big cam in a 109 with stock lifter bores - cause oil hemmorage?

Blazer406

Mechanical Engineer
Joined
May 2, 2002
Someone recently mentioned to me that they had an issue with a 109 motor with a cam that was around 600 lift or a little over.....that they found the lifters to be too high in the bore causing oil to be lost in the roller area of the lifter during times near peak lift. Another words... at near peak lift... the oil galley was being exposed to the roller itself that can't seal it off..... therefore causing the oil hemmorage. The 109's oil galley is huge. I am wondering if that is the issue I am having on my 109. My lift is over .590 on the intake with the 1.65 rockers. It sure would explain alot.

One way to solve this is to bush the lifter bores and reduce the size of the opening feeding the oil band on the lifter. Another way is to not run a high lift cam I guess.....

I assume that core shift in these blocks might move the lift threshold so-to-speak before the oil would hemmorage out the bottom of the lifter. Shielded foot lifters help this but at some lift point... would still do the same.

In my case, I've tried Morrel's as well as stock hyd rollers.....both of which....I would say... the foot is shielded pretty good.
 
your "cam" lift

is .357
it makes no difference what ratio rockers you use,
that is a common lift cam in hi perf use, is it a small base circle cam?
if its a large base circle, yes, you could be uncovering the oil gallery in the lifter bores.
I'd check who ever did machine work for you and see what they recommend,
shielded lifters probably won't help, you need to lower the lifter in the lifter bore, only way I'm aware of is to use small base circle cam.
hope that helps
 
lift

Look @ a stock cam versus a high lift cam --you will find that the top of lobe is almost in line or same height as the top of bearing journal. The high lift will have a smaller base. May not be explaining very well. Take a stock cam --lay a straight edge across the bearing journals and you will see that the top of lobe is amost as high as the straight edge. Same with a high lift cam. Now check the base--there is your difference. What I'm trying to say is no matter what cam the lifters will be @ or near the same height in the lifter bore.
 
You could bush the lifter bores with bronze liners.
Although I have not send a 109 with this done, I don't
see why it could not be.
 
I don't know if this is the issue I have had or not.... going to try and figure out how to prime the engine with it upside down and the pan off....without making a huge mess....

Lee..... I see what you are talking about..... makes sense. With that logic... I don't see how that could be an issue at all.

I am thinking at this point I have some cam bearing issue.... or a crack in the block that hasn't been noticed as of yet....
 
I cant see running .590 lift with a hyd and having decent revving ability without floating the valves. You will need a lot of spring.
 
By using a smaller base circle

you lower the OVERALL lifter placement.
you still achieve the desired total cam lift,
it WILL place the lifter lower in the lifter bore, do the fact you are starting from a lower starting point.
ask comp cams, or one of the cams grinders, they can explain this to you,
I use small base circle cam in a stroker motor, to clear rods and piston skirts.
it WILL allow the lifter to sit lower in the block or lifter bore!

your problem may or may not be related to this .
 
Good Point here

you lower the OVERALL lifter placement.
you still achieve the desired total cam lift,
it WILL place the lifter lower in the lifter bore, do the fact you are starting from a lower starting point.
ask comp cams, or one of the cams grinders, they can explain this to you,
I use small base circle cam in a stroker motor, to clear rods and piston skirts.
it WILL allow the lifter to sit lower in the block or lifter bore!

your problem may or may not be related to this .

I would look @ this. Don't the guys running TSM bush the lifter bores? I assumed it was because they were running solid rollers. Could be 2 reasons. Best of luck.
 
I cant see running .590 lift with a hyd and having decent revving ability without floating the valves. You will need a lot of spring.


Cam is only 218 @ .050..... I was hoping for 5800 - 6000 RPM.......
 
post

I remember your posts from some time a go with oiling issues .Just out of curiosity what is your oil pressure with the car cold and then warm ,what are your bearing clearances ,what has been checked so far .?
 
I remember your posts from some time a go with oiling issues .Just out of curiosity what is your oil pressure with the car cold and then warm ,what are your bearing clearances ,what has been checked so far .?

It has been some time since I pulled the engine (it is sitting on the stand waiting for me to do something..... ) but it had 80 lbs + cold idling. Priming with a drill yielded the same. Once cranked.... within 10-15 min the pressure at idle was down to say 25........ another 15 min of idling..... 10-15 psi...... get in the car.... ease around the block..... pull up... pop the hood.... valve ratteling.... 0 psi idling. Let it cool off an hour...... pressure goes back to 80+ at startup.

rods and mains between .0015 and .002.
 
had you ever tried a different front cover?

sounds like the bypass get stuck open when the cover gets hot.


have you ever tried a oil pressure gauge, one at the front of the block and one of the rear cam galley?

might see a pressure difference is the lifters really are hemmoraging oil....

just thinking....

A.j.
 
had you ever tried a different front cover?

No. The cover came off my '87 GN with 159k miles. I had a booster plate and a HV kit installed initially in it after rebuild. After reading up on it here and talking with Earl Brown and Lee Thompson on my thread or PM's, I tried several different things. Some of the last stuff I tried was I ditched the HV gears.... and lapped all the scratches out of the cover plate..... and did the Earl Brown mods..... set my end clearnace around .001....still has made no difference. I did buy another used cover to put on it at some point.

dr_frankenstein said:
sounds like the bypass get stuck open when the cover gets hot.

Could be. I did take the bypas all apart... check it... seemed to travel in an out freely when you push on it.

dr_frankenstein said:
have you ever tried a oil pressure gauge, one at the front of the block and one of the rear cam galley?

might see a pressure difference is the lifters really are hemmoraging oil....

just thinking....

Not tried two different gauges there.... only the one at the front of the block where the pressurized oil ties in for the turbo feed. I would expect to see some difference.... but not sure at one point what difference it would take to point to oil hemmoraging...??
 
+

I am no expert but I would say you are not loosing pressure because of the lifters just because it would be noticable at the start of the engine with much lower pressure.It almost sounds as your bearing clearances are too loose - just my two cents.
 
Cam is only 218 @ .050..... I was hoping for 5800 - 6000 RPM.......

I doubt you will get it that high with that much lift. You will hit coil bind before you have enough spring pressure unless you arent running any boost. Or you will collapse the lifters with excess spring pressure. You will need some boost to pull to 6000 rpm with a 218@.050.
 
I doubt you will get it that high with that much lift. You will hit coil bind before you have enough spring pressure unless you arent running any boost. Or you will collapse the lifters with excess spring pressure. You will need some boost to pull to 6000 rpm with a 218@.050.

My current setup was around 140# on the seat. It might not pull that high. I am in the process of accumulating some more parts and doing some swapping..... cam might change slightly......
 
I am no expert but I would say you are not loosing pressure because of the lifters just because it would be noticable at the start of the engine with much lower pressure.It almost sounds as your bearing clearances are too loose - just my two cents.

It was just a thought. I am thinking cam bearing issue or crack in the block....
 
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