran a crank comp. test and all cylinder was around 190 on a cold motor and also did a leak down test on a cold motor.BDC all plugs look good no oil .and burn brownish white
#1-20% #2-12%
#3-12% #4-18%
#5-15% #6-12%
#7-12% #8-12%
This test was on a cold motor with no leaks on intake or exhaust and no bubbles in the rad. only leak I could pick up was at the dipstick also do you think on a warm motor my % would be down some?

On a 5 yr old engine I wouldn't worry about it if the blowby is liveable. 20% isn't a terrible #.You probably have some minor cylinder scoring from when the lobe barfed. All that crap gets heaved everywhere and car engines get 100% of their lower cyl lube from splash.

Theoretically hot tests will be better. I take leakdowns with a large dose of salt, a piston ring is a dynamic seal not static. You are only getting a reading of the seal at one point of contact. It's a useful tool but what are you expecting is the first thing to answer.

I mean, unless you're just itching to overhaul it. Damthing has been together 5 years anyway huh?:)

Yea I got the picture, Iam tring to save money a for frame up retro. Car runs like a bat out of jasper big diff. just from a cam change.

Is this in your 10:1 406?

Yes but I not sure on the 10:1 number thats just what I was told between 10:1 and 10:5

Well, I like your new cam. I was figgering it would be a blast.

If your comp test is 190ish, I'm bettin you're closer to the 10.5cr, especially with 64 cc heads. Do you know what pistons are in it? Flat top or dish? Hafta be dish.... if they were flat tops you'd be 12ish with 64cc heads.

I know there dish I think around 17cc the cars a blast I dont get traction to around 50 in second with my 275-50-17 nittos check out my home page.

Good lookin car. Get some traction and you may say hi to 11's.

Before the test the car has been sitting in my garage for about a week and a half due to Hei probs. It has not been cranked and ran so all the oil is in the pan Could that have something to due with the % I still haven cranked it.

if shes hittin on all 8 shut the hood! i have hung up the leaker man its great for finding damage but dont get too freaked about your bigger leaker cuz when you drive and check it again it may be ok, we went nuts about 15 years ago we were lapping valves between rounds and swappin motors cuz sonny leanord and john kasi and all the builders were saying send it back for a freshen up if its leaking x%, some of the stuff ran best at the send it back leak %. ring seal suffers a little with senthetic oil. ring gaps waste air too. the leaker is a must for some jobs.

I'am about there man I did a crank test a week before and all cylinders was @ 190 except #1 and #4 and they was around 185 , checked it about 3 times some reading and just 2 day ago when I got my leak tester I did it again and all read 190 so what gives Iam going to run the h--l out of it and fix what breaks.

Leak down testers don't allow/compensate for difference in displacement. A larger cylinder has more area to leak past the top ring. I bought my Snap tester way over 20 years ago and it proved itself worthless on my bigass engines (6" bore is small to me) new out of the box on a brand new engine it showed 100% leakage. PTUI:)

Like I said, dose of salt. The tool still has merits, especially on PM basis if same tool/same engine records are kept.

Leak figures IMO are about worthless, you can't leak test and engine running and thats really what must be done. Mercury marine states in service manuals don't even worry about an engine unless it is over 30% leak down. It runs great so run it...

sometimes you can drain synthetic oil and put some cheap stuff in and kill some blowby, takes a little driving around to seal up. got syn?

I run valvoline VRI racing 50 with ZDDP only oil this motor ever seen.