1F compression specs (1 Viewer)

[piecemeal]

I got a 74 with a 1.5F in it. I got a mechanic working on it, but not nearby and I left my reference material in the truck, I looked in the FAQ and couldn't find the information I'm searching for. What's the compression supposed to be for a 1.5F??

He said he's got between 110 and 115 on four cylinders and 45 and 35 on the other two. Apparently the exhaust valves are toast on those two cylinders. He wants to pull the head, mill it, and put new exhaust valve in those cylinders. Is this the right course of action??

 

[65swb45]

Compression should be close to 150, but with age, those numbers drop, and consistency is more important. Two low cylinders like that mean it's time to do SOMETHING.

If you trust your mechanic's diagnosis, then go for it. The bigger question is can you afford Plan B if he finds more/other problems. IMO, it's best not to start down a road like that if you're not sure how many places it could lead? Cracked head? Bad block? Has he given you any reason to be more or less sure that two bad exhaust valves are your ONLY likely problems?

That kind of info might yield you better advise.

Best

Mark A.

 

[piecemeal]

He did a "leak down" test and said the bottom end of the engine was ok. I guess based on the tests he did, he was able to know for sure that it was the exhaust valves. If compression is supposed to be 150 and I'm running 110 in 4 cylinders, shouldn't he just replace all of the valves after he mills the head? I ask this b/c if he does the two and they are like new-ish, won't they much higher than the others making it inconsistent?? This is new territory for me here....

 

[piecemeal]

I spoke w/ my mechanic at length and let him tell me what the compression specs and valve tolerances should be, which put me at ease. Apparently, he's going to pull the head, take to the head shop for milling and they'll determine if the valves are ok to be re-used (basically getting the carbon off) and still be able to get 150. He's thinking $1000 for the head work assuming all the valves are ok. I think this is in the ballpark.... Any opinions??

 

[brackenb5]

I spoke w/ my mechanic at length and let him tell me what the compression specs and valve tolerances should be, which put me at ease. Apparently, he's going to pull the head, take to the head shop for milling and they'll determine if the valves are ok to be re-used (basically getting the carbon off) and still be able to get 150. He's thinking $1000 for the head work assuming all the valves are ok. I think this is in the ballpark.... Any opinions??

Holy crap that's a lot to spend. I pulled my head about a year ago, had it resurfaced and had a valve job done and it cost me roughly $200 dollars + 40 for the new gasket. Grant it, I pulled the head and reinstalled it myself but pulling the head is fairly simple and I would be leery of that price.

 

[Pistorman]

I'd do a total rebuild for 2K. Or I could sell you my F once I change it over to a 1.5F later in the year.

 

[piecemeal]

Its a 1.5F already. what does a total rebuild entail?? new pistons, cam, etc....?? I would have pulled it myself, but I had it towed to him to do what I thought was going to be carb tuning, since I'm NOT comfortable to do carb work myself and while he was at it, I had him check compression, which happened to be the culprit as to why it has never run "right". I'm kinda stuck and being that he's a client of my companies, I'm sorta screwed. Anything that should be replace while the head is off?? Re-use valves if they are in good shape or replace regardless?? The pickins are slim in my area for help w/ the pig. I don't know ANYBODY within 50 miles w/ a pig.... It stinks.

 

[FJforty]

piecemeal, if you trust the guy then I guess that's OK.
Rant:: He is guessing the $$ for head work!!! How about I get a quote for pulling the head and handing it to me. Can that be quoted honestly? I think so!. Then I carry the head to the head shop and instruct the mechanic to remove the valve springs and show me the bad valves. Lets all count them together 1 to 12..... Now can you quote this? I think so! Fix it. Now we hand the head back to the mechanic and get a quote on how much to put it back on. Now how much ... rant done::
Head removal time~3 hours.
Head install time~4 hours.
Valve job~ unknown
This is what a good mechanic will tell you, everything else is just guess work to suck you into feeling good. Oh man beer-thirty.

 

[Toyo FJ40]

Jim
Greg, the guy doing your head at the machine shop is top notch.
He just did my 74 head with magna fluxing, 2 valves, all new seals, glass beaded for $350 cash.

Now what George is going to charge is a different story

Let me know if you need anything else.


Kevin

 

[piecemeal]

Kevin:

Thanks again. I'll let you know about the wagon wheel. It was great to meet someone in the area w/ a 40. My buddy had a good time chatting w/ your son too. I know it'll all be worth it in the end, but I really wish I would have checked the compression and pulled it myself before I even took it in. Oh well. I'm sure he'll do a good job w/ the re-assembly.

 

[74fj]

He did a "leak down" test and said the bottom end of the engine was ok. I guess based on the tests he did, he was able to know for sure that it was the exhaust valves. If compression is supposed to be 150 and I'm running 110 in 4 cylinders, shouldn't he just replace all of the valves after he mills the head? I ask this b/c if he does the two and they are like new-ish, won't they much higher than the others making it inconsistent?? This is new territory for me here....

My comp on my f1.5 before rebuild was 125,125,125,30,120,40 if I remember right. my comp after was 130 across the all six. 150 sounds high to me. I only have about 6 hrs run time so mybe my comp will go up some when the rings are seated better. I spent 400 to get the head rebuilt and I do all the labor. That was milled, 6 valve guides, 6 valve seats, all new seals and spring seats(whatever you call what the springs sit on). Certain parts for the f1.5 are getting very had to find like pistons b/c they were disconued acording to specter and maf.

 

[74fj]

Holy **** that's a lot to spend. I pulled my head about a year ago, had it resurfaced and had a valve job done and it cost me roughly $200 dollars + 40 for the new gasket. Grant it, I pulled the head and reinstalled it myself but pulling the head is fairly simple and I would be leery of that price.

A valve job and resurface does not require buying new parts for the head. That is when money starts flying out the window!

 

[Toyo FJ40]

Kevin:

Thanks again. I'll let you know about the wagon wheel. It was great to meet someone in the area w/ a 40. My buddy had a good time chatting w/ your son too. I know it'll all be worth it in the end, but I really wish I would have checked the compression and pulled it myself before I even took it in. Oh well. I'm sure he'll do a good job w/ the re-assembly.

George is a good guy and he won't charge you for stuff you don't need. Remember to tell him to leave off the air filter bracket unless you think you might go back to the stock filter.


I forgot to say my head was milled also for that price.
Kevin

 

[piecemeal]

I know. This is the first thing I've had anybody else do, so it's hard to part with the $$ even though I know it's well spent. X2 on the bracket. I'll make sure to give him a buzz early tomorrow morning.

 

[Toyo FJ40]

So whats the story on you FJ? I saw it still sitting there today. Doesn't have it's head back yet?
Did the valves work out ok?

I was going to stop and put a for sale sign on it for you...

 

[piecemeal]

I called him this morning. He got it back and said it's gonna cost $900 now :[ He also said he can't find a gasket set. So he tasked me with finding a set (felpro if possible) So, I'll have it shipped there then he'll finish it. you don't happen to have any extras do you??

 

[65swb45]

I can't be sure from here at home at 10:22 pm, but off the top of my head, I think the part number is a 21218B, and I think I have one in stock.

Best to call me at the shop Monday afternoon to follow up. I forget most of what I read late at night by the next day.

 

[piecemeal]

Thanks Mark. I got antsy and already found and ordered one and luckily, the part numbers matched up I have some upcoming modifications and upgrades I'm looking at doing and I'll call you first.... I appreciate the help

 

[Toyo FJ40]

I got my set peicemeal .. some from napa and some from toyota. Toyota didn't have a head gasket but had the thermostat gaskets. Napa had the head and valve cover.

The guy at the Toyota dealer didn't know what points were

 

[Arekusan40]

I'm coming in to this old thread because I am rebuilding the 1F in my '71 Cruiser and have similar questions about compression, heads, and such. Plus, I am north of Allentown, PA in Jim's neck of the woods so I would love to get names and references for the good machine shops mentioned in this thread. In my case I think I have minor valve issues and a bigger need for rings and a hone, but welcome expert advice before going further. Here's the story: My truck sometime in its past had a rebuilt 1F installed with a 0.060 overbore. It started easily when I got it, but had carb issues, vacuum leaks, backfiring, low power. Dry compression test was 90/71/73/59/70/62 psi. Wet compression test was 140/130/155/151/120/105 psi. Off came the head, and it looks pretty good, and the wet test would seem to indicate a valve clean up and resurface should get them all up around 150+. The dry numbers worried me until I inspected and mic'd the bores. My average wear (6 measurements per cyl) was only .0025 over spec (spec being 3.54+.06=3.60 with the overbore), with the worst single reading .0031 over... well within wear spec of .008. There is no ridge at the top, and walls are glass smooth (no scoring or corrosion whatsoever). I'm thinking this truck had few miles added after the rebuilt motor went in. So why the low dry compression? Incorrect rings? Stuck rings? Upside-down rings? Improper honing? Will they glaze from low usage?? My plan is to get new rings and give it a ball hone job, but this is my first 1F engine experience and welcome advice from some 1F veterans! Thanks.