High compression engine?

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jagnut66
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High compression engine?

Post by jagnut66 »

Hi,
In order to help get Elsie May up and running again I have acquired a spare engine.
Unfortunately the engine number ID plate is gone, so I can't just look for a 'H' or 'L' on that.
It has dished pistons, which I am given to understand from another post on here are an indication of a high compression engine block but are there any other things to look for?
Before I make the decision on whether to refurbish it I just want to make sure of what I have.
Best wishes,
Mike.
Last edited by jagnut66 on Sun Jun 13, 2021 4:09 pm, edited 1 time in total.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
philthehill
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Re: High compression engine

Post by philthehill »

Only the dish of the pistons dictate as to whether it is a high or low compression engine. All other parts are the same.
https://www.ebay.co.uk/itm/284179473896 ... SwAblgI7hO
https://www.ebay.co.uk/itm/304006016979 ... SwidxgqOWo
Last edited by philthehill on Sun Jun 13, 2021 2:37 pm, edited 1 time in total.

jagnut66
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Re: High compression engine?

Post by jagnut66 »

Thanks Phil, I understand that Low compression engines had flat topped pistons, in which case the 'dishing' tells me it's worth investigating the state of this block further.
Best wishes,
Mike.
Last edited by jagnut66 on Sun Jun 13, 2021 4:10 pm, edited 1 time in total.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
philthehill
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Re: High compression engine

Post by philthehill »

Flat topped pistons indicate a high compression engine. Low compression engines had a deep dish.
See the two links in my post above to see the difference in dish.

jagnut66
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Re: High compression engine?

Post by jagnut66 »

Ah, the post I read seemed to indicate the opposite.
I think from the above it is a HC engine however I think this is also one case where pictures tell a thousand words, so:
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Last edited by jagnut66 on Sun Jun 13, 2021 4:10 pm, edited 2 times in total.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: High compression engine?

Post by jagnut66 »

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There is staining on the bores but no ridges that I can tell.
I also don't know how long or where it was sat. The outside is 'cruddy' but nothing I can't clean up. The back waterways behind the drain tap are, as usual, silted up and will require flushing.
Next for me, if you concur this is a HC unit, will be to put my straight edge accross it and open up the sump and inspect the crank shaft etc.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
philthehill
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Re: High compression engine?

Post by philthehill »

The pictures above indicate to me that the engine is a high compression lump.

jagnut66
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Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
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Re: High compression engine?

Post by jagnut66 »

Thanks Phil, I wanted to be sure.
The chap I got it off likes his vans (he has two nice ones), he therefore has a Low compression unit in the more original of the two.
He also has a spare rebuilt LC unit and would have a use for these.
I had to assume the person he got this off would know this.
Better for me to ask questions now, before I fit any new parts to it, an LC unit wouild be of no use to me.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: High compression engine?

Post by jagnut66 »

Well the engineers straight edge has revealed an uneven surface on the block, maybe head gasket failure is what took it out of whatever car it was fitted to in the first place.
So that means a complete strip for reskimming..........
oh, well............
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
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