VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Engine problem, low compression & date unsure

I have a 1922-27 Superior truck. The wheel base is 124 inches, inside tag, 1R or TR 1681, Head: overhead valves with push rods, lifters and rocker arm exposed, stamped in the head casting: P & 4 - 1920 407 - 7, Block -H4 P-9 967 422. The body maybe is a Martin Perry.
We have very low compression and feel that maybe two different engines are incorporated. The top clearance on the cylinders is 1 1/4 inches. We have .1 over sized pistons and plan on boring and going with .2 or .3 over sized. The distance from the center line of the crank to the bottom of the cylinder casting is 4 1/4 inches. The manual we have says that dimension is incorrect. We have not been able to find new rods and think we may have to build up and grind the crank to increase the throw and therefore decrease the top cylinder clearance. Anyone out there that has a theory or solution we would appreciate hearing from you.

I am unable to decipher the numbers you have posted for the head and block.

What really bothers me is the numbers associated with boring the block for new pistons. Take a real close look at the bridge between 1-2 and 3-4. When you finish you must be able to seal that bridge. I think you are perhaps over the permitted figures.

Hi Ray,
The distance between 1-2 &3-4 is about 3/8". We will take another look at it prior to boring. We may need to just hone the additional .002 or .003 and go with the next size up. Thanks for the input. Any thoughts on the what we think is excessive clearance when the piston is at top dead center of 1 1/4 inches.
Thanks
Steve

I don't see how this is feasible or even possible except for a minute amount that would make no practical difference. Maybe there is a mythical tool out there somewhere called a "Crank Stretcher" that I haven't heard of before.

By excessive clearance do you mean the distance from the top of piston to top of cylinder block? Or is it the amount of distance from the side of the piston top to the sidewall of the cylinder? The top of most pistons is much smaller diameter than further down the side of the piston. You must measure the piston fit by the book. A long feeler gauge is a must.

Arend,


This used to be done quite often when warming up the opposition's flat head V8 engines. The crankshaft big end journals was built up with metal spray on one side, then reground with a longer center distance from the main bearing journal. The idea never appealed to me! I wonder how often the metal spray separated form the parent metal? I suspect it would have caused major problems.

Frank.

I have been trying to make sense of the numbers. Is the engine a right hand drive one? I wondered if 'TR' was a rhd truck one. Is the 'TR' etc. stamped on the pad? Is there a known engine number stamped on the flywheel?

I have been looking at the casting details: the P stands for Romeo Foundry, Port Huron, MI. The other details check out as well. I keep thinking that the head could be a 1920 and block 1922. The casting date code on the block side will confirm. 967 = up to 1920 head casting and 407 = up to 1920 head casting from what I can see. It is possible that the block is a replacement from 1922.

Early engines are not my forte so please excuse my wavering!

Big Spike, You have created a little confusion in your postings. In the first post you said you wanted to bore .1, .2 or .3 for oversized pistons. Ray pointed out that that would be going over any boundries between cylinders. .1 to us means one hundred thousandths, not as you stated in a later post of honing out .001. There are .099 diference between the 2 ways that you posted the .1 and the .001. Now that we understand you are refering to .001 to .003, honing would be the best, but woudnt require oversize pistons. When you talk about the distance from piston being at top dead center to the top of the block being 1 1/4 inches. That is perfectly normal on the 4 cylinders. I don't know what the exact distance down into the block that the piston stops at, but it is close to the 1 1/4 inches. BE VERY CAREFUL ON REDUCING THIS DISTANCE. A great reduction in this area to "boost" compresion, will lead to catastrofic failure. These engines were not designed for big compression.........

Hi gang, me again.
sorry about the 100 thousandths. We have .011 thousandths difference between the existing over sized piston and the sidewall. Regarding the top of piston to top of cylinder clearance it is presently 1 & 1/4 inches. We felt this was excessive and was the main problem with low compression. We are only able to get 20 to 30 # with the existing.
Re: increasing the crank throw, we would send it out to a local engine re-builder who does this type of work on race engines. But based on your responses, this sounds like something we should not be doing.
Thanks for the feed back on the possible year of the head and block. Regarding the inside tag- I will take a closer look this pm and get back. We have not looked for markings on the flywheel. Will do that too.

