Tgtack 779 #1 Posted July 29, 2017 Does anyone know if the Lauson/Tecumseh HH55 and HH60 engines are physically the same size? Heard you could substitute an HH60 engine for the HH55 on a WH model 551 tractor. I can get a clean running HH60, good luck finding an HH55! Share this post Link to post Share on other sites
oldredrider 2,553 #2 Posted July 29, 2017 Patience and persistence are the key to finding anything. I found a H55 under a bench in Greece NY. Took me almost 2 weeks to find it! They're out there, getting people to part with them is the real challenge. When I get in my hands, I can verify dimensions for you. 1 Share this post Link to post Share on other sites
Howie 899 #3 Posted July 30, 2017 Physically they are the same size. Have not worked on any for a long time as to the differences. 1 Share this post Link to post Share on other sites
formariz 11,988 #4 Posted August 5, 2017 (edited) On 7/29/2017 at 11:54 AM, Tgtack said: Does anyone know if the Lauson/Tecumseh HH55 and HH60 engines are physically the same size? Heard you could substitute an HH60 engine for the HH55 on a WH model 551 tractor. I can get a clean running HH60, good luck finding an HH55! The correct engine for the 551 the H55D-2113 has a cast iron base attached to engine. On all H60s that I have there is a steel base that places the bottom of engine 1-1/4" and shaft at 4-3/4" from frame as opposed to 3/4" and 4-1/4"for the correct engine. There are some H55s with that same base as you can see in photo. Those are identical in size to the H60s but place shaft 1/2" too high for the 551 as the H60 will. Although I cannot verify it since it is on tractor and deck is in way, the bottom cast plate should be removable since it is attached to block with bolts as you can see in engine parts diagram. In all the others I have the steel base is bolted on block as you can see in photo so the one on the 2113 spec should also be bolted on block. H55 with steel base H55 and H60 side by side Bottom plate attached to H55 Edited August 5, 2017 by formariz Share this post Link to post Share on other sites
Tgtack 779 #5 Posted August 7, 2017 @formariz So if the correct engine was an H55, are you saying that it used the aluminum block engine? An HH55 model has a cast iron block where an H55 had an aluminum block from the info I have found. Share this post Link to post Share on other sites
Howie 899 #6 Posted August 7, 2017 All the H series engines were aluminum blocks and the HH series are cast iron. Some H series blocks had cast iron sleeves and some were aluminum bore. There is probably a way to tell which is which on the block but I don't remember how to tell. 1 Share this post Link to post Share on other sites
formariz 11,988 #7 Posted August 7, 2017 Correct, the H's are aluminum block engines where the HH's are a cast iron block engines. The HM's are aluminum blocks with an iron sleeves. The correct engine for your 551 is the H55D-2113 which is an aluminum block. I am pretty sure that it was never manufactured in HH version. That engine had a very short manufacture run, hence its scarcity. Also the fact that it is an aluminum block it did not have the durability of a comparable engine like a Kohler. The one on my 551 was totally rebuilt years back having been re bored with an oversize piston. I was told at the time by the shop that did it, that if needed it could also have an iron sleeve installed. 1 Share this post Link to post Share on other sites
oldredrider 2,553 #8 Posted August 7, 2017 Can you give us the parts list to accompany the IPL? Share this post Link to post Share on other sites
formariz 11,988 #9 Posted August 7, 2017 (edited) Let me know if you need any other information. I have everything (Information) to do with that engine including starters and the Tillotson carburetors magnetos etc. Edited August 7, 2017 by formariz 1 Share this post Link to post Share on other sites
