Did a compression test tonight, numbers higher than they should be?

[8v-of-fury]

The engine has.. 118k or 218k, I am unsure if it rolled twice or not.

I got 155-160psi on all but number 6, which had about 145psi. I am impressed.. here I was all along thinking these late 80's teeners were turds with small valves/heads. They do have small valves/heads and a horrible exhaust! But there is some serious potential to be had there.

9.0:1 apparently for an 88 318?

 

[8v-of-fury]

Also, this was on a cold engine with the throttle wide open and all plugs removed - as it should be

 

[jasperjacko]

could be great or may also be carbon

 

[89.Fifth]

Mine all read 160-165 except 2 that ready 135 and 145. Anything around 160 is normal for a fresh 85-89 motor.

 

[8v-of-fury]

160 is good for a freshy, so mine is fresh as can be basically? LOL

The gauge jumped right up to near 140 on the very first squeeze of all but #6 cyl, and then the 160 came from three more compression strokes. This is really good news to hear that this engine isn't going to go anywhere anytime soon.

 

[Aspen500]

Compression pressure isn't tied to compression ratio. It has more to do with the came profile, duration, overlap, etc........... With the right cam you can run 12.5:1 on pump premium, if you were so inclined. That's how new cars can run high ratio on pump gas. Some Audi's are 12.5:1 but with variable cam timing they run on premium. School dismissed now, lol.

 

[8v-of-fury]

I was always "told" that a higher CR engine will naturally have a higher cylinder compression number.. but as you state it.. the higher CR engines generally have a wild cam LOL. So, yes and no.. they go hand in hand. Nobody is building a wild engine and throwing in a mild cam.

9.0:1 stock and still pumping 160psi is a healthy engine to me. Also I think having the pistons be below the deck might be slightly beneficial to either hanging the stock valves (and heads obvi) open longer with a big lift/dur cam, or running large valve aluminum's with the stock cam.

Any body have any profile specs on the 88 318 2bbl cam?

 

[Oldiron440]

88 2dl cam / why the hell would you care?

 

[8v-of-fury]

Not everything is about the peak hp numbers? Drive-ability is never about peak hp numbers.. lol

Perhaps the stock cam isn't horrible but the tiny 2bbl, heads, exhaust and 3 catalytic's are what makes the engine a dog? I don't know, I don't have the specs

If its even remotely respectable, it would likely do fine to open large valves on some aluminum heads. If not, then it needs to be replaced.

 

[Oldiron440]

The OEM cam past emissions for the masses, all you need is that it works for you......a cam with a more aggressive profile will still pass emissions and give you a butt load of torque.

 

[Oldiron440]

Year's ago I worked for a Ford dealer and I was working on a 289 of my own.
A 1964 2v ,c4

 

[8v-of-fury]

Ayye capitan! sometimes the budget is not endless either lol I'd love to tear it down and build it up with snarling power, likely won't happen.

Ideas on what size cam id be looking at to keep that mid range grunt and really push this boat?

It's not horrible now, it grunts off the line and gets going quite well for a 4k lb car with 140hp and 2.22 gears. LOL

 

[MoparKidD-4]

@8v-of-fury you're onto something here. I also have an '88 5th Ave and believe these later 318s do have more potential than the earlier ones. I have added a homemade dual exhaust system and swapped the rear for an 8 1/4" with 3.07 gears and it LOVED it! Really pulls from idle straight to 3500 or so with the stock 2-bbl. I have a cobbled-together Thermoquad I want to put on an Edelbrock Performer manifold and convert to electronic dist with MSD box, but I also worry the factory timing set is worn out. Might as well put in a new cam while changing the chain and sprockets right? Lol...

Check this out:
Voodoo Hydraulic Roller Cam - Chrysler 273-360 (W/ Long Snout) 258/264 - Lunati Power

 

[BudW]

Before changing out the camshaft – I highly recommend changing the differential gear ratio from the 2.2 - to a 2.9 or 3.2 (or Jeep ratio of 3.07, as MoparKidD-4 did).

The car should get the same mileage with 2.2 as they do with 2.9 ratios.
3.2 are more fun for city usage and can be used for some highway – but for slightly less mileage.


My ’77 station wagon with 318 2-bbl has 2.9’s is 4 seconds faster in quarter mile (17.6 sec), than my ’86 5th Ave with 318 2-bbl with 2.2 ratio (like yours) does (21.06 sec).

The cars weight about the same – the only difference between the two is wagon has no A/C (very slight weight advantage – but not that much).

From start of intersection to end of intersection, the wagon feels like it could run two circles around my 5th Ave.


I have a ’84 Gran Fury police 8¼ differential with 2.94’s, that I have plans on rebuilding then installing into my 5th Ave, soon. Then I will perform more timed acceleration trails and will post back – but I expect it to be closer to the 17.6 range, then.


Those 2.2 gears – gotta go. It’s like dragging a boat anchor behind you.
BudW