You are quite right that you should not be increasing the stroke of the crank. I too have done this with great results on Small Blocks. But it is almost a thing of the past now days. Now it is cheaper to have a custom crank made verses welding one. The engines have low compression to start with. So the crank, block and head bolts will not take great increases in compression. Someone will probably chime in with what you should be getting on a compression gage. Incresed compression leads to more heat,and since these engines don't have a pressure cooling system you would have trouble keeping it cool if the compression was incresed very much. Ray (AntiqueMechanic) has done piston swaps and incresed compression in several engines, but he keeps it to a safe amount that he seems to have perfected through the years.

Hi Kent, Ray, Oracle and others, First thanks for all your research and wisdom. The truck is a left hand drive, i.e., USA, second the tag is as indicated earlier. We will pull the engine tomorrow. I have all the bolts out except the ones connecting the drive shaft to the transmission. Anything I should be looking out for? There are numbers on the flywheel and will relay those tomorrow. After Ray's warning about the bridge between 1-2 & 3-4 it is 1/4 inch now, definitely not a boring candidate. We checked the head today for warp and plan on machining the head and block based on those readings and lack of a good seal by the head gasket. We have another challenge, the rod ends have insert bearings that do not snug down within tolerances (i.e., not babbit). I still am not sure if the rods are compatible to a 22-25 Superior Truck. Oracle you provided more info on what year vehicle I have than any one over the past two years, thanks. Enough for now. Fire away.

Just wondering something. Is there a cast iron ring type thing that the oil pan bolts to? If there is the engine may be the 224 CID large 4 like was used in the FB models. That engine was also used in Oldsmobile trucks and may have been in the early Chevy 1 tons.

Bob,
I don't think there is a cast iron ring, but will take a closer look today.

Spike,
Are there shims inbetween the rod and the rod cap? If there are they are still babbit bearings, but have seperated from the rod. I have some spare rods that this has happened to. Just because the bearing has seperated from the rod doesn't make them insert bearings.

Hi Kent,
Yes there are shims between the rod and caps. So is it ok to reuse or should we purchase new? They appear to be like new.

It should be ok to reuse them. Just shim to the correct clearance and check for correct fit. They might be egged, so use caution doing this. If you are unfamiliar with what you are doing, get help.

Hi Oracle,
Thanks for the info on truck and engine dates. The flywheel number is: 71020? or 77020?

Hi Oracle,
The flywheel has the letter P then 7 space 1020. After pulling the engine I am certain we have a hodgepodge. Your earlier analysis is probably correct. Second reason I think we have a 20's head & 22 block is because the front motor mount is through a cast cross brace bolted into the block with two bolts. The rear mounts are two pieces of 2" angle iron welded to the frame. The front headlight rod is flattened and fastens to the fender with two carriage bolts. The windows are square therefore I do not think it is a 1928 body. The truck shows no evidence of ever having doors, but a hook for a chain. Any more feed back would be appreciated.

How about posting some pictures? If you have problems posting pictures if you will email them to my profile email address.
I will post them for you.

Thanks, I will do that.

Hi MRMACK,
I am unable to access your e-mail address via profile on this site. It says it is blocked. How about a private message to me with your e-mail address. I did go to the LS site. What part of TX. We had a house in Navasota, TX. a couple of years ago. Which one of the charter members is you?

Spike look for a PM

Big Spike, maybe the stuff on my profile is a bit confusing. I am a member of LSR, but not a charter member of LSR. I am a charter member of the Chat Group Non Geographical Chapter.

use your regular email and send to:
mrmacc@cctc.net

I use Outlook Express and the one used here is the other one.

Hi MrMack,
I e-mailed a note and 6 pictures. Let me know if it did not come through.

PICTURES of Big Spike's Truck