Questions for Bob Smith about Lehman 120's

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
Kolive,

Are you going to torque your heads prior to adjusting the valves? I just set our valve lash last month and checked the head bolts for proper torque.

On a side note we are slip neighbors with SAGA. If you guys need the tools for this project I would be happy to loan them out.

Bob
 
Greetings,
Mr. BC. There was a thread about whether or not one should re torque head bolts in the recent past. Quite mixed opinions as I recall but I DON'T recall what thread it was-go figure. Maybe one of the younger whipper snappers can put you onto it.
 
Just curious if Mr. Smith mentioned it is all. I had read that thread also and chose to check mine since it was open.

Cheers,
Bob
 
Bob,

Yes, he did say to check the torque before adjusting. We were planning on doing that as part of the baseline info on our engines. We have only owned our GB for a little over a year so I want it in my maintainance records. Pretty easy to do too. Thanks for the offer of tools. I just got feeler gauges in the mail today and I think we have a torque wrench but will keep your offer in. Ind. thank you very much. Small world out there, next to Saga. They are wonderful people. W had a great time laughing about stories from the Okanagon at a Willard Rendezvous with them. Do you know John and Penny in Second Wind on your dock too? We are cruising buddies and I taught school with John in Yakima.
 
We just know them in passing. My wife Jill is a teacher here in Bellingham. It is indeed a small world! Did you make it to Roche Harbor last weekend?
 
Yes, I did. I went over in a friends 1969 GB 36. We had the starboard shaft produce a violent wobble vibration and had to lock the shaft down and come home on one engine. We were only at the Rendezvous for Saturday boat tours. Regardless, it was a fun trip. We overnighted in Garrison Bay.
 
Which boat? We were on Ebbtide, 32' with a hardtop over the cockpit and blue canvas.



ForumRunner_20140515_200216.jpg
 
We were out on the guest dock by Customs for a few hours. My friend had to run his boat because he had a new shaft installed and new PSS dripless seals and cutlass bearings on both shafts. I have not heard what the outcome was yet. North Harbor Diesel is doing the work.
 
Bob had mentioned at one point about running the boat up to WOT and letting it get, or try to get, to the 2500RPM which is its max rated RPM. he then said to bring it down 300 RPMs and run it for 5 or 10 minutes as a stress test.

I know these engines are rated for the higher RPMs but the general consensus from everyone I hear is 1800 is the highest normal RPM they would run. Most run around 1600 or so.

I have an old boat because it is what I can afford. I would hate to have to spend 15K to swap a motor. I will try my best to take care of this one. I agree with Kieth on Bob Smith. The class was informative and fun. Got to meet some really nice people.

Jeff
 
Oil Leaks on FL120

I have an oil leak from the oil pan. Several mechanics at work said that I should just tighten the bolts on the oil pan because being a cork gasket the oil pan just worked loose. Is it that simple to stop the oil pan leak? Do I need to worry about proper torque pound when snugging up the bolts?
 
Graham,

Are you referring to the valve cover cork gasket? If you are, one thing we learned and saw was when the bolts are tightened too much it distorts the cover around the bolt area and we had to take the cover and take flat block of wood and lightly hammer the cover area flat again instead of the dome shape from over tightening. This helps get the gasket area flat again to make a good seal. Then apply a new gasket and snug down, not torque the bolts. Make sure the head and cover are clean and try not to distort the gasket by over tightening. This is how we were instructed.
 
I was referring to the oil pan gasket. This is at the bottom of the engine. I believe it is cork also. So what you are saying is to just snug these bolts because over time they have gotten loose. There is no need for any torque wrench.
 
grahamdougladd said:
I was referring to the oil pan gasket. This is at the bottom of the engine. I believe it is cork also. So what you are saying is to just snug these bolts because over time they have gotten loose. There is no need for any torque wrench.
Click to expand...

I'd use a torque wrench on the oil pan. That way you'll know and won't over tighten.

I have the FL SP135 (380). My service manual (Nov. 1977) lists the torque limits in foot-lbs for 4 different Ford Dorset engines. The oil pan to cylinder block is 22-24 ft lbs and the valve (rocker arm) cover is at 12-18. I'd check your book for the correct values though.
 
I would agree with Larry, check your engine manual for torque numbers at any engine location. I was referring to the valve cover gasket, NOT the oil pan gasket.
 
As a new owner of twin 1984 120 Lehmans, does anybody have a service checklist of when to do what maintenance?

_________________
Rick Duval
1984 Cheermen PT41
Whitby, Ontario, Canada
 
Service manuals are all on line in PDF's
Do a Google
 
If truly leaking from a pan gasket and not a front or real seal, I would just put a wrench on with a light tough and feel how they are, like others have stated cork gaskets are not great at over tightening or old and re-tightening. Again I would just like to give it a little feel to see if loose, if not I would leave it until you can drop the pan and replace it. Just my 2 cents.
 
$5 it's not the pan gasket but the lift pump gasket!

Just kidding, I'm a boater and I don't have $5.
 
Restrictive rocker cover vent and a little extra blowby can pressurize crankcase slightly, forcing leaks where they otherwise would not occur. I've solved a couple of these by enlarging vent on rocker cover.
 
Wxx3 said:
Service manuals are all on line in PDF's
Do a Google
Click to expand...

Thanks, I have found a lot on line. There seems to be a lot of discussions where suggested time in the original manual have been superseded by 30 years of experience.

I was wondering if anyone has put together a quickie service interval sheets with some more tried-and-true numbers.
 
Rduval said:
Thanks, I have found a lot on line. There seems to be a lot of discussions where suggested time in the original manual have been superseded by 30 years of experience.

I was wondering if anyone has put together a quickie service interval sheets with some more tried-and-true numbers.
Click to expand...

Even the pros will debate and disagree on some numbers...

Obviously the original manual has been rethought as things like oil improvements have been made and things like viscosity and multiweights can be thought through rather than base it on 30-50 year old tech.

All you can do is read it all and make up your own mind.

I use the "what has really changed" and what new tech procedures can update a 30-50 year old manual.

I have to think some thing are like using leeches by doctors...some will say use what the manual published in 1963 says...totally ignoring the manual that was republished in 1975...so like leeches they say...good for then...good for now. You decide...I like to think I can do better than follow antiquated thinking.
 
Did you check your lift pump gasket???!!!
 
When the cork gaskets shrink the first check should be with a little box wrench , the bolt will feel LOOSE and easily turn.

Snug it a bit till some resistance is felt and when the cork warms it should become pliant again and seal.

This is common on auto trannies and older cars so there is Better Living Thru Chemistry , a can of gasket expander at your local auto supply if required.
 
You must log in or register to reply here.

Similar threads

Caballero II
Highest RPM for Lehman 120 hp?
Replies
5
Views
683
jleonard
jleonard
rustyScupper
Lehman 120 rebuild or replace in 2024?
2
Replies
42
Views
4K
rslifkin
R
Taras
Lehman 120 Turbo Delete
Replies
7
Views
979
DDW
D
Slowmo
  • Locked
Odd questions from Canada Customs
2 3
Replies
66
Views
7K
Shrew
Shrew
M
Sea Strainer Maintenance
Replies
5
Views
500
MilesD
M

Latest posts

Back
Top Bottom