Author Topic: Mystery crossflow engine  (Read 1492 times)

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Offline Midnight

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Mystery crossflow engine
« on: Saturday,February 17, 2018, 10:54:42 AM »
I have just acquired a crossflow engine :pirate: I was going to go down the Zetec route with my build but I came across a Renault crossflow for sale on ebay and I won  :))
 Just picked it up today and cleaned some of the muck off the engine block to see which one I have and the number is stamped 807 704??? The person that sold it to me said he doesn't know any of the history of this engine as it was part of a job lot. I can't imagine it's anything racy, otherwise it wouldn't have a stock cast header and webber down draft. I can't find any mention of this engine anywhere.

Offline skippopotamus

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Re: Mystery crossflow engine
« Reply #1 on: Saturday,February 17, 2018, 02:21:07 PM »
I hunted around and couldn't find info on an 807 704 either.
This is where I look...
http://www.syer.net/donor_cars.htm

Offline Steve_Lindford

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Re: Mystery crossflow engine
« Reply #2 on: Sunday,February 18, 2018, 01:34:26 AM »
It might be worth joining a Renault forum...

Steve

Offline 4129R

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Re: Mystery crossflow engine
« Reply #3 on: Sunday,February 18, 2018, 01:40:45 AM »

Offline Steve_Lindford

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Re: Mystery crossflow engine
« Reply #4 on: Monday,February 19, 2018, 12:41:35 AM »
Those queries go back 5 years - so pressumably not you...

Offline GavinT

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Re: Mystery crossflow engine
« Reply #5 on: Monday,February 19, 2018, 04:12:51 AM »
Can’t find anything on the 807-704 but those three digit suffix engines are later versions, I think.

Other than that, the engine looks similar to a R16TS going by the exhaust manifold and the Weber DAR. Also seems to have the correct water pump flange for the Europa.

Presumably you’re going to rebuild it? . . in which case it can probably become any spec you want.

Offline Midnight

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Re: Mystery crossflow engine
« Reply #6 on: Wednesday,February 21, 2018, 10:13:19 AM »
Yep, it turns out that its the later type of engine ID tag. Turns out to be a 807-04, originally fitted to a Renault 16TS, 1565cc, 8.6:1 compression. Just as a thought, doesn't the 821-30 have high compression (domed) pistons? In theory (amateurish) wouldn't it be possible to swap the head on my original block and the cam? My engine has only done 51k miles (no idea if that's genuine) just musing if I have a poor man's option to the rebuild.

Offline skippopotamus

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Re: Mystery crossflow engine
« Reply #7 on: Wednesday,February 21, 2018, 12:42:54 PM »
If I understand the question correctly you want to put the 807 (hemi) head on the 821 block to get the high compression pistons. 

Am I right?

I know that the pistons from the 821 block won't work with the 807 head because the dome on the 821 pistons is made to work with valves that are both on the same side.

Offline jbcollier

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Re: Mystery crossflow engine
« Reply #8 on: Wednesday,February 21, 2018, 02:20:35 PM »
Wedge and cross flow engines have different pistons (valve pockets) and different cams (valve order).

Offline GavinT

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Re: Mystery crossflow engine
« Reply #9 on: Wednesday,February 21, 2018, 06:44:00 PM »
. . just musing if I have a poor man's option to the rebuild.

 :FUNNY:

OK, sorry . .
Yep, as has been said, the 821 is a wedge head, so different pistons that aren't designed for the cross-flow valve arrangement.

Other than that, the R16TS will bolt right in with minimal trouble.
One thing though . . when I initially did the conversion, I used the stock exhaust manifold for a while. It was a pain to rout and modify the downpipe mainly because the manifold outlet kinda faces forward.

It's always good to have a spare engine though.
You could just rebuild it at your leisure.

Offline jbcollier

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Re: Mystery crossflow engine
« Reply #10 on: Wednesday,February 21, 2018, 08:50:41 PM »
Crossflow cams have a different valve order.  You have to change camshafts as well.

Offline Midnight

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Re: Mystery crossflow engine
« Reply #11 on: Wednesday,February 21, 2018, 11:43:47 PM »
Thanks for the info, as I say it was just an amateurish thought. I'm just off to Spyder cars today to discuss my chassis requirements, no doubt that's going to be an expensive trip and engine rebuild plans may have to go on hold for a short while.

Offline jbcollier

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Re: Mystery crossflow engine
« Reply #12 on: Thursday,February 22, 2018, 06:45:32 AM »
Lucky b#%€£?d!

I drove a 30 hour round trip to get a good used chassis (thanks Dan!) that I then had to extensively modify to S1 spec.