compression percentage diffrernce.

[V153]

Re: compression percentage diffrernce.

Can you tell me how I would identify if at some point if the heads were replaced with 140's?

When you have the heads off to replace the gasket(s) just look at em. There's an extra ridge, or built up section on the hi-comp heads.

edit. Hi-comp on right in pic.

I gotta agree those are some purty impressive decarb results, 'bout the best I've ever heard.

re. Surfacing the heads: You're not 'milling' them yer 'decking' em. Perfectly acceptable.

 

[boobie]

Re: compression percentage diffrernce.

I can't tell you about the heads but the BRP de-carb engine tuner is one of the best you can buy. I've used it for years and can't tell you the amount of mtrs I've brought bad to life with it. The longer you let it soak, the better it works.

 

[maryhannaj]

Re: compression percentage diffrernce.

Thanks for the pic V153, and I am pretty sure im sold on the decarb product too boobie. I also gained at almost 2 mph after I used it. That's saying something for sure! I dont know if you had a chance to check out my first video post on this thread but you can see the gps speed hit 44.0 exactly at it's peak. Before I used it I could only hit 42.3 to 42.9 depending if I was sittin on the rear casting deck or not.
So im pretty happy with the result. When I pull the heads off I will post some pics and hopefully find out for sure. I plan to try and have the motor off this weekend. Thanks again!

 

[maryhannaj]

Re: compression percentage diffrernce.

Oh yeah V153, if you happen to have a set of those 140's just sittin around cryin at you because they feel neglected or something like that, I would be more than happy to put them to good use by the way of property means if you know what I mean? Of course I would have to I.d mine first.
It just seems odd to me but I beleive I did read that the 115's were stock comp at 125 psi. I did hit 135 one time on the top port side cylinder(#2 I think), so it was either a fluke, or something weird is going on.

 

[V153]

Re: compression percentage diffrernce.

Sorry mhj, nice try, but mine are spoken for. Heh heh heh. Keep an eye on clist for a cheap, "was running", 135 or 140. They pop up frequently. Or watch ebay, heads show up there sometimes.

I picked up the '78 140 I'm preparing to rebuild for $100 bucks, sans gearcase. Otherwise complete.

Yes low comp motors are/were 120 - 125 psi. And yes the top port cylinder is #2. 'Member top to bottom. It'd look kinda like a inverted "Z" if'n ya drew a line from #1 plug to #4?

Sorry I cain't hep ya with heads, but I am running a special on blocks & gearcases ...

 

[maryhannaj]

Re: compression percentage diffrernce.

Thanks again V153. Just thought I would ask. Im gonna put up some other pics and info on my newer thread about lean bank, rich bank. Your opinion is always of high value to me. If it works out maybe you vould have a look too?
Thanks again.

 

[emdsapmgr]

Re: compression percentage diffrernce.

The original heads on your 115 were part numbers: 326504/505. The high compression 140 (only) heads were part numbers 326502/503.

 

[maryhannaj]

Re: compression percentage diffrernce.

Thanks emdsapmgr. There a bit of thick paint on these heads, would you by chance know where the numbrr is located? Thanks for all of your help also!
.

 

[V153]

Re: compression percentage diffrernce.

Part # might be stamped into a lil dime sized circle. On the boss for the upmost coil bolt(s).

You will sometimes find it on a lil beveled edge outboard of the middle head bolt(s).

Fyi the '78 hi-comp #s are 322864 & 5. Think I remember somebody saying the '76 140 heads were sposed to be the tightest. Sorry, don't have that part# for you.

Btw my '83's the same as what emdsapmgr posted.

 

[maryhannaj]

Re: compression percentage diffrernce.

Sure enough. There was the mark on each side on the coil mount posts. The port side is a 324528 D3, and the starboard side is a 324529 D3.
Are you guys familiar with either of these? I'm going to do some digging too. Thanks!

 

[maryhannaj]

Re: compression percentage diffrernce.

Here's what I managed to find. The cylider heads are numbered for the year span ending in 1980. The crankcase is marked with two numbers thats I am unable to find. They are 477E11981115 with a less legible 7 15 85 stamped beneath the first number.
This second set of numbers leads me to believe that the crankcase was made in 1981. The hydraulic tilt/trim mount brackets are marked as J115TLCNB with a serial #J5691856.
Is this a Frankenstein motor? Can anyone help with the numbers on the crankcase? Why the higher compression? Thanks again!

 

[maryhannaj]

Re: compression percentage diffrernce.

Hey V153, hit me up on the private message board about block specials if you could. Got some questions for ya.