Identifying RV8 Spec without stripping down?

[MikeE]

I have a pre-cat Griff with a preserp RV8 but not the original engine. I’d like to identify the capacity but don’t have an engine number (I’ve checked in the usual locations next to the dipstick and on the front of the block on the near side and no sign of any numbers.

I believe it’s a 4.5 (not a 4.6 from the Chimaera) but without an engine number or stripping down is there anything that might give me a clue from the outside of the engine?

[Boosted LS1]

First off look for cross bolts on the side of the block. Also is there a collar slipped over the nose of the crank. Cross bolt bosses with no actual bolts would indicate a 3.9 engine. Fitted cross bolts indicate a 4.0/4.6. Has it a distributor fitting in the timing cover?

[MikeE]

Boosted LS1 said:

First off look for cross bolts on the side of the block. Also is there a collar slipped over the nose of the crank. Cross bolt bosses with no actual bolts would indicate a 3.9 engine. Fitted cross bolts indicate a 4.0/4.6. Has it a distributor fitting in the timing cover?

Thanks Boosted. I know what to look for with the cross bolting but not sure about your other two points, do you have a picture of each feature?

[MikeE]

Ok I can see it’s cross bolted, picture below captures two of the cross bolts on the exhaust side



These three pics show the distributor






And the crank pulley

[rev-erend]

Sounds like you engine might have been decked at some point, unfortunately this removes the numbers.

It's probably not possible to truly identify the engine size without stripping down the engine but here is an
idea, remove a spark plug (or all or them) and measure the stroke from TDC to BDC.

I believe 4.0 are 71.1 mm, 4.3 are 77 mm , 4.5 are 82mm, 5.0 are 86.4mm


Useful Rover v8 engine number table:

https://rimmerbros.com/content--name-Rover-V8-Engi...

[Boosted LS1]

So it probably looks like a 4.0/4.6 fitted with an early type cover to take a distributor. I can't tell if the crank has a long snout sticking out from the front of the damper or whether the snouts been shortened. If it's an intermediate front cover it may have the later type oil pump iirc. OP is there an oil pump on the side of the front cover as per the earlier engines?

Measuring stroke will certainly help. You could have a 4.0, 4.6, 4.8, 5.0 etc.

I once had a genuine factory 4.5 and 4.5 was even cast into the plenum chamber lid. It had an 80 mm stroke and used an 'iceberg' crank which had a short snout. These cranks were sold off to tuners as the engine never entered production. They were small journal cranks so couldn't be used in the later crossbolted blocks. The intermediate 3,9 block's had the cross bolt bosses on the block sides but would have needed custom made bearing caps in order to fit the cross.bolts. Your block could be an intermediate block. This is actually more likely come to think about it.

Looking at the back of the block either above the starter or on the other side of the block is there an aluminium disc about 2" diameter. It faces forwards and is easy to spot. If you have it then it'll be a 4.0/4.6 block. if not there my guess is an intermediate block.

Edited by Boosted LS1 on Wednesday 16th September 08:58

[GreenV8S]

Boosted LS1 said:

If it's an intermediate front cover it may have the later type oil pump iirc.

I think the V belt rules out it being a serp/intermediate cover.

[MikeE]

Boosted LS1 said:

So it probably looks like a 4.0/4.6 fitted with an early type cover to take a distributor. I can't tell if the crank has a long snout sticking out from the front of the damper or whether the snouts been shortened. If it's an intermediate front cover it may have the later type oil pump iirc. OP is there an oil pump on the side of the front cover as per the earlier engines?

Measuring stroke will certainly help. You could have a 4.0, 4.6, 4.8, 5.0 etc.

I once had a genuine factory 4.5 and 4.5 was even cast into the plenum chamber lid. It had an 80 mm stroke and used an 'iceberg' crank which had a short snout. These cranks were sold off to tuners as the engine never entered production. They were small journal cranks so couldn't be used in the later crossbolted blocks. The intermediate 3,9 block's had the cross bolt bosses on the block sides but would have needed custom made bearing caps in order to fit the cross.bolts. Your block could be an intermediate block. This is actually more likely come to think about it.

Looking at the back of the block either above the starter or on the other side of the block is there an aluminium disc about 2" diameter. It faces forwards and is easy to spot. If you have it then it'll be a 4.0/4.6 block. if not there my guess is an intermediate block.

Edited by Boosted LS1 on Wednesday 16th September 08:58

I'll try and get some pics of the areas you mention and post them later. Thanks for your help so far