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Piston Swap Questions.

PostPosted: Sun Aug 12, 2018 1:20 pm
by Awdsome001
I have a 4-152 in my 64 C900. The head cracked on it, but I managed to pick up a 304 from a '79 Scout cheaply. I pulled the head off of the 304 to put on the 152 but ran into a snag. The 304 had the flat top pistons while my truck has the contour type pistons. I know that the piston types are specific to the head and have to match.

So my question is, can I just swap the pistons from the 304 to the 152 with a fresh set of rings. If so what measurements will I need to check? And how difficult is it to remove the pistons from from the enginr? (Are they accessible without removing the connecting rods?)

Re: Piston Swap Questions.

PostPosted: Sun Aug 12, 2018 6:14 pm
by nikkinutshop
I have never heard of a Scout Cheaply until now. If the 304 is in good running condition, install the 304 and scrap the 152. If the pistons are good enough for a transfer, maybe the rest of the engine is OK.

Re: Piston Swap Questions.

PostPosted: Sun Aug 12, 2018 7:36 pm
by Awdsome001
Fair enough Nikki! I meant to say that I got the 304 at very low cost.

I don't particularly want to scrap the 152, as unique as it is. Also I'm on a short timeframe atm. I am under contract on a house and will be moving soon. I planned on waiting until I got moved to tear the 304 down and rebuild it. Plus I would have to get mounts fabbed up for it as they are different from the 152.

Re: Piston Swap Questions.

PostPosted: Sun Aug 12, 2018 9:42 pm
by 1975IH200
To remove piston:
1. remove oil pan & valve cover(s)
2. remove cylinder head(s)
3. unbolt the rod cap bolts (2) on each connecting rod
3a. keep each con-rod cap with each corresponding connecting rod
4. push piston & connecting rod up thru block
5. remove piston pins from the pistons & connecting rods

Re: Piston Swap Questions.

PostPosted: Mon Aug 13, 2018 7:37 am
by Awdsome001
1975IH200. Thank's that's exactly what I needed!

Re: Piston Swap Questions.

PostPosted: Thu Aug 30, 2018 9:17 am
by Awdsome001
Well, after a very busy weekend, I managed to get pistons and rods. swapped in, the head bolted up and the motor put back together. But now I'm having trouble with hard starting and keeping it running without the choke on.

After some research, I'll be checking compression, distributor vacuum advance line, timing, and looking at the carb. Anything else I should be looking at?

It should be noted that I don't know very much at all about carbs, I'm fairly certain I have a Holley 1904. My guess so far is that the carb needs to be cleaned, when I open the butterfly, no gas comes out from the accelerator pump. I had previously opened the carb up due to issues with fuel flow, and am wondering if it may have gotten some junk in it while sitting or if I might have messed something up. Should I just grab a rebuild kit for the 1904 and take it apart? I found the videos from Mikes Carburetor Shop so I'm fairly confident I can rebuild it.

And while I'm at it... Any tips on reinstalling the rod for the clutch slave cylinder?

Re: Piston Swap Questions.

PostPosted: Thu Aug 30, 2018 1:15 pm
by PaulH
If you aren't getting a squirt of gas down the carb throat when you open the throttle, then you do have an accelerator pump issue, and a rebuild is in order. It's an easy straight-forward carb to rebuild. But my guess is that the accelerator pump isn't what's causing the poor running you describe. If you have to keep the choke on, it's too much air, or not enough gas, and the accelerator pump wouldn't be in play at an idle. Might be dirt blocking the main jet, etc., and might be cured with the rebuild, but I'd also check for any vacuum leaks at the carb base, manifold, etc.

Re: Piston Swap Questions.

PostPosted: Thu Aug 30, 2018 4:21 pm
by BlindSquirrel36C-30
Also, just for $hit$ and giggles. There is a rebuilt 152 for sale up here in my area which seems fairly cheap but shipping would probably kill you.

https://portland.craigslist.org/clk/pts ... 33955.html

Might be able to work something out.

Re: Piston Swap Questions.

PostPosted: Thu Aug 30, 2018 7:30 pm
by nikkinutshop
I have seen a few of those 152 engines, but I have never heard one run. How are these engines for power? The idea of using a half block is interesting for sure. I am going to have a look on You Tube, right now.

Re: Piston Swap Questions.

PostPosted: Sun Sep 02, 2018 3:07 pm
by carbking
A good friend had one of those back in the day.

We pulled a car trailer with a Jaguar on the trailer about 220 miles with no issues. We purposely stayed off the interstate so we wouldn't impede traffic at 55 MPH, but it did very well at that speed.

However, the term "fuel economy" was an oxymoron!

Jon